A thread for discussion on all purifi driver builds.

A place to brainstorm and speculate on drivers and potential speaker builds for arguably, objectively, the best no-nonsense engineering-first traditional speaker drivers' money can buy - If you have a complete project underway, please start your own thread and post a link to it in here. Otherwise posting occasional random progress pics and info here is fine but we will keep full build discussion elsewhere.

We are also pleased to have @lrisbo of purifi occasionally check in and post here of which is much appreciated.

A tweeter is on the way 🤓

Updated 26/01/23: Added more build links and intro - (I may stop updating commercial builds moving forward as they are now coming in thick and fast)
Updated 16/06/22: Added builds and review links, updates to builds
Update 17/03/22: below

Time for a bit of consolidation due to this thread getting some hits, and purifi has now released quite a few scrunchy woofers

Links to known projects & commercial speakers using the Purifi drivers (please PM me if I need to add any)

Of course - www.purifi-audio.com , and the team behind the drivers here


Full DIY:

DIYA user @spresto9 has come up with these beauties with the 8" purifi woofer like to details and more pics HERE




Check out this 4" pocket rocket proof of concept build from the Purifi team - all the info you need to DIY!

Spk8 appnote download (.pdf)



@lrisbo Proof of concept Purifi SPK4 (superseded) - Passive stand-mount



@lrisbo Proof of concept Purifi SPK5 - Passive stand-mount - I believe these were at some point being made and sold commercially but have since been discontinued - there may be some floating around second hand market see here Celuaris SPK5 review ASR



@xrk971 PTT6.5/RS28F Waveguide Harsch XO - Passive stand-mount later evolved into a nice Stand mount and Floor standing Transmission Line



@Joe Rasmussen Somewhat Legendary 'Elsinore' - Has been given an (expensive) purifi remodeling. Wow. Skip ahead to post #4,746 for the juicy bits.




Rick Sykora and team's Directiva - Active stand-mount with excellent (objective) reviews, requires external amplification for each driver and an external DSP crossover.





@xrk971 's Raal 70-20xr and PTT6.5 - this one the tweeter is not readily available to DIYers but there may be ways to get it if you're crafty.

(sorry X, couldnt find a finished pic, and I'm out of attachments for this post)


User tktran303's Collection of DIY designs here looking great




Some mindfood for the 8" - a concept by Purifi.



Paul Carmody's Virage - a full design, light on measurements but a fairly reputable designer.



.....and many more concepts within this thread, start reading. Most not fully documented or taken to finished stage though I suspect a few people are still perfecting their builds before showing them off. Remember you can drop people a friendly private message asking about how their progress is going.





DIY-Kits/Semi Commercial:


Yevgeniy’s PuriWave - 2-way stand mount with dual purifi passive radiators



Troels Gravesen Purifi 6661 - Semi-passive/Active plate amplified floor-stander



Troels Gravesen Purifi 6R - Passive bookshelf




Troels Gravesen Purifi Be - Looks like a revision to the above due to ribbon tweeter supply issues.




hificompass Puri Bliss BeWg - Passive bookshelf - I believe the plans are/were for sale.



Joseph Crowe's 1198 - I believe you have to get in touch via the webpage - floor-stand transmission line








Full Commercial:

March Audio Sointuva - arguably where "the bar has been set" for the Purifi 6.5 in a bookshelf chassis.



Jones Scanlon Baby Reds - self powered studio mixing monitors.



The Late Rick Craig's Selah Audio Purezza - A nice stand mount ribbon tweeter design, was available commercially but afaik discontinued, check SH market



Jachim Gerhard Surveyor's - stand-mounts , I believe there is/was a floor-stander made too



Dennis Murphy & Jim Salk's BePure2 - Floor stander - The legends behind the philharmonic BMR and BMR tower



and um, what ever this might be! https://www.audiocircle.com/index.php?topic=175599.0 - probably just a concept, I didn't read the thread. Likely Unobtanium tweeters and probably bottomless pockets required, if it is sold commercially.

Correction - the above was a concept which later evolved to the BePure2 - see this thread at AVSForums Post #10,174
https://www.avsforum.com/threads/th...rs-and-discussion-thread.939744/post-61186397


Further Build links:

Thrax Siren - a 2-way standmount

Jern 35 - 2 way standmount

Buchardt A500 Signature - Active 2 way standmount

WVL Serendipity - 2 way standmount

Taipuu Kero L active with FourAudio PPA-1000 dsp amps. - Not sure if available yet

Salk Sound BePure3 ... Holy **** I need to hear these.



Links to independent driver reviews:

https://www.erinsaudiocorner.com/driveunits/purifi_4/
https://www.erinsaudiocorner.com/driveunits/purifi_ptt65w04/
https://www.erinsaudiocorner.com/driveunits/purifi_ptt80x04-nab-02/ - the eight inch aluminum mid-woofer
https://www.erinsaudiocorner.com/driveunits/purifi_ptt6.5x04-naa-08/ - the 6.5 inch aluminum mid-woofer
https://www.erinsaudiocorner.com/driveunits/purifi_ptt6.5m-08-nfa-01a/ - the 6.5 inch dedicated midrange

Also - please consider visiting Erins Youtube Channel and subscribing! - a much needed light in the dark world of audio subjectivism.

https://audioxpress.com/article/tes...udio-6-5-midbass-transducer-from-purifi-audio

https://hificompass.com/en/reviews/purifi-audio-ptt65w04-01a-midwoofer
https://hificompass.com/en/reviews/purifi-audio-ptt40w04-01a-midwoofer
https://hificompass.com/en/reviews/purifi-ptt65w08-01b-ptt65x08-nfa-01
https://hificompass.com/en/reviews/purifi-ptt65m08-nfa-01a-65-true-midrange

http://www.troelsgravesen.dk/Purifi.htm


Original Post 02/04/2020:

With the group buys well underway the idea was bought up that a design thread be started to discuss build options.

Mine have arrived but I have no build materials and will not be able to get any until we come out of quarantine in (hopefully) three weeks time. I planned to start with a hybrid of purifi's SPK4/5 builds using the same AMT tweeter but maybe using a slot port with the 2.5khz crossover. That and I haven't done any AMT builds so it seemed like a good place to start.

I read of a guy in Aus planning on doing a line of passive and active speakers with the woofer so be interesting if he could chime in here.

So with no materials for the next at least 3 weeks, what better time to discuss build options! Fire away

It is finally the time to post my Scinnies...

One Ohm model. One speaker OK, while other has bass ribbon panel damaged & removed...a multimeter fell onto the foil as I was completing the "Silicone fix" years ago (still have not gotten over it)...

• Both tweeters are there and functional, albeit both ribbons appear stretched.
• I do have a pair of replacement Bass Foils (actually the entire Kit) from Patrick in Germany that I bought many years ago (not cheap at $1300).
• Covers are painted Matte Black (used to be that ugly Beige)
• Been sitting in my back room past few years....wife would like them gone.
• Pics taken years ago attached...

Pick up in West Sub of Chicago, no shipping. I also cannot assist on the repair.


Asking $1500.

A less-than-two-minutes, eight years old news video of a man who paid for his own utility transformer and pole to get "pure electricity." I vaguely recall reading about such a person years ago - perhaps it was this man, or maybe there's several who have done this:
Login to view embedded media

Hello, I have two Xa60 mono blocks that I love and that I use for my Tannoy Kensington GR with a Mcintosh pre-amp. I bought them used some time ago from a professional. I wonder what the needle on the front is for, in fact when I turn on the device, the needle blocks towards the right, I don't know if this is normal, because I see an intermediate position at noon but the needle never went there. I would like to point out that I don't listen at very high volume. Thanks for help

Can't understand why to use differrent gains for negative and positive rails ? What is purpose ?
This is a piece of schematic from one factory made device. "Balanced" in quotes because of input.

Hi there!

Inspired by the Monitor Audio Monitor 3 enclosure recycling project


i am thinking about the recycling of a very old pair of Monitor Audio Monitor One speakers



I have some very different chassis already available for the exchange of the old chassis

I have a mini DSP 2 X 4 HD box and still struggling with the power amps

best thing would be to flip to something like Hypex FA122 but for the first development approach i will probably use the power amp section of an old Yamaha AV receiver



next post with some options about the new chassis

I have the CLIO pocket measurement system and unfortunately a big lack of ability to use Vituix CAD but a dozen of years of experience with Visaton Boxsim

Building Bela's aka euro21 801A preamp https://www.diyaudio.com/community/threads/801a-tube-preamp.395883/

I will use Ale's Moglia aka Bartola Hybrid mu-follower as anode load.

I will need to mod the Vout LT PSU for filaments, I have a couple of Lundahls Filament Current Choke LL1694 that can be configured as serial or parallel also common mode choke and choke input. Could be configured as choke input CMC?

More questions will follow.

TIA

Hi,

Planning to mod my CD104.

Anyone suggests any mods ? I have replaced the captive leads.

I was thinking of first looking at the capas in the analogue section. My main problem is how you get the analogue board out . I figure you go in from underneath and remove a torx screw holding the board in place. Is there much more dismantling to be done , or is there a special way of removing the card ?

Recently I came across Mark Johnson's thread "VRDN: bipolar regulator PCB for line level ckts: ±11V to ±20V @ 1.5A with "De-Noiser" "
https://www.diyaudio.com/community/...l-ckts-11v-to-20v-1-5a-with-de-noiser.355883/
and instantly became a fan.

Here is a redraw of his schematic done just for fun. I named it "Butterfly DN". The PCB can be made by hand if you like, it has only two layers.

IT HAS NOT BEEN TESTED YET!

I have ordered some PCBs and will be testing soon.
I will be updating this thread with pictures.

For how to set it up, please visit the first post of the original thread:
https://www.diyaudio.com/community/...l-ckts-11v-to-20v-1-5a-with-de-noiser.355883/
BOM, Part numbering on the PCB and component sizes are exactly the same.

Heat Sink thermal resistance: 6.2C/W - 11.4C/W, depending on the length of the heatsink used (ref. attached pdf)
Board Size: 103,5mm x 91,5mm


Added:

• Optional half rectification diodes D98 & D99 have their own place on the PCB. Remember, they are only used for half rectification, when using a transformer with only ONE secondary. They are marked with a *
• Added an optional resistor (R23, R24) in parallel to every one of the Variable resistors (VR1, VR2), in case you want to replace the Variable resistors by a fixed one.
• 2x Outputs, CON1 and CON2. CON1 supports many readily available connectors. CON2 supports Faston terminals OR Europlug
• Added R100, a way to connect the ground plane to chassis via the top right mounting hole. You can short it or use a resistor 3-10ohm

Have fun!
Alexander

Disclaimer
This thread is made by a fan, it is not affiliated in any way to Mark Johnson's work and the original VRDN thread.
This layout is a DIY project done by me, provided "as is", with no official guarantee it will work.

Hi

I'm here to learn and read many repair suggestions for A/V equipement.

In the next few months I expect to start the build of a corner vertical array pair of speakers.

This will be used in a fairly small lounge living room with multiple sources, digital and analogue.

• Vinyl
• CD
• Streaming, media etc
• TV
• Computer files

My hopes and expectations are.

• To put them right in the corners, out the way. I took the pic attached when moving the furniture around just to show where they would go, right in the corners outside where the current speakers are standing at the time of the picture. I should explain that the current speakers are not normally diverging and the polystyrene sheet next to the TV is just old packaging! – the sound bar etc would go. The room is very asymmetric, the left “corner” of the listening area being created by a pillar that holds the structure for upstairs. I don’t know what happens with the structural beam running across, in terms of reflections.
• To significantly exceed the sound quality available from commercially available loudspeakers.
• To reduce to a minimum the listening position sensitivity one normally finds with two speaker stereo speakers, which I understand these should help with.
• To hear some of the magic attributed to vertical arrays of full range speakers.
• Ultimately to make it fairly simple to operate and control, remotes for source and volume would be nice.
• I imagine my project would be a decide, design and build and use project, not numerous constant experiments, and so would not follow the depths and details of projects like the two towers, admirable though I am sure they are.

I need to decide what to build, I have taken some ideas from kind, patient and encouraging friends and read about the Roger Russel IDS 25, and I have looked carefully at Murphys Corner array. I have read lots of the threads on the forum and it’s fair to say one can easily become confused!

Consequently I thought to start a thread that others might follow later if they wished.

Some current outstanding questions for starters are;

• Amplification, I have an existing old Musical Fidelity A100 that might be pressed into service?
• EQ, I have no experience other than that gathered from operating my Hypex plate amps that drive the bass and provide room EQ of my 3-way system I built a few years ago to the Troels Gravesen Fusion design for another room. So I have the UMIK1 and measured and adjusted to achieve a reasonable in room plot with those.
• I have read about different wiring, shading etc and am rapidly moving out of areas I understand!
• Currently I would intend to build a wooden cabinet (maybe black MDF) version of Murphys Corner array or some of the others, with around 50 (25 per side) Vifa TC 9’s, and move on gradually from there.
• If I build a cabinet with 25 units at 83.7mm each that totals 2092.5mm and the room is 2425 high. What happens to the remaining 332.5 mm, a little bit for the base etc, but then the arrays are not fully floor to ceiling, does this matter?
• I understand its sensible to buy some spares, so maybe 55 units, I wonder if I can get a reasonable price somewhere on that number?
• I have read of volume per unit at 1.5 to 2.7 litres, some sealed some not………..To fit the corners neatly the small end would be easier, a triangle section or similar with knocked off corners.
• If the cabinets are suitably designed they could bolt into rawl bolts on the walls to keep them as rigidly mounted as the walls?
• A black grille finish, as seen on threads appeals to make them as inconspicuous as possible.
• A foam/felt strip either side of the driver lines might keep the grille/cover at a reasonable clearance and deal with some edge effects satisfactorily?

I am comfortable with the woodwork and simple electronics.

I have read a good part of the many threads and contributions and would greatly appreciate input of guidance, knowledge, experience and expertise from those of you who have the kindness and patience!

I would then document decisions and results as they come along.

Many thanks in advance

M

Hello Everyone, Thanks for accepting me. I'm from the US and retired in Chile. I've been interested in Hi Fi audio since my 20's using primarily Sansui, Teac, and Akai components. Alas, all that equipment was sold long ago and I can't replace it with my current budget. So I've decided to try my hand at DIY and buying some kits online. Will see how it goes and maybe learn something along the way.

Hi everyone,
I have a orion hcca 2100 that I repaired..... partially. The mute mosfets are not getting turned on, I have the opamp output but the mute fets off..no output. does anybody have had this problem. Any help appreciated. When I remove them I have output.

Thank you,

Raf

I thought,

It might be a good idea to have a "What are you watching" thread Like the music thread, Only linked to AVI which seems to be taking over the "Just music Idea"..

Perhaps it could be a thread on its own like the music thread?..🙂

Regards
M. Gregg

hi All,


I'll explain right away that this is not about any kind of design, vector, cutting, milling or anything else - I have any design and drawing program for work experience and staying in a home made creation, I wanted to understand from you, crossover experts, what you use and how you make them.

I made one with the multi-hole base, but I won't show it to you otherwise you'll laugh until late, very late 🙂

I am trying to put together a quasimodo test jig. Does anyone have a board they could spare? I can order them no problem, but wanted to check here first. thanks

Hi All,

I am a total noob at electrionics and audio gear. I'm hoping to learn some new stuff by working on this first project. Basically I have an Audio Technica LP60X that outputs a signal at around 36dB LINE (100mV @ 1kHz) and currently it goes to a set of Logitech desktop speakers with a max input rating of 10W and a continuous rating of 5W RMS. (I know its probably an insulting setup to any harcore audiophiles but Im working on a budget).

My goal is to create an ESP32-S3 Mini 1 controled PCB, which will act as passive volume control in between the turn table and speakers. It does not need to amplify the signal, just be able to fade out and then fade back in using the ESP's wifi function and a digital potentiometer. I did some consulting (chatGPT and Youtube) and settled on using the MCP4231 as it seems to be the only chip that can handle stero input with single power supply and SPI control. (its also cheap).

The plan here is something like this: Audio from record player --> Passive Wifi-enabled volume control --> Speakers

I have attached a schematic I drew up in KiCad. Would you be able to look it over and let me know if there are any crucial errors I might be missing? Also if you have any tips/tricks or recomendations that would be appreciated too.

Kiitos! (Thank you so much in Finn)

Joel.

One lightly used (no scratches, never abused) pair Faital 12RS430 woofers. Very nice curve for a big-motor twelve, high x-max & Qms, deep bass, Faraday ring. $370/pair + shipping. https://faitalpro.com/en/products/LF_Loudspeakers/product_details/datasheet.php?id=151050115

SOLD: One lightly used (no scratches, never abused) pair Faital 10RS430 woofers. Same excellent motor and high Qms as 12RS430 on a lighter 10" cone. $340/pair + shipping. https://faitalpro.com/en/products/LF_Loudspeakers/product_details/datasheet.php?id=151040095

One lightly used (no scratches, never abused) pair Faital 8RS340 woofers. Easily notchable 1.5 dB bump @950 Hz, otherwise smooth to 2.7 kHz. $250/pair + shipping. https://faitalpro.com/en/products/LF_Loudspeakers/product_details/datasheet.php?id=101030204

I find two problems with the DMB-A mid, which are at the low end (resonance) and high end (distortion?)of it's useful range. I will address these a bit further-on here.

Click to expand...

I have not put the driver into it's intended system yet. The plan is to modify the 1976 vintage AR-16 to a 3way. The mid+tweeter will be overkill as far as power handling, but the parts don't cost too much, and I thought that it would be interesting to see what lowering the woofer crossover to 800hz (from1500hz) would do for the sound. The 8” sealed AR-16 should have satisfying bass near the wall, and should accept tone control boost gracefully at reasonable levels. The cabinets are only about .64cuft internal volume. System sensitivity should be about 85db. I will make the cabinets nice looking walnut veneer; stock they are dated-looking vinyl wood grain.

Click to expand...

On the upper end, distortion seems to limit the DMB-A to about 4500hz. Super low distortion until about 5khz, then up it goes, dramatically. Is this breakup, or is something wrong with my test set-up? There is a few dB dip in FR around 4300hz

Have others noticed the rapid rise in distortion? I wonder: Could it be my settings in ARTA? I have checked advanced Windows settings for mic and speaker through Sound blaster card, are all at16bit/96khz.

I am OK with crossing to a tweeter at 4500hz, I just wonder why I see distortion rise so quickly.

I did get it to roll-off well enough, but that was by using a parallel notch filter---1.5uF/.14mH/30ohm. For some reason, the calculator I used gave very different values than these, so these are the result of trial and error, with measuring.

For others working with the DMB-A: To tame/roll off the low end resonance/ response; here is a starting point that looks good for an 800hz high-pass: 20uFseries cap plus a series notch filter (parallel with the driver): 40uF/1.2mH/3.3ohm

This looked good after measuring/swapping parts; I did not do a simulation.

Too bad it is hard to find “acoustic suspension”(compliant suspension, Fs/Qes below .5) woofers like the vintage AR units nowadays. Seems like Dayton could sell an 8" steel frame for $40-$50 retail, if they wanted to. Maybe the cones/spiders/surrounds that are easily available overseas don't have the characteristics required?

Ported speakers are popular, but I find that sealed lets me hear the deep bass notes more clearly, even though the mid bass may not be so powerful. Dayton, and others, have drivers that work in sealed boxes without DSP, but they roll-off earlier on the low end, and most have more breakup in their upper range. Highly successful vintage 2ways, with larger woofers, tended to have woofers that rolled-off more gracefully on the top end. They did tend to have less distinct mid-range sound though, likely due to more internal damping of the cone material.











.

My cabinet conversion is nearing completion and I am getting ready for set up.

As a newbie, I am in danger of trying too many things at the same time and therefore getting confused. So I have to try to move in clear, simple steps, in the right order of priority, with clear objective, constraints and method for each.

So far I have the following plan which is limited by my current level of knowledge. I was mainly using this thread by @AllenB for guidance (although it goes more into passive filter design and is not specific to active filters) and I am now trying to make it more specific to active/DSP. I also used advice given in the build thread so far by @Busdriver02, @svp, @temp25, @Juhazi, @hifijim. I would like to build this guide so I can follow it myself and also make it available for others to use with DSP-based 3-ways. Would appreciate if experienced people can have a look and help me put it together.

Anyone tried this DMM from Aliexpress?
Do they work as they should.
https://www.aliexpress.com/item/100...JcbdsJ89&utparam-url=scene:search|query_from:

Hello all. I built a Chinese PP tube amp I have had laying around for a few months. As we know there are no instructions aside from the schematic they send with it, which isn't great.

I followed as best as I could here: https://www.diyaudio.com/community/threads/problems-with-chinese-pp-kit.353111/

I have the transformer marked as 110v, same or similar to the one in post #98 in the above link. I am still not sure how to wire the primaries or the 2 yellow and one black (Yel-Blk-Yel). They show going to the 6.3v/0 and I assume the black go to chassis ground. And the primaries? Red-Blk/Red/Blk. I see only 6+ volts on one of those primaries. Are they marked incorrectly, perhaps?

This is a very compact and cool looking TDA1541 DAC for your consideration.
I am providing quite a bit of details, so please read with patience.

The first thing to note that the TDA1541 chips are de-soldered from Cambridge Audio CD2.
I have obtained it from a very kind member here, I only paid for shipping from UK : TDA1541
The chips came with the boards, with aluminium plates glued on as heatsink or other purpose that i may not know.
As i removed the aluminium plates, most part of the prints on the chips were stucked to the adhesive used.







The chips were all removed by me, no pins are damaged, all in full length and clean.


If you mind the cosmetics of the TDA1541 chips, then this DAC board is not for you, I suggest you skip this post.

More details of the DAC board in the post below.

Here's a list of various drivers I've tested. The vast majority are garbage tbh. I don't intend to update this list or publicly rank drivers going forward though hopefully this list provides some benefit to diy builders of the world. I've ranked those which I prefer in the top section. Then beneath are those which I find "good" and below those are garbage labeled "The Ugly". There are a handful of drivers in the ugly section which I intend to retest at different less strain inducing crossover bandwidths though the vast majority of my sentiment is specified here albeit a bit negative. I haven't tested every driver ever and there are certainly many gems to be tested that are not on this list.

Call it conspiracy or what you will... There's an inner circle of pagan colonialist imperialist federalist guitar worshipers who seem to hold chair as gatekeepers of various audio industry related things and speaker gear. These people may also happen to be stingy as hell. That fact aside, as such, many of the best products, high sensitivity low mms cone drivers for example, are disguised within the realm of guitar speaker drivers. Two example companies are Celestion and Jensen. Both make some fine drivers and again some junk... The ladder makes at least a couple drivers that I consider to be among the best and competitive with any I've tested. The brands which I consider to be honest, science oriented and therefore gain the rank of S tier are: Visaton, Fostex, Beyma, Mark Audio and Seas. Of similar quality though presenting a less consistent and or less focused and or less updated product line are Jensen, Ciare, 18Sound, LaVoce, Kartesian, and Faital. Oberton, PHL, and Audax seem to be landfill grade. B&C, Eminence and Celestion exhibit an imperialistic monopolistic political brand identity that I deem gross and reflective of oil baron level greed and orkishness. Through the lines I observe some sort of mining union business scheme clinging to stale traditions as though somehow holy, and claiming both land rights and music as of their own invention. Celestion does make some good products available to the masses... In general my preference is for less landfill quality quantity best business practices stagnant christian values anal retentive control freak bs. Preferable would be zero corporate influence in favor of scientific progress, though also an acceptance that we're dealing with mundane devices here, and if applicable achieve quality through real innovation.

Here's a simplified list of my favorite drivers in order of preference from best to worst. With regards to crossover frequency and driver size selection I am mostly optimizing for midfield level playback.

Sub Woofers // ~0hz-~50hz
-18Sound 15W500
-B&C 8PE21
-Seas H1878-08
-Visaton W200

Low Mid // Mid Drivers ~+40hz-~+1200hz // FR
-18Sound 10NMBA520 // 18Sound 10MB400
-Fostex FE206NV2
-Beyma 8MI100
-Visaton B200
-Seas Exotic W8

Mid Drivers // ~+600hz-~+10000hz
-Visaton B100
-Visaton B80
-Mark Audio CHN-40P // CHN-50P
-Kartesian Wib70_vPA
-Bliesma M74P-6

Tweeters // ~+1200hz-20,000hz
-Seas 22TAF/G
-GRS PT6816-8
-Visaton SC4.7ND
-Visaton DSM50 FFL

Full Range Drivers
-Fostex FE206NV2 // Unnamed favorite
-Visaton B100 // B200
-Mark Audio MAOP 7
-Mark Audio CHN-50P
-Jensen 10 Tornado Classic 100

Compression Drivers:
2":
-JBL
-Beyma CP800TI
-TAD TD4001

1.4":
-Beyma CP755ND Al
-Great Plains Audio 288C

1":
-Faital HF108
-BMS 4552
-Kartesian CMP35_VPA

———————————————————————————————————————————————————

Here are two additional lists of drivers which I tested for my project. The "Good" list are drivers which I found to be very performative though inferior to the my "Favorite" drivers. And the "The Ugly" are drivers which I found to be inferior:

Good:
Tweeters:
-Visaton BF32
-Visaton BF45

Bass // Mids // FR Drivers:
-Atlas PD5VH
-Beyma 12XA30ND
-B&C 8PE21

-18Sound 6ND430
-18Sound 10MW400
-18Sound 12NMB1000
-B&C 6MDN44
-B&C 8FMB51
-B&C 8MBX51
-B&C 10PE26
-Beyma 8G40
-Beyma 8MC300ND
-Beyma 8MC500ND
-Celestion CF0820M
-Celestion CN0617M
-Celestion G12H 55/75 Heritage
-Faital 6PR160
-Faital 8PR155
-Faital 8PR210
-Faital W8N8-150
-Fostex FE83NV
-Fostex FE126NV2
-Fostex FE166NV2
-Fostex FF105WK
-Fostex FF165WK
-Jensen 10 Mod 70
-Jensen Classic 100 Tornado 10
-Jensen Classic 100 Tornado 12
-LaVoce FSN020.71F
-Mark Audio Alpair 7MS
-Mark Audio CHN-40
-Mark Audio CHN-110
-Mark Audio CHP-70
-Mark Audio CHP-90
-Mark Audio CHR-70
-Mark Audio MAOP 5
-Mark Audio MAOP11
-Monacor SPH-102KEP
-Oberton 6NM150
-Purifi PTT4.0X
-Purifi PTT6.5M08
-Seas CA18RLY
-Seas CA22RNY
-Seas ER15RLY
-Seas FA22RCZ
-Seas OR002-04
-Seas OR004-04
-Seas OR005-04
-Seas OR006-04
-Supravox 165 GMF
-Supravox 285 GMF
-Visaton SL713
-Visaton W130S
-Visaton W170
-Visaton W250
-Visaton W300
-Wild Burro Betsy
-Zenith 49CZ852

Bass:
-18Sound 12MB1000
-B&C 10MD26
-Beyma 15G40
-Beyma 15P80FE/N
-Beyma 15MI100
-Seas CA22RNY
-Seas L26ROY
-Wavecor SW270WA1

Compression Drivers:
-18Sound 1480A
-B&C DCM414
-B&C DCM50
-Beyma CP22MF
-Beyma CP385ND
-Beyma TPL200
-Celestion AXI2050
-Faital HMF200


The Ugly:
Tweeters:
-Beyma CD1ND
-Beyma CD10ND
-Beyma CD11ND
-Ciare HT050
-Fostex FT17H
-Hivi RT2 Pro
-Seas T35C-002
-Visaton BF32
-Visaton TL16H

Mids // Low Mids:
-18Sound 5W430
-18Sound 8MB500
-18Sound 8NMB420
-18Sound 12W500
-Audax PR170Z0
-Aurum Cantus AC165
-B&C 2NDF26
-B&C 320K/C
-B&C 4NDS34
-B&C 6NDL44
-B&C 6PEV13
-B&C 6PS44
-B&C 6MBX44
-B&C 8FMB51
-B&C 8MDN51
-B&C 10CL51
-B&C 10MD26
-B&C 12MH32
-B&C 12NDL76
-B&C ALT002NDF
-Beyma 10BR60v2
-Beyma 10G40
-Beyma 10MI100
-Celestion AN350
-Celestion G10 45 Creamback
-Celestion G12H Heritage
-Ciare HW210
-Ciare HWG130
-Ciare HWG160
-Ciare PNDI 2.25CP
-Dayton Exciters
-Dayton RS180P
-Eminence Legend 1028K
-ER Audio Mini Panels
-Faital 2FE24
-Faital 5PR160
-Faital 6RS140
-Faital 10FE200
-Faital 10RS430
-Faital 15PR400
-Fostex FE208E Sigma
-Fostex P1000K
-GRS PT5010-8
-Hivi DMBA
-Jupiter 10LAP
-Kartesian Sub120
-Kartesion Wib50_vHP
-Kartesian Wom120
-LaVoce FAN030.71
-LaVoce FSN020.72
-LaVoce FSN021.00
-LaVoce FSN021.02
-LaVoce FSN030.72
-La Voce WSF121.70G
-Mark Audio CHR-120
-Monacor SPX-32M
-Oberton 8M150
-Oberton 10M150
-Peerless NE85W04
-Peerless TA6FC00
-Peerless TC5FC07-04
-Peerless TC7FD04
-PHL 1752NDU
-PHL 2530
-Satori MD60N-6
-Satori MR13P-4
-Satori MW19TX
-SB Acoustic 65WBAC25
-Scanspeak 10F/8424G
-Seas CA12RCY
-Seas FA6RBND/2
-Seas FA22RCZ
-Seas M15CH002
-Seas MCA12RC
-Seas MUR10RB-SL
-Seas U22REX
-Supravox 285-2000 MK2
-Visaton FRS 5 // X // XTS // XWP
-Visaton FRS7A
-Visaton FR8
-Visaton FR8M
-Visaton FR8TA
-Visaton FR13
-Visaton FR 6.5
-Visaton R10S
-Visaton R10STE
-Visaton SC8N
-Visaton SC13
-Visaton SL70NDV
-Visaton SL87
-Visaton TI100
-Visaton TW70
-Visaton W170S
-Visaton WS13E
-Yamaha JA-0801

Bass:
-18Sound 12ND610
-18Sound 15NTLW3500
-18Sound 18W1300
-Audax PR240M0
-B&C 10PE26
-B&C 15NW76
-Celestion TF1525
-Faital 12FE330
-Faital 15HP1020
-Faital 18FH500
-Kartesian Sub250
-Seas A26RE4
-Seas CA26RFX
-Seas ER18RNX
-Visaton AL200
-Visaton W200S
-Visaton W250S
-Visaton WS20E
-Visaton WS25E

Compression Drivers:
-Altec 290
-B&C DE500
-B&C DE980TN
-B&C DE1095TN
-Beyma CP380M
-Beyma CP750TI
-BMS 4591
-Faital HF1440
-Faital HF206
-JBL 2453H
-Yamaha JA6881B

Hello guys .

I have in my pre for b+ two 100mf 400v film caps installed. I want to bypass them with 0.1 mf film caps which rated 250v. In the b+ rails i have in tubes plates 217v dc measure exactly. This voltage is after the ECL82 and goes to tubes plates . The transformer winding output is 230v ac and i suppose (didn't measured) that is approximately the same after the diodes and to the 100mf caps.

My question is.....
Is it safe to bypass them with 250v caps? Is it enough 250v . I ordered them and i didn't pay too much attention by mistake to the voltage rating.

I will post pic of my external tube preamplifier PSU.

Also pics of the actual pre inside. 12au7 12at7 per channel. All hook up cables are pure silver, dact pot, visay and takman film resistors and all film caps , tube sockets of teflon and pure ofc cooper , rca jacks pure cooper. Aslo in the PSU the heaters regulators are SPARKOS discreet regulators SS7812. The construction is pure dual mono from pre to psu. The preamplifier WAS KORATO KVP20 dual mono version from factory. WAS. ........ Now is something else . Its completely reconstructed and rebuilt but the circuit remains as it was from factory and the actual values of all the new and higher quality parts (resistors caps diodes regulators) also as it was from the factory.

Hallo DIY audio. I am a new member from Greece. My background is a Physics degree and my hobby is audio electronics. I am trying to build a Goldmund mimesis 3 and so far I have build the power supply using 2 transformers of 300VA each. Is somebody aware where I could find boards for the above amplifier?
Thanks

SUCCESS by Graham Parker

The dreams and hopes of men are powered by addiction
And who am I to say that this is an affliction
When everybody gets suckered in and lives their lives like fiction
Writing their own stories of success

They say they want you for your colourful evocation
The way you turn a cliche into a sensation
But all they ever wanted was that same vibration
The one that shimmers round success

Success success
All you ever need:
Success

You can't be happy while someone else has a fistful
They glow from TV screens healthy strong and fiscal
And everybody slaps their back while you're alone with a wristful
Jerking to the rhythm of success

Success success
All you ever need:
Success

Login to view embedded media

I'm working on a setup to measure amplifier noise output, SNR, crosstalk etc. and see that a number of people are using a USB soundcard as the basis of such a setup.
Can anyone comment on improvements to the following setup?

• Scarlett 2i2 USB interface (this seems to be a popular USB interface). Are there USB interfaces with a better noise floor than this one (at a similar price level)?
• Is anyone using the TinySA?
• Oscilloscope 10:1 probe with 1 MOhm input impedance to connect between amplifier output and the USB interface. Will this impact the measured noise?
• Software - SpectraPLUS-RT seems good but I'd like a cheaper or free alternative, preferably that works cross platform.

Hi,

My name is Dimitri, i am from the Netherlands.
New here because i followed a threat and wanted to give a reaction so thats why i signed up to give some tips.

Greetz!

Hello,

I am undecided what analyzer to purchase. Currently I am using EMU0204 with SprecraPlus and for the most part it gets the job done, however when it comes to measure balance phono, it becomes tricky to get proper results. Plus the voltage range and therefore performance dependency it too large.

'This prompts me to get a new analyzer and since there are nice Audio precision on the market some system one and two at a more reasonable price. However they are old need special interface and computer and if they break it is not easy to repair.
In parallel I was looking at QA403 and I was wondering if nowadays, it is still worth to look at this older equipment as this perform as good but yet cheaper and more reliable, or these analyzers still set a standard?

Thanks!

How do people structure and layout their workspaces?
I do a variety of work, maybe metal for amplifier case or woodwork for speakers, also the usual home renovation, bicycle maintenance etc.
When I moved it all ended up in boxes, tolerably well sorted, like Hammers box, Saws box and so on, easy to find.
Time to unpack and layout the workshop, and "easy to find" may not be the best way to do it. For instance if I do a metal chassis I probably want a hacksaw and perhaps a soft face hammer or other metalwork tools conveniently co-located, while for speaker boxes I want the wood saw near the claw hammer and other wood tools, no use to have the wood saw next to the concrete saw.
But lots of tools are not material specific, drills for instance, or measurement tools.

One option is a kind of work flow layout with a materials input and preparation area (saws to cut to size etc), assembly area (spanners and screwdrivers etc), finish area (sanders, polishers, paint etc).
But not so suitable for ad hoc repairs and the like.
So, what do people find convenient and efficient?
Curious to have some fresh perspectives.
I have about 32 square metres at the moment but plan to at least double that.

I’ve been building subwoofers for years now, and I’ve always used car audio drivers. However, I recently started building speakers using pro-audio drivers, specifically mid-woofers and horn loaded compression drivers. I love how dynamic and clean-sounding these drivers are, so it was only natural that I decided to give pro-audio subwoofers a try.

I did some research on pro-audio subwoofer drivers with relatively low Fs (resonant frequency) and high Xmax (maximum linear cone excursion), and the Lavoce SAF184.03 stood out as a promising candidate. It features a beefy 4" voice coil and 1500W power handling. Some might scoff at the Lavoce’s 30 Hz Fs and 13 mm Xmax, but keep in mind that I plan to build multiple subwoofers in tiny sealed enclosures – at least by 18" subwoofer standards, so deep bass output likely won’t be an issue, and I’ll still be able to keep enclosure sizes in check.

I eventually settled on an enclosure design featuring generous 4" radius rounded corners even though I knew it would be somewhat challenging to make. Using 15 mm kerf-bent Baltic birch plywood not only keeps the enclosure weight in check but also is stronger than MDF, not to mention the wood grain looks very nice when stained a light color. The braces and baffle were made from 18 mm MDF.

I used a biscuit joiner to cut slots in the plywood. The two MDF braces are attached to the plywood using biscuits, essentially serving as the form around which the plywood was bent.



The braces also feature circular openings to support the heavy subwoofer motor, which probably weighs close to 15 kg (~33 lbs) by itself.



The front baffle and rear panel were painted black, and the birch plywood was stained white with a two-component oil. I lined the walls with polyfill sheets.



I placed four pillows filled with polyfill inside to improve deep bass response. In total, I used about 1 lb of polyfill per cubic foot. The gross internal volume, before accounting for driver displacement, is approximately 3 cubic feet (~85 liters), which is about 25% smaller than the typical minimumenclosure size recommended for a standard 18" car/home audio subwoofer.



With the addition of polyfill, the subwoofer’s resonant frequency decreased from about 61 Hz to 56 Hz. The impedance curve reveals that inductance is well-controlled, allowing this subwoofer to be easily crossed over as high as 500 Hz. The nominal impedance is 8 ohms.



The near-field frequency response indicates a roll off that’s less steep than the expected 12 dB/octave for a sealed enclosure, thanks to the driver’s strong motor. When placed along a wall in a typical sized room, the subwoofer should deliver flat frequency response down into the mid-twenties, especially after reducing the ample mid-bass output using EQ or an AVR’s room correction capabilities.



Finally, a complete build video is available below. Please let me know what you think.

Login to view embedded media

One MOSFET and One resistor ...

This amplifier is for you who have a headphone: 8, 16, 32, 60 or 64 Ohm impedance.
The trafo is 2x12VAC.
The MOSFET can be any TO-220 or TO-247.
For example IRFP240, IRFP140, IRFP044, IRF540. (IRF520 and IRF610 gives a little more distortion = more MOSFET sound)
The resistor should be 5 Watt.

If you have some MOSFET laying around, this project is for you.
You get good use of your MOSFET.
I have not built it. But the SPICE test shows it is a good, solid and fun design.
It works 🙂

Hello guys!

I think its time for a giveaway!

This morning I woke up a bit early and like usually I started with checking my emails.

Well there was a particular email that jumped into my eyes. Always when I receive emails from this person and another particular one makes me very happy.
Well this time the email made me double happy 🙂)

To mention that I am not a rich guy, impression that I left around here because of giving away stuff.. its quite the contrary. In life no matter if rich or poor.. if you want to get you always have also to give so.. here I am making room for new stuff 🙂)
This time a stereo xa252 pop kit will be given away, the shipping will be on me.
One channel in the kit looks like this.

Both channels are new, tested and working. I will provide the thd measurements to the winner.
How it'll work:
To enter, just copy the list of entrants, paste into a new comment, add your DIYA username to the bottom of that list and post. Sunday at 10pm my time(or a bit later if I forget), I'll make a comment saying that entries are closed. I'll take the final list of entrants, paste them into an online randomizer, and the name that appears in the top (#1) position will be the winner.

And big thanks to everyone specially to Pa and ZM!
For this giveaway you should thank to them and not to me, if it wasn’t them to be so generous and share their ideas this wouldn’t have been possible.

Good luck!

Hi all 🙂

I have an Audio Precision System One with DSP. I want to build an USB interface for it to extend its life with newer operating systems than XP.

I know that the newer Audio Precision Systems have an USB interface option.
Unfortunately Sys1 and older Sys2 are not supported.

The APIB is described in detail in the Sys1 service manual.
The idea is to use an Cypress FX2 to convert the APIB Bus to USB.
The Audio Precision Software needs to be patched to support the USB interface. The AP Software itself will run on Win8 (without the driver).
Would be nice if the hole circuit can be built into the connector housing.
(The attached picture shows that the print dimensions should be smaller than
25 x 35 mm)

It would be great if the USB interface can support the older System Two (Sys2322 ...) too.

Do you know if the Sys2 interface is fully compatible with Sys1?

Sys1 uses 74LS245 with 2n2 capacitors at the output as bus drivers.
Would be great if anyone can find out the chips in the Sys2 or in the modern Audio Precison USB interface for Sys2722 🙂 ( i have only acess to Sys1)!

I am especially interested if the newer sys2 use the rather big 2n2 capacitors at the output too. They reduce the data rate strongly.

Are you interested in such an interface? Any help is welcome 🙂

Thanks,
Udo

Update April 2016:

Meanwhile the USB adapter development has been finished 🙂
Some photos of the adapter can be seen on page 2 -
actually the hardware was the fastest part!

The adapter works with APWIN 2.24 and supports S1 and S2 up to Cascade
and any peripheral which is supported by APWIN 2.24.

Supported operating systems are Windows XP, Vista, 7, 8 and 10.

The greatest delays were because of missing hardware for testing.
During development tests my S1 shows various signs of dying slowly.
This was caused by connector contact problems.
John helped me to repair my S1, and now it is working like new 🙂
Michael and Duke helped a lot with finding remaining errors in S2 and
in optimizing the speed. Evan did a lot work on reverse engineering the bus timing.
Many thanks!

Anyone who needs an adapter: please send an email
with your shipping address to apusb@krebelder.at

Thx,
Udo

Hi all, I was browsing through Tectonics website to check out some BMR's. And I saw this, which seems just released:

"The SDW70C is a force balanced Symmetric Drive Woofer (SDW), combining an ultra-compact dual diaphragm structure with an efficient motor. This allows for incredible bass in space constrained products such as displays and soundbars."

It's a very small woofer (96 x 96 mm size) that uses some nifty technology. Seems excellent for some very small nearfield desktop speakers. Combined with their smaller BMR's they might be nice for a small surround/atmos speaker too. Here's a link to the spec-sheet.
The technology reminds of one patent that two young Dutch guys sold to Sonos. Ah found it: this one.

I can't find it on any webshops yet, but might also not be available for consumer-sales. That would need to be asked, I guess.

Anyways, I wanted to share this with you guys and share thoughts.

Multibit DACs with current output have had a cult following for a long time but recently they have become very popular at diyaudio e.g. due to Miro's diy dac boards. Diyers have tried a variety of I/V stages and there are quite many subjective evaluations of these. However not that many measurements. So I decided to provide measurements of some of the popular alternatives.

DAC

The DAC used in this test is my PCM1702 board that uses PMD100 as digital filter. The board has PCM1702 L-grade chips that were used in Denon CD players. L-grade is not specified in the datasheet but all my L-grades measure about the same as K-grade. I have also J-grade chips but they measure much worse than the L-grades.

Here is the DAC board with separate I/V stage.



The DAC board caters directly for OPA1611, AD844 and AD811 (by populating appropriate I/V resistors and capacitors). Other I/V alternatives can be built as small "hat" boards that fit directly to the op amp sockets on the DAC board.

Here is a picture of the test setup.



The PSUs for the DAC board and the ADC board (ES9822PRO) are my "silent switchers" powered by power banks. DAC PSU board has 2 TPS7A39 dual regulators for +/-12V and +/-5V and a "raw" 5.5V output for the digital filter regulators on the DAC board. The connection to PC from DAC/ADC is provided by my STM32F7 USB-to-I2S board.

Lineup

Here is the I/V lineup for this test.


From left to right: OPA1611, AD844, AD811, OPA861, Folded cascode CEN clone, BJT

OPA1611
OPA1611 is often recommended for I/V duties. Here it will be used as typical op amp I/V stage in DAC datasheets so it will act as a baseline for other measurements.
BOM cost (single): 5 EUR.

AD844
AD844 is used without feedback (as in AYA dacs by Pedja Rogic). Input impedance is relatively high (50 ohms) so some stack 3 or more AD844s. Here only one is used.
BOM cost: 15 EUR.

AD811
AD811 I/V stage is based on Walt Jung's article in Audio Amateur 2/92. I used 1k stabilizing resistor. Input impedance is about 1 ohm.
BOM cost: 15 EUR.

OPA861
OPA861 is used as in the I/V stage of AYA II by Pedja Rogic.
BOM cost: 10 EUR.

Folded cascode CEN clone
This is based on the folder cascode CEN by EUVL. This is not the original folded cascode CEN but a clone.
I used 2SK209GRs as buffers. Input impedance is about 13 ohms up to 100kHz.
BOM cost: 30 EUR. This is the only one of the tested I/V stages that uses obsolete parts (2SK170/2SJ74). BOM Cost assumes matched jfets from diyaudiostore.

BJT
This is a slightly modified version of ES9018 I/V by Sérgio Santos (@smms73).
I added a similar 2SK209GR buffer as in CEN and modified some resistances for lower current consumption.
On paper (i.e. simulator) this I/V stage has very low impedance (200mOhms up to 100kHz). Parts count is high but it uses ubiquitous BJTs.
BOM cost: 10 EUR.

I/V resistor and cap is 1.5kOhms || 2.2nF on all tested I/V stages.

Measurements

I made the following measurements on each I/V stage:

• THD(+N) at 0dBFS
• Noise (DAC playing -180dBFS)
• THD vs. level sweep at 997Hz.

Measurements are shown in subsequent posts.

I tripped, fell and accidentally purchased a giant lot of tubes 'n' other goodies. I can't recall how I first caught the tube bug but never the less here I am. Sooooo, now I have a hangar full of tubes of all kinds and conditions. I kinda have an unlimited supply of a variety tubes to play with. While I don't expect to find large lots of the popular tubes, they are popping up here and there. I have have barely scratched the surface though so I have high hopes to find some gems as I make my way through them.

I hope of find fun and interesting ways to use what I find. AF amps, RF amps, power supplies, etc. etc... I am a ham, somewhat of an audiophile (ok, not really) and have a decent understanding of electronics and have been boning up on tube knowledge. My hope is to enjoy the journey of learning more about electronics, "vintage" electronics and tubes 'n' stuff. I think I have most of the basics covered from a tools and test equipment standpoint and I aquired a few chassis with the lot of tubes so now I just need to pick a project and get started.

So by now my reason for being here should be relatively obvious. I need to absorb some of that juicy knowledge from y'all and hopefully share my journey along the way!

Looking forward to it!

Pete...

Hi 👋everyone
My uncle always talked about how he is going to build a lp12 subchassis one day, but it's been years already. So I would like to spend time and build it for him as a surprise.

After searching online I can't find any schematic for the actual subchassis itself.

Can someone help provide me a schematic for it so that I can mill it?

I am studying for bachelor of engineering, so I have access to tools but I don't have much knowledge. Please tell me anything I needed to know

Sincerely
friendlyengineer

Overall, I am pleased with the sound of the upgraded HK system in my 2024 Outback Touring. I would describe the sound as balanced and enjoyable (after tweaking the 3 band eq to my liking). It is just lacking punch and only plays so loud, lacking upper detail and after 2/3 - 3/4 volume it just breaks apart and goes to crap. Now, after 1 year of driving around, it is time to do some upgrades and get it to the next level. The HK system is basically a black box but I have found some good info on the Outback forums.

Lets get to what I have done so far and what I am planning in the future.

I have replaced the left and right factory mid/tweeters with JL Audio C2-350x 3.5" coaxials. This was a PITA as the factory locations do not allow a 3.5" to drop into place. The factory speakers are mounted to a plastic base which is just too small for a 3.5" speaker. Time to pull out the dremel with the flex shaft extension and start grinding away. I would give this a high difficulty rating (luckily no damage to my dash or windshield)
These sound pretty darn good I have to say! I was a bit worried as the HK amp/DSP is tuned for the OEM speakers. Definitely an improvement from the crappy OEM speakers.

I pulled the front door panels off and applied sound dampening pretty much everywhere. But first the plastic membrane had to be carefully taken off.
I first instlalled JL Audio C1 - 650s (93 dB; just used the woofers) and then later replaced them with Hertz C-165 woofers (93 dB) not sure why I didn't use the C2-650 to match with the dash speakers (oh right they seemed pricy). As I found out later by others in the Subaru forums, a higher sensitivity speaker works best here. Both the JL and Hertz can't match the levels I am getting from the dash speakers. (need a bit more midbass) This is the problem you get when dealing with a black box. So that raises the question whether I install an aftermarket amp/dsp. I will probably add this design in a future post if i plan on going that route.

A was brave enough to pull apart the car to get at the OEM subwoofer. You have to remove the rear back seat bottom (pretty easy - 2 clips and pull up) Then unbolt the back seat section on the driver's side where the seatbelt runs through. Then pop away the panels, remove the rear tie-down points (4 or 5) and 2 other screw/bolts that are hidden away Then the whole plastic panel pulls off and then you can access the subwoofer.
I replaced it with an AudioFrog GS8ND2 8" thin-line subwoofer. I just had to make a spacer/bracket out of 3/4" mdf to mount the sub to as the factory holes don't line up. There is definitely some improvement from the OEM sub; namely cleaner/less muddy bass. But it is lacking the whole point of a subwoofer in my opinion.
Again...
The black box...
need more juice to get things moving.
Next step will be installing a link1000.1mini amplifier. My plan is to install it in the rear cargo area to the left of the spare tire. Will be cutting out the styrofoam that lies below the cargo bed so that it will retain the factory look. Autoharnesshouse.com makes some harnesses that I will be using. I plan on tapping into the front door speaker signal as it provides a full range signal and is prob not as adultered as much as the sub signal. The 1000.1.mini has a built in low pass and parametric EQ for my tuning needs.

Okay, thats's it for now. Sorry for the long post. Check out the pics as well.

Are there any, or should we believe the view an LP12 is like an old violin?

despite reading many threads, views on the commercial products vary widely. As for DIY mods, damping is thought to be the wrong principle for its design, or so it is said.

But in which case there seems little on diy stiffening.

Mine has Valhalla/ Basik LVX.

Replacing the psu with an external one is an obvious path but are there no mechanical DIY projects that work?

Anyone had any success with table or arm mods?

For Sale: Sony CDP-C100 with Philips TDA1541 chip. I installed a socket on the motherboard so the chip can be swapped. Original TDA-1541A chip replaced with the TDA1541.

Works great, but some of my CD that are in bad shape do occasionally skip, but good CD have no issues...

Would like to sell locally to confirm proper operation. Pickup in West suburb of Chicago.

Bought this Amp cage thinking it would fit my amp and as my luck would have it, a little too short width-wise... so up she goes...

Its a tube cage for a Jadis Orchestra tube amp.

Bought it for $50, so $50 + ship

For Sale: Pro-Ject Stereo Amp Box RS Integrated Tube based amplifier.

Many inputs including XLR. Pair of 6922 tubes driving a pair of Hypex UCD 180LP based amplifiers. Works perfectly, but does not come with stock +48vdc / -48vdc power supply. A DIY power supply was made for this amp (more amps than stock), and is included.

Case has some wear and tear form previous owner, but functions as intended.

Comes with aftermarket universal remote programmed for power on/off, volume up/down, and input selection.

$525 + ship.

hi, all
i make winisd simulation for SB34SWNRX-S75-6

box volume 80L
tuning freq 24Hz
port size 340mm x 30mm 57cm long

air velocity @ 24hz is 17m/s

cone excursion is under max @ full power


what do you think about group delay ?

I’m trying to teach myself a new skill/trade and I was wanting to know if there any go to books that I can read on PCB repair. It’s something that I have always been interested in and I thought I can be a good hobby for me to pick up. I have engineers on both sides of my family and it was always my dream to go to college for engineering but poor life choices I’m my early years ruined that. If I could make it work I’d love to take some adult classes for it as well if anyone knows of any in the Philadelphia region. An apprenticeship at a local shop for a few hrs a week would also be amazing.

Any help would be greatly appreciated.

Hi as my first loudspeaker I am building a "clone" of the qualio-iq speaker.
There are much information about the speaker on their website and from test.

Final specifications for this visiting Polish intelligentsia would be 102×38.5×31.5cm HxWxD, 32kg/ea., 4Ω, 30Hz-31kHz and 89dB. The AMT comes in at an unexpectedly tall ~8kHz on a 2 order slope whilst the Satori widebander adopts shallow 1 order entries/exits on either end. It meets the Satori woofer at a high 600Hz. The woofer enters on another 2 order filter.

Click to expand...

I can't find out where the resistor and one of the capacitors goes. It looks like they site on the midrange

Some pictures of the new and updated filter taken from the website

Hi.

Ive tried/tested/thought about many different (compact-ish) sub-configurations around 10" and 12".
The scope is not HiFi or accuracy, More like an exercise in output vs size vs price.

Here I would like to present the measurments on 2 different subs (one of them, maybe not actually in the "sub"-category...): a Tham10 and ThMini-inspired Tapped Horn with a 12". The ThMini-inspired horn is 40x60x60cm outside with 20mm ply and thus around 100L actual internal volume. A Tham10 is approx half the volume.

Ive measured both like this:

• Indoors in my basemest right at the horn-mouth
• Outdoor at about 1m distance. Sub and mic placed on a piece of ply, on the lawn. Some buildings 5-10m away. Windy day, and thus high noise-floor.

The measurments are imported to google-sheets and adjusted to be around the same level for indoor vs outdoors. Raw data and a smoothed version shown. My interest was not absolute level, but response. My measurments are very crude, but Im supprised how well the indoor response line up with the outdoor measurments.

If the measurements are correct, the Tham10 drops off at 70Hz, but it works supprisingly well for playing very loud modern pop/dance. - yes the lowest notes are missing, but I very much doubt that most people notice. As far as I remember the measurments for both tapped horns were at similar settings and if thats correct the Tham 10 is as efficient as the ThMini above 70Hz. - but much, much smaller.

Maybe of interest to some of you. Please share thoughts and ideas.

ThMini clone with a 12-280/8-W from Thomann: Thin line: raw data, Thick line: smoothed by google sheets.




Tham 10 with a Car-sub from Eminence (very solid driver): same setup as above

Gday all, Thanks for accepting me. I have been playing with car audio for years and am now interested in amp repairs and mods. Looking forward to learning about repairing and testing amp circuit boards and components.

Hello everyone,
I've been designing a tower speaker lately with the chr-120 and the sb acoustics sb29rdc-c000-4. The main reason why I'm pairing a tweeter to a fullrange is because the off axis response of the chr120 alone is not the best and I wanted to make a tower that would sound nice in a good range of positions in my room.

The design is a 60 L ported box, the vent is 18,3 cm long and 9 cm ID, made it so that turbolence is not a problem even at the highest volume the speaker can play.

I started the design by tracing the responses from the manufactures datasheet and modelled this crossover in the image (i attached also a zip with all the files). Since I don't have the speakers in my hand yet and am not prepared to make measurements I was wondering how far off this design would be from reality, especially considering the phases are calculated from vituixcad and in the woofer i set a z offset to match the impulse response calculated by vituix as well.
Since I'm a student and don't have much money to spend experimenting, am I fine designing a speaker this way and getting all the parts, rather than buying parts and changing them later?
I'm open to any kind of advice!

For sale 2 brand new PCB boards for a GainWire mk3 CFA preamp/phone amp. Can be used for balanced operation mode.

All info in the thread: GainWire Mk3 CFA pre/phone

22 euros/pcs I would like to sell them together. + shipping, paypall f&f

I have a few very old mylars without clear (to me) units, or no unit specified at all.
One reads .001 with 10% and 1KV beneath it.
A second reads 82 with 10% beneath it and 1KV on the other side as it is about half the size of the ".001!"
A third reads .1Z with 10V beneath it.
Looking on the net I found different interpretations of that 'Z:' one stated it was the tolerance, another that the 'Z' meant it was in picofarads.

H E L L L P P!!!

Selling my HP 54542C oscilloscope, a reliable 500MHz, 4-channel unit. It's been well-maintained and is in good working condition.

$450 USD

Selling an HP 54657A Measurement/Storage Module, compatible with HP 54600-series oscilloscopes, along with an HP-IB (GPIB) to USB interface

$100 USD

I have added one of these to a dual mono class D amp I built with 2 mono IRS2092 boards. I have tried to check that these work if DC is present by attaching a 1.5v battery to the speaker OUT terminals but the relays are not doing anything. Have I got the wrong idea of how to check that they will work if there is DC present?

As above. Would a few of these, screwed/glued to surfaces, perhaps filled with felt/foam help reduce standing waves and reflections? 🙂

https://www.amazon.co.uk/Suwimut-Flexible-Training-Activity-Basketball/dp/B097PM736F/ref=sr_1_15?crid=SD87ZBZWA6NW&dib=eyJ2IjoiMSJ9.Un9uyLddcefvvNxpqxFoPm52GjgjR43MJu0W-nWkqfyrCElDYc2LMcNFcB4VoP_8-VlZ5u9zfoJBviy2jrDUwR-SM7DpLCzrqMOO1ELhv3yApyMzJ5QlOQNye9Zpocbmv41X7kfVRWo2axlynSJ8G6I4ri4Rsonv6o9PsbqR4xmN7ARNVegBS0n4qktcbsGLrb7zaZ2tjBXAjbZx_mWxLzm0_g7zy3c1rjSuusuolTc8cdLV2lZOSZMYciMyHN0fIo_E93e6G8Tx_cPraamEDBW1PZn4rJWzgRiiw4OQxp7vg1JfM9yvtUilJwqaOcJ1ZD70kyrviGJXoH8jqYw9PD45s8hypYeefoFWXcH45cLwfCPILE43Uga8hkqCkWOP68kLhw5Uuht6aXnVBwlvL1YcmDckr_VRMU-LPHeZR5TJ6VWtFCAxQGjhcps1rQqm.NyZU2Q4t5vmuqSljTw8nAMcHzTuaQPu_5uUXlaS2mpk&dib_tag=se&keywords=plastic+cones&qid=1743431284&sprefix=,aps,163&sr=8-15

I'm curious if anyone who's built an Aikido has done any distortion measurements, especially harmonic distribution. Some circuit particulars, too, please.

I am interested in this driver but can't find the Thiel Small parameters for it. Has anyone here who has used it measured them .

I am looking for replacement TO220 transistors. Checked Mouser and DigiKey: NLA. Also checked alternatives 2SC2907/3163/3186: NLA. Both transistors are used in a Sony Audio power supply regulator circuit +/- 25V DC input, +/-15V DC output. 2SC2275 has transient failure. I guess I should replace the pair. Any recommendation? Many thanks!

I'm playing around with the Grok AI and so far its an absolute beast - I really like it and compared to Gemini and ChatGPT the answers are much more coherent. A little bit frightening maybe, but absolutely helpful.

Hi folks, it's been a while since I last posted. I have dabbled with horns and high efficiency for the best part of the last 20 years, bit of an addict you could say, but following a recent house move I have had to 'make do' with a pair of Castle Winchesters... Whilst I miss the air and openness of good compression drivers in the upper frequencies, I must say I am rather taken by how the Winchesters do bass, especially considering their very domestically acceptable size. With the right amp there is a lovely sense of articulation down below (and they go quite low). This has given me ideas for a DIY system using a similar driver layout, i.e. one front firing, one upward firing (as illustrated by the cross section below), but using bigger and more efficient drivers, say 12" or even 15". I have a pair of of 400Hz 2" Stereolab horns waiting in the wings, which I could use for the HF. Any thoughts on which drivers could be made to work in this context would be welcome, or for that matter any feedback from those who have embarked on similar projects 🙂

Audio Analyzer with AK5397/AK5394A and AK4490

For more than 3 years I have been working on and off (mostly off) designing a high-end Audio Analyzer. Parts of the design have been implemented as separate units. I have finally put the pieces together on one PCB (+ some small existing interface PCB's).

Some of the design goals were:

1. The Audio Analyzer should work as a sound card, enabling use with a wide selection of Audio Analyzer SW packages.
2. The performance should be somewhere between a good high-end sound card and an AP, R&S, SR etc.
3. The performance should approach the limits possible with the ADC and DAC used.
4. It should be possible to use it with any relatively modern PC. This is the reason for choosing a USB interface to the PC. SPDIF/Toslink was considered, but this makes it difficult to use portable PC's.
5. The PC should be electrically isolated from the Analyzer to avoid ground loops and noise.
6. No fan for cooling!

I have selected to use high-end converters from AKM. I have previously made a design based on AK5394A and AK4399. This design shows a very good performance, but it was not ideal in terms of flexibility, due to limitations in the input and output stages. The input stage was a relatively straight-forward design based on OPA1612 and OPA1632. The performance is fairly good, but there is no attenuator, so the input range is limited.
The output stage has a limited drive capability, since it is based on the OPA1632.

For this design I originally chose the newer AKM converters AK5397 for the ADC and AK4490 for the DAC. After testing the AK5397 I decided to go back to the AK5394A, since the distortion is much lower.
The input stages of the new design are based on a JFET/op-amp combo, with LSK389 and LME49990. This part of the design has been verified on a separate PCB, with attenuator and gain options.
The output stages are based on LME49990 buffered by LME49600.

Main features:
1. AKM AK5394A 24-bit Super High Performance Stereo ADC, 192 kHz sampling, 123 dB SNR (changed from AK5397)
2. AKM AK4490 32-bit Premium Stereo DAC, 192 kHz sampling, 123 dB SNR
3. Dual fully differential inputs and outputs on XLR connectors
4. Dual single ended outputs on BNC
5. AC and DC input switchable
6. 44.1, 48, 88.2, 96, 176.4 and 192 kHz sampling, selected by the Analyzer SW. Potentially 384 and 768 kHz sampling later on (TBD).
7. Full scale inputs from 100 mV (-20 dBV) to 100 Vrms (+40 dBV) in 10 dB steps.
8. Overvoltage protection on the inputs.
9. Full scale outputs up to 10 Vrms differentially (5 Vrms single ended). Can be attenuated to 1 Vrms and 100 mVrms full scale differential output.
10. Single ended output impedance of 50 ohm (changed from 25 ohm)
11. Single ended input impedance of 100 kohm
12. On-board low jitter crystal oscillators (NDK NZ2520SD).
13. Parallel control lines for relays, controlling the attenuators, gains and AC/DC settings.
14. Power supply is integrated on the board (except for the transformer).
15. USB interface is implemented using a completely isolated XMOS based design (changed from USBStreamer).
16. Expansion connector for future digital I/O
17. 20x25 cm PCB

The parallel control lines may be controlled from either manual switches, e.g. rotary switches for the level settings. Other possibilities are to control it with a microcontroller or from the PC via a USB to serial converter. Initially I plan to use manual switches. Update 161222: Settings can be controlled from the PC via the USB interface.

For the power supply a 2 x 15 V and 1 x 9 V transformer is needed. I plan to use an R-core transformer with 2x15 V and 2x9 V, 30 VA, which I have also used for the AK5394A/AK4399 design.
The transformer may be changed to a 2x15V or 2x18V ring core transformer with a slightly modified power supply design. Update 161222: A ring core transformer is used. Primary voltages selectable between 100 to 120V and 220V to 240V.

The isolation between the Audio Analyzer and PC is done with a Master Clock and Isolator, see:
Master clock and isolator for the MiniDSP USBStreamer
Update 161222: The isolation is now part of the XMOS based USB interface.

I have just received the PCB this morning. It will take some time before I will be able to start testing, since I plan to mount the PCB by hand. And I still need to get some of the parts. There are around 750 parts in the design.


I would like to thank Demian Martin (1audio) for his design inputs, reviews and encouragement.

Update April 8, 2017:
GB is now open. See:
GB for RTX6001 Audio Analyzer with AK5394A and AK4490
Update:
Group buy is closed.

Hardware modifications:
To make it easier to find the descriptions of the hardware modifications, I decided to make a list here.

Disassembly and assembly + overvoltage:
GB for RTX6001 Audio Analyzer with AK5394A and AK4490

The overvoltage modification was originally described here:
GB for RTX6001 Audio Analyzer with AK5394A and AK4490

Shield and stability:
DIY Audio Analyzer with AK5397/AK5394A and AK4490

*Moderator note: Second block diagram added at Member's request.*

Has anyone direct experience with a FirstWatt clone that has gone from a CRC supply to a CLC supply? I'm talking same amp.If so are there any sonic benefits to doing so? In addition it is a standard 1 toroid,dual secondary,dual FWB rectifiers.I can get a couple of Hammond 159Zl 2.5mH 10A chokes for about $40 each.I can see from simulations quite a reduction in ripple voltage but would there be sonic benefits from this relatively cheap mod?

Hi - I’m a new member from Leadville, Colorado, living at 10,000 feet of altitude. My favorite current hobby is multichannel audio of all flavors, which I particularly enjoy over headphones using a binaural processor (Smyth Realiser A16).

I’ve been working on two projects lately. The first is using an RPI5 + DAC8x + ADC8x (HiFiBerry hats) to convert the 6-channel analog output from my Surround Master V3 to HDMI (my AVR does not have analog inputs). This has been very successful, and I’ll probably go on to explore using CamillaDSP in addition. I’m also using it via Audacity as a replacement for my old Korg D888 8-channel analog recorder.

The second project is exploring ways of extracting HBR audio streams from HDMI. I have an old Unigraf frame grabber which works, but I need to write some code for it to work better. I have a Chinese HDMI input to I2S x4 board that should work but I haven’t had a chance of hooking up my logic analyzer to the 4 I2S outputs yet. I have a Rock Pi 5b that has the necessary hardware, but I need to wait for the mainstream kernel to support multichannel audio in from the HDMI RX (6.15-RC1 is just out and may do the trick; the current kernel driver only supports 2-channel). Finally, I have an HDMI extender over 10 gigE TCP/IP with a managed 10gigE switch that will allow WireShark or similar snooping.

Selling a pair of Faital Pro 8PR200 8ohm drivers for £100, which is 50% of the retail price (£200).

• Condition: Good, with only minor blemishes on the chassis foam surrounds.
• Usage: Used only in my front room at low levels, crossed over at 100Hz to subwoofers. Never pushed hard.
• Packaging: Original boxes are stored in the attic and will be retrieved upon sale.
• Details: An excellent driver that needs little introduction - manufacturer page here: https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=101030200

Postage for drivers is £7.00 in the UK

Optional: I can also include the cabinets for the cost of extra shipping (~£10). These are 10-litre enclosures with a 50mm PVC pipe port (friction fit), Neutrik Speakon connector, and Van Damme cable. Birch ply and MDF. Not perfect nick...

I have a Philips FB297 model 3-way speaker. I wanted to change the electronic capacitors in the crossover circuit, but the capacitor shown in the picture (blue) which I thought was 1uf showed 4.5uf in the measurement. I was surprised. Old blue capacitor with 1u0 written on it. What could be the real value of this capacitor?
Sorry for my English. Thanks for any help.

I'm putting this up as a place holder for the new nx2-Amplifier (hereinafter just called the 'nx2') which has been in gestation for some 15 months now. I've had quite a few nudges from various people via email asking about progress. I can understand that some folks have fallen into believing the nx2 is 'vapourware' (if you've worked in semiconductors or software product development, you'll now what that means!).

I started work on this in September 2023, assembled the initial proto and decided it needed more refinement - details which I will cover when the documentation is released. However, things came to a grinding halt when TraxMaker (part of the CircuitMaker CAD suite) stopped working in early 2024. I made the decision to switch to KiCAD (a good move!) and had to redesign the board from scratch. After another 2 proto/dev cycles, the amplifier module PCBs are finally where I want them to be, and quick bench testing shows peak mains hum harmonic components at below -125 dBr reference 60W RMS into 8 Ohms (the power limit of my test lash-up) and <35ppm distortion.

I am currently finalising the PSU +inrush PCB and that will go off for manufacture sometime next week. In parallel with this, the mechanical layout is also being finalised.

Part of the delay in this project has also been the fact that I became a grandfather (yeah, I'm old) for the second time and that entailed putting a lot of stuff on the backburner, and the decision to move closer to family, which we will do in the next 3 weeks. Its chaos here with boxes all over the place, packing etc.

For all of the above reasons, the nx2 won't be completed and released for at least another 2 months, but hopefully you wiol get an idea of whats n the pipeline from this intro. The boards will be available on the hifisonix web shop if you want to build one (but only after I release the completed amp + documentation).

Here are the specs (note these may change once the completed, housed amplifier is re-measured)



I've attached some photos below - taken in my workshop today in amongst the packing boxes. (note the front plate is still being assembled so looks a bit manky - it still has to be cleaned, screws fitted and then polished)

"Hello, as already mentioned in my introduction, I am inexperienced but use the soldering iron for basic tasks, like soldering RCA connectors, etc. Well, I bought a used Tricord Dino phono preamp to connect it to my Rega Planar 2 turntable. As you know, Rega turntables share the arm ground with the left channel. This turntable uses a very cheap direct cable from the arm to the phono preamp. I wanted to modify this cable by cutting it and mounting a metal box under the turntable with female RCA terminals so I could choose the cables based on construction or length. Now, when I turn up the volume without music, there is a hum coming from the speakers. If I touch the box, the hum increases, and it also increases if I touch the arm. The RCA connectors do not come into contact with the metal box. I think I’ve created a ground loop; how can I fix it? Should I connect the left and right negatives to the metal box? Should I connect the metal box to the negative terminal of the phono preamp?

Building the Pass/Firstwatt F4

This is a fantastically good sounding amp - read more about it here before staring;

https://www.firstwatt.com/wp-content/uploads/2023/08/prod_f4_man.pdf

The thread at DIY audio -

http://www.diyaudio.com/forums/pass-labs/97540-f4-power-amplifier.html

And this the the corrected schematic (The schematic in the Firstwatt article has a typo, also this one agrees with the PCB)



Here you will find a build guide for the Pass / Firstwatt F4 power amplifier using PCBs and chassis from the DIYaudio store.

The 5U 'BIG Amp Chassis' is shown, because that's the one I have. It will fit comfortably in a 4U 'Jack of all chassis' and have enough heatsink as well.

~~~~~

There are plenty of places that you could start, but for the sake of illustration let's begin with the heatsink assemblies -



This is the heatsink(s) from the 5U 'BIG Amp Chassis' It has a mirror-imaged set of pre-drilled heatsinks and brackets to hole them together and make a mounting point for the rest of the enclosure. The 4U is similar, but the heatsink is a single piece.




This build will also utilize the 'DIY friendly' baseplate, here shown with the feet and hardware, and also the heatsink's brackets.


There is a hardware package available for the pre-drilled back and heatsinks, including input and output jacks, IEC module, and hardware for the PCB and heatsinks.


The contents of the hardware bag.


Using the brass PCB standoffs, install them into the PCB mount holes as shown, to get the following pattern;


Now there is a place to mount the amplifier PCB


Speaking of PCB, it's a very nice layout, plenty of room, and the ability to use many sizes of resistors and caps. This is the front.


Here is the back.


Stuffing the PCB should be done in the usual order, from smallest device to biggest - so that would be diodes and resistors first.

Of note, I got the bigger (Dale/Vishay RN60) resistors to see how they would fit on the PCB. They are the size of the PRP resistors that are quite popular amongst the fancy parts crowd. They are great everywhere except the row flanking the small transistors right in the middle. They don't fit there side by side. You could mount them soldier style, or just mix in a few smaller resistors like I did. Or just get RN55's. They are the smaller size.


Pots and transistors next. (yes, I didn't stuff the input pair when the photo was taken…)


Ah, there they are.
The ziptie is just to help their thermal tracking.


And finally the capacitors.


There is a top and bottom to the Universal Mounting Spec holes, the board mounts as shown


I find it helpful to bend the leads of the transistors first, and mount them (a little bit loose) to the heatsink.


Like this


And then mount the PCB. You can snug all the screws down and then solder and trim.

Ok, now lets move on to the Power Supply.


Here is a photo of the PSU board, I am going to use integrated bridge rectifier blocks, so you need to remove the part of the PCB that mounts the diodes. The new PCB, not quite yet available at the time of this writing, will have a similar feature with the diodes, as well as room for more/bigger capacitors.


As always, stuff the small components first - the light blue resistors are the filter resistors, the darker ones with the teflon are the bleeder resistors, and the small ones are for the LEDs.

This PSU board is the exact same DIYaudio PSU board, just without the top blue soldermask.


This shows the INPUT edge (from the diode bridges)

The capacitors are Panasonic T-UP 33,000uf 35V


Connecting the bridges to the PCB




This is the OUTPUT edge of the PSU - the colors are
Red V+
White GND
Green V-
The black connects the PSU GND to the CL-60 to the chassis.


The wiring from the PSU to the amp PCB is clearly shown.


Here you can see the bridges with the wires attached from the transformer secondary. Remember that the green attached to a bridge must have continuity with the blue attached to the same bridge. (As it's the 2 ends of the same piece of wire)



As long as were are tailing about the transformer, here is a photo of the terminal block shown wired for 120v. The Blur lead is the AC Live, and the clear the AC neutral. The reds and blacks are the transformer primaries.

Transformer is an Antek 400VA 18v+18v, part number AN-4218.



The last bit of the PSU wiring is the chassis connection, the black comes from the PSU GND, and the green is the AC safety earth.

The AC to primary wiring confuses everybody, so;

Let's look at the PSU schematic just to make sure everything is OK... Remember that I am wiring it for 120v operation, so the transformer primaries are in parallel. People wiring for 240 with a transformer like this, please ignore.



Notes in red are mine.

Look at the connections of the transformer primary, through the thermistors and line cap, to the mains.

Hot AC is connected to the "120" (which in my case is the red leads on the primaries) One red primary is connected to AC hot through a thermistor.

Neutral AC is connected to the black "0" leads, one of which is connected to the AC through a thermistor.

AC Hot and Neutral have a cap across the leads.


So, yes, the AC will be connected to the center 2 posts, which is across the cap.


(This photo lifted from my F5 thread, but it's the same PSU…)

Left to right we have post 1, 2, 3, 4

POST 1 - Transformer primary 'B 0' which will be connected to AC Neutral at post 2, through the thermistor between post 1 and 2.

POST 2 - AC Neutral in (not shown in photo), connected to Transformer primary 'A 0" , a thermistor to post 1, and a line cap to post 3

POST 3 - AC Hot in, connected to transformer primary "B 120", thermistor to post 4, and line cap to post 2

POST 4 - Transformer primary "A 120", connected to AC Hot through the thermistor to post 3

If you look at the red and black wires in the photo you will see that the Mains AC must to pass through a thermistor to connect to each of the 2 primaries. And that is the point of them, to keep inrush under control during powerup.

Ok!

Now we need to put everything together -

But first a bit more mechanical assembly.


This is the pre-cut back plate and the thick front plate.


Gather and mount the IEC plug.




The speaker posts.




And the RCA jacks.

Note that the shoulder washer goes on the inside, so the metal of the chassis doesn't touch the metal of the jack. There is a similar washer on the speaker posts.




The inside of the back panel.


And the outside. Looks good, yes?


The IEC module is wired as shown. This will switch both the Live and Neutral. The blue (live) and clear (neutral) go the the wiring block with the thermistors, cap and transformer primaries.


The amp PCB completely wired.


A bit closer.


The top connections labeled.


This happens to be the other channel, but the connections are all the same.

Remember that V- / GND / V+ is always left to right as you are looking at the format of the PCB


I'm not entirely sure what I was trying to show here, other than the screw and washer. It looks cool. I will keep the photo in the guide.





A few notes on bias -
P1 controls the bias, measured across any of the 3W source resistors. Adjust for 0.13v when it's cold, and watch that it doesn't get higher than 0.2v once it's up to temperature in about an hour. Adjust for 0.2v when hot.

P2 is used to adjust the DC offset on the output to zero.


Attach a DC voltmeter across the speaker outputs to measure offset.




If you find that the P1 doesn't have enough range, I.E., you can't turn it up enough, replace R9 with a smaller resistor, I used 4.75K and it works well.



Connect a voltmeter across any of the source resistors. The outboard ones are easier to clip across.

Adjust for about 0.13v cold, and once the amp is up to operating temperature, trim for 0.20v - It takes a long time to warm up, take your time.

Adjust P2 for zero offset, then re-trim P1

Here is a photo of it all connected and working -



I'm driving the F4 with an O2 Headphone amp sourced from an iPod; Driving 85.5db speakers. Although it is a small room, it gets louder than I want to listen. It still can't drive it to clipping, but it does get really, really loud.

One thing worth mentioning, and it speaks very highly to the quality of the amp, is that it is completely non-fatiguing, and more interestingly, very easy to listen to turned up too loud… I don't realize how loud it actually is sometimes. Complete transparency is a word used a lot when describing this amp - but I have to agree. It's fantastic!





Please comment away if you desire.

Also please feel free to ask any F4 questions here, and if you would like to post photos of your F4 completions, old or new, please do!

I have a chifi C3850 clone preamp and LM1875 amp that sound great together. I bought them as stuffed boards from Aliexpress. Total cost was about $150 and together they beat my multi-thousand dollar amp investments from 20 years ago. Specs for these chifi units indicate 110v supply input but mains voltage in my apartment here in Sin City varies from 120 to 125v.
Each unit uses a single linear IC regulator providing fixed output voltage, and both ICs run way too hot to touch. What can I do to keep them from burning up aside from powering the amps permanently through a variac to reduce supply voltage?
Could I swap out the regulators for ones having higher max voltage input and max amps rating as long as the output voltages are the same? None of the other components on either device run hot. I have a tiny heat sink on one of the regulators, it seems to accomplish nothing.

In the same vein as 6L6's MK2 thread, I thought we should start one for a related, formidable, Technics beast.

There's not a lot of information out there on these, even if you can read Japanese, or want to try your luck at deciphering Google Translate... Sometimes I think reading Japanese would be easier.

Should any pertinent links or information come up, I'll try to document them in this first post. Skip down to get to the good stuff. 😀

-------------------------------------------------

I thought it would be a great idea to open a thread on proper ways to mount transformers/chokes/Output transformers.

I cannot find my copy of a great book on the subject.

I was looking for the do / not do of mounting flat chokes on a chassis. I could not find anything on the subject.

1. Rule : never place metal across laminations

I am new to XSim and still learning. This is and all Dayton audio 3-way design with the following speakers.

DC28F-8 tweeter
RS180P-8 ohm paper driver for the midrange
RS180P-4 ohm for the for the woofer. (It looks like the impedance is drop to 3 ohm around 130 Hz.)??

Just a note on my amp. I am using the Outlaw seven channel A/B amp which is rated to 130 watts in 8 ohms and 350 watts into 4 ohm all channels driven.

Enclosure info.

3/4" mdf material
Midrange has it's on sealed compartment
Woofer section 1 Cu/ft. ported to 35 hz.

Can someone take a look at the attached to see if I am on the right track or totally off base. Any recommendations would be appreciated??

I've bought the FX-502SPRO, a very nice and surprising amplifier.
I understand I can replace the ne5532 with another model and to achieve a different sound.
I'm looking for another OAMP with a warmer sound and more weight in the low frequency.
Any recommendation?

What is the benefit with Open Baffle?

So I've got a 3 way build about to begin... And my midrange is a JBL 2251 10" mid and the plan was to use what I have on hand... That includes either a pair of Selenium D220ti or Celestion CDX1-1745 drivers and these 2 waveguides/horns:

https://usspeaker.com/dds cfd-1-90pro-1.htm

Or

https://www.parts-express.com/B-52-PHRN-1014-10-x-14-Plastic-Horn-Waveguide-299-2303?quantity=1

I'm guessing I want to keep the width of the waveguide closest to the woofer, and the one has a lower C2C distance. As I've not figured out anything other than my midwoofer and bass woofer, I was curious if there was a set of drivers and waveguides that stood out as the obvious choice to start with.

I am starting active and want to make a passive crossover for the MT section, and will be taking measures etc. Just wondering where the best jumping off point is. Thanks

I currently am running a pair of k402MEHs as a 3 way with a pair of f20 subs. I just picked up a Yamaha sp2060 and it offers a 2 way + sub configuration and a 3 way configuration. I like having the full range for my stereo setup (my MEHs will dom20hz to 20k, but I am pushing the M3H 15"Celestion woofers too hard..hence using as a 3 way now).
What is the difference, and what would the advantages and disadvantages be. I am using a Denafrips Athena 2 channel preamp for my stereo setup and feed my Marantz av8805a into one input on the Athena for movies.

This is the module:
https://www.tianjiarun.com/post/125.html?language=2
My aim is to have a BT receiver that supports "advanced" codecs and that can output a I2S stream.
The QCC3083 is not directly available to consumers.
This module seems a reasonable solution (~ €10 on aliexpress), but the documentation is just an enumeration of pins...

Hello. I'm simulating Frank's 6sn7 preamp and have a question about output 5uf capacitor. If I leave it with 5uf than the operation will stabilize around 30 sec (please consider red and purple waves in the plot) . If I use 0.047uf instead the amplifier will work from start. What's the use of such capacity?

I built the attached amplifier circuit using OPT’s with the specs indicated in the 2nd attachment, I paid pretty good money for these. My system is located in my small office which is 11’ x 12’ x 8’. Finally got around to running test-tones and saw that I’m not getting anything below 50hz and the low end starts rolling off at 100hz with my speakers. I can fill in the bottom end with my subwoofer. Just for grins I hooked up my mobile amp, a little Dayton T-amp which cost me all of $35. Without my subwoofer the low end is not missing with this little amp. Can anyone point me in the right direction on what could be causing the low end rolloff with my 2A3 amp?