Hello, I have plan to build pair of speaker boxes and my priority was that speaker need to be efficient, so I made plan in Boxsim with 2x Visaton BG20, 2x Visaton SC13 and 2x Visaton DT94. Can that Visaton BG20 handle bass frequencies as I will not power them by amp which is more than about 30w? Also box I putted in Boxsim is 72 liters bass-reflex.

I built a 80Wrms with <2% THD without any feedback. This thing is amazing ion terms of power, smoothness and musicality.
I've been using a GU46 in triode mode at 1500V plate and screen.
This voltage is way above the 650V limit stated in the datasheet. Still it works really well, very linear, similar to a huge 300B, but had a couple of flashing issues that destroyed the 1000V coupling cap in G1, at turning on.
So I was thinking I could drive the tube via G2 with some (350V) DC and control the bias current with just a negative DC voltage in G1.
I need someone really knowledgeable in emission tubes to guide through this.
Mainly concerned in stability (plate current), linearity and G2 driving current.

Thanks

I've found nice and stable power PSU circuit using TL431 IC. It can be converted to higher/lower voltage and higher current with ease. I used TIP147 instead of BD244 and it works fine. Output voltage is nicely regulated by 10k pot. Just want to share it with DIY fellows.

I got an old philips dac960 recently. It has regulator mod according to the Pooge 4, does anybody know where can I find the article of Pooge series mod? Thank you.

Since around 1977, I've been DIY with ESLs, mostly bits and pieces from Mike Wright and ticknpop. But now time to move on, and "down-sizing" (in quality) is my path.

Anybody care to cart off my stuff for a minimal payment?

1. my excellent DIY speaker panels with DIY "interface" box containing two Dayton-Wright transformers and HV bias
2. a trunk of DW cells, some visibly defective, that Mike Wright sold me long ago
3. ESL HV long cables
4. two DW ESL step-up transformers (each weighs 39 lbs, no kidding)
5. high-value high-voltage resistors, etc, etc.

Send me a PM.

Ben
Toronto (Bathurst / St. Clair West)

I’ve got a Juno 106 apart that’s driving me nuts. I have dead keys and I cannot find the culprit. I’ve checked traces, solder joints, and replaced diodes on the key matrix and the unobtainable Motorola 4069 cmos chip too. They don’t correspond to a common address line in the matrix, it’s not dirty contacts, and it’s not broken pcb traces. Does anyone have a Roland tech in the southeast?

Looking for a pair, ideally the 8b but would consider the 8a.

Hello everyone.

Sorry for my english.

To fully use a good class D +900w amp i own with the DSP and averything already set, i'd like to build a new compact subwoofer with 2 4ohm drivers. I tried to find some 15" 2ohm or 4+4 or 1+1ohm drivers but i haven't found any with the good characteristics yet (at a good price at least).

The best i have made with decently priced drivers is with 2 fountek fw322-4. I've tried a simulation with many different types of enclosures and the DBR (double bass reflex) enclosure showed interesting results (serie-tuned 6th order bandpass boxes were showing good results too but i couldn't fit the 2 drivers correctly without making some very weird abstract architecture designs).

The problem is that the results in hornresp seem weird as the first port was giving better results when larger and shorter - so it could become just like part of the inner walls of the enclosure (and then become like a simple bass reflex).

I have found a way to have a good result with a smaller port but i still have some doubts if my enclosure plans would be corresponding to the hornresp simulation as changing the first port size a little makes the result seem incoherent.

Would the first port really act like a port or just like the continuity of the first chamber ?

(The two drivers are on each side and the second port is on the front of the speaker, maybe it'll cause some issues but i'd like to know if this enclosure would work like a double bass reflex first)


Depth is probably not Lc in hornresp but the depth from the front to the back of the speaker.


Here is the hornresp record:





I already thank you for reading.

Hi,

I have a NAD C326BEE stereo amplifier. The right speaker channel is buzzing, but the music is still heard. There is no problem with the left speaker channel. I have opened the amplifier and there is no visible fault in any of the components. Does anyone have experience with a similar error and how to fix it? I don't have much experience in repairing amplifiers yet, so any help is appreciated.

Thank you!

Bought from member felixreal over here: https://www.diyaudio.com/community/threads/pascal-t-pro2-ii-modules.374320/#post-7001880

Bought them for a project, but decided to build something else.

Please be aware these are modules that have been repaired as stated in the original thread by felixreal.

Looking for 200 AUD + shipping.

Hello everybody,
Will someone please explain to a newbee why do I need decoupling output caps in my simple DAC, how do I find whether I have some DC in my output and from where this DC is coming there.
Many thanks for your explanation and best regards,
Ignat

HI guys,
A question arises that I did not find an answer on the web: Can I connect home speakers to a professional amplifier that has outputs 50V/70V/100V

I see some interesting small subwoofers on the Tang Band website that Parts Express doesn’t carry. Particularly a
4”x6” subwoofer that would allow me to build a ~25cf reflex enclosure tuned low. I own a pair of Anarchy 554’s, a TB W5 and Dayton Epique 5.5” but all seem to need a larger cabinet to allow a low tuned reflex alignment. Running any of those woofer pairs sealed will allow ~90db @ ~30hz but I loose a lot of headroom making big cuts in the midbass to get a flat response.

I’m shooting for a 27 hz tune, likely with a passive radiator. I’d be building a pair, maybe into the actual front L&R mains or maybe one under each front main on my lamp shelves. I currently have the 554’s in a .23cf sealed enclosure with Tang Band W3 bamboo fullrangers. If I can build a small pair of low playing subwoofers I might use a pair of RS100’s with soft dome as front L&R. The RS100’s would roll off naturally for an acoustic xover of ~125hz.

This is to be used in a townhouse where 90db of bass is about the maximum and I’m pretty sure the Kartesion Sub120 or one of the smaller Tang Band units would get me there. A pair of 4” Dayton TCP115’s with 5” passive radiator theoretically gets me around 85db at 3/4 excursion (4mm total xmax) but I’ve seen measurements showing high odd order distortion below 100hz on them.

I build all my audio toys small as there’s just not enough room for even .5cf cabinets to look like they fit in. Also if my girlfriend sees larger speakers she thinks everything is always loud, if she sees a compact setup magically it’s not loud 🤷🏼‍♂️
I enjoy the challenge also, I love the idea of a pair of smaller bookshelves that play low and get just loud enough to start bothering the neighbors. And, a pair of .5cf reflex enclosures with a long throw woofer model up to like 100db below 30hz which is just asking for trouble if I’ve had a few.

Thus a pair of ~.25cf cabs seems appropriate. The Purify 4.5’s are way out of budget. I’m very open to learning about any other brands offering small low fs drivers with good xmax.

Thanks in advance

http://www.tb-speaker.com/en/products/w46-1316n

I'm looking for some feedback from people who have pushed their T34B tweeters harder than usual in a hifi setting and whether a WG was used.

Looking at overall specs, the T34B should be good for at least 110 dB combos w/o a WG if crossed high enough. The question is how low with how steep xover vs how loud with or without a WG?

Whats odd is the T25B is rated higher according to specs than the T34B at similar xover. That doesn't make much sense, unless I'm missing something else spec wise.

Xtant 604
Is anyone now the part number of this transistor locations is
Q810
Q811
That's is in short

Long time lurker, first time asker of guidance

The short:

- I have 4 seven inch woofers from a pair of Polk RTi10 I dismantled.

- I want to design 2 subs to go with my Polk SDA-1C.

- Musicality is more important than overblown thump.

- And I know very little about subwoofer design =(


What I thought I would do as a plan

- Doublecheck the cabinet volume the dual 7s used to occupy in the RTi10.

- Redesign a cabinet that fits those dimensions, moves the PowerPort to the bottom (like the Polk HTS subs), and matches the height of the bass unit on my main speakers (passive radiator). (I still have the PowerPorts and port tubes from the RTi10.)

- Determine an adequate starter plate amp, hopefully no more than $250 a unit, to use in each enclosure. (If this actually works, maybe I'll upgrade the amps later.)

- Build and hope for the best.


But I know I'm a complete n00b at this, so I would GREATLY appreciate any and all help, guidance, insight, and warnings.

And there we have it.

If anyone wants to help me think this through, and offer opinions on the best musical plate amps around $250, I could use the help.

This is definitely a learn-as-I-go potential project. If it's a fool's errand, I'll stop, but I think there's a possibility this route would be better than a $600 sub purchase new.

Thoughts?

Have a wooden windshield on my terasse.

Converted it to an open baffle it's the first time I try open baffle.

Cheap car Hifi fullranges meant to radiate to both sides, half of them turned back.

With TDA 2003 in current drive mode sounds very good.

More than enough bass, turned 3db down at the preamp. Classy sound without boxy distortions.

I am impressed as the wooden corner horn type enclosure generates good bass. On the backside it's much less.

So an open baffle can profit from this horn effect.

Two types of fullranges used.

The ones with heavily structured cones what gives stability to the diaphragm sound great as these really go up to 20khz. The other ones have a heavy polyprop cone but sound nice in open baffle, too.

Hello,
I am looking for service manual for Marantz CD-40. model with big display.
Thanks.

The short Q? - I want to add a mid “M” to an existing MT speaker and still run it on AVR power, both mids are 8ohm BUT…. Re is 5.17ohms. Is there a way I can use these and also have a weird ohm rating?

I assume I cannot parallel the mids (too low) so if I series them will this work?
I plan on building a passive XO network (with help) and running them off my AVR for LCR.
The drivers in question are the

Eminence Deltalite II 2512​

In this case I am only using these drivers, if it doesn’t work then it doesn’t work, I’ll move on. Please set me right, can this be done?

Looks like this bad boy will make some noise
https://www.precision-devices.com/products/all-products/pd-24603br/



this is how it looks inside Jbell Stadium Horn with 3kw power
( active filtering enabled and some corrective EQ to smooth things out )



2 cabinets with a budget Inuke6000 will hit 140db

I kinda ‘fudged’ the exit in the sim ?? Any ideas/opinions Before it gets wired up and plays?

My buddy built/rendered this after we looked around in HR for something fun .

New (NOS) Analog Devices AD743KN FET Opamp from a bonafide USA distributor. 8DIP package. 2001 datecode. Still an excellent performing opamp for MM phono preamps or Rotel RQ-970BX phono preamplifier upgrade. Selling off old shop inventory. 15 are available.

Hello, im making an irs2092s based amplifier which im hoping will power my 4 ohm subwoofer with 500w, maybe 750 if I'm lucky.
My amp uses two 12v 30a smps supplies each wired to a "400w" rated 12v to 65v buck boost converter. These two isolated 65v stepups supply the irs2092s with +-65v (120vdc)
I measured the current draw on one of the power supplies whole playing at full volume, measuring a current draw of 2.8A at 12v.
I'm not entirely sure how many watts I'm outputing, based off the current draw mentioned is it likely that I'm getting 500w output?
Is this the right equation:
2.8 A x 60v = 170w (so one step up is putting out 170w?)
Efficiency of stepup is probably around 90%
90% x 170 = 150w
There is two stepups going into the irs2092s so:
150w + 150w = 300w
Am I right? Is the irs2092s only putting out 300w? Not considering losses from the irs2092s

Hi All,

Just wanted to know if the PCM63 dac chip can be faked? is there any direct replacement dac chip for it so it can be "rebadged" as a PCM63 ?
If not then how is it possible that there are so many Chinese suppliers for this rare dac chip? (PCM63)

Cheers

I'd like to essentially design a bass preamp/DI with IR cabinet emulation, like the ones that are now starting to become popular. Of course it would be a homemade effort, so that rules out surface mount components (for me, anyway). I already have the preamp design, and I'd be looking to add either a digital compressor + IR feature or just the IR. Through-hole DSPs are too weak for IR cabinet emulation, since this really means FIR filters; one could approximate an IR by converting the 3000 or so filter taps to an IIR filter, but that would be worse yet for processing power. Of course, one could also just smooth the 3000 taps to, say, a bank of a dozen biquad filters or so, which should be OK, but since there are plenty of IR cabinet emulators on the market, I'm presuming there must be a low-cost chip allowing you to go with FIR filters, which means there might be a ready-made module to be added onto an existing design. I've seen this:

https://store.sure-electronics.com/product/AA-AP23122

which could fit the bill? Perhaps? Are there any alternatives?

Are these for tube amps?
Are these for DAC's?

They look top be new old stock.
Make offer in thread if you want.

Hello!

For me the FET transistors are not good enough, because their characteristics are non-linear. Definitely the tubes are much better. But the tubes are expensive, not mobile and require dangerously high operating voltages. In addition the output transformer ruins the sound.

I would like a robust amplifier with no tendency to oscillate. I often work in rooms that are heavily "contaminated" with electromagnetic fields. Therefore, the use of global negative feedback loop is out of the question.

After much deliberation I designed the following simple amplifier. And its sound surprised me...

I guess this thread is here as the Blogs remain inactive. But I also suspect there may be a few of the more hardcore set who think that hacking our C code for an audio DSP makes sense...

Well I did, so that makes at least one of us (me)!

The current version of this crossover is solid and stable, but I haven't thrown in some of the more crazy bells and whistles that a "roll your own" in software allows.

The thing looks like this:


By my standards, tidy enough that I am happy - but not a thing of beuaty and wonder.

What is it? What is going on in that box?

The heart of the thing is the PIC32MZ2048:


This is a generic PIC32MZ pcb that I use for all my projects. It comprises the PIC32, EEPROM, regs and headers for LCD and general I/O.

Running this 2 way crossover with 4th order slopes, and two parametric EQ's the memort is like 5%, RAM 7% and CPU load about 40% from what I see at 49,218ksps.

Huh? 49,218...

The reason for this is that this is an integer divisor of the 252MHz PIC clock, meaning the MCLK and LRCLK and BCLK are all nicely locked together without jitter.

In an embedded DSP, sticking to "normal" clock rates might look nice when you write the number down, but is actually meaningless. Unless you want to process digital data from external. Then I'd need to do a SRC... This clock rate works really nicely for the hardware...

The DSP has two "things" going on:
- The entire SPI read, DSP processing and SPI output occurs in an ISR that is triggered by the SPI buffer being half empty. Meaning this is rock steady on timing for keeping the SPI full for / from the ADC and DACS.
- The user interface is run when the ISR is not keeping things busy...

Other things in the box are the power supply and header breakout for the ADC and DACS...


Not a lot to say here, supplies power and stops cables getting too out of control. Again I sent this PCB off to the fab, as I tend to do a bunch of audio stuff from the PIC, eg my signal generator uses this, as does my PC based distortion meter.

The ADC plugs onto the power supply PCB. Samples data rns across the ribbon cable (every second wire earth) to the power supply board, then back to the PIC.

The PIc sends SPI / I2S to the DACS, two of them in this case, again via the power supply PCB.

The user interface is on a 128 by 64 LCD, and is about as pretty as an engineer is likely to make it...


Volume control, with bar graph. In this case I am doing volume digitally. The tests I did against analogue volume chips showed that a CS4398 generates less distortion (if you can measure either of them). Its not that the analog chips are bad, but that the CS4398 is really good!

If you look on the right you might see the unloaded spot for the volume chips...



Save,Load config, Set up crossover, PArametrics.




Select crossover slopes etc.

And delay.

The parametric is similar, choose your CF, Q and gain and off you go.

Things I ponder adding are compressors, limiters and suchlike. These would be a complete doddle to add, as it really is just peak tracking and comparisons - but the audiophile in me always stops me at the last minute.

With about 60% processing spare, I could add an extra channel or two, or a bunch more parametrics.

All audio processing in this is:
- 24 bit SPI / I2S in and out
- Converted to 32 bit data
- With 64 bit accumulator for all DSP functions which is shifted back to 32 bit for storage

By doing all this in integer things really click along, so there is great lattitude for other things. I am pondering effects eg for guitar.

This is all coded in C32, microchips free compiler, which at times frustrates the hell out of me. I am not really a programmer so relearn every time I do these things, and their documentation is - lets say - complicated.

So whats it cost me?
- The PICS cost less than a burger
- The breakout board has more in value in LM317s than the PIC I suspect...
- The ADC and DAC are the expensive bits...
- CS4398's are probably US$10
- CS5381 are a touch expensive, I have lots of these as I was using them for my distortion meter. Perhaps a CS5361 at US$10ish would be more sensible - their performance is not far off the CS5381.

As you can see those boards are home made - the input and output op amps are either NE5532 or LM4562, which in this implementation I cannot tell the difference between even using fancy test gear.

All up this is probably $200 of stuff from my shelves, and a ton of time.

If you would like to play with this, or the code, feel free to drop a line and I can copy it to you.

By the way, the code is close on identical to the code that controls my ADAU DSP crossover, but the DSP ISR (plus SPI/I2S interface) replaces the external ADAU chip...

Tell Me,

How many of you Really Like ThreadJacking........i was asking just because I have seen many users here on the forum which really liked this phenomena.............
Whats your best thread which is JACKED UP!


😀 😀 😀 😀 😀 😉
Moderators : I don't encourage threadjacking , but just want to get the opinion towards it.....
K a n w a r

Hello everyone,

I am really struggling to find a replacement part for my SE Munro amp:-

https://www.soundonsound.com/reviews/se-electronics-munro-egg-150



I have a lot of noise on the Source selection switch (Main / Aux) , and discovered one of the 10 pins was lose, and then came away from the switch package completely. It seems to be a 2 position, I assume 2 Pole(?) rotary selection switch, but I just cannot find a suitable replacement:-

I have found 3,4,5 position - and 3 position could work I guess, but please could someone help me identify exactly what I am looking - i.e. how do I meter out the old switch to find out pin configuration and do I need to be looking for any specific attributes given its purpose is to switch between two stereo audio inputs, rating etc?

The throw is about 30 degrees, the shaft is a D-shape, with thread. 10 pins. The only markings on the switch is 'CTR' one side and '23' the other.



So questions are:-

• I have exhausted all the keywords I can think of, but I don't know I am describing the search correctly, e.g. "2 Position Rotary Selection Switch" - how do I specify it mounts at a 90 degree angle? And are there other search phrases that would yield better results?
• If I cannot find a 2 position - could I use a 3 position? e.g. https://www.ebay.co.uk/itm/126093504744

Any help, advice or recommended places to search would be really appreciated - thanks!


Jerry

I hope someone is familiar with this problem ( I made a short post in Solid State a few months ago w/o answers).

This radio's tuning started acting up. Turn the tuning knob and the digital display/received frequency might or might not change. Then turning the knob had no effect. Now the display doesn't change and the frequency doesn't change. The radio still works stuck on one freq.

This radio uses string, spring, pulleys and a variable capacitor to change frequency. I suspected a mechanical problem with these parts but all is intact, except . . .There's a large string driven wheel on the variable capacitor shaft. It turns the shaft but the capacitor does not rotate. There's some sort of micro gear reduction (?) box between between those two parts. It's hard to see with the radio intact. Too inaccessible for foto. Any help??

The Repair Guide has a mechanical diagram of the radio and it shows the tuning cap as a single device to which the large wheel attaches. No detail about a "gear box" if that's the term. The Guide also says the tuner section can be removed as an assembly. Removal would probably afford a better view but I'm seeking advice before I dig in. For other owners, there is a useful diagram of string/spring/pulley system

These radios sound quite good, they weigh a ton but are very cramped inside.

Thx for any advice/experience.

dizmayed

Hi Guys!
I’m a full range fan! And most of my designs are crossover less!
Now I’m planning to create a high efficiency tower.
This will be a 2 way tower, and my thought is to make it crossover less by placing a sealed full range roll off at 80hz and designing a 4th order bandpass sub which rolls off at approx 75-76 hz to avoid peak at the crossover. Both drivers have similar efficiency post modelling (3db boost on the sub due to BP)
Question is:
Has anyone tried this method?
How can I merge these 2 simulations to get a combined output?

P.s: it’s a 12 full range 96db with 12 sub 93db drivers.
Total volume will be 4cft. (1.25 sealed + 3.75 BP)

Thanks in advance.

When resistors are noisier than transistors or know-how about how replacing a cheap resistor is better than paralleling 15-$ JFETS (with multilanguage subtitles)
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Well, I have little choice but to sell this kit for what I have into it. Stuff happens in life, so here we are. Price is $200 Plus shipping.
Includes everything offered in the SE kit. I put components in that I had in stock. BD139 and BD140 were not yet mounted as I was still looking for a pair of heatsinks that might have been somewhere in the shop, but no they weren't. Yes, there are more parts to place on the PCB such as relays, heatsinks with the BD139/140 mounted and a couple of trim pots. Not much really. All soldering was done with WBT silver solder (4%). Guys I am not going to wait long on this before posting it at USAM, but just wanted to give fellow members a chance first.
NOTE: It is the buyers responsibility to check that all components are correct on the PCB and in the right place. Common sense to check this just as I did. Murpheys law is a killer.

This is for a matched pair of 10" Dual Voice Coil Subwoofer drivers. Can be used with both coils in series for 8 ohms or parallel for 2 ohms. Poly cones. Heavy magnets. High efficiency, large voice coil, 20Hz resonant frequency. Hard to find drivers with specs this good at this price. Check the full specs in photos. They can be driven nicely with 20 watts, or can take 200 without a sweat. Will shake your environment if that's what you want. Great for theater or music, electronic or acoustic. Free shipping. Lower 48 states only please. SOLD

Hi there. The beyma SB18 cabinet is large 54cm and tall 54. what could happen if i build it 2 cm less large? The trunk of my car allow me 104cm, so if i build 2 of them i can fit them inside. Would the frequency response be drammatically affect?

Does anybody have a datasheet for the Tamura F-2012? I've tried looking all over the 'net and can find no detailed info.

Or, at least, does anybody know what the turns/impedance ratio to the cathode FB winding is?

I know I can measure it, but I'd prefer to have the manufacturer's datasheet... Japanese language is fine.

TIA!

Pete

Hello,

Up for sale is a pair of JeLabs simple 45 monoblock amps.

Built on hammond chassis using onetics level 1 opt trans and tamura power transformer. Rectifier used is 6ax5.

These will only come with the 6ax5 rectifier tubes. Will not come with 45 and 6sl7.

No hum on my cornwall and altec 19. Preamp used is scott lc21.

Im asking $950.00 or best offer.
Will post pics in about 2 days when i get back from my trip.

Best regards,

Tubo

Selling my Fostex T925A horn super-tweeters, in mint like-new condition, for £ 500 for the pair. Original wooden stands included.

Optionally also available for sale the premium Fostex P30 solid brass stands, for an additional £ 150 for the pair. [EDIT: P30 stands now sold]

Payment by PayPal, or cash on collection in person (London, UK).

Possible shipping by Royal Mail tracked (£ 15).

Hello,

This is a video where a professional musician in Nashville, named James Lill, does some crude testing to try and find out where "tone" comes from in a microphone.

Yes, there are a lot of other factors that we know about that affect the final sound we hear in our heads. That is not covered in his discussion.

I hope it is useful for those of you who have not seen it yet.

There is a lot of DIY scattered throughout the video. (edit: wanted to add this note)

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There are a lot of describtions to read concerning this topologies - go to

http://www.valvewizard.co.uk/SRPP_Blencowe.pdf
vs.
http://www.valvewizard.co.uk/localfeedback.html
http://www.valvewizard.co.uk/pentode.html

and

http://www.valvewizard.co.uk/mufollower.html
vs.
http://www.valvewizard.co.uk/accf.html
http://www.valvewizard.co.uk/pentode.html
https://www.tubecad.com/2011/08/blog0212.htm#:~:text=The cathode follower relies on,voltage relative to input voltage

more URLs:
https://www.tubecad.com/articles_2002/SRPP_Deconstructed/SRPP_Deconstructed.pdf
https://www.tubecad.com/2018/06/blog0427.htm
https://www.diyaudio.com/community/threads/srpp-vs-plate-loaded-musicality-and-details.170999/
https://www.diyaudio.com/community/threads/differential-srpp-gain-control-reduction.337617/
https://www.diyaudio.com/community/threads/how-a-srpp-stage-sounds-like.189729/
https://www.diyaudio.com/community/threads/newbie-to-srpp-and-tubes-1-question.249209/
https://www.jogis-roehrenbude.de/Verstaerker/SRPP-VV/SRPP-VV.htm (German language)

But what happens regarding the sonic character in the different circuit topology as the tubes get older ?
under
https://mesaboogie.zendesk.com/hc/en-us/articles/217178237-How-long-will-tubes-last-
are describe some unwanted effects in general, but wasn't mentioned the associated circuit topology.

I have heard and read often, that SRPP and Mu-Follower are only suited for tubes special made in long life version.
Is this true ?

In one of the German speaker builder magazines "Klang & Ton" or "Hobby HiFi" from 90s this question was describe in detail from Holger Stein (his old URL: www.steinmusic.de) maybe in the issues mentioned here:
https://www.audiomap.de/forum/topic/13705-steinmusic-holger-stein-vorverstärker-inaus-klangton/

Thank you for upload this papers resp. calling the associated issues of magazines and some URLs in this case.

P.S.: The question arises in general (i.e. related to line and phono RIAA stages) but also specifically in my case, where the question is which topology is the best for an active high-pass filter. Regarding the question of multiple positive feedback (Sallen-Key) or multiple negative feedback (MFB), the question is answered here:
https://glass-ware.stores.turbify.net/nostmfbcr.html
But not regarding the question mentioned in the head line for topic.
This I want to know to make a decision,. whether I order the PCB boards under
https://www.tubecad.com/2021/08/blog0543.htm
or not.
Similar question I ask here:
https://www.diyaudio.com/community/...-stage-to-acf-aikido-cathode-follower.374073/

As a relitive greenhorn to DIY builds, i find excel is a horrible tool to mange my BOM's..
In a previous life and years ago, I spent a little time (very little) creating databases for on line and off line uses..

Id like to tap into the hive of much more learned folks out there and explore a better solution.

The Diy crowd is im sure well accustomed to ordering from multiple vendors too fill the BOM..

My current build has 8 separate companies im ordering from and the counter is rising. Im certain you fine folks have probably found a way to organize that works for you, and im searching for one that suits my needs..

I envision an application (access, mysql, etc) that manages a BOM database containing fields that we find useful...

If any like minded individuals with knowledge are interested in collaboration with the intent on a 100% open source and free to all solution willing to spend some time let me know here..

Im hoping at least a few folks might have a little time to create something useful..

A few years ago I listened to a preamp at an exhibition that impress me for good sound quality ... schematic was roughly the one on the right ... I couldn't find any feedback on the net and I don't know if I understood the meaning of it. .. I still tried to adapt it with different tubes and new parameters ... what do you think about it?

There are a great amount of threads regarding replacement, but not regarding implement of backup batteries.
There are a lot of vintage FM stereo tuner models in which the programmed stations are not saved for long after disconnect the power cord (instead battery or super cap only usual electrolytic cap arround 470uF or 1mF resp. 1000uF), because the electrolytic capacitor only supplies power only short timt for the memory cell.
That's why it is mentioned in the user manuals, that the programming is lost after unplugging the power plug longer than some minutes.

Some examples from Luxman:
T-530, T240, T-105 and R-113 (Receiver - i. e. include pre- and power amp).
https://hilberink.nl/luxmanl30/t530/luxmant530tuner.pdf
https://www.techtrader.ch/auction/2015/06/Luxman-T530-manual.pdf
https://www.diyaudio.com/community/attachments/luxman-r-113-service-manual-pdf.1023003/
https://elektrotanya.com/luxman_t240_sm.pdf/download.html

What should one consider in general, when retrofitting storage batteries (usually versions with 3.6 volts) ??
In the datasheets of used MCU's there are only an explanation in short form - go to pg. 682 of pdf attachment of NEC's uPD1704C resp. µPD1704C datasheet for an example.

To learning the general rules I want to know some such projects.
Thank you for calling of associated URLs.

I know there in the store but shipping to the UK is just too pricey .

Looking for 2 x Pass F5 amplifier boards, preferably unused. Will need shipping to the UK.

Thanks

Hi,

I am recapping my old DMagic as everything has leaked and wondered about the design of the main +/- 15V supply with the capacitors C400 and C401, can anyone explain the circuit as it looks like C400 receives voltage agains the capacitor polarity, and they are just normal electrolytic and not BP

Hello everyone!
I'm planning on building a pair of rear surround speakers for my system. They will be used mainly for music, but movies too. I have quite a few 5.1 albums which I'd love to listen.
I have a pair of Dayton Audio RS100-4 (4", long-throw, aluminium cone, 4 ohm fullrange speakers) laying around that I would like to use for this job.
Usually, I'd use them alone by themselves without any tweeters, but since I'd be listening mostly off axis I'd love them to have a good off axis response. Therefore I think I need to add a tweeter.

I've been thinking on how to do this and every approach I can come off with has its own set of drawbacks and I can't decide. I'll list them here.

1. Just to add the tweeter, let the RS100 run full range and filter the tweeter at about 3.5kHz (30 degree off axis FR plot here, green line it's for the 8ohm variant but the 4 ohm version should be pretty similar).
I think this is the simplest approach but if I aim for a flat off-axis response, the on-axis will look like trash because it will be both tilted upwards and I will also have to deal with comb filtering because the tweeter and the woofer will play the same frequencies, and due to the wave travel paths not being equal based on how I move it might look a little be better or worse. Impedance also might become an issue. I have no idea how bad this might be.

2. Treat the RS100 as a regular midwoofer and use a regular 2-way LP/HP 1st or 2nd order crossover and cross lower (I'm thinking in the 2.5kHz/3kHz ballpark). In theory this should be the approach the will provide the best on-axis and off-axis, closely matching the directivity between the two speakers. However, the damping factor will be pretty low. The RS100 already have a high Qts, which is already somewhat compromised by the 10m (32ft) of wire that I will have to run from my receiver to the speakers. I would prefer to avoid adding another choke point in the form of an inductor.
2b. What if I did this but instead of using an electrical crossover on the RS100 I used a "mechanical" one (eg. a piece of cloth in front of the woofer)? Would this work? Has anyone had any experience with this?

3. Get a very small tweeter (I'm thinking SB Acoustics SB14ST-C000-4), remove the phase plug of the woofer, and make it into a coaxial. Then I'd just filter the tweeter and let the RS100 run full-range. This way I'd have to deal only with the rising response on-axis and not with comb filtering, because the wave paths of the woofer and the tweeter would be equal.

4. Sell the RS100 and get something else :'

I can use DSP on the entire channel, I'm using a PC as a source that is running Equalizer APO so I have access to many filters. The speakers will be hanged on to a wall, at the two opposite corners of the room, near the ceiling. I don't think I have to deal with baffle step because of such placement.

Has anyone had any success with the spice model for the VOM1271T given on the Vishay website?
https://www.vishay.com/docs/80045/spicemodelvom1271.zip

At best, I can get it to work with 100s of mA on the input, mostly it just stops the spice simulation converging.
If the spice model is not trustworthy, please could someone post a circuit of a SSR using the VOM that is known to work.

Thanks

My system is a complete 1980s ADS atelier system. Regrettably, it’s considered to be obsolete now.

At present, I’ve switched my listening behavior from CD to streaming. My current digital source is a combination of Yamaha YBA-11 bluetooth receiver and a/d/s/ DA20e car’s DAC. Currently, I’m looking for a hi-end DAC, with limited budget (secondhand), to fulfill my system.

Since my system is a complete ADS system, I’m thinking to go for a higher model DAC from ADS. I’ve known that the flagship ADS’s DAC is the “a/d/s/ DA44” where it was actually the twin of “Museatex IDAT-44”. Both models were designed by an audiophile engineer, Ed Meitner of EMM labs/Meitner Audio and had used the same chip.

However, my local shop has a rare item hi-end DVD player; Denon DVD-5000 for sale. Both Museatex (Meitner) and Denon have similar price (secondhand).

To date, I’m hesitating which way I should go. So, I’d like to ask everyone’s opinion and comparison about these two models.

Note: The chips of them are as follows:
Meitner’s IDAT44: 2 x TDA1549T – SAA7274P
Denon DVD-5000: 4 x PCM1704-J – PMD100 – CS8414-CS

Hi all. I believe that this is the best options of what I have available as the DACs inside of my computers are so so at best and are subject to so much interference. Let me know if this is untrue.

With this solution in mind How would I go about determining which of my AVR's has the best DAC. I have Pioneer Elite, Onkyo TX-SRs, Sony DH series.

What are your opinions on the various manufacturers?

Jeremy

3 new in box ,
End up not needing them for my project
Fostex T96A super tweeter

600$ shipped

I have an 18" sealed Ultimax in a sealed & perfectly painted box, and it has a Behringer NU3000dps. I want a 15" ported sub to use with my home theater because the 18" is a bit too much for my current setup. It seems to overpower my other subs even at lower volumes. If you've got a 15" and were hoping to buy an 18" someday. This is a great opportunity for anyone looking to trade up! Take a look at the pics, and contact me if interested.

My Denon PMA-280 started to occasionally play at lower volume and to occasionally produce crackle in the right channel. The crackle doesn't happen by itself, but only with a signal, most easily heard with a sine wave.
I'm attaching a recording of the crackle with a 60Hz sine wave playing. I'm changing the volume a little bit throughout the recording. The crackle is more or less intense at different volumes, but this varies wildly over time. It's not the volume pot that's causing it, because it happens with the changes in input volume as well.

I can hear it through the headphones output too, but only if a load is present on the speaker out (a speaker or a resistor). Without that load, it sounds just fine on headphones.

I've read in some other threads that you can find the faulty component by freezing them, but I'm clueless about this stuff and I was hoping at least to get some pointers and to narrow down the issue. I also have a multimeter I could use to measure something, if it helps.

Since there has been a lot of focus on driver distortion lately with Purify entering the scene, I thought I would post a question on distortion measurements.
I like running multitone measurements on amps to get a 'general overview', so I thought why not do it on speakers? I think it gives a good visual overall indication of the 'signal to distortion' vs frequency. I find two tone tests a bit hard to interpret, and it seems the tones used can influence the result if they happen to hit 'problem areas' of the driver or not. More tones, more excitement 🙂 'More is more' like Yngwie Malmsteen claimed (guitar nerd joke)! 😀
(Edit: Login to view embedded media )

Is there a reason for not doing it?

I ran some quick measurements where I took seven averages/measurement because of a noisy garage environment. One is a PA 8" woofer, the other is an old Mission speaker with a 8" woofer & 1" tweeter. I have no SPL reference, just my ears, and the level in this graph was what I would call normal listening level, so this is not really a scientific example, just a general question about the concept. I'm hoping Lars or other smart people would comment on using multitone for driver testing, and I would also be curious to see what a similar measurement on a purify driver looks like.

I have a new DVC 2 ohm Alpine S Series 2 ohm sub

I plan to run it at 4 ohm to the amp. I want the dampening and I think wiring to 1 ohm is muddy.

I don't have a ton of money to dump into this (I'm wasting some running at 4 ohm but I think it's worth it) so my choice are this stinger 1500 or the D4S mm1000

Heard the D4S units run dirty as hell. Not sure I'll notice as this is actually a track car with zero sound deadening so not a quiet ride (yup, I run a full system in my track car, come at me)

Heard stingers are great units but can't find a lot of info on them. So far found nothing negative about them. Larger, simple bass knob. Bigger so heavier than the mm1000 (track car, weight is a consideration. Let's not get into weight transfer equations)

Mm1000 seems nicer. It has a fan and the clip light on the bass knob which I like. The "dirty power" reports are plentiful. I don't need this sound super loud, I want it tight and crisp.

These will be tucked into a tight spot but I'll have some brushless fans wired up to cool them off.

Let me know what you'd do with your money.

You can sell under your own brand.
The material and weight of the turntable and base can be customized.
The number of tone arms that can be installed can be customized, and up to 4 tone arms can be installed at the same time.
Currently, there are two types of turntables to choose from: magnetic levitation and air levitation.

Due to the large workload of individual customization, OEM products start with 5 units. Prices are quoted individually and privately based on quantity and specific design requirements.
The price of a single customized unit is around US$2,000-8,000 on average depending on the configuration and requirements.

ebay link：https://www.ebay.com/itm/204391721784
Email：cengruyue@gmail.com

Need help with REW for measuring speakers. My setup is with the Behringer 8000 into an audio interface then into my laptop. Last night I measured my current two way project and came up with the top graph which is "normal". Today all my readings / graphs. have the distortion dropoffs at 2.4Hz, 7.6 Hz, 13.Hz, and 18.8Hz. Anybody know what settings or equipment connections could be causing this. Anyone every encountered this and figured out what is doing this.
Thanks much!

Hello, I have a PCIe card with AES/EBU 110 Ohm output that I want to connect to the AES/EBU 110 Ohm input of my DAC through a cable.
I would like to add galvanic isolation to this connection using the 1:1 transformer LL1572 by Lundahl.
Which schematics do you suggest, among the solutions A-B-C below? Thank you in advance.

Solution A:


Solution B:


Solution C:

I've bought a FAST cabinet and driver set from an eBayer. Its the RS225-8/Visaton B80, 25mm MDF cabinet with 25mm ply baffle, which is not yet attached.

My plan is to have two sets of binding posts so I can have an external crossover (and use my active setup). And also, to drill the 104mm baffle hole for the B80 and also (at 45degree offset) an SB29 tweeter, so I can see how the RS225 sounds in both cases.

Now the interior of the cabinet is not treated yet. I have (mostly Monacor):

• 3mm bitumen panels
• 10mm high density foam panels
• BAF wadding
• some acoustic tiles (not actually eggshell but similar)

The volume of the cabinet (excluding driver, brace, and the enclosure for the B80) is about 21l after allowing for foam panels so I don't think I need/want 'heavy fill'.

I feel with the 25mm enclosure the bitumen might be redundant. I will probably add the 10mm foam, put the acoustic panels on top on the back, and some BAF wadding on the sides (and maybe top/bottom). Maybe a bit at the back.

Is that sane? Any other suggestions?

Talema 2x25Vac transformer 500VA. 50€

Hi,

Not sure if this is the best thread for such question, but I will take the risk...

I am a complete beginner in audio tube world. I have intermediate knowledge and experience in electronics, but I face tubes for the first time in my life. However, that is my goal - to learn how to build an audio system based only on tubes (not a product or any kind of homework, just sole knowledge expansion...) I want it to be universal, so the source could possibly be a 3.5mm jack, USB stick or even BT, Ill take care of the digital part myself, but how about:

I have heard that GM70 are really powerful tubes used in the last stage of any amplifier. However, can you suggest me, what parameters should I consider (or even better) or exact tube part numbers should I use for lets say first stage (or even first and second stages, considering the GM70 to sit in the third stage) preamplification. I intend to use 2x GM70 in a push-pull configuration for the full audio band. I guess I am looking for an answer that no book could give me, I am looking for pure knowledge and experience, considering audio tubes to be somewhat beyond regular electronics...

Some of you will say that this project is not for a beginner and I should start with something way easier. But Ill take the risk, as I mentioned, the goal is only the knowledge and experience, so time and money (to some extent) are not an object to me.

Hi All,

Bit of a noob here regarding audio. I am currently planning to create an Arduino powered radio for one of my vintage cars, and I am looking for a small amplifier for it. It will only run 1 speaker of 4 ohm, 25 watts. I would like to have it all in 1 unit, so not in a seperate case.

If you guys could perhaps give me some suggestions that would be helpful. Thanks in advance.

Greetings to all of you on the forum. I'm a new member and I've actually known the forum for a few years.

Good. I state that I am a self-builder technician and I am writing to you because I am thinking of buying the pair of audioresearch classic 150 model amplifiers, one of which is not working. The seller says one works and the other is broken. Missing 2 transistors inside. Do you think they are worth buying? For both, 3,500 euros are being asked. As far as I know, audioresearch doesn't release codes for broken transistors, how can this be done? Can you help me understand what is right to do? Is it worth it? Thank you.

Hello,

I hope I am not breaking the rules, but I have too many things to list and I don't have a fixed price for them (all being auctioned) I can only send here a notification diyAudio members that I am getting rid of my collection of MC cartridges and SUTs.
All can be found on the famous auction site (.de or .com) where my username is LACUNIA.
Since it is being auctioned it would it is impossible to list all of them here. All prices start from 1 euro and the auction will end on Tuesday.
Location is Budapest and as usually all are in very good or excellent condition. Photos can be found on the site.
Each cartridge has been checked and tested before advertising them.

These gathered during many years, some of them I received broken so I repaired them to original or better specifications with the usual care as some of you had already experienced from me.

Please feel free to ask questions here.

There are some rare and interesting cartridges.
I hope you will be able to find something for yourself and make a good deal.

Thanks for checking them and I apologize if I am breaking any rules here.

Best regards,
Vencel

Hey,

Im having trouble finding why the output stage rails are 0V.
Friend brought the receiver to me. Told me that out of the blue there were sparks flying inside the case while he was casually listening to music while doing house repairs.
Took it apart, on the primary side the main mosfet had gone kaboom and took some diodes/pwm controller with it.
Swapped everything out and now receiver powers up fine but output stage is silent. EVERY other accessory voltage is present and at correct voltage but +/- rails for the output is at 0V. I have checked all the semiconductors and even took the transformer off to get to the optocouplers that are underneath it and everything seems to be okay.
Output stage itself seems to be okay and rail caps start charging when checking in continuity mode.
Maybe someone has come across similar problem?
Attached a pic of the psu unit.

This week a pair of MarkAudio Alpair 10.3 drivers are arriving. There has been much discussion about these drivers in particular as needing quite a bit of break in (200-400 hours ultimately before any fine tuning is done).

My plan is to place the two raw drivers in my sauna downstairs (speaker boxes are not yet built, and the sauna will not be in operation). I'll run a pair of wires under the door and simply let them play what ever is on the radio 24 hours a day (168 hours in a week). This will probably be 70's pop music and not too bass heavy. Acoustically, the sauna is fairly isolated from the rest of the house so 24/day is not a problem.

For the first several days the level will be about 55 dB. The remainder of the week will be about 60 dB (level of conversation). After that will be several days at 65 dB, and then several days at 70 dB. That should give me two weeks of break in (about 300+ hours).

For folks who have gone through similar procedures, I would appreciate your thoughts?
-Tom


BTW, I am planing on building the "Eland cabinet" graciously supplied by S. Lindgren
https://www.diyaudio.com/community/...audio-fostex-tb-dayton-seas-etc.323051/page-3

Hi all,

I've been recently looking at grounding in the purpose to make a high end mixer with multiple balanced inputs and I won't lie, it is giving me some headaches.

I've read a lot, but couldn't find concrete answers about this. For a balanced line input, Rane Note : "Grounding and Shielding Audio Devices" suggests to chassis-grounding the pin 1 of XLR with the smallest path to chassis as shield is the carrier of interferences and the length of this wire determines the filter frequency in RF domain.

The best way to do so that I've found is to use Neutrik XLR connectors such as the NC3FAAH1 which incorporate a direct path from pin 1 to the chassis with a sharp piercing tab.

But in star grounding, we often talk about connecting ground of our system to one point of the chassis only, as it is difficult to predict return path currents and that can cause internal ground loops to happen.

So I'm kind of torn between having the shortest path to chassis and therefore having all Neutrik XLRs with individual connections to chassis, or connecting all pins 1 together with a thick wire and sending it to only one chassis point but with the risk of sending more RF interferences to others PCBs.

What do you guys think or would do?

Thanks for solid explanations or experience feedback.
Cheers,

It's a good time to be alive - to see this kind of pioneering continue. I was too young to appreciate the Apollo Missions so for me, Artemis is my chance to live the same excitement that my parents did.

Since I wanted to run my small 2 way MEH (https://www.diyaudio.com/community/threads/ikea-kallax-meh-unity-synergy-speaker.382400/) with a single 300B amplifier, I built a simple first order crossover. The sensitivity of the planar tweeter is almost matching the sensitivity of the LF part and the overall FR is equalized with a DSP (basically a low Q cut of a few dBs to make the midrange flatter). Sounds fine and measures reasonably well.

I remember reading that for a MEH it is beneficial for the tweeter to have an inductor in parallel so that it is effectively shorted at low frequencies - to protect the tweeter from the pressure caused by the LF part. For the powers involved (300B SET), it does not probably matter much - but would there be any benefit in using a series crossover, where the inductor is in parallel with the tweeter?

And if I extended this to my larger 3 way builds, I could save 2 channels of amplification by using a first order crossover between HF and MF. I can see some potential issues with the upper end of midrange above the cancelation notch.

Would it be worth using higher order passive filters (parallel) with this hybrid approach?

Hi there -- I'm building an SSE to work on UK voltage (nominally 230v). Apart from making sure I get the correct power transformer (thinking the Hammond 374BX), are there any additional modifications I need to make? Does the 50 vs. 60Hz have any influence, for example? Or is the output from the transformer identical regardless of the input voltage?

Thanks!

Was wondering what specifications a Single Ended transformer would have for a 450TL ?
I'm thinking 145 watts class A-1, with 2500 volts to 3000 volts. The transformer would probably be rated for 4KV @ 175 watts perhaps?
I was more interested in the Plate load resistance?
Thoughts, ideas?

Hello there!

The potentiometer (ref : CVV9Y13B503Z)of the master volume of my marrantz pm4001 is actually dead.
I would like to replace it, but i can't find it on internet .
I've seen some say that's the RK16812MG099 from ALPS is an equivalent, but after buying it, it's not...

Can someone can help me ?
Thanks

Hello, All --
Was looking at this design for a 140 Watt Mosfet Power amplifier. The Claimed figures for this are less than 0.005% THD, and also less than 0.006% Intermodulation Distortion at
a 4:1 Ratio of 50Hz and 7Khz; these look like good figures. Yes, it uses the older TO3 cased Hitachi Made Lateral Mosfets, - (which I have), and was wondering if anyone on the forum had built something similar, or have any ideas on how this could be improved?
Circuit Schematic is attached --
Thanks, Telnet100

are there some Ribbons or amt which go down around 500 hz ?

Thanks to a very fruitful cooperation with Dr. Bernd Ahlswede from www.sphericalhorns.net, I can introduce my second large 3D printed horn (the first being the multicell horn for JBL2445). It consists of 9 parts and almost 3 kg of PLA. The 62 cm wide horn was cut to fit my Flsun Super Racer printer, it took more than 60 hours of printing time.

It is glued with Mamut construction glue with a few M3 bolts and nuts for alignment. The inside is only roughly sanded, coated with photo resin and two layers of grey spray paint.

The pictures show the construction and building process. It is still work in progress, the prototype was put together as a feasibility test. It seems to resonate quite strongly, so I will try various ways of damping the horn walls and also second unit with added ribs was printed and is waiting for assembly.

It is intended for BC DCX464 coaxial driver.

I decided to document my Visaton LTS 50 experiment of two drivers here. I saw some usage of LTS50 on some full range drivers before, but all are long time ago, and without any modern drivers. So here it is.

First on some basics. Doping drivers might improve or worsen a driver. But one thing is for sure: It will decrease HF response and extension since it adds weight to drivers cone. So I will not choose drivers with limited HF extension. "Overly bright" drivers are good starting point. Better if they have shorting rings in motor, so the response will raise with frequency. I choose FF125WK because it fits these requirements and has a very high peak at 7khz. I use a modified IKEA turntable to apply LTS50 as smooth as I can:

Here's before and after:


Overall I think the coated driver looks great. Like Seas CA* coated paper drivers. Coating was easy too, use a few layers until you satisfied. And here's frequency before/after:

It's easy to see one 12db peak has now became two much smaller peaks. I think it works great. It's very obvious when the original driver connected to a noisy amplifier, you hear a SSS noise at 7khz but with the coated driver, it sounds like a white noise with even frequencies.

Next is the famous FE103SOL. Actually I was a bit nervous on coating this driver since it's a limited edition driver, but the reason is the paper cone started to develop some yellowing, and I think it looks awful. And I know how it will develop in the future. You can see the yellow stuff grown on the center dustcap, it was used to be beautiful white when new:


But apply coating on FE103SOL is MUCH MORE difficult. The "metallic eyelets" will affect coating, and the paper absorb the liquid with different rates. In the end, it's much more difficult to get an even result.

Finally here it is:


I think they looks better with actual driver, the shinny texture still looks good to me. Frequency response wise, the real improvement is driver matching. Before the pair of driver don't match quite well:

You can see these two drivers peaks and dips at slightly different frequencies, one of the reasons the sound stage is not as good as it can be. Also, the dip at 1.8khz was very significant and high-q (~6db) (Also found in hobby-hifi)


After coating:

The two FE103-SOLs basically peak and dips at very similar place. Although the curve looks a bit more "rough" than uncoated drivers. It's easier to EQ this time. The biggest improvement was the surround dip at 1.8khz. BTW I lost around 1khz high-frequency extension due to added weight, but it's still a bright sounding driver due to strong energy at 10~12khz.

With thick black coating(black is perfect for absorbing UV), and additional protection, hopefully I will no longer be bothered by aging issues of the Fostex Banana cones.

I have for sale stereo amplifer, based on Holton HPA-NXL200 R4.2 modules, precisely installed in custom build beautiful enclosure. I could say this is one of the nicest and solid built of this amplifier around. It`s superb sound desire top notch components, so amplifier consist of one 500 VA (230V) transformer, made by my own specifications, with separate windings for each channel. Special part of this amplifier are top notch separate power supply for each channel. Power supply not only provide +-50V to the amplifier output stage, but also has built in capacitance multiplier for delivering clean +-55V to the amplifier front stage (amplifier boards already provide this option). Power supply consist of high end components as soft recovery diodes, Vishay main 4x10000uF 63V capacitors (per PSU) and Nichicon FG capacitors for capacitance multiplifer. Amplifier also has special soft start circuit which is connected to the mosfet DC protection pcb boards (prototype version) on speaker terminals. In case of DC on speaker terminals, amplifier (soft start) will shut down. For wiring speaker lines, Jantzen solid core wire was used. For power supply wiring, Jantzen stranded wire was used. Dimensions of amplifier are: 33x31x12,5 cm (WxDXH). Amplifier is in perfect operating condition. Amplifier should put out minimum 120W/8 ohms and 180W/4 ohms (in practice possible even more, due higher input stage voltage). Input is provided with high quality Neutrik XLR terminals.

Link to the (R4.5 boards): https://holtonprecisionaudio.com/co...xv200l-r4-balanced-xlr-input-amplifier-module

Price is 650 EUR + PayPal fee + post costs


NOTE: I am not responsible for any customs fees, taxes, import duties.

There is no doubt that I should improve my stereo system. The next step, however, has to involve the proper placement of speakers in the room. At present I have the Diamond IV next to my desk, on either side, great for near-field. If I am ever to get out the near-field, though, I need the speakers to be placed in the room. about one third of the way into the room. Many other arrangements have been tried: open baffle speakers, on wall open baffle speakers, and even attempting at home to move the floorstanders to the floor where they belong (Sony SS-333). That did not work out well.

Initial tests with this arrangement have been encouraging. Paul McGowan of PS Audio ("Ask Paul") talks about attempting to design speakers that can be placed "2 -3 feet' from the walls, this seems to be the minimum. One third into the room, and if I sit one third of the way into the room, things get quite good as far as listening goes. The equilateral triangle means then that the speakers have to be placed apart. In all my years of listening I did not experience the stereo effect (outside of headphones) until 2019 or so, at my desktop.

We had a rack "home H-Fi" system (1980s) but the speakers were placed on either side of the rack, like large blocks, the stereo effect was unheard of, we just wanted to play it loud and fill the room with sound. That we did.

Since any room will look strange with a set of boxes on stands in the middle of the room, these will have to be pushed back after use each time, and be able to be stored unobtrusively. There is a potential problem here. Wikipedia, with rare literary flair, puts it this way:

The JBL TI 5000 loudspeaker boxes are 1.15 m tall and, like all large HiFi boxes, ideally should be placed distinct from room corners. Such devices are an example for a rather low WAF.

Click to expand...

https://en.wikipedia.org/wiki/Wife_acceptance_factor

Click to expand...

This thread will then describe results.

How fast can a LF353N be turn off and on.

Dave

I'm working on my other 1002, the previous one is a 1000-2, (newer version) which is now working well.
The 1002 is the one that gets very hot. All final output semi's are NOS along with the front-end boards and VAS stage semi's. Rail voltage is +- 49.5 and about 2mV ripple.
DC offset is 0.5/2.0 mV. Power for the opamps is +- 16. Bias is set to 1.5mV.

So during some sound testing with a 25amp power supply and powering two small speakers at a moderate level it would pull too much current from the supply and make the over current lights blink.
The heat is coming from one of the channels, on the finals. I did not check or change the Zobel networks.
I can't find anything wrong.
Could it be an oscillation problem caused by the Zobel network? I think I read something about this...
Any advice is welcome.