Bought this used 10" driver. The sticker says "K10" so assumed it was a Celestion. The magnet with the vents seems typical but the dust cap is concave. The surround has a single roll whereas in pictures the K10 has two. Also the K10 has a pressed steel basket and this basket is cast.

Any ideas?

I'm John from South Carolina! I do some repairs to audio devices for friends and family. Working presently on a Telefunken Magnetophon m3002 r2r.

I am restoring a Fisher RS-1015 receiver, and the parts list refers to some of the capacitors as being "sint alu" type. These caps are quite small and are polarized, and have low capacitance and voltage specs. I cannot find much about it, other than some recommendations that I just use normal electrolytics as substitutes. Can someone help me out with this? thanks! Brad

I am looking for a driver with excellent performance, I have seen TAD drivers made with Beryllium dome, and also BMS 4507ND coaxial drivers, but they are too expensive, and I plan to buy them in the future, but for now I am looking for a driver with good performance, I saw a 1" BMS 4528ND controller, and also a 3" Celestion CDX20-3020.

I have seen speaker manufacturers add 1" high frequency drivers to 15" woofers and I have also seen 3" high frequency drivers with 15" woofers.

Which driver would be the most recommended?
All I'm looking for is fidelity and precision.

This is probably a silly question, but I lack specific experience, so I'll ask anyway 🙂

In a push pull output stage that shares a current lol resistor, I.E both tube cathodes are together, and then share a 0.5 ohm resistor to ground (A) there's no issue with changing it to 2 resistors (B) so the current can be seen individually?

That's not going to make it upset, right? If the cathodes aren't directly connected to each other anymore?

Hi all,

The Spectrol 100 volume control in my KSP-7B has gone funky. It looks like the shaft is able to slide in and out almost 1/8" (3-4 mm), as though it had a missing or broken thrust bearing.

When the shaft is pushed in, it can rotate continuously past 360 degrees, in other words it glides right past the stop pegs. The rear gang measures randomly in a way that is not consistent with logic. But when the shaft is pulled out, the pot behaves more or less as expected, although the two gangs still don't measure quite the same.

I found a datasheet online for the modern Spectrol model 100 as manufactured by Vishay, but none from the pre-Vishay era to which mine belongs. My pot has 5 pins per gang, but new ones only have three. I was hoping to find out how pins 4 and 5 are connected internally.

The 11258 ohm resistance rating that's printed on my pot seems kind of unusual.

My pot was once a fine, well-made piece of kit (pics follow) and I hope to refurbish it rather than replace it. I searched for info on vintage Spectrol restoration but came up empty. If anyone here has done this kind of work, any information will be greatly appreciated. Thank you!

PS - This guy wrote a piece on refurbishing a PAM-7, a Krell preamp similar to my KSP-7B that also has a Spectrol volume control, although his has model number 100-5528 whereas mine is 100-5529. His shows a 10 kOhm rating, which seems a lot more normal than the 11.528 kOhm on mine. He states that he has serviced the pot, without further details.

I have one for sale. Condition as shown in pictures. No burnt components.

No power supply. Roll your own with 24VAC transformer.

€100 + shipping at cost. Ships from Sweden.

R

Hello !
I am interested in a small diy solution in order to transmit a high frequency sound to a long distance (approx. 50-70m).
My first thought was, well that is not going to be that hard, you have a good amplifier and speakers, find an app that creates a 20-25khz signal and done (yes, as others in here, i try to solve a dog barking issue unfortunately), but that seems not to be the case.

Reading several threads here, i found out that my solution are not normal coil speakers but piezos in combination with a ultrasonic generator (like Kemo M048N Ultrasonic Generator) . As my knowledge on electronics is really limited, except of the basics about speakers/amps wattage/impedance etc, i got lost in the information found here. Like the need of a resistor or capacitor that i read in some topics. On this topic i would like your help. Allow me to ask a few things and excuse my ignorance on this topic.

1) I got an old 2x100 Watt 4ohm amplifier. If i would connect the signal generator and the correct piezo speaker on this amplifier, would i end up with the results i want or i will fry my amp?
2) If the first option with my amplifier is not possible, what is alternative simple solution for this purpose ? How else can i drive the piezo speakers to output in such high volumes ?
3) What specs to look on the piezo speakers for this scenario? Any recommendations ?
4) Is the Kemo M048N Ultrasonic Generator fine to create those frequencies ?

If possible, give me some details of what i will need after all to buy. Is there a simple explanation in this forum of how to connect all those components together? This would be really helpful.

Thank you!

Hello gents,

I've got some KEF Reference Model 3's which I'd like to give some proper maintenance. These guys are amost 30 years old and I assume nothing has been done to them. Visually they look fine and the rubbers of the midrange/tweeter combo and woofer appear undamaged but that doesn't say much about the actual state of the material.
The 2 subs can not be visually inspected as they are mounted vertically inside the box.

I found a guy who is specialised in the KEF Reference and Q-series speakers in the Netherlands. I'm going to unmount all the drivers myself he is going to inspect them and redo the foams of the subs and maybe the rubbers of the woofer and midrange as well. He is also going to clean the tweeter magnet and redo the ferrofluid.

For the cross-overs I'm thinking of only replacing the caps taking into account the difference in ESR.....if possible at all

My questions are these. I do have the DATS V3 so this might be a very good moment to do the pre and after measurements measuring the free air parameters including the measurement with the added mass as well.

Would there be any use of measuring it besides the fun of measuring?

thx in advance

willem

20x2SK389 GR, BL and V 8 euro each
~100 x SJ74 1,50 euro each
~100 x SK170 1,50 euro each

All together 450 euro incl shipping world wide (PP friends or add 4%)

I've been into audio for as long as I can remember - building simple amps when I was a kid and more recently more involved projects, like a passive preamp project, some DAC stuff and a small music player for my kids. I've always wanted to build speakers and I just took the first step - I'm currently building a pair of compact bookshelves (Soundblab's Dynamites). I love the idea of designing/building something like a pair of line transmission speakers, but I'll build up to that!

So, now I want to design my own, and I thought I start with something simple - I have a spare pair of spare Dayton Audio DSA90-8 full-range drivers that I thought would be a good place to start. These will be used for near-field, probably without a sub. I used Dayton's recommendations for enclosure side and modeled three options, a sealed enclosure, a ported enclosure and a passive radiator option with Dayton's matching DSA90-PR.

I've done a lot of reading (/lurking), and it seems that a good option with this driver is a single driver in a small cabinet, or a larger cabinet that also has a woofer to add some bass. I wanted to keep things simple to start with, so I'm looking at the single-driver option. Maybe I'll have a stab at crossover design next time!

The enclosure sizes are 0.04 cuft for sealed, 0.06 cuft for ported and passive radiator.

I'm using WinISD so I added the specifications for the DSA90-8 and DSA90-PR and modeled a few options. Orange is sealed, green is ported and purple is passive radiator.

Transfer function magnitute. The passive radiator seems like the most linear response.


Cone excursion. This one I'm less certain on what to do with this information. I think it means that a high-pass filter would be needed with the ported enclosure? Would is be recommended on all of these? I've seen recommendations for high-pass filters to protect the drivers on full-range designs.


Cone excursion (PR). It seems that a single passive radiator is sufficient in this design


Air velocity. It seems that 25m/s and below are considered safe, from my research, so there shouldn't be any chuffing on the port. This is a 1" diameter port.


From this, my takeaway is that the passive radiator design seems to give the smoothest response and have the least compromises, although the ported design will go slightly lower and have a bass lift before rolloff. Is that accurate? I would assume the bass in the ported design could be tamed with a high-pass filter?

I know that placement of the driver on the baffle, and baffle size make a difference, but I'm not sure how to model this. Does anyone have any recommendations on where to start with that?

I'm really new to this but I'm trying to research as best I can so please be gentle! Any recommended reading would also be appreciated! I know that's a lot of questions, but I'm not quite sure how to get answers to them all.

Building an ultimate low power class A amplifier – my way

After realizing that loud listening with my equipment and listening conditions, requires 1 W average at most, I started contemplating my own design of a suitable low power amplifier that could be considered as close to perfect as it gets.

This is short list of requirements taken in the account during design:

Objective

• Extremely low distortion (single digit ppm) up to full power of 10W/8Ω or 10W/4Ω
• Monotonic harmonic profile with high order harmonics at very low levels
• High slew rate
• Soft clipping
• Thermal stability
• Stable operation with any capacitive load
• High damping factor
• Negligible DC offset
• Very high EMI immunity by use of Zero Signal Planes
• Low output noise

Subjective

• Clean and very detailed sound with no specific coloration
• Wide and deep soundstage absolutely detached from the loudspeakers (they simply must ‘not exist’)
• Very enjoyable sound reproduction, with no harshness but sound must be very transient with no ‘dullness’
• Whole day listening must not produce any listening fatigue, rather you ask for more

Audiophoolery or not really essential

• No capacitors in the direct signal path
• Dual mono power supplies

Why not as we can

• Very wide power bandwidth
• Regulated power supplies with excellent PSRR, transient response and noise

Execution
Last summer I started with OS evaluation and settled on the diamond buffer with BJT CFP output. Circuit variations were assembled on the breadboards and careful listening and measurements were performed. It was very good but not good enough. Switch to lateral MOSFETs was done, as they provide low distortion, thermal stability and monotonic steeply falling distortion harmonic profile. After satisfactory results, my preferred operational amplifier was added as a VAS stage to make amplifier circuit complete. After much more listening and measurements, final evaluation build was assembled on the PCB and listened to and measured again. All good, followed with required parts order and a lot of assembly work. Final measured results are here:

Frequency response DC to 1.3 MHz
Max. power 10W/8Ω, 20W/4Ω

Distortion:

• 1W/8Ω 0.00005% -126 dBc
• 8W/8Ω 0.00021 -113.5 dBc
• 10W/8Ω 0.00024% -112 dBc
• 1W/4Ω 0.000074 -122.6 dBc
• 10W/4Ω 0.00035 -109.2 dBc
• 16W/4Ω 0.0011% -99.5 dBc
• 20W/4Ω 0.0016% -96 dBc

Output noise 20 Hz - 20 kHz unweighted – 4.9 uV
Damping factor 945/8Ω, flat line from 20 Hz to 20 kHz
Slew rate 86 V/us for a +- 12.5V swing (290 ns rise time)
DC offset less than 400 uV

Sound
Everything I declared as a goal and much more. Yes, there are reproduction details never heard before and soundstage was never that wide, deep and detailed.

EDIT:
PCB fabrication gerber files added.
10/10/23 Mouser BOM added
17/10/23 correct DC offset value. Previous measurement had preamplifier DC offset included.
Added result of 32 tone test at post #54

I have a Fishman Loudbox Artist wired for 240 V and I am trying to rewire the transformer to achieve 110 V so I can use it here in America.

I am starting a journey in audio electronics and will be a newbie who is probably older than many (most!?) who visit this site. I spent most of my career as a systems/software engineer, but now I have caught the DIY audio bug after spending a couple years studying electronics and fixing vintage audio receivers, turntables, speakers, etc. I also am a musician and vinyl collector (over 4k albums in collection). I look forward to new relationships and will do my best to avoid trying the patience of those who instruct me.

Best!

Years ago, in the 1990s, my then brother-in-law and I did a lot of DIY audio work. We made OK omnis with 4" full range for my shop (4 of those really lit up the showroom), a variety of highly tweaked enclosures, a few being rather good, and some riveting open baffles from junk 4 x 8 sheets of plywood. Absolutely no acceptance factor anywhere outside of a garage or basement workshop, but really surprised us. I built a pair of transmission lines with full range drivers at the time. None of this stuff exists any more.

After many dislocations and downsizing like mad I ran across some Polk RT55 loudspeakers with a decent self-powered subwoofer, picked up a nice used hybrid amp, and find that I still enjoy crisp reproduction of technically excellent music. Of course, my tendency to be engaged with design and construction has emerged (I make things. Boats. Violins.), and run into model capability for modeling and a slew of incredible concepts and ideas.

I'm OK with the Polk speakers for TV with my partner, but for home alone listening time I'm looking to get / make some mobile speakers I can pull out and enjoy. These have to be small footprint and easy to move, but can be very tall. I'm looking for clarity, image, wide soundstage. Preferably with no or simple electronics, and will be run with my subwoofer which has high-level input with crossover, crossover frequency selection, and phase adjustment, as well as volume.

I could really use omnidirectional speakers that would fill my woodshop nicely. I had cross sectionally tapered tubes with upward firing full range before, too short for 1/4 wave, but stuffed to the gills, and they were OK. Received numerous complements, but I could hear the issues if I listened at all carefully.

I'm also annoyed with the computer speaker status. I put together some pipe TL using 3" and 2" PVC driven by HiVi B3N. These are surprising me, but are far from perfect. I'm trying the B3N in a 2 L sealed system next, but have a lot to think about. Makes sense to me for vertical narrow enclosure that washes sound across the screen, drivers at about ear level. My thoughts are uncertain and muddy on so many aspects there.

Hope to learn a good deal here, and perhaps contribute from my long experience with musical instruments and bizarre thought experiments.

Hello All, I Martin from Slovakia.

Hi all,
I'm new at this forum, but I'm not newbie in electronics. I hope to make some interesting posts about designing audio amplifiers, and also learn something new from you.

Hi all!
It seems I registered 15 years ago for something I can't remember and never used the forum afterwards.

Anyway, it's never too late, I'm battling a bluetooth module and it took me back 🙂

Hi All,

Somehow managed to get myself into this rabbit hole of thinking I can build myself some Studio Monitors, so looking for some help to navigate these infested waters...

Be gentle

Hey everyone,
New to this forum but I like what I have seen so far. Working on a pair of Mellow Monsters from 1970.

Hi all,

This has been a great resource to browse information on audio circuit design, and I'm looking forward to being a part of this community.

-Justin

I was looking into buying a couple of transformers and went to their site and it was gone. Are they out of business?

Hello. I spend too much time modeling and not enough time building. I'm currently working on a few projects. Some are taking advantage of some drivers I've collected, and others are more pragmatic as I'd like to add sub-bass to my current bookshelf speakers. I'm playing with satellite subwoofers vs building two more robust transmission line subwoofers (subscribing to Martin King's math and theory).

Thanks for having me!

e

I'm am looking at building a omnidirectional loudspeaker with a Ripole subwoofer section.

The lows/mids is handled by a 15" pro driver in a "Hartley boffle" Expected DSP crossover for the Ripole sub is 24db slope @60 or 70Hz.

I am looking at two Kané brand 18" pro woofers locally available. One is largely based on a RCF woofer and the other one on a B&C.

Kane 18tbw100 (B&C) / Kane 18X451(RCF)
Fs 37hz / 36hz
Vas 227lt / 198lt
Sensitivity 98dB/ 97dB
QMS 12.7 / 3.16
Qes 0.6 / 0.35
Qts 0.56 / 0.31
BL 19 / 26
MMS 166g / 197g
Xmax 14mm / 14.3mm
Efficiency 1.8% / 2.7%

So both drivers have almost the same fs, vas and xmax but very different QMS, qts, bl and MMS.

Which one is the best choice for a Ripole? Does QMS have any influence on sound quality? Is the higher QTS better or doesn't it matter when using DSP?

They are priced similarly.

Hi everyone, my name is Joe and I'm currently an aspiring mixing engineer in University in the UK. Looking forward to reading peoples threads and asking my own questions about gear and equipment!

I have a couple early behringer MDX2100s i happen to be quite fond of and plan on getting a couple MDX1000s, as these are pretty accurate clones of desireable units that also mod pretty well for an unbeatable price. To the question, a common mod for these seems to be filling the unpopulated output transformer slot intended for a model OT-1 transformer, similar to later DBX 160X/XT units with Jensen 123 transformers (i think). Now, the only way to get these transformers nowadays appears to be shucking them out of DI100 and DI4000 active DIs, which are sporadically available for very cheap, so i wonder if a suitable replacement can't be found that is available off the shelf. Does anyone have one of these transformers on hand that would be willing to measure at least DCR and check the pin configuration? I'm inclined to suspect that these are identical to the dbx ones (JT-123-DBX), the pin spacing and connections to the board appear to check out at least, the jensens might be a touch on the pricy side for what they're going into however. Another possibility is the Vigortronix VTX-101-00x line, these are mechanically identical to the jensens and are also used in the Klark Teknik DI boxes, while not the finest iron on the market they at least ought to be as good if not better than the OT-1s. Finally, for the OT-1s 9th pin, i suspect this pin is n/c and is only there for alignment, could someone confirm that please? Thank you!

I am starting a ribbon mic project build. Since it's my first build, I don't want to invest much money into it. I'm having a hard time finding a low-cost transformer? The cheapest, after shipping, seems to be in the $40-$50 USD range, but I'd like to get cheaper, even at the cost of quality. I figure I can always upgrade.
Can anyone recommend a good source for something around a 1:37 ratio?
Thanks

Hello everyone I would like to build an OTHORN subwoofer and I saw that the Beyma 18SW1600ND was one of the compatible drivers. Well those drivers are no longer in production, But Beyma tells me they have a substitute that should work, the 18LEX1600ND.
Now my question is how could I tell if this drive is really compatible with the OTHORN sub design? Any help or suggestion will be greatly appreciated.

Hello there,

I've been having problems with an NAD C541i CD player, which has developed an intermittent crackling noise from its audio out, which comes on for a second or so intermittently (every now and then... perhaps 10 minutes between occurrences, but less/more frequently at times). I bought a cheap DAC and it doesn't occur on the coaxial digital out (I'm sure about this, as I recorded the latter while listening to the former, and no sign of it on the recording at the points where I heard it happening).

Any thoughts on what this sounds like (snippet below)?

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I'm wondering if it's dry/cracked solder joints, so it would be good to confirm/disconfirm that's a good guess before trying. I've tried cleaning the sockets, changing leads etc. If you think I should try even harder cleaning the RCA sockets then a few tips on how to do it best would be welcome!

All the best,

Sam

New member, first post (not counting intro) so please be gentle. I have acquired two Hashimoto transformers, HW-25-8 (25W, 8k, PP) and PT180 (multiple 6.3V, 280,250,0,250,280V) and I am looking for advice or suggestion what to build. Medium size room, 15x20, speakers will be around 90-93db efficient. I have EE degree but experience from industrial electronics, nothing audio related and zero knowledge of tubes. Have necessary test equipment and can do pcb or ptp, Hopefully, with your knowledge and experience I will succeed at producing (famous or not) tube sound.

Hi everyone,
I am very new to the technical side of audio and therefore will probably ask some things within this question which are not particularly well-thought through haha.

I've recently acquired myself a Studiomaster Series III 24 channel mixing desk to learn how to fix up my audio equipment when things go wrong and, hopefully, end up using it as my summing mixer. It was only £25 and therefore I'm expecting a lot of issues, the first one being the lack of a power supply unit.

I am wondering if anyone has any ideas other than buying one from a site like Ebay or Reverb (etc) as they are few and far between and often fairly expensive once shipping is lumped on - or, if not, what PSU a series III took as I can't seem to find any schematics or much info in general on the desk (also could do with schematics and owners manual if anyone has them lying around). From having a look at Reverb it seems like both the Studiomaster EP2 PSU and the EP5 PSU have the right connection (6 pin) however I'm wondering if anyone knows what it would have originally come with when newly bought and/or if either of the aforementioned PSU's will be compatible and also if it would be possible to just rewire the power cable so that it is compatible with a more common PSU? Thanks for your help,

Joe

NEW L12/2 version 5. I have just received a pair of these amplifiers. I stopped testing because the boards are unstable.
Full details of my tests can be found here. Has anyone else tested these yet?
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Hey folks.

I'm repairing a Fisher 400. Customer wanted new 7868 bases - done. I've replaced the filter caps with the Hayseed Hamfest excellent replacement set - fine and dandy so far. Voltages all fine.

However, I'm getting an oscillation when the PI and power valves are inserted (can even by one PI valve and one 7868):



Here is the relevant section of the schematic, have attached the whole thing hopefully:



Oscillation goes is the PI valves removed or the power valves are. It builds up as the valves come into emission. Theres a 1200 ohm 10W resistor which drops the HT down to the screen node which then goes off the other rest of the HT, the voltage drop without the oscillation is about 25Vdc, when both the PI adn power valves inserted that voltage drop goes to >100Vdc. I thought a short but cannot find one, even isolating other parts of the circuit.

I've rebuilt one side with new components - no help

There was a thread:


Which mentioned droping the grid leak resistors from 330k to 220k and increase coupling cap value from 0.47 to 0.1-0.2uF to account for newer valves

Feel like I'm missing something obvious but going slowly mad at same time. Anyone think those mods will help? Also wondered about adding in dedicated screen resistors for each output valve?

thanks for any help

Brand new NOS/NIB Sylvania 6L6GAY beam tetrode tubes/valves/Röhren. As all good stuff comes in uneven numbers it is a lot of 5. All new, never have been powered up except when they were produced. The boxes are worn because of me wanting to look at beauty the past 3 decades. There, I admitted it.

Good stuff apparently made by an early LHBTQI+ community in 1951 in a factory where devices were produced that brought peace and democracy.

If you want these then make me an offer I can not refuse by PM. No tube tester here but it is very likely that JAN stuff was made according specifications and also to last. No guarantees but I do guarantee they will be packed very well and definitely shockproof. These just wait to be used in a nice design. 73 Years old but new/unused tubes and no Chinese knockoffs with fantasy names made of recycled refrigerators, these are truly the real deal made of pure materials. By virgin angels in moonlight. You will have a veil unlifted and blacker than black background 😀

EU ONLY!

As tube technology gets old I thought it might be a idea to produce a Hi-Fi tube amplifier using components and technologies that were available 100 years ago.

Maybe a competition, the prize, the glory of doing it.
The rules, let us all make them up.

My ideas:

Capacitors, resistors, transformers were all about 100 years ago so they may be used.

The UX250 audio power triode was introduced in 1928 so it may be used in a build for 2028.

The UX245 was available in 1929 so any type 45 even a modern production could be used in a 2029 build.

The UX201 was introduced in 1925 so any 01A type could be used in a 2025 build.

The 6L6 was introduced in 1936 so it could be used in a 2036 build.

The speakers are not part of the amplifier.

The power supply is not part of the amplifier as batteries were about.

Spice sims allowed in the simulation class.

I personally have some 45's and 01A's so the best I could do is a 92 year old build, maybe I could scrape a year or two off it.

Spice sims allowed in the simulation class.

Ken Kranz
Australia

I want to build mtm loudspeakers with Dayton Audio DA215-8 speakers. The division is probably a little below 2 KHz (probably better lower - maybe 1.6 KHz). the waveguide will be milled to converge the acoustic centers.

P.S.
The choice fell on Wavecor TW030WA11 tweeters

I have here for sale severall capacitors from Elna new and used.
1-Raw
Used Elna Silmic 12000uF 63V 20€/unit or all 4 for 60€
Used Elna for Áudio 10000uF 63V 12€/unit
Used Elna for Audio 10000uF 63V 12€/unit
2-Raw
Used Elna Silmic 5600uF 63V 10€/unit
Used Elna for Áudio 10000uF 56V 10€/unit
New Elna for áudio 10000uF 25V 5€/unit or all 6 for 24€-sold
3-Raw
Used Elna for áudio 3900uF 63V 5€/unit
Used Elna for áudio 3300uF 35V 2,5€/unit
New Elna for áudio 10000uF 25V 5€/unit or all 6 for 24€-sold

New Elna RSE 2.2uF 50V 20units per lot at 10€,10 lots available(200 units)
I can sell the whole lot together for 200€ "230 capacitors"
All used capacitors here for sale have been measured and are within 10% of its rated capacitance
Regards

Hello,
I'm planning to build my first pair of DIY speakers as an complement to my current Klein+Hummel O300D + 2x Adam Sub10 Mk2 setup. I mainly use them for mixing and post-production, but I'd like to do more mastering in the future and therefore I want a second (hopefully "better") set of speakers.

Since most mastering speakers are way out of my price range, I thought I try to build a good set of speakers myself. The last few months I gathered information about speakerbuilding and found many helpful posts on this forum, so I'd like to share my plans with you.
I'd be grateful if someone could point out some mistakes in my design or things that could be improved!

My design is mainly inspired by speakers like Egglestonworks - "Viginty" and "Kiva", Amphion - "Krypton³" and Lipinski "L-707".

I want to imply following features:
a) MTM/D'Appolito Satellite (maybe with a passive cardioid like the Krypton)
b) TL or vented Sub, high enough that I can put the satellit on it and have the
tweeter at about 115-122cm (my earlevel), but in a separate box to have
the freedom of experimenting with different room locations if the bass
response is not smooth enough at the triangle.
c) Drivers:
Mids: 6" Morel TSCM-634
Tweeter: Morel TSCT-1044 with Waveguide (Visaton WG148 or Monacor
WG-300, I'll have to test which fits better)
Bass: 10" Scan-Speak 26W/4867T00
d) Active analog 3-way Crossover: I have the Rane AC23S, which has fourth
order Linkwitz-Riley filters and a delay up to 2ms for the low and mid
channels.
e) Separate amp channels for woofer/mid/tweeters. At the moment I have 2
PAS 2002 PCA Stereo amplifiers. But I need at least 1 more (if not different, more powerful
amplifiers). This is one of the points where I am not sure about.

Around 4-5 months ago I got the PH-16 kit from Tubes4HiFi – and started putting things together. Attached are the results.

It was a challenge, especially getting parts to the bottom of the planet (Auckland - New Zealand), but I got there in the end. The amp sounds amazing – wide soundstage, open separation, punch at the bottom end and clarity at the top end. I’m running it from my Rega Planar with Ortofon cartridge into a Cayin A88T power amp - heavily modified with Mundorf caps, and Gold Lion KT-88’s among other things. As an aside, I’ve found the Cayin amp to be awesome. Extremely high build quality, much better than some amps I’ve seen at 3 times the price and the circuit design is simple and robust.

The PH-16 is a great design, and I added Mundorf caps and Gold Lion tubes. There is very little hum as I placed the transformer above the aluminium mounting plate well away from the signal board. One of the challenges I had was to fit the volume control at the output of the circuit. I managed this with a Ladder Stepping Attenuator (Dale resistors) and this seems to work OK, although I haven’t quite got the linearity required, but I’ll experiment.

My family will now be subject to large amounts on Pink Floyd, Mozart, and the occasional Iron Maiden experience.

Has any one had any experience with the Dynavox LY 401F driver?

In 1977 I built a pair of transmission line loudspeakers, similar to the famous Webb design, but somewhat larger. When I went to graduate school in 1980, they were too bulky to bring along, so I sold them. Now, both myself and a friend from those days want to build a couple of pairs. So I'd like to locate a copy of the plans.

With that as an intro, does anyone here have a catalog or plans from the company that produced the kit? It was called Accurate Sound, and was at 1213 M Street, Lincoln NE 68508. Below, I've reproduced a copy of an advertisement of theirs, from the January 1977 issue of Audio Amateur, page 49.




Does anyone here recognize this, or have an old catalog or plans?

Cheers,
Bruce

I wanted to see if someone had real world experience and can rank the top ten amps they have actually tried. For example Brax, Sinfoni, Celestra, Steg, Audison, Arc Audio, Mac, Linear Power, Genesis and TRU Technology...the real high end.

It does not make sense these days to waste your time putting an average system in a car, do it once and do it right.

Also do you prefer regulated vs. non regulated

Hello I am Ruiqi Jiang. My interest is full range driver and vintage amplifier. My current set up is lowther premium pm7a with 1970s solid state amplifier.

Has anyone bought any of these?

I have been trying to get some measured data on these Falcon drivers for many weeks now, without success. Multiple emails requesting information have been met with vague, terse and evasive responses from the owner Jerry Bloomfield. His replies have lead me to believe that these drivers have never actually been measured under any kind of realistic conditions (eg. IEC baffle), not even in prototype form.

Having used the KEF originals many years (decades) ago, I am genuinely interested in how the new versions perform, but the lack of cooperation from Falcon has been extraordinary.

For all the Greedy Boyz,

The M2 officially discontinued, here is the official schematic, assuming that
it has not otherwise been posted.

In particular note the interesting bias circuit that you can use elsewhere.

😎

I have 6 total 8fe300. I used them for 3 months.
Looking to get $30 each
Buyer pays shipping

Just a "heads up" that Bob Cordell wrote what I think is a pretty good article on transistors in audio. You can find it on the HomeTheaterHiFi site here.
Especially good for some of the newer folks that are coming in.

Thanks Bob - good job!

P.S. Moderators: I wasn't sure of the best place to mention this info. Please relocate if appropriate!

Hi folks,

I recently moved to France, and I am looking to reconfigure my amps for 230V/50Hz. Most of the amps I have are restrappable (dual primaries), but the PS Audio 200c does not appear to be. This amp is very powerful - it's nominally 200WPC into 8 Ohms, but keeps doubling, up to 800WPC into 2 Ohms, and 1000WPC into 1.5 Ohms. But it does not seem to have a line fuse or a VA rating on the chassis. It's not UL rated either. They do have a bit of a reputation for pyrotechnics...

Anyway, it looks like dual 104VCT secondaries, with no other voltages. But I've no idea what this original transformer is rated for current. It was made by Paraline, who was very helpful 15 years ago, when I got the amp - they revarnished it to see if they could make it hum a bit less, which I think it did - but they seem to be out of business now.

Any information, or educated guesses?

Thanks,
Paul

I have a pair of these. Cause I like lost causes I would like to refurb to a reasonable extent. To my ears classical music is nice and open and the stereo imaging is pretty decent.
If I was to do some checking, reasonable maintenance to keep any costs within the worry of these speakers what would you do?
The drivers are all pretty decent and everything on a visual check is as it should be......I think. 😜

In addition to earlier posting I have these high speced resistors. Non-magnetic.

€3/pcs, min 10 pcs.

Ships from Sweden.

R

I have been a long time view of diyAudio.

Hi everyone,

I’m working on a Amplifier 100W and looking to implement a system where I can inject a negative noise signal directly into the signal path after the output buffer, specifically between the output buffer and the speaker output terminal. The goal is to cancel out unwanted noise via destructive interference, without affecting the main audio signal's quality.

Here’s what I’d like to understand:

1. Can I use capacitive coupling to inject this inverted noise signal into the high-power signal path?
   
   • If yes, what would be the appropriate capacitor value and voltage rating for this setup?
2. Are there other methods (e.g., inductive coupling or resistive networks) that could work better for this purpose?
3. What precautions should I take to ensure that this injection method doesn’t degrade the audio quality or interfere with the main signal's integrity?

Key considerations:

• The amplifier runs at (100 W into 8Ω), so the components need to handle significant currents and voltages.
• I’m trying to avoid transformers, op-amps, or any components that could introduce distortion or phase shifts or are not suited in terms of Voltage rating.

Looking forward to your insights and recommendations! If someone has experience with noise cancellation systems in high-power audio applications, your advice would be invaluable.

Thanks in advance for your help!

My dreams are always about solving some problem. Never "drifting, falling, floating weightless, coming home" or "Let's break out the booze and have a ball". Always some problem to solve. This morning was a big wind is coming, most danger from flying debris. Get underneat the house? Inside cars in the garage (what if the door tears off?) Inside the small truck downstairs in the RV garage? Better act quick, outside exposure is dangerous! No matter how arbitrary, abstract, disconnected from current reality, the problem solving aspect is always at the core. Anyone else?

For an analog active crossover, I was thinking of using this ground layout.
I would ask if it makes sense to isolate the signal ground from the power ground, or being a circuit with low currents, is a single ground plane sufficient without isolating the signal ground?
Thanks for any support.

.

Hello folks,

Due to current events, I would like to hear about your experiences with selling DIY speakers.

My initial research (here and in the neighboring forum) shows that the market for DIY speakers looks even worse (from a seller's perspective) than it did 5 or 10 years ago. Lots of high-quality chassis and speakers are practically thrown at you

While others are no longer available, like the Monacor WG300 and DT300.

What are your experiences?

Hello All,

Just to briefly introduce myself, I’m currently living in the UK, but have also lived in Europe. I’m a screenwriter and film-maker by profession and have been passionate about audio since my early teens.

After moving on from my Dad’s simple all-in-one record player and speakers in the 70’s, by the early 80s I had my first hi-fi, which was a Dual CS505mkii turntable, Denon PMA-250 amp and Monitor Audio RS252 speakers. I thought it sounding fantastic and I’ve never looked back!

I’ve since run everything from full analogue to high end digital, including DSP speakers, full surround systems and purist 2-channel setups. I’ve spent thousands on cables (and would not do so again!) and learned more than I need to know about room modes!

My first “DIY” projects were building a solid state amp from a kit, and removing balance pots (replaced with suitable resistors) from a Naim preamp.

I’m now interested in taking matters into my own hands by building some valve amp (and preamp) kits and making my own speakers. For the learning and fun, and to try and get a sound I love even more.

All the best.

Gona be bringing this gal back to life, it's been a wile, gotta open her up and look her over.
Any suggestions?

Hi Everyone, To make a very long story as short as possible, I bought a Soekris DAM1021 v1.1 on February 1, 2015. Due to many moves, and very little free time, the project was "lost" in one of our hundreds of boxes for almost 10 years, until the other day when it was "found"!

I have the main Soekris Board, as well as a Normundss Input Board, Front Panel Board, an STM32 Board, a USB Board, and some hardware.

Can anyone direct me to a complete build thread, or at least a parts needed list, in addition to an appropriate enclosure that can be used?
Your help in completing this long overdue project is greatly appreciated!

Roger

I found this commentary on the Reddit platform striking. Parallels here, in the context of Audio and DIY?

[–]PackOfWildCorndogs 4 points an hour ago

I feel the same, I love being forced to reconsider my opinion or perspective, and that’s something I am regularly pushed to do on here. Spending time on Reddit over the years has increased my empathy for, and understanding of, the experiences of people with different worldviews than me. Less quick to judge, more tolerant in general. Plenty of complaints and fully aware that you can forget it’s an echo chamber itself sometimes, but I think my time is much better spent here engaging in, and reading, (mostly) civil debate with people who think differently than me, and have had vastly different experiences than me.

I lurk in a lot of subs that I don’t engage with, because they neither need nor want my thoughts, but reading their thoughts and debates helps me be a more informed fellow human with a more tolerant worldview. I wouldn’t otherwise be exposed to these groups organically in my day to day life. It’s also helped me to become a more discerning and skeptical news consumer — reading some of these conversations helps give some nuance to headlines and the claims they contain. I can go to some of th subreddits where I know the group or event referenced in the headline likes to congregate, and almost immediately I can see where the headline is sensationalized, or the motivation behind it (positive or negative), by reading the conversations of the people involved or affected by the event. Again, not perfect, but it’s a really effective way to add some depth and texture to the topic, beyond just the news as it is being reported.

Aside from being an endless source of satisfaction for intellectual curiosity, some redditors are funny as ****. Little unexpected bursts of dopamine/laughter in the comment sections isn’t something I can regularly expect in comment sections on Instagram, which usually only leave me feeling a tinge of deflation seeing the lack of critical thought and hardcore tribalism, with zero nuance or effort at coherence. Reddit upvote system isn’t perfect and it’s easily manipulated by users and mods, but the highest effort, most thoughtful, valuable comments are often the most visible, so I feel like even my time spent is more efficient on here than in the comments of platforms like TT & IG, where there is no rhyme or reason to the most visible comments, and more concerningly, where the comments that are most visible to you are dictated by the algorithm.

For example: My mom (right leaning views) and I (left leaning views) looked at the same Instagram post with thousands of comments, at the same time, side by side, from our own phones/IG accounts, and the comments that were visible to her were entirely different than the comments I was being shown. The algo exists to reinforce your echo chamber over and over again, by serving you the content and comments that the algo has determined you’re most likely to engage with. Two people looking at the same post, at the same time, in the same physical location, are having two entirely different (and oppositional) user experiences. It’s a bit disturbing, even when you know why it’s happening. And yes I’m aware Reddit algo does similar, and has of issues with brigading and bot manipulation, but at least I can see all of the comments if I really want to. On other platforms, it’s not as easy to see the full spectrum of comments when you want to.

Hi all, got myself a MF A5 intergrated amplifier thats using the sap15 transistors.
These transisitors have the emitter resistor built in and are prone to failing. Ive read that you can lift a leg on these transistors and put your own cement 0.22ohm resistor in its place.
Question is can anyone advice what leg to lift and where to solder new resistor please, or any pictures of this done or drawings would be fantastic!

Thanks inadvance
Richard

Hi guys,

I have a weird issue with an Audio System X-ION 280.2. It similar to audio_system_f2-190 in the attached pdf, but not exact. I've used those schematics as a referance.
There is crossover distortion once You apply any load to it. Goes for both channels. If there is no load applied the sinewave behaves differently. There is distortion on the bottom half and the top half is being chopped off.

Rails are exactly the same and correct +-50v, +/- 15 are present, There seems to be some issue with the bias, at least to my understanding, but using the bias knob make little to no difference, there is almost no increase in current draw between min and max position. And i've repaired amp like this before, this is not correct behaviour.

I've changed already the LL4148B diodes and the Zeners but with no avail.

Any idea what can cause this issue for both channels at the same time ?

In 2020 it was no problem to buy these TPA3118 boards for like $4 each. They sounded decent and put out about 50w mono at 24VDC / 3A supply.

Now, every one I order has 28 pins instead of 32 and is a fake. The power is less, and half the time the fake (faulty) board will put out DC on the speaker output (fried one 6x9 in this way).

Before these counterfeits hit the market, this was a nice little amp board for almost no money. Are they still available anywhere or are those days gone?

Is there a better option at 12 or 24 volts supply?

Hi,

please critique my first attempt at a crossover for a Living Voice Auditorium clone I'm working on.

The speaker is a 2-way MTM with 2 x Vifa C17 6.5" midwoofers and initially a Scanspeak D2608/93000 tweeter. I got better measured response with Morel CAT 378 tweeters, so I used those in this simulation. I measured all drivers according to the Vituixcad procedure, however I only have on-axis response for the Morel since I just got it. So I have to leave out power response and directivity for now. The last image shows the response of the drivers without filter, for reference.

I'm a little wooried about the broad overlap area between 2khz-5khz, is this any reason for concern? I think the phase tracking in this area looks pretty good though.
Also would the large impedance hump centered around 3khz cause any issues?

Hi I am a new member from so california.

I bought a BEOCENTER 2000 stereo system (Made in Japan) with the intention of further developing my idea of replacing the B&O cartridge(s) with an Ortofon OM series cartridge. Compared to the MMC20, the OM series specifications (stylus pressure, compliance, etc.) and generator size are somewhat similar, so a replacement might be possible. And the generator can be removed from the plastic part of the OM cartridge by simply pressing.

I made a quick 3D model of the new cartridge holder (it does not have the exact offsets, angles etc):




This actually turned out to be looking quite ok.

BUT: this modification would be irreversible, so you would have to break or replace the whole original tonearm tube. And I had the (positive) problem that the cartridge and stylus that came with the system I bought turned out to be still in good condition, so I didn't feel like continuing with the cartridge replacement.

So this is more of an idea that someone else could continue with...

These kind of potentiometer are use in a lot of mixer console.... but these pot are good for HI-FI audio ???

Somebody tried it ?

Saligny Power 1 piece

I built myself a BB3 phonostage, initially in a relatively small box, but suffered a bit of hum from time to time.
Recently, I decided to rehouse it into a bigger case, which is pretty much finished now - see below.

I am wondering if there would be any benefit from fitting a 5mm thick aluminium “shield” Between the BB3 PCB and the mains related side of the case. It will not be expensive to do, or take long, but will there be any benefit?

It was suggested to me to start a thread regarding the actual practical builds of horns and waveguides, mainly designed with the Ath. So here it is, for everyone to share their own way of converting their design into something real and listenable. Show off! 🙂

So far the tool can generate:
- STL file,
- coordinates files to be imported into Autodesk Fusion 360 as splines and/or smooth surfaces.

There may be other useful features implemented in to tool to enhance the practical possibilities - just let me know.

this is the anniversary of almost succumbing to hypothermia on the the side of HWY 11 in northern Ontario while on tour...

I have a Rockford Fosgate Prime R750-1D good blue led, no sound.
The only thing getting hot/warm is the Led, 494 and the 1GM transistor beside it. (picture)
None are over heating just around 96-98. Any help wound be appreciated.

Thanks

Hello everyone,

I am looking for a copy of the schematic of the Sugden A48B , early to mid 90's version with horizontal fins heatsink on each side.

Mine has just developped a heavy waterfall noise. I am alrready suspecting a PS problem but would like to refer to proper data before diving deeper.

Thanks to anyone able to help .

I bought an AD5933 eval board some time back to facilitate measuring capacitors and inductors. I just got around to actually fooling around with it (using an Arduino Uno) and initially had some problems. While the calibration procedure seemed to work OK (I used a 100K resistor for that), results for different-value resistors and capacitors were WAY off. I thought there was a problem with the driver code, which I downloaded from github. I thought perhaps there was a problem with the board, like a cold solder joint.

But it turns out that the code and board are OK. The main problem was that I was using the maximum-gain setting for the input amplifier so the AD5933's ADC was overloaded.

Once I figured that out I was able to get much-more believable resistor and capacitor measurements. In turn, I measured the capacitance of my headphone cable, to build a load tester for DIY headphone amplifiers. 200pF will do it!

I just recently checked ebay to see what the current prices are for an AD5933 eval board. I found some in the $30-$40 range. However, for about the same price you now can buy a "component tester" that can test R's, L's and C's, but you also get the ability to test some active devices, too. So while the AD5933 eval board is a nice thing to have, i probably would have bought a component tester had that class of tool been available at the time.

I have 3 Uni-q drivers for sale.
They are all working.
I used them in custom surrounds.
Looking to get 300
Buyer pays shipping and paypal fees

Hello,
I recently purchased this small NVArcher BP1048 DSP Board.
It worked fine for the first two days, but when I came back the next day and turned it on, the output was extremely quiet. So quiet that it took me a while to realize it was even running. I did not make any changes in the software.

After opening the ACP Workbench software to see if any volume sliders where turned down, everything seemed to be fine. All the volume slider where roughly at +-0dB. I had to increase one of the volume sliders (PGA0 - Line_in_4_5) to +40dB (!) to get any proper output volume, but obviously this distorts the sound like crazy and still was not very loud.

I turned all of the "Audio Effects" off, to make sure I did not mess anything up there.
The board itself is running and the problem is the same in both AUX and USB Input mode. Also the same on both outputs DAC0 and DAC1. I tried using different input devices, different cables and different amplifiers, but the problem is always the same. As soon as I plug the DSP inbetween, it is extremely quiet.
I played around with selecting and unselecting a few things and experimented with some sliders, but without success. I tried to reset it to factory settings, but I feel like this did not reset anything. Visually I can not see any damages on the PCB itself.

Am I missing something? It seems weird to me, that it worked fine at first and instead of completely dying, it still runs, just extremely quiet.

I am regretfully selling an incomplete project of a Lii Song Leonidas build. This follows Leon Huijgen's plans from the Audio Dandy Website.
It includes Lii Song Crossovers, a pair of Silver 10 + a pair of W-15 drivers
Too heavy and awkward to post.
Pick up from Australia 3134.
$1400 or nearest offer.

I've been looking for a service manual for the Marantz SA14S1 so I can figure out the output impedance(I've got a picky tube pre-amp which doesn't like anything over 200ohms single ended).

The above website is the only one I've found which has it available but the site seems kind of shady and they want a lot of personal information before letting you download the .PDF.

I found a manual for the SA15S1 but I can't confirm if it's the same design or not. I'm not sure if I'm reading it correctly but it looks like the output impedance is going to be 100ohm for the single ended outputs?

Thanks for your time!

Olá a todos.

Eu tenho um Zapco Z100c2, acho que era das primeiras versões, faltavam esses capacitores de cerâmica no pré, alguém sabe o valor original deles?

C20,21
C27,28
C30,31
C32.33

PRICE REDUCTION


Literally downsizing.

These originally drove my Tuba HT subs.

Pair of used Lambda TD-15x drivers available in Massachusetts, USA.

Currently mounted in TOA EV monitors (free if wanted at asking price)

$600 includes domestic shipping to contiguous 48 States.

Will ship to any verified PayPal address for actual freight costs.