I have a Denon DN-X1500 mixer and the output was a little crackling, I have noticed that 4 out of about 50 capacitors are bulging on that one board so I was going to replace them.

Question: Do you think I should replace them all? Or replace all the caps in the area of the bulging ones? Or just replace the faulty ones?

Question: is it due to faulty caps or bad circuit design causing them to malfunction? How do I know this?

Oh and also the mixer does get quite warm in use BUT I don’t think it means it’s faulty as it’s a common thing with those models meaning it’s just what they do. (bad design maybe causing them to fail prematurely)
The faulty caps are SMG 35v 100uf which only 4 are bulging out of about 8 on that board but the rest could be in a different circuit.
I have attached a photo of the board, about 99% of the capacitors are the one brand SMG I hope this brand is a reliable component because the boards are riddled of them 😱


The capacitors with the red dots are the bulging ones and the ones I have circled are the same value as the bulging ones.

Any thoughts are greatly appreciated!! Thankyou 🙂

I'm very much a beginner to speakers and have a lot to learn, but here is the results of some testing I recently did to select speakers for my living room TV audio setup. Purely subjective, I just listened to them with my ears to decide which ones I liked the most. I got fairly cheap speakers.

I got 7 different in-wall speakers that I could try out to select the ones I liked the most. I built a simple connection box with banana plugs to use as a speakers selector. I connected the speakers to the center channel and played some of my favorite movies and listened to the actors' voices and other sounds in the movie like doors closing etc. I was listening for the speaker that made the scene in the movie sound the most like it happened right there in front of me. I repeated some moments and sounds many times over a couple days with sleep in between to "reset" my ears (very unscientific). The amplifier is a Pioneer VSX-D509S I got off craigslist and the input was Dolby 5.1 over optical S/PDIF from my TV.

First two enclosed in-wall speakers. These come in small plastic enclosures and I could listen to them without mounting them in anything. They sounded so bad compared to the other non-enclosed ones even played unenclosed in free air, so I returned them immediately. The main problem was the tweeters, they sounded to be severely lacking in the upper range. They're not even in the photo.

• Pyle PDIW57
• Pyle PDIW87

I built simple boxes out of particle board to mount the unenclosed in-wall speakers in. The boxes have a volume of about 110 litres, except the shorter one that's made of what was left of the three 4'x8' particle boards. I used double sided foam mounting tape around the edges to avoid having to engage the plastic drywall mounting hardware the speakers have (somewhat irreversible). I tested them with their grilles on but took them off for the photo. Forgot to take the grille of the Klipsch KSP-C6. The Klipsch KSP-C6 and the Dayton Audio B652-AIR are not in-wall speakers but I added them for comparison.

1. Monoprice Alpha In-Wall 6.5in
   This one and the other Monoprice one had distinguished treble, I suspect because of the 1" tweeter and the 3" tweeter? They sound to me to both reach the highest frequencies (subjective), but also the whole treble sound range sounds great. The Monoprice Alpha 6.5" surprisingly has deeper low end than the Monoprice Caliper 8". I don't know why but I compared these two a lot and the Alpha 6.5" has better low range. The Monoprice 6.5in is my choice any day over the Monoprice 8".
2. Polk RC65i
   Of every speaker I tested this shared 2nd place of overall best speaker with the Monoprice 6.5 (subjective). It had the most low end and mid range of all the speakers except for the Klipsch KSP-C6. It beat both the Monoprice 8" and Dayton 8" in low end. Maybe the Polk driver was just better at moving air than the other ones, even though it's a smaller diameter? This opened my eyes to that some drivers can really be a lot better than others. The only reason this speaker did not take a solo 2nd place was that the Monoprice 6.5 had better upper range treble, not by a lot but the Monoprice 6.5 was noticeably "brighter".
3. Dayton Audio ME825W
   Very disappointing. 2nd worst of all the speakers in the photo. Very lacking in midrange, very noticeable in voice reproduction. Voices did not sound natural. Treble was greatly beaten by the Monoprice speakers and the low end was only ok.
4. Monoprice Caliber In-Wall 8in
   Treble great but very disappointing in low end, and disappointing in mid range. I suspect that the 8" driver in this speaker is just not good?
5. Dayton Audio ME525MTM
   This was the worst of all the speakers in the photo. No low end, bad mid range, sup-par treble.
6. Klipsch KSP-C6
   I bought this older speaker off Craiglist. This speaker beat every other speaker in the photo. It did almost make the movie sound like it was happening right in front of me. I'm very impressed by this one. Voices sound the most real through this one and it also has the deepest low end of all the speakers I tested. Treble is great. Only the very highest frequencies are possibly reached by the Monoprice 6.5in which are not reached by the Klipsch KSP-C6 (not entirely sure, the Monoprice 6.5in just sounds like it reaches slighly higher). I'm not sure why this one reaches deeper than all the other ones with it's 6.5in drivers. Is it because of some resonance influenced by the enclosure volume or is it just a better driver?
7. Dayton B652-AIR
   Good treble but lacking in upper mid-range (subjective). Voices did not sound as natural as the Monoprice speakers.

My subjective ranking of how much the speakers made the movies sound like they were happening right in front of me:

1. Klipsch KSP-C6
2. Monoprice Alpha In-Wall 6.5in shared 2nd place with Polk RC65i (I have a hard time selecting between these. Polk is better in mid and low range but Monoprice 6.5in is fairly good in mid and low range but is brighter than the Polk)
3. Monoprice Caliber In-Wall 8in
4. Dayton B652-AIR
5. Dayton Audio ME825W
6. Dayton Audio ME525MTM

Conclusion
I learned that different drivers really can sound very different, and that a 6.5" diameter driver can have deeper low end than a 8" diameter driver (this one surprised me, please tell me if this can't be true, as I only listened using my ears and have no measured data to support that).

Since I love the Klipsch KSP-C6 so much I think I'm going to have to take the drivers out of the original enclosure and either create a new elongated equal volume enclosure that can fit in my wall, or try mounting them directly to the wall in a infinite baffle like setting (? please advise on this, I think I'll have to check out the suspension properties of the drivers).

During my journey into speakers so far I have learned that drivers are probably the most important part of a speaker. Please advise if otherwise. The enclosure is mostly there to baffle the canceling waves coming from the backside of the diaphragm. The enclosure only supports the driver up until the limits of the driver. Except for one resonant frequency perhaps where the enclosure will amplify that specific frequency. This is my understanding so far and I do want to learn more. I've only dealt with sealed boxes, no ported boxes.

Anyway, thanks for reading and hope this will be useful to someone looking at in-wall speakers.

Edit: After listening to these again a 3rd day I realize the Monoprice 6.5" does not go lower than the Monoprice 8", I think the 6.5 might be louder in some frequencies of a low pitch human voice but when you go lower the 8" does actually seem to play slightly louder in than the 6.5" in those frequencies. Only trust real measurements!

What will happen if I use one of these Seas woofers:

Seas H1471 (CA22RNY) 8" Paper Cone

SEAS Prestige CA26RFX (H1305) 10" Coated Paper Cone Woofer


with one of these Seas tweeters that would best match the sound characteristics and blend well with the woofer ( I don't know much about selecting tweeters. That is why there are so many here):

SEAS Excel T29CF-002 (E0040) Crescendo Fabric Dome Tweeter

Seas Excel T35C-002 35mm Mid-Tweeter

SEAS Prestige 27TFFC (H0881) Textile Dome Tweeter

https://www.madisoundspeakerstore.c...s-prestige-27tdfc-h1189-textile-dome-tweeter/

https://www.madisoundspeakerstore.c...stige-27tffnc/g-h1396-1-textile-dome-tweeter/

https://www.madisoundspeakerstore.c...s-prestige-25tffc-h0519-textile-dome-tweeter/

https://www.madisoundspeakerstore.c...ters/seas-prestige-29tff/w-h1318-fabric-dome/


in a vented Parts Express cabinet:

https://www.parts-express.com/Dayton-Audio-MTMC-1.0BK-1.0-ft-MTM-Curved-Cabinet-Gloss-Bla-302-751

with no crossover?

I am trying to use 2 drivers for near full-range sound but without crossover.

I have one of these.

H10RW Horn Waveguide 10" - Dayton, Speaker Drivers | Wagner Online Electronic Stores

How do I match it to a driver? or will any old 1-3/8in treaded driver be good? What do I look for?

Don't ever get old...lol My hands shake a little bit from exposure to Agent Orange, Some days not at all and others a little more.

I have been trying to come up with some mechanical device to assist in soldering small surface mount components.

I have both optical and digital microscopes.

Any ideas for an old guy like me.


Thanks,

Billy

Hi All,

I had read somewhere that there's a formula which relates pipe length to circumference and cross sectional area for determining the Q of a pipe. Can anyone provide the formula or point me to a link? I tried to Google this, but was unsuccessful.

I'm evaluating a design for a Hegeman style subwoofer, but need to adjust the pipe dimensions to better fit a larger driver. I'd like to find out if there are any constraints I'll need to contend with.

Hello Everyone!

Feels like it's been a while since I've posted anything here, Anyways I've been testing some 300B that I bought back in July of 2020 from Victor. I'm talking about the Nature Sound Linlaitube 300B Black Plate.. now rebranded as Cossar.

If your not in the mood for reading I'll say it here... The Cossar 300B Black Plate are by far the longest lasting mid range 300B I have ever tested!! Up until now tube longevity was mostly dominated by JJ and Psavne with around 2,500 hours roughly. The sound signature of the Cossar 300B Black Plate are somewhere between a JJ 300B and a Gold Lion 300B, it doesn't have the strong bass of the JJ or the high rich highs of the Gold Lion, it's just a well balanced tube.



Now for those of you who are up for some reading here are all the details!

Back in July of 2020 I had one of my Gold Lion 300B lost half of the heater. Thankfully it wasn't catastrophic this time. Victor had recently posted about some new tubes he was offering from a new company. I was very interested in trying these out especially from a new player in the tube market. I ended up going with the Cossar 300B Black plate.

I received tubes that were well above my expectations. Especially for its very modest pricing! It's the very small details that let you know if a product is made with care and it makes sense since Cossar was started by ex Psavne folks. Like Psavne they make sure each tube is alike.. meaning the labeling all face one direction, and even the internals all of the tubes are aligned the same, if you care about aesthetics then you will like these details. Also the construction quality of Cossar tubes feel nice and strong too! But these are just the things you notice from the outside.

Before slapping these tubes into my TU-8600 I needed to make sure that I had some way of testing these tubes before and after. Fortunately I was nearing completion of a major 2 month long restoration project I was working on over the summer of 2020. I fully restored a Hickok Cardmatic KS-15874-L2 tube tester.. every single capacitor and all resistors (except a few wire wound resistors) were replaced, it was a massive undertaking considering that it was 90% stock and someone had made questionable repairs around the 90's to get this tester limping along for a few more years. Functionality was was tested using some 90 plus program cards that tests every circuit and components of the Cardmatic, and it passed with flying colors!



Another thing I needed was a way to keep track of the hours on these tubes and I looked at logging hours manually or something like that and maybe even a meter on the wall or something... but then I realized I had a brand new TV that I had just bought before Christmas of 2019. Through the Samsung app on my phone I can see the service hours on the TV... and my TV is always on when the TU-8600 is on. even when listening to my vinyl, I always throw on a visualizor to go with the music.. one is not on without the other!

Originally I was going to test the tubes every few weeks or maybe even monthly but in the end I decided against that..I would just run the Cossar 300B until they died, I didn't want to mess with them too much.. I was expecting them to last about 2,500 hours maybe less... but here I am almost a year later and the Cossar 300B are still pumping out sound. They are slightly above the 5000 hour mark let's see how they are doing!

Here are the test conditions under which they are tested through the cardmatic, as you can see it tests for Plate current. I allowed each 300B to heat up for 30 minutes before running the test.



So back in late July my TV only had 2193 hours, this is our starting point.



I measured each tube fresh out of the box.

Cossar 300B #1 measured 66mA
Cossar 300B #2 measured 69mA

So not bad, very closely matched in plate current!

Now with 5,000 hours on the tubes



Cossar 300B #1 measures 61mA
Cossar 300B #2 measures 64mA

So output has obviously dropped but only my 5mA each. These tubes are still good!

For the price I don't think you could find a better tube. When you go with cheaper tube you have to make sacrifices in materials and construction quality. Cossar is making some top notch heater filament here while keeping quality high and what you get is a very well balanced tube!

Highly recommend!

My next test on these tubes will be at 8,000 hours!

What transformer brands are good, but not incredibly expensive? I want something better than Hammond, maybe double the price. I'm going to make a 300B SE amp and I'm having a surprisingly hard time finding something.

Also, is it worth paying for a more expensive power transformer? I understand how the output transformers will perform better or worse, but does power really make any audible difference between brands?

Pick up in Ventura CA. NOS USA military surplus. It's huge.😀 and potted

So I understand the star topology and why they would ground the op amp and first input drivers separately, but alas something is amiss!

In the schematic, both op amps are wired the same and tied to case ground (0v on the primary), while the rest of the driver is tied to 0v on the secondary. However in the diagram, L and R are wired differently. Am I going crazy or is there a reason they did this? I verified the traces on the board and they agree with the diagram rather than the schematic. Many thanks.

I have highlighted the grounds and the ground-ties. The red circles are 10ohm resisters between the two grounding arms.

First of all - a kind and big Hello! to everyone! 🙂
I hope I found myself in the right place to talk about such ideas and obviously to ask questions in the search of answers and solutions. I'm happy to have found this forum.

I'm in my 20's doing some electronics as a part of my lifetime hobby. Usually it's digital, less analog and hardly ever tubes, so I'm not that experienced with them and usually can't understand the bigger theory. I have made a few amps, but these were more of a "kit" than "design".

~~~

Recently I wanted to make myself a cheap guitar amplifier/combo of a kind for home practicing, so I found an old tube radio which isn't functional. This gives me most of the construction basis, together with a speaker, output stage, some preamplifier and a power supply, not mentioning the whole box. I have a bit of trouble understanding it though, so I'll attach the original schematic for it - see Sch_Original. I also added some markers which will come in handy next.

All the signal tubes (4 total) here have a rimlock base (B8A) (excluding the magic eye which is not relevant to my trouble) and I would really like to keep it that way. So, I found tube types that might be useful. I'll refer to each one later.

- EF40: a precedessor and equivalent of later EF86 - looking forward to an input stage with it;
ECC40 - instead of ECC83/12AX7 types and the one triode from EBC41;
EF42 - for reverb circuit instead of EF80, explained later;
EL41 - output stage of below 5W.


Regarding schematic, firstly I would like to try and leave the EM34 for later usage as a crude VU meter, maybe adjust its sensitivity. Then, my instinct says to cut the connections marked with orange X-s and connect input jack to one of the points indicated by the green or blue arrow. By doing this I would probably have a functioning amplifier with a drawback of its frequency response. This gives me the circuit on Sch_1.
A question arises: What is actually happening here with all the capacitors, filtering and feedbacks and is it worth keeping for a guitar usage? I simulated this circuit with the triode only and it seems to alter bass response on low volume (5dB increased gain up to 300Hz), in the middle the frequency response is quite flat, and then it increases 300Hz-4kHz by 2dB on max volume (all values approximate - I'll skip the graphs for now).

Then, the input stage, where I somehow look towards pentode input. I probably can substitute EF86 with EF40, which is said to be a precedessor and almost equivalent tube - not, that I am right, but looking at the datasheets we are really close. The schematic for this stage, probably found by me long time ago from some other guitar amplifier, is most probably to be the one shown on Sch_2. On this part of my idea I hardly have any doubt, and if any, it's the R9 resistor value and further integration with reverb stage.

The reverb stage - I found this nice idea: LINK . Also attaching the schematic as Sch_Revb.
The first concern here is swapping EF80 for the EF42. Why EF42? - I tried to compare the tubes' Typical Characteristics and EF42 seemed to be a close one. Using it would probably need some components adjusting around it; it seems to be a basic pentode gain stage which should be even possible to recalculate. Am I right to this point?
Another trouble is, how to integrate it with the input stage? Am I correct when I think, I can 'delete' the input triode and connect the "Dwell" potentiometer after input stage? But what about the "Mix" potentiometer? EF40 (input stage) is cathode biased, so copy-cat-ing after the input triode from this design is a no-go. I wouldn't want to exceed 4 tubes in total because of the current draw from power transformer and rectifier tube, AND heater supply. Also, based on previous simulation, the EL41 needs a fairly big amplitude to drive it, so the reverb recovery triode probably won't do it. This is very troublesome for me and I'd be very thankful for any ideas.

Next and possibly last is the power supply and output stage. I noticed that usually the screen grid (second) of output tube is connected through resistor in some way, supplying it with lower voltage. Should we alter it or leave as is? The EL41 tube datasheet says Vgs2 = Va = 250V for a SE class A amplifier - so maybe it's correct. 😀
The matter of power supply is, most if not all tube designs use a multi stage filtering which also gives multiple voltages for respective gain stages. Should we leave it as is or change to "the standard"? I'm having in mind the AZ41 tube which is specified for output capacitor of 2x 50uF max only.

At the end I would expect the signal path to be: EF40>ECc40>EF42>Reverb>EcC40>EL41 with controls such as Volume, Tone (somewhere on the way, not necessarily with the input stage), Dwell+Mix and Master Volume (if it has any sense). The longer I look at it though, the more I doubt it is achieveable. Maybe I could squeeze somewhere a subminiature tube if another stage would be needed somewhere? Maybe a MOSFET in a place it won't alter the sound? No idea here. 🙁 (wouldn't want any semiconductors though)

For any questions with actual sound, I'm looking for just a little distortion, but mostly clean sound. If the gain could be changed for more distorted sound with a switch, I'd surely take it! I'll also leave the original speaker in hope of some fancy "vintage" sound.
Let's also say I will not be using any old capacitors, as the original 70 years old ones need replacing just from looking at them. Also please do let me know, if I am forgetting something.

I will be plugging the radio and measuring its working conditions - voltages and currents - in a few days, so it will help in determining this project feasibility and basic parameters.


All kinds of help, whether it is a straight solution, example, suggestion or some article to read, will be greatly appreciated! In no means though I am expecting a ready fix and I'd rather learn than copy.


Many thanks to you all and everyone for any input to my post. 🙂

Cheers,
Jakub

Hello guys, I'm working on a loudspeaker protection design based on UPC1237. In it's datasheet there isn't provided any example of overload circuitry.
Designing such a circuitry isn't an easy task because there are lot of variables that should be considered in it since different amps work with different voltages and etc..

I have attached the M9 Amplifier schematic from "Analog Metric". this design benefits from upc1237 + overload detection circuit.

I want to know if it's possible to use and adopt the overload detector circuitry introduced in the M9 amp for another amplifier? say a MOSFET one like the Bora jagodic's designs.

Someone asked me to design a 3 way speaker with a middome. So i started looking what is arround (not much it seems) and found this Visaton G 50 FFL middome.

I can't find any reviews or user reports from it but the specs look very good. Anyone got experience with this middome? Is it any good? I know they fell out of favor as they are hard to use it right to modern ways of speaker designing, but this was an explicit demand from this guy.

https://doc.soundimports.nl/pdf/brands/Visaton/G 50 FFL/pdf_Visaton_G 50 FFL_1.pdf

Picked up this huge beast...which apparently is blowing fuses.
Hoping to find any relevant Circuit diagrams that might be 'out there'.....please!!
Grateful for any information.....😉

Hello all, I have some few problems with my tube amp. The most important one is those nasty high frequency parasites (more than 100Khz) after my EF86 first stage. You can see it on the picture (5mv/div, 5ms/div) (the 100hz noise is clearly audible, I dont ear the 50hz one)


I guess it's because of the current rush in the main reservoir of the power supply, it stops as soon as I stop the amp. Those parasite are not present in the output of the power supply.

What should I do to get rid of this ? Filter it after the preamp ? adding some resistor before the main reservoir (right now there is 220ohms on a 150μF cap, I fear that more could be too much) ? A small inductor before the reservoir ?

I feel like filtering is would be the better solution.


Thank you really much for your attention and your help !
Regards,
Simon

Hi everyone

What would you recommend as a 15 inch bass driver for strong deep LF output in a sealed 50-75 litre cabinet?

Upper crossover will be around 200 Hz, as front main Hifi speakers, secondary use as front HT speakers.

There will be subs, but I want these to run as extra subs, and hand over at the lowest frequency they can. DSP will be available, so that might factor in to your thoughts.

Sadly, money is a factor, so premium and affordable alternatives are sought. I don’t have a hard dollar limit, but cost-no-object suggestions will be fun to read but won’t be the answer.

Thanks

What do you guys think of my handsome new capacitor discharging tool? 😀

Check this out, fellas!😀 1kW LLC Converter with GaN the Future is Here with EPC

Please, kick me please.
TransFiles - бесплатный файлообменник без регистрации

TLDR; for the actual question skip to the bold bit.

So, it seems like an obvious one that shouldn't be hard to google the answer to, but not for me... Hence I turn to the diyaudio forums. While I suspect it won't take much brain power from someone with the knowledge I lack, apologies for the potentially dumb question and thanks in advance for your time even just reading it.

THE ACTUAL QUESTION:
If I have two 1v RCA outputs producing identical audio signals, would using a Y-cable to connect them both into a single RCA input give me perfect a 2v audio signal at the other end?

Reason I ask: I'm wondering if two linked (so allegedly identical) channels at 0.9v from a standard miniDSP would provide a healthier 1.8v "close enough to line level" signal at the end. A simple question made complex by my lack of knowledge in this field.

Should anyone cleverer than me reply and it's a simple yes/no... That's a perfectly acceptable one word answer as far as I'm concerned.

If it's a "technically yes ish but there's a few other issues at play which one would need to factor in and compromise the etc etc etc" sort of answer... The chances of me grocking it are slim to none. In that case free to just paste "yes but no" straight into the reply box😀

Thanks for any help... And even just reading it this.
jjams.

hello everybody.


I read in the building article of the VTV line stage it can be use with solid state amplifier but not all. I use a Bryston 10B crossover in my active set-up who have a input impedance of 20k and i have a nice collection of 6SN7 and a pair of Duelund .47uf caps.


I want to use my supply of 6SN7 this is why i prefer a two 6SN7 line stage instead of a 4 one.


It will work correctly with this preamp?



Thanks and regards.

Is there any disadvantage to using a larger capacitance (~4,700uF) on the output side of an LM317 regulator?

when using a different tube.

Say an 5842?

[WTB] Sony 2SK82 V-Fet matched pair

Wanted one matched pair of Sony V-FETs 2SK82 graded KD or KE or KF-33
Contact via PM, thanks

CLOSED, thanks

Hi folks

No experience with speaker design (though lots with woodworking!), and I want to build a set of speakers into a console / cabinet.

I am planning to use a kit - probably the Samba MT Bookshelf kit from parts express. However, because of the dimensions of the console, I will have to adapt the enclosure size for the speakers, and move the port.

My questions are:

1. The kit includes a port which is on the rear of the kit enclosure. My console will be wall-mounted so I cannot do this. What are the implications of moving the port to the front baffle of the speaker? What about the bottom?

2. Can I adjust the dimensions of the enclosure as long as I retain the same internal volume as the kit enclosure? The kit enclosure is 0.56 cu ft internally. The woofer (Dayton Audio RS180P-4) says it is rated for 0.27 cu ft sealed and 0.64 cu ft "vented" (which presumably means ported?). How much leeway do I have with these measurements? Is it going to sound dreadful if it's in a 0.8 cu ft box or a 0.5 cu ft box?

3. The kit enclosure is mdf. My cabinet will be solid wood, but I could always line the speaker enclosures with mdf if it would be beneficial? Or is solid wood OK when lined with damping foam?

Thanks very much!!!

Charliefreak

Are Psvane (or chinese) 300B tubes durable and reliable ?

Hello everyone,

As this is my first post, I'd like to thank the members of this forum for solving a lot of questions I had before - there seems to be a lot of knowledge here, so here's my "problem":

The noise floor on my Denon PMA 900V is a bit high for my taste and seeing that I can only twist the volume knob for about 20° before my neighbors are complaining and never turned it over 9 o'clock until it was "loud enough", I'd like to lower it's gain and/or swap the opamps for less noise.
It's service manual can be found here, the opamps used are Mitsubishi M5218 for IC1, 5, 7 & 8 (datasheet here) and a Sanyo LA6458 for IC2 (datasheet here) in the Phono-Pre section.
All opamps are dual versions, but I'm not shure wether they are J-FET or bi-polar types (or wether they are used for current or voltage feedback in the circuits).

Any suggestions on what opamps to swap in and/or how to lower the overall gain (or noise) of the circuit to optimize it for modern day >1.5V rms sources?

I thought it would be a good idea to come and ask here before the monkey in me takes over and I put LME49720s with a ceramic caps between pins 4+8 everywhere 🙄 ...

There's a service manual for the Sony EV-S2000 floating around online, but it's missing all of the schematics. If anyone has a copy, please let me know. (And if you've ever worked on one of these, let me know that, too!) TIA.

Hello
Due to health reasons I am downsizing my belongings and wanted to offer up some free electronic chassis, heat sinks, various transformers etc.
Pick them up in Oakley Ca.
Thanks for looking today

MODS - PLEASE FEEL VERY FREE TO DELETE, I FOUND THE ANSWER TO THE QUESTION


I think I recall reading several mentions that the MarkAudio CHN-50 will (or may?) work in many enclosures that were designed for the Alpair 5

Would the CHN-50 be likely to work in the uMar-Ken enclosure design found at:

EDIT: Planset URL deleted, I may have accidently found a URL of a part of a paid planset online and I do not want to detract from Planet10's paid plansets, Dave is already beyond exceptionally generous in all that he shares


Thanks!

Hello Folks,

I'm restoring active 3-way Backes&Müller Speakers from the early 90s. For their feedback systems to work, the input signal of each of the three ways with sensor feedback is integrated with a simple 3-Transistor circuit before the feedback signal from the sensor electronics is subtracted to then feed the poweramp. Current advice from an analog designer is that the old circuit works just fine, but I don't have an explanation.

My question is simply: Which approach is better and why? The existing 3-Transistor circuit or a circuit with an OPAmp and why?
An explained "do not worry" would be as acceptable as an explaination why I should go for an OPAmp replacement.

If any additional info is needed to give a reasonable answer, please ask.

Thanks a lot!
Winfried

a new unused selenium Midbass driver.

Hi,
in December 2015 I bought a class D module "DPA-600/F" from Audiopower (Audio Power | Professional Audio Equipment) to build my own amp bass (I'm a bassist and a diy-er) and have a light amp to carry for my gig.
I equipped this amp with a simple preamplifier (no tone controls, my bass is active) that I built time ago using an OPA2132 (non-inverting configuration).
Since the DPA-600 provided onboard power (+/- 15V, 250 mA) for external boards I used those outputs to power the preamp.
Everything has worked very well till March 2016 when suddenly the DPA-600 went into protection and some smoke got out from the case.
Then I contacted Audiopower and sent the DPA-600 to be fixed: one of the voltage stabilizer broke down due to my preamp, they told me.
It was strange for me since the preamp is really simple and I've used it in other projects without problems but I took their advice to disconnect the preamp from the DPA..and so I did (the repairing costed me 50 Euro, anyway).
I built then a separated power supply and everything has worked well till last december when after 10 minutes of playing (on a gig) it went into protection and after a few secs turned off dead !!
Fortunately the bassist of the other band (we were two bands) gave me his amp head so I was able to continue the gig.
The loudspeaker was the same for us bassists (1x15", it was mine loudspeaker) so I can exclude that the cause of the DPA-600 fault was the loudspeaker.
In December, 21 I contacted Audiopower support through email but I've got no reply.
I thought that maybe they were closed for XMas holidays so I wrote them again last Jan, 11 but I've got no reply so far.
Ok...I'm not certainly a big customer but I don't like to waste my money (210 Euro, including the repairing), the most irritating thing is not to get any reply from them.
So I had to buy a new amp (a TC Electronic BH800) since I have several gigs in the next weeks and I had no other amp.
I will wait for their reply for a few days more and then, if I won't have any contact from them, I will decide what to do.
How can I say? It's really a pity.
Regards,


Roberto

Here's a start with UK's big band drummer "Sticky Wicky".

he plays the style appropriate for each vintage kit in the videos below moving from the 1920's to the 1970's


Slingerland Radio King 1942 - Drum Solo Sticky Wicket on Next Level Chops
YouTube

1936 Premier Swingster Drum Kit in Wonder Finish - Sticky Wicket
YouTube

Vintage Chops and Grooves Part 1 - Sticky Wicket
YouTube

Vintage Chops and Grooves Part 2 New Orleans and Early Jazz - Sticky Wicket
YouTube

Vintage Chops and Grooves Part 3 - Chicago Jazz and the Road to Swing
YouTube

1950's Gretsch Broadkaster Drum Kit Peacock Sparkle- Sticky Wicket Drummer
https://youtu.be/AeebfCK7dlw

You're The Cream In My Coffee by Jack Hilton and his Orchestra - Sticky Wicket
https://youtu.be/8dvUr_owWZc

My Pretty Girl by Fletcher Henderson and His Orchestra - Sticky Wicket
https://youtu.be/aAF18q-qZOg

The Drum Also Waltzes: A Tribute to Max Roach - Sticky Wicket
https://youtu.be/l70CxT7o8TQ

War Time Ludwig Victory Drum Kit - Sticky Wicket
https://youtu.be/puUFVFLJya0

1898 Style kit playing along with Scott Joplin pianola "Maple Leaf Rag"
https://www.youtube.com/watch?v=N45DtWoV_l0&feature=youtu.be&t=790

Ludwig & Ludwig 1920s New Orleans Drum Kit - Sticky Wicket
https://youtu.be/_Zl_z4n_T9M


Slingerland Radio King Drum Solo - Sticky Wicket
https://youtu.be/v-T45fXyA10

1970s Rogers USA Drum Kit- Sticky Wicket on Next Level Chops
https://youtu.be/oMyrsbrOFCg

I have a behringer euro power mixer, a dbx crossover, two crate amps, two jbl speakers, 2 subs, and a couple mackie speakers for monitors. All the speakers are passive. The crossover only has xlr inputs and the main outs on the mixer are 1/4”, so I am waiting on some balances 1-4” to xlr patch chords. From the crossover I can run xlr patches to the amps, low channel to the subs, mids to the speakers, and run the monitors off of the power mixer speakon outs. Does this seem like the best way to go. For some reason we always use to piggy back the speakers from the subs, and we ran one amp per left and right, and the sub cables had two connectors on the amp end. Not sure how the crossover could be used in that set up.

Is there by any chance someone who know how to find out which models of cd players that are compatible with a Nad cd 3 remote control?

Hi,

I observe non-flat frequency response in SRC (SRC4192).
I admit a tiny unevenness on 18-20 kHz, but I have a slope down starting from <1 kHz that ends with – 5-6 db at 18-20 kHz (freq2.png)

I would deeply appreciate somebody could suggest me an idea for how to explain that and what to try to fix that.

The stand A (expected flat frequency response freq1.png)
(connected sequentially)
1 A PC based sweep generator
2 USB sound card (analog out)
3 Passive mode I2S ADC
4 DSP (all filters are off)
5 DAC
6 Level Meter

The stand B (non-flat frequency response freq2.png)
1 A PC based sweep generator (the same)
2 Tried 2 options
2.1 USB to SPDIF (tried also USB to COAX) with SPDIF\COAX receiver (I2S output finally)
2.2 Or USB to I2S (without a receiver obviously)
3 SRC4192 based sample rate converter (passive IN\passive OUT)
4 DSP (all filters are off, the same)
5 DAC (the same)
6 Level Meter (the same)

Tried to verify 2.1 (USB to SPDIF/COAX) frequency response separately it's flat as expected
Tried to change input sample rate (from 44.1 to 98 kHz) and input signal bitness (16 and 24) without any difference and still have significant signal degradation starting from < 1kHz

SRC4192 board is pretty straightforward, just default connection layout with the both In and Out in passive mode

Would be happy if somebody could find an explanation of the above and/or suggest an idea for what to try to make FR flat.

Thank you in advance,
Serge

Hi all,
I'm new to this thread...!
This is my 1st amplifier layout. I've been working with small layouts earlier.But this one seems to be a BOMB!
Any Suggestions related to placement of components welcome!

Thanks and Regards

Mark

for sale /shipping costs velleman PC USB generator PCGU 1000.

max 2Mhz 2 channel. AWG etc.

Is there any reliable equipment out there that can test transistors while in circuit? I don't want to have to de solder if I don't really have to

If you know him let us know if he's okay.
He had about 207.000 Youtube subscribers.
He is one of the best DIY Audio and loudspeakers youtuber.
Kirby Meets Audio

All brand new, never used foil inductors.

Goertz 3.399mH/0.3700R - 12AWG
Goertz 3.405mH/0.3781R - 12AWG
Goertz 3.396mH/0.3755R - 12AWG
Goertz 1.904mH/0.2409R - 12AWG Just for fun I ran a capacitance test - 14.66uF/ESR 0.5818R@120Hz, 0.8337R@1kHz, 1.2R@10kHz
Goertz 0.3310mH/0.1826R 14AWG Just for fun I ran a capacitance test - 1.993uF/ESR 0.2647R@120Hz, 0.5161R@1kHz, 0.9538R@10kHz
Goertz 0.2302mH/0.1261R- 12AWG
Goertz 0.2286mH/0.1526R - 12AWG
Goertz 0.2074mH/0.1227R - 12AWG

Make offers.

With the help of the forum I succeed to make 24db active XO suite specific to my drivers .The design of it I made with Xsim 3d and LT spice .
I am using 3 amplifiers to drive them .
for my opinion sound is good , without any flews .
but if you have any good adjustments i will glad to hear .

I'm just moving from speaker building to amplifier building. I'm willing to build a my own Class-D amplifier. I confess that I don't have as much knowledge about electronics though. At the moment, the work I can do seems to be the output filter.

I'd like to ask everyone that are there any Class-D amplifier modules without output filter sold? If not, Is it worth if I would buy a complete module and modify only its output filter section?

My plan is to use a 4th order Linkwitz-Riley, or Butterworth if L-R is not possible, on the output filter. Is it an acceptable idea?

Will I also need to adjust the feedback circuit?

You can take the signal direct from the 4398 through caps (ballabced,adapter cable single follows.
Or you can take the signal from the back of card (original)With another opamp than original.
So you still using PCI on your PC,then this is for you...





60 euro plus shipping.

I'm going to make a new amp and use this schematic, but I don't understand one part. Right after the rectifier tube is an unmarked resistor. I thought the rectifier needed a cap first? If a resistor does make sense here, what value should I use?

Also, the pot on the 300b isn't labelled either. 100 ohm linear for that spot?

I want the system to sound great for both music and movies room dimensions length 25 x 15 wide x 10 height

7.2.6 Atmos speakers might just be RSL since I can't hange these on the ceiling plus 2 GSG devastators with kraken subwoofers and 2 Rythmik dual sealed subs for left and right channel with minidsp active crossovers to make the left and right full range for when I do stereo listening
My current list

HIVI 3.1A with perfectionist modified crossover 7 pieces

2 NX-oticas LCR plus 4 NX-Studios

2 LX521.2 1 LX521 4 LXminis these will be expensive when it comes to amps

3 CSS audio criton 2tdx LCR 4 1tdx

GR-Research LS set

hi seen a few of these on ebay- i like the mechanical operation and good looks-anyone know if they sound good? to use as a walkman-not much info on the web

So I may be touching a controversial topic here (Car audio drivers for home audio), but it's worked well for me and so just wanted to share my experience.

I have been looking for a set of bookshelves for my home and I liked the Polk Audio S20 sound signature.

Long story short, I decided to make my own bookshelves. Had no experience in making speaker systems so took this as a learning opportunity. I know it could have ended not so well, but I was willing to take the risk.

First step was driver selection. Where I live, there is a good presence of car audio drivers/component systems and since I like to "touch and feel" the stuff that I am buying, decided to go in for what was available rather then order online and get surprises.

I homed in on the Hertz ESK 165.5 two way component system as the driver set, which was affordable and had suitable TS Parameters. Moreover, it was a component system with matching woofers, tweeters and crossover. This actually solved 70% of the design for me. This turned out to be one of the advantages of going with a car component system. All I needed now was a properly designed box.

Used UniBox to come up with the box volume and port design. Used MDF as the box material. Hand polishing after creating a faux wood grain took care of the exterior looks.

I for sure wanted a front facing port since I did not want placement issues against walls. Yes, ideally, the woofer and tweeter ought to be next to each other, but I went with this arrangement since I felt it looked better. I didn't find any issues with the sound based on this arrangement.

The ports are hand made by heating & shaping the flare on a calculated length of PVC pipe.

The Beginning Of High End Audio

This is where it all started.

The best phrase : IS IT A RELIGION OR DISEASE ??? Lol

BBC Archive - 1959: Monitor: Hi-Fi-Fo-Fum | Facebook

Pair of First One Large modules, with two sets of cap bank modules (i.e. the full complement for one negative and positive cap bank per amplifier module). Good working condition, flying leads attached to allow bias to be set (will leave these on, but can be soldered off as required). Taken from working amplifier.

These are V1.4 modules.

Asking £300 for both modules and the cap banks. Original prices where 220 euros for each amp board and 68 euros each per cap bank.

Also, available a used Hypex SMPS 3kA400 (originally used with the used set of modules advertised here) now also available. Asking £150.

So I got a large amount of C3g tubes and Im looking for projects that fits this tube perfectly

So what can you really do with these tubes?

They are really great tubes, the curves look beautiful and the build quality is superb

I feel bad to let them waste away on a shelf

so enlighten me!

Hello everyone,

I'll let you know as much as I can about my actual setup (it will be important to achieve a conclusion about my problem).



First, I have a ADAU1701 on a board that I designed. I'm using all ADC and DAC, one of MP pins I use for an digital external volume pot.

The ADC0 is my main input, receiving a balanced signal from my audio interface. I put two ampOps before DSP for a few reasons. First is to receive balanced signals (ofc), second to protect the DSP in cases of surge (rare cases but they happen).

The ADC1 is a generic input, for tests, phone input, etc.

The DACs, I use to send audio to a dual TPA3116 board (2.1). DAC 1 to Mid | DAC 2 to High | DAC 3 to Low.

At output, I use a active output filter like the datasheet, and another ampop to gain stage. (I prefer to do analogic gain over digital gain inside the DSP).



OK, now the power supplies



The supply is provided by a switched 24v/15A (generic chinese but with good and double core filters), and for +/-15v, I'm using two LM2596. One of then I put as inverting configuration (It does a regulator and a negative supply.. I'll show).

To make 5v, I use a LM7805 from +15v, simple and basic.

3.3v from a LM1117.



PS.: Look at the number of switched sources (maybe so much RF)


AND THE PROBLEM:

After a while (about 30mins) my output start with a little distortion, until the output is completely distorted and the audio pratically disappear after a few minutes.


Things that I already tried:

-Change the PLL_LF caps (same value, different materials)
-Another ADAU1701
-Place a 2.2uF and 100nF caps at Reset pin
-More capacitance before and after 3.3v regulator
-Another VDrive transistor (Same BC327)
-Make a new sigmastudio project from the scratch, nothing changed. A simple bypass (input->output), nothing too.

Ah, PS.: when fully problematic signal, I do a simple pertubation (touch with my fingers any V+ pin) and everything back to normal.

In Attachment, the files you need to analyze the case.

Hi guys. Again I need advice.
This is NAD integrated amp.
At the output of regulator IC901 M5231L - pin2 there is 0V
I desolder and tested, it is defective
My question is can I replace it with another regulator or zener diode (the emitter of Q901 should be obtained +46V)

M5231L

Cheers!

Once someone gives me the answer I'll feel foolish for asking-

-but-

I have been working on and with and enjoying tube equipment since the late 70s when all of the old timers thought it was mighty curious for a kid to be interested in obsolete equipment -

and, during all of that time, I have never known rhyme or reason why a relatively small subset of low/medium power output tubes - usually 6V6 and sometimes close kin like 6K6 - very commonly have an opaque black or dark gray lining on the glass. It doesn't seem common on lower dissipation tubes or higher dissipation tubes and I am at a loss why it is so extremely common on these low/medium output tubes.

Hi,

There are online reports of this tweeter (MCM 53-5165, http://www.farnell.com/datasheets/2329960.pdf) sounding very good above 2000Hz.

I plan to use it in a conical waveguide of 8" size and cross at ~1400Hz, 2nd order HP. Since the waveguide will give a bit of gain on the lower side of its range, is the xover too low or ok?

Thanks and Regards,
WonderfulAudio

Hi, I've just got a faulty Peavey MAX115 from a friend for repair.
It shows 28.75V on LM3886 pin3 (output).
I have 3.85V on pin10 (input) and cc 35mV on the positive leg of C116.
Not familiar with IC, I guess that the LM3886 is faulty.
Any advice will be welcome,
Cheers,

Hello everyone !

I'm about to finish my first 2 way speakers. I have a problem where my speaker seem to be clipping at a certain volume (DIY 2-way speaker "clipping" - YouTube). It does that no matter the amp. Could this be due to a bad crossover design ? Or a result of my driver reaching its max power handling ?

Thanks again for your help

I would like to replace this dual op amp with new op amps but it has some features I am not familiar with and I having difficulty find sutitute(s). I'm not looking for pin to pin replacement.

Look at the LAG PINS, it seems to have more in's and out's than a typical op amp. I'm used to Vin+ Vin- and Vout+ Vout-

Cheers,

Shawn.

A couple of questions on my plan to use a true midrange driver in a design.

I picked up some PHL 1660 midrange drivers off of eBay to build a high efficiency design. My intent was a MTM arrangement with a high sensitivity tweeter. These will be crossed on the low end somewhere from 300-400 Hz. If I run the mids in parallel, their sensitivity will be 100 dB @ 1W.

Looking at the spec sheet for this driver, it indicates using an enclosure volume of 3L/driver. That is a pretty small volume, and I was wondering if making the internal volume larger than that would create any performance issues for the driver. My thoughts were going larger and using a fair amount of stuffing material behind the drivers in the hope that it will absorb the back wave and give me clearer mids. I do not intend to play this speaker at high SPLs. For me 95 dB is about as loud as I ever play my systems, and the average is likely closer to 85 dB. I’m building this speaker simply to see if the dynamics are better than what you get with a lower sensitivity speaker. It’s basically an experiment to see for myself what the high sensitivity crowd likes so much. It also gives me an Avenue to try some low powered tube amps down the road.

The other question is in regard to Zmin. I didn’t consider this initially when I bought the drivers, but a later review of the spec sheet revealed that Zmin is 5.8 ohms at 650 Hz. With two drivers wired in parallel, is this potentially a problem for my Adcom amp considering that it will be delivering like 1W at my typical listening levels?

Other details are that the crossover will initially be a miniDSP, and the tweeter has a sensitivity of 96 dB. I want to adjust driver output levels with either the DSP or with the amp gain potentiometers.

Thanks in advance.

Hi all,
I have set up my main monitors and I am in a bit of a bind as to the noise output. I think the culprit is the line-level analog crossovers, but I'm baffled by that, because those speakers and their electronics are supposed to be used in high-end studios, and that's definitely too much noise. The noise is white noise and it's mostly constant but fluctuates in loudness every now and then which would indicate to me either RF/EM pickup, or bad power supply capacitors. However, the thing has a grounded, steel, 1mm sheet box, so I don't necessarily think it's RF/EM pickup. The noise is put out via all transducers. It's the same loudness on both sides. I don't have an SPL meter capable of measuring this noise, but it's much too loud for room-level listening, to where it already gets tiring mid-day. I am a little more than 2m away from the speakers. Turning the power amp sensitivity on the rear panel down from 1V to 2V helps alleviate the issue (predictably the noise is 6dB lower), but it's still present. I perform main output attenuation in digital, before the DAC.


Do you think that based on my testing I am right to point to the crossovers as the culprit?

Is this sort of noise output to be expected from this level of equipment? (I list everything below)

How can I improve this without compromising monitoring quality?

A visual inspection of the insides of one (right) crossover revealed no obviously leaking or blown up capacitors; everything seems to be in order; the PCBs were signed off on 3.4.09, so I wouldn't expect there to be an issue here. Everything is very clean, but there's clearly a bunch of botching done at the factory due to the customization done for PMC.

I tested that the issue is at the crossover by doing the following:

1. Turn off left crossover - noise gone from left channel.
2. Turn on left crossover - noise back in left channel.
3. Turn off right crossover, disconnect cable from DAC going to crossover, short left channel pins 2 and 3 on the DAC end, and move the DAC and its associated cabling far away from the crossovers and amps - noise still present in left channel, no noise in right channel.
4. Restore the connections to their normal state; turn on both crossovers; unplug the cable feeding left HF from the left crossover to the HF stereo amp, unplugging it at the crossover - noise gone from left channel.
5. Plug the cable back in - noise back in left channel
6. The same tests provide the same results on the right channel


My electronics are as follows:

1. PMC MB2 XBD quad-amped main monitors, stereo
2. the standard electronics supplied by PMC for that, which are a customized version of Bryston SST2 electronics:
- PMC 10B crossovers. They are not the same as Bryston 10B. PMC 10B have main and LFE input and HF, MF, and LF output and all I/O is balanced XLR and there is no (front-panel) frequency adjustment; Bryston 10B have only line input and only split to HP and LP, have single-ended I/O, and allow frequency adjustment for each band using front panel rotary switches. Also note that the Bryston 10B is a stereo crossover (one box for both channels); the PMC 10B are mono crossovers, so you have to have two of them.
- PMC-branded Bryston 3B SST2 (stereo, 250W/channel), 4B SST2 (stereo, 500W/channel), and a pair of 7B SST2 amps (mono, 900W/channel). As far as I know those are exactly the same as Bryston, just with PMC branding. The 3B goes to HF, 4B to MF, and one 7B feeds LF and XLF to the left channel while another 7B feeds LF and XLF to the right channel.
- The XLR cables are 1m store bought ones, they're not amazing but they're fine. Two conductors + shield. I opened all the male plugs and cut the connection between the shield and pin 1 and insulated it with heat shrink, so now the shield is only connected on the female side.
- The crossovers are at the top of the stack, so they're pretty warm, but it's not like they're burning, they're merely warm to the touch.

Thanks

Hi,

Owned this amp for 30 years then managed to drop it on the floor today and now no power, completely dead. I'm an idiot

Can anyone advise what I have most likely broken? I will start with the power supply but after that I'm just guessing.

thank you

Standard version:
Made in USA Push Pull OT22PP EL84 6V6 Tube Output Transformer 6.6KCT 4/8/16 Ohms | eBay

Hi-Fi version:
Made in USA Push Pull HiFi OT22PP+ EL84 6V6 Tube Output Transformer 6.6KCT 8ohms | eBay

Im hoping to build a low voltage tube preamp module for my existing modular preamp that uses lm317/337 regulators for the psu. As part of the design constraint i need a way to increase the voltage coming out of the 317 regulator which means a voltage multiplier will have to go AFTER the regulator. Seems not likely since the multiplier is a passive circuir but will i risk oscillation regardless? And if so what are some better alternatives?

Hi! I am making a 2-way stereo for my small apartment:

Dayton rs100-4 + SB19st-C0004

Have never designed a crossover network before, so I would really love to have some feedback on this one, does it seem alright? Will correct baffle step with dsp at later stage.

Thanks in advance!

Kris

Hello everybody.
Could someone tell me which are the flattest fullrange drivers?
91 92dB are enought.
Because when I look for the frequency response measured by users, not by the manufacturer, it is tremendously irregular, with peaks and bumps.

Could be Fostex, Audax, Mark Audio , Seas , etc.

Until about 200uss each.

Voxative , AER , Davis , Feastrex , etc are out of my budgeThanks

Hi All,
At the moment I use a Little Dot MK2 with a pair of KLH ultimate One headphones. While I love the cans they are a bit of a bugger to drive at 32ohms and can cause clipping when playing music that's a bit busy and loud.

To that end I fancy building my own amp that will drive them and have been looking at the schematic of the Darkvoice 336se for inspiration as I already own some nice NOS 6080s and 6SN7GTs.

My question is that I can see the output caps are 30uf per channel so would upping the values help to drive my 32ohm cans without clipping? If not, how would you go about it?

Please don't kill me due to the basic level of my system. I am restoring a 50 year-old Citroen Mehari and want to add sound. The easiest/most cost effective retrofit without cutting etc. is a surface mount kit for 5-6".

I will be using a bluetooth class d amp and to compensate for the lower voltage/power, I am looking for some relatively high sensitivity 3 way drivers. I found some cheap Pioneer one at 88db, but this still seems pretty low. Does anyone have any recommendations?

Many thanks.

Hum in Pro-ject Debut Carbon TT - getting better!

Hi. I haven't been listening to vinyl records for a time and now that I'm back, I have noticed some background hum. It's not the typical hiss inherent in phono preamps when you turn up the volume, it's an added grainy hum. It's present with my old amp and also with my new ifi set (zen phono and zen can headphone amp). The sound changes its character and loudness if I touch the RCA connectors, be on the TT or on the preamp).

Any idea? Advice welcome! Thank you!

Hey guys I can't seem to get this amp to produce a drive wave. With 12v input my tl494 reads....
Pin1: 1.140v
Pin2: 3.165v
Pin3: 4.788v
Pin4: 4.174v
Pin5: 1.624v
Pin6: 3.566v
Pin7: 0.000v
Pin8: 4.965v
Pin9: 0.000v
Pin10: 0.000v
Pin11: 4.965v
Pin12: 11.95v
Pin13: 4.965v
Pin14: 4.965v
Pin15: 1.986v
Pin 16: 6.950v

Also the lm358
Pin1: 7.95v
Pin2:0.328v
Pin3: 1.076v
Pin4: 0.000v
Pin5: 9.30v
Pin6: -0.111v
Pin7: 3.010v
Pin8: 2.470v

Thank you in advance for any assistance.

Hi,

I am considering building a 2-way with a Faital 12PR320 as a bottom and a compression driver on top. I had a look at the 18Sound XT1464 horn coupled to a ND1460A driver.

I cannot seem to conclude whether the beam widths will match at a reasonable crossover frequency as the horn is quite narrow and whether I have missed anything else.

Your thoughts, please 🙂

hi all,

I have one of these beasts which I bought from a guy in Czech republic. It's an invaluable piece of test gear. So far I did a couple of hacks on it:

1. The display was dying, and I couldn't get a new one for a sensible price. I have retro-fitted a more modern display that uses the same controller (you wouldn't know from the outside). I designed some adaptors and 3D printed them to take care of mechanical issues. The new display uses low voltage backlight, so the internal high voltage inverter could be pulled out.

2. I built a gadget based on a PIC demo board to grab printer graphic output and save them to a USB stick. I can then use PrintCapture software (commercially available for about 70USD I think) to convert the files to PNG or whatever. Also possible to capture raw text like this, it would be possible to write a script so results could be pulled into CSV.

Now what I'd *really* like is to be able to automate the thing from PC - but almost impossible to find a GPIB card. I am wondering if it would be possible to make a USB adaptor that could plug into the GPIB card slot - so the AP would become programmable ... hmmm.

No real reason for all this except to share it. I'll see if I can find some pics. if anyone wants more info contact me. (I don't come by here very often, but if you google my name you'll find my website.)

cheers

Dan

[book=HP339a]%[/book]
[h=Introduction]%1[/h]

The HP339a was a state of the art distortion analyzer in the 1980s.
It was and is a full featured all-in-one product including a volt meter,
low distortion oscillator, analyzer, AM detector, and VU meter.

There was an in-depth analysis of low distortion oscillators
on DIYAudio <Low-disortion Audio-range Oscillator>
followed by the specific HP339a thread:
<HP339a>

This is a summary of those threads along with the links
and conversation, posts, etc about the research and development
that went into the suggested modifications to this analyzer.

[h=Outline]%2[/h]


[h=Why HP 339A?]%1[/h]

[h= Cheapest quality instrument for DIY mods ]%2[/h]
#1146:
The 339A is about the cheapest instrument that DIY'ers will ever be able to do simple mods to (parts, value changes and IC replacements) and get excellent results. However, next up the ladder of affordability might be the popular HP 8903_ or others? If the full potential can be realized in that one or other readily available used gear, what rewards will they bring? This little 339A excercise shows us there is a lot that can be had in refurbishing them for improved performance if the fundamental design is sound.

[h=Wide range of frequencies and input voltages]%2[/h]
#1577
-- just change the IC's and a few caps and trimmers and you are done with the mods. Then just use its' own analyzer to tune the thd with the trimmers for a null. That's about it. The nice thing about the 339A is that it has a wide range of frequencies and it can be used as an rms voltmeter with db scales. The analyzer will accept a wide range of voltages on its input. It will give you a fast indication of the thd+n with a minimum of fuss and cost less than any other options.

We here got carried away with the oscillator and have been curious as to how low can we make it can go... far lower than the THD meter/analyzer part... but an indication well under .001 (-100dB) should show that you have a pretty good amp/preamp circuit.

[h=Accepts up to 300 Vrms on attenuated input]%2[/h]
[h=Similar to Dick Moore's project ]%2[/h]
#1554
For all those thinking of using an HP339A and want to improve it:
I just looked at a similar project by Dick Moore. He copied the 339A oscillator circuit and put it into another existing chassis. Didn't use the 339A analyzer section. If you go to his site, you will get a well written, detailed summary of what to do on the oscillator. -- RNMarsh

[h=Link to Dick Moore's Lab Pages]%3[/h]
Our colleague, Dick Moore (aka RichEEM), and his mod pages w/FFT plots:
http://www.moorepage.net/IG-18-3.html


[h=Base line performance.]%1[/h]

Post #980, Low Distortion Analyzer
[h=Stock 339A Performance Numbers -]%2[/h]
Being able to have a wide range of test freq is a nice convenience.

So far the complete HP339A system -- reading its own oscillator at almost stock (osc + analyzer distortion) - with just a tune up and changing the two null trimmers (using a 3580A spect analyzer on the output monitor port of the 339A) -- gives a noise floor of -145. The H2 is -105 and the H3 -130. Its a good beginnng and its getting better! 🙂 Thx-RNMarsh



Intro to the 339A boards. Unmodded
1. Pic
2. Pic
3. Pic
4. Pic
5. Pic

[h=Modified HP339A Performance Numbers ]%1[/h]
[h=FFT Plots w/Test Equip #2156 on ]%2[/h]
RNMarsh - Post #2156
The 339A is a thd+N meter. The osc and analyzer spec is .0018% or better. That is a tick below the 0.2 mark on the 0-1 scale (-80dB =1).

After opamp and parts changes and upgrades, the thd+n is near the 0 mark -- well below -100dB. This is THD+N.

Using the 339A monitor output shows the two dominant harmonics at -106db and -110dB for 3H. The top is -100dB and 10dB/div. and measured with shibasoku 725D analyzer ported to an HP 3580A Spectrum Analyzer to measure individual harmonic and noise levels. This is a compromise tuning for a wide range of freqs; For minimum thd+n at only one freq, it can be much lower:





[h=Disassembly and Cleaning]%1[/h]

[h=Things to be careful about]%1[/h]
Careful when making adjustments that you don't short the case of the Jfet.
It's very close to one of the trim pots and if it shorts it's toast.

Stability Build Before Modding:
1. Testing and Replacing power supply electrolytic capacitors.
2. Other Platform stability building.

[h=Modifications]%1[/h]
Most bang for the buck and reasons go here.

Davada - Explains the HP339a configuration
and the limitations of the mods:

[h=Output Level Pot]%2[/h]
Davada - Post #48:
Davada found the output level pot to be a source of distortion. You can
find the voltage level output pot for under $10 at Mouser or other suppliers.
The pot is a Bourns cermet type, p/n 51SADU25A15L.

The output level pot is easy to change. Loosen the screws on the shaft extender and spin the nuts off. 20 min tops. The pot shaft is longer than needed so you
have to cut it to proper length about 8 to10 mm.


[h=Oscillator and Pot change ]%2[/h]
RNMarsh - Post #45, #47 (HP339a):

If you wanted to do the minimum, just changing the oscillator opamp
(AD797 etc) and replace its control pot with a new multi-turn and add
another trim for the fixed resistor that is feedback on the control jFET (d-g)
with a multi-turn (for 2H only).

But, a must do is replace the output level pot. That pot introduces a lot of harmonic distortion.

AND

Most used oscillator change:
[h=Most used oscillator change]%2[/h]
Davada - Post #75 HP339a:
The bottom of the board is completely exposed once the analyzer is opened up.
It's a bit tight from the top of the board but all your doing is inserting
components. Just remember to remove all the compensation and clamping
components around the op amp for the oscillator.

If you use an LT1468 the compensation is wrong and not needed.
There's is not much to go wrong. Just be careful when making adjustments
that you don't short the case of the Jfet. It's very close to one of the pots and if it shorts it's toast.

[h=FFT with These Mods]%2[/h]
Post #83
FFT at this point:


[h=A1 Board Oscillator Schematic]%2[/h]
Davada - Post #88 Schematic


[h=A1 Board Specific Mods]%2[/h]
RNMarsh - Post #86

[h=The jFET feedback R51/2K.]%3[/h] Replace with 28 turn pot/trimmer. It is in series with a 60mfd cap (C30)..... together they go from jFET gate to its' drain. Replace C30 with 100mfd 105c bipolar.

[h=The Oscillator Amplitude Adjust pot (R30/2K)]%3[/h] replace it as this old has contact issues and makes the adjustment difficult and 'touchy'. Replace.

[h=The output pot is R3 (10K). Replace.]%3[/h] Bournes pot above.

[h=OSC IC - A1U1 (LT1468)]%3[/h] is all you need to do to have the level of THD shown above.


[h=Notes and errata]%1[/h]

[h=Service/Test Notes ]%2 [/h]

[h= PhotoCell LED Measurement]%3[/h]
Dick Moore wrote this up to help us
test the Photocells and see if they are
still good or not. Thank you Dick, R.I.P.
Link to Post#39

Basic Mumbo Jumbo
Hocus Pokus Dominatrix

Probably up to about post #2300 is the low
distortion analyzer thread.
Start Photo before mods example
End photo after mods exemplary example
How to get there what to do.
Parts
Resources
Work arounds
Steps to get there
To do
To not do
[h=Brought to you by these fine folks at DIY Audio:]%1[/h]
[h= Davada ]%3[/h]
[h= Richiem, R.I.P. ]%3[/h]
[h= RNMarsh ]%3[/h]
[h= 1Audio ]%3[/h]
[h= et al ]%3[/h]
[h= and a cast of 10s]%3[/h]
[h= on thousands of written pages]%3[/h]
[h= Boiled down for the average Joe by SyncTronX.]%3[/h]

Hi

Can anybody help with this please?

I plan to build a PCM1798 DAC using the attached circuit for I/V conversion if its input can be adapted for connection to the PCM1798's differential outputs. I have been using the circuit as shown with a TA1541A, without the FET output buffer shown in the diagram, driving the following amplifier via a stepped attenuator and like its sound very much, therefore if it can be adapted for differential input I would like to try it with the PCM1798.

Can this be done and if so what would the new circuit look like please? I hope this isn't a stupid question and thank you in advance to any help offered.

Tim

I have a very nice pair of Electra-Print output transformers for sale.

They were bought for a 300B PSE amplifier that was never finalized. The transformers have the following specs:

Primary: 1.5K
Primary current: 150 mA
Single secondary: 8 ohm
Power level maximum: 30 Watt
Weight: 7 kg. each.

These transformers are big and heavy.

The current retail price at Electra-Print for this type of transformer is 405 USD each - total 810 USD. On top of that I paid 120 USD to have them shipped to Europe + VAT.

As can be seen from the photos the transformers are in 100% like new condition.

I am selling these transformers for 460 Euro + shipping. Price reduced to 400 Euro.

IXYS 10M45S CCS for 6E5P tube driver

Hi, i have an 6E5P KT88 triode amp with resistor load for 6E5P.

I will change and will use a 10M45S CCS.

Somebody know about resistors values ​​of the resistors to have 25-30mA current.

I put the present diagram with load resistance 6E5P and the future diagram with CCS 10M45S for 6E5P.

Proac are a little mean on what they divulge, so I thought I would share a little of my hard earned knowledge, and give a kind of database of proac info for fans and curios
.
for some great proac klones check this out.

http://audioclone.free.fr/scanspeak.html

Older proacs are divided into 3 ranges,

1/the tablette

2/studio

3/ response

tablette 3, 50, 2000 inc. signatures use seas woofers and seas or scanspeak tweeters...2010 on signatures.

further info added: tablette ref. 8 still using seas bass unit, but treble is now changed to vifa tweeter, these appear to be oem units.

xover is still the std proac seas type, 2nd order on bass, with rlc across woofer, between the inductor and cap.
cabinets do not feel as substantial, terminals are cheaper too, but it is true to say after listening to the 3s, 50s, and ref. 8s, that in every incarnation, they have subsequently sounded more open, better bass and clearer mid, so it would appear they get better with every new model, and its not hype.

studio 1, 100, 200 use scanspeak 8543 paper woofers and seas tweeters
studio 125 are like the tablette 2000, and use seas woofer
studio 150 use seas p14 woofers, and scanspeak 2008 tweeter.

studio 200 and 250 use the 8543, like the studio 1, in the 200 they are in a dapplito and the 250 there are 2 of them, not sure if a 2 or 2 and a half way.

response 1s use seas t14 woofer, scanspeak 2010 tweeter
1sc uses a different woofer.
reponse 2.5, well you know!!
reponse 3 and 3.5 both scanspeak polypropylene woofers, scanspeak 9000 series tweeters

apparently, the r3 cones were made by rogers, and were changed for the 3.5. They are plastic coned.

response 3.8 uses 2x 8535 woofers, 9300 tweeter
response 5 2x8535, atc mid, 2010 tweeter
response 4 atc 9 inch short voice coil woofers, atc mid, scanspeak tweeter.

response 4 crossover is 2nd order bass, 2nd order on the mid(lower and upper) and 2 order on the tweeter, a departure from the normal proac xover.

response d150 and later proacs are now using volt woofers, and some using scanspeak tweeters.

You see a lot of the drive units are similar, the favourites are seas woofers, usually the plastic polyproylene cone: t14, p14 or p17....in the seas woofers, the letter is the cone material, t for TPX a kind of plastic, p for polypropylene, L for aluminium, and the number is the diameter in cm,

and the tweeters usually scanspeak 2008 or 2010 tweeters, and there is really little distinction between the ranges, the tablette are the small ones, some studios are uprated tablettes:
the studio 150 is like the tablette 50, studio 125 is like the tablette 2000.

Studio 200 are the same as the studio 1 or 100 just another drive unit and bigger cabinet.

response d15 is like the tablette 2000 signature: same drive units, bigger cabinet.

response 2.5 is like the studio 125 only different drivers which is the floorstander version of the tablette 2000

Proac seem to favour a d'appolito configuration which is used on studio 150, 200, response 3, 3.5, and the latest responses.

crossovers: the standard proac crossover is 2nd order in the bass, 3 order in the tweeter, with one attenuation resistor as the first component in the tweeter. No L-pads here.

They are in phase, but the components are the opposite way around, ie in the negative path rather than the positive.

With the 2.5, the bass is 3rd order,a change for proac with a 47 ohm resistor across the first inductor.

The 3.8 crossover is 2nd order on the bass unit, at 300 hz, and the rest I think is identical to the 2.5 ie 3rd order midbass, 3rd order tweeter.

With the scanspeak woofers, no resonant filter is used, but with seas, a series RLC circuit in that order R, then iron core L, then C is used, ACROSS the woofer. The bass signal first passes through the series inductor, THEN comes the RLC, then the parallel capacitor...check this out for a typical proac crossover:

http://audioclone.free.fr/responseONEsc.html

The cabinets are lined with bitumen and acoustic foam, terminals are michell rhodium plate.

with the crosovers, the FINESt components refers to air coiled inductors, solen capacitors, and ceramic resistors. Pretty standard, and some standard multilstrand cable, a la qed or bandridge.

latest response d100 uses Volt 2500 type woofers, atc mids.


series RLC on the seas woofers comes after the bass inductor but before the parallel capacitor.

Values are typically: 4.7 ohms for the tweeter resistor, 5uf cap, choke, 6.8uf cap

woofer: choke, 10 ohm resistor, choke, 20-40uf cap in parallel with woofer, 5uf cap parallel with woofer.


that's about it, good luck....data by name, data by nature.

all this has been written in the belief proac are mean with their specs they divulge, and it ought to be in the public domain.
Its a shameful practise when you see the specs. some makers give, especially in the pro audio domain.

IMO there is no need for it, as proac use custom drive units largely, so no one can reproduce the designs at home.

Also, I consider Mr proac a minor genius, he manages to produce excellent speakers, and interestingly they all sound similar, despite having differing drive units, I supsect its a lot in the xover design, which are frighteningly similar on all the speakers. Minor tweaks are obviously the way he designs.

Speaker cabinets are made by the castle factory, and I have heard the xover boards are by bk electronics, who used to make the amplifiers for rel subwoofers.

I assemble LM3886 Amp using PCB of circuit basics project i make 3 board and 3 boards are getting -21 volts at speaker output i don't understand what's is going wrong.
without connecting speaker board not taking any current but only showing -21 volt .
If I open mute circuit diode then no -21 volt showing at output .
What is wrong ??