just received my Faital Pro 6RS140 drivers and I'm rather disappointed in what I see.

The dust cap is off center by quite a bit. Should this be acceptable for a $170 driver?

You would expect this from cheaper drivers, but for a premium product this isn't acceptable IMO.

Over the past year I've been helping to clean out the basement of a family friend who passed away.
As a former electrical engineer and life long tinkerer he had accumulated quite a bit.
I bought all the cabinets he had there which amounted to several truck loads of 12x8x3" parts bin cabinets from the 1940's or so.
With the bins came the parts.
My interests are much newer and my intent for the cabinets was to use them for other purposes.
After sorting through and bagging the contents of those cabinets, I ended up with about a 15lb box or so of carbon comp resistors.
I see them selling on eBay but have little interest in going through all that.

What is a massive assortment worth? There's roughly 100 to 250 of each value in what i believe are 1/2 and 1 watt values.
Each bin was put in a bag and marked with the value on the drawer label.
Lot size is roughly a box the size of a case of long neck beer bottles or so filled to the top.

Is there any value in these other than taking a $150 offer from some artist who wants them to make jewellery out of them?

This is me being stupid and trying to coax some linearity out of an EF9 remote cutoff pentode. The question is, how stupid? I'll be the first to say I don't know much about tube design, but feel free to point and laugh 😀

Recently my AudioPro Addon T3 died, but the 3 speakers themselves still work fine. I want to get some kind of Audio amplifier with an aux cable, and wire it back up so I can use the speakers again.

The speakers are two tweeters and one woofer, all 6 ohms.
Currently I'm confused by how to set up the circuit to incorporate the 3 speakers together.
Audio amp boards are either 1 or 2 channel. I'm unsure as to how i'd wire this up to get a good all around sound. Although, I'm not sure if just wiring in mono would sound okay? I've heard people mention crossovers, but not sure how I'd incorporare them

Thank you
Speakers i have :https://www.ebay.co.uk/itm/195089406177?hash=item2d6c3c18e1:g:kK8AAOSw09tikbQf
Board i was considering: https://www.ebay.co.uk/itm/195089406177?hash=item2d6c3c18e1:g:kK8AAOSw09tikbQf

Well, as Greedy Boyz did share (tnx!!!!) some interesting info in https://www.diyaudio.com/community/threads/odd-sit-vfet-2sk2087c.385288/ , frenzy is there and who know how it will end

Yeah, impossible to keep low profile, but lets just hope that price isn't going to sky and over

So, officially - parts are Iznogood, everything above 2$/pc is steal and overpriced

Anyway, CodyT sent me few, and they arrived pronto

Have some more arriving, sent from friendly Greedy Boy from Japan, but they are still collecting dust in my Customs , that will be covered ( along with my official gratitude) when I see them

pics of package sent by CodyT, along with basic Ugs measurements (Uds 24Vdc, Iq 1A8, Igate~20uA (0mV2 across 100R gate resistor)

more specific info can be seen in thread linked above

Never mounted
$150 for both OBO
PREFER USA Only
Plus you pay for shipping. Use if it fits it ships USPS.


Bohlender Graebener Neo8-PDR Planar Transducer

roduct Details
Brand Bohlender Graebener
Model 111-913205-01
Part Number 264-7541
UPC 848864034461
Unit of Measure Each
Weight 0.95
Product Specifications
Tweeter Type Planar
Power Handling (RMS) 40 Watts
Impedance 4Ω
Frequency Response 700 to 20,000Hz
Sensitivity 92dB 2.83V/1m

I am trying to see the effect of the DC voltage filtering if I were to use CRC filter. I have drawn the simulation, but it does not seem to be working. I also wanted to check on the effectiveness of the snubber capacitors right at the transformer AC secondary coils.

Any help will be greatly appreciated!

Thanks in advance,
Pavlo

Ok gents, time settle the formula for creating a DCR (double chamber reflex) enclosure, once and for all. Notice that we're not talking about DBR (Double bass reflex) as that is something else entirely (with a confusingly similar name). Creating a DCR is in on itself not particularly difficult. However all discussions and tutorials seems to go full fitness industry mode and no one says the same thing. This is why we need to agree on this once and for all.

I've not built a DCR yet because I don't got the time to find out what all of the parameters on the build should be by my self via endless testing. Using Claudionegro's guide (DCR) goes a long way, but his talk about ports falls short in explaining. On other websites and forums (the little that there is on the subject) everyone has their own interpretation. In addition, the DBR and DCR is constantly mixed. Stirring all the information together, my take on the DCR enclosure so far is:


1. Pick a suitable driver of choice (EBP and that jazz still apply).
2. Make/simulate a 4th order alignment that fits you liking.
3. Simulate the enclosure from step 2 with two ports. (Keeping max port velocity to 5% of sound speed etc. still apply)
4. Take the enclosure volume from step 2 and divide it into 1/3 and 2/3. Such so the total volume still equals the volume from step 2.
5. Put the port (not total area x length, but the area x length of one of the two ports) you found in step 3 in the three different place that makes it a DCR. (One in each chamber to the outside, and one in-between the two chambers )
6. Place the driver in the larger chamber.


Simple enough, however it is the parameter rules that gets confused. Here is what I think is correct:

A. The port dimensions result is a product of the tuning in the full enclosure (regular 4. order BR), not in any of the 1/3 2/3 divided chambers. (I'm not sure on this one).

B. The driver should always be placed in the larger chamber. (In DBRs it doesn't matter as far as I know.)

C. All the three ports should be of exactly the same dimensions (or at least the same tuning). (I've seen someone say that the port connecting the two chambers should be twice as long as those connecting the inside of the enclosure to the outside, something I think is incorrect as it would throw the tuning of the smaller chamber right off.)

Please add/correct/give idea if you got any.

Hello Members,
I'm pondering a new build but haven't decided what. Here's my dilemma: I have the Alpair 10p in a Pensil enclosure, which I like alot, and the 12.2p in a 19L bass reflex standmount, which I'm not too crazy about. I listen to rock and a bit of everything else except classical. I would like to have a floorstander, for rock, and a bookshelve/standmout, for everything else.
I am really interested in trying Scott's DCR, Juliet(12.2p) or Titania(10p).
Since I listening to a lot of rock, I was thinking of building a SuperPensil 12.2p and compare it to the Pensil 10p and then keep the one that suites my taste. I would then use the other driver in one of the 2 DCRs. Unfortunately not too many DCR using the Mark Audio drivers have been built, so, I would like to pick your brains as to what is my best option based on your experience with the Pensils and the DCRs specs on paper?
Thanks

Hi,
I'm looking for some Siemens w295b replacement knobs (the round ones with a collet system, not the chickenhead ones),
either NOS or similar, but can't find anything at all ...
Anybody knows where to look to find some ?!

thanks in advance !!
Fred

I thought some would find this interesting. We are subjected to expert reviews and optimistic specs in glossy brochures but where do manufacturers spend money and where do they skimp when it comes to speaker systems.

Recently I've had occasion to dis-assemble three sets of floor-standing speakers with surprising results. First came the 2-way Toshiba SSPJ1. With a mediocre Peerless SKO165 bass driver a cheap and cheerful mylar tweeter it seems Toshiba spared every expense! This is confirmed by the 12mm MDF used to construct the cabinet. Any bracing was deemed superflouous and unnecessary. Surprisingly Toshiba found some loose change under the sofa cushions to spring for a 12dB crossover.

Sony went in a different direction. Their 3-way SS-MF450H boasts superb build quality, 19mm construction with bracing to boot, any rodent would see this cabinet as a formidable bomb shelter. The bass driver looks like it can handle itself (outperforms the Peerless in the same cabinet) However, the cradle is plastic - not sure if that's a good or bad thing. At this point is where the money ran out. Technically, the SS-MF450H is not 3-way. The budget didn't run to an actual crossover. The mid-range driver and tweeter are protected from low frequencies by a simple capacitor.

Finally, a pair of Eltax Concept 180s found their way to the butcher's table. The cabinet is well constructed, 12mm MDF with the appropriate bracing. Everything, even the drivers are designed to be neat, shiny and pretty. Performance-wise the drivers are crap, Who am to advise Eltax but there's a reason the Concept 180 has reputation for lacking bass. The pre-moulded ports you pulled off the shelf tune the port to 39hz, the driver couldn't get that low if it was equipped with a JCB (Trackhoe). With money left over Eltax, at least installed a decent cross-over.

Epilogue: I got the Sonys for £0.99 because some new-age types had painted the cabinets green - they could never come back from that. I put the Sony drivers in the Eltax cabinets, with the Eltax crossovers.

Hi folks,

Looking for a pair of the multiple tap Amorphous version RAAL 70-20XR

Preferably in EU but willing to import if it makes sense.

Thanks for looking 🙂

I have been sitting on a large stash of Scanspeak (12MU + 18WU) and RAAL (various) tweeters for close to 10 years now, with the intention of building a home theatre system.

Recently I have come across the Illuminator Centre http://www.troelsgravesen.dk/Illuminator-CENTER.htm Which is essentially what I want to build, but with a RAAL tweeter instead of a Scanspeak one.

Unfortunately I can't just change tweeters and be on my way since the shape of the RAAL in question https://www.raalribbon.com/products_flatfoil_140-15.htm
doesn't really lend itself to a straight swap out.

I could mount the RAAL tweeter horizontally but I fear what that might do to the response. I have a CNC so I could custom make something to mount it vertically.

If I am going to go to the trouble of deviating from the standard box is it worth my while adding more mids to the speaker? Bare in mind this is a centre speaker for home theatre where most of the content coming out of it will be dialog, and the RAAL have a fairly high sensitivity (95dB@1m/2.83v).

I use 2 of the 12MU's in each of my open baffle speakers, but they are open baffle not in a box. Why is it that most speakers only ever seem to have one mid driver?

Is there any reason I couldn't use 2 or even 4 mids (series / parallel) in the centre?

I bought a new set of Gold Lion Genalex for my current-production McIntosh MC275. The factory tubes are fine and I wanted to pull and save those (as in, they still work, everything has been perfect with the amp and tubes, not one single issue).

When I powered the new tubes on for the first time, the KT88s made a lot of noise (like the metal heating and expanding...way more than subsequent power cycles) and there was a quick quiet 'pop' from one of the channels about 30 seconds after power on (as I could still hear the metal heating, expanding). I saw a very small blue spark at the base of a tube (specifically the round flat disc at the bottom of the actual insulating spacer...I think that is what it is called).

Everything looks and sounds good.

I got a second (small) pop again today (again, less than a minute after startup) and everything is working fine. I was not watching and not sure what channel or tube it came from.

It 'feels' like there might be some crud burning off vs. it failing but I am not an expert.

Curious if this is normal (or if it goes away, not worry about). Either way, with the holiday weekend and me working from home part of the week, I can put a TON of hours on these. In other words, let them fail if they are going to fail...or see if everything normalizes.

Thanks!

I've added a couple of components to y set-up and I need a new powerboard with 8 outlets and an on-Off switch.
I have a gripe and a question, do the cheap surge protectors and filters in ordinary powerboards actually work?
Also why the heck can't I find a multiple outlet powerboard rated to 15Amperes at a reasonable price?
When we did the house rewire I had our sparky add a 32A rated circuit for the stereo and H/T just because we could and it only added a few dollars to the overall cost, it has a 4-gang GPO but I need powerboards to run all the bits and bobs and I thought it would be easy and/or simple to find a board that would handle 15A, not so, why is that?

I purchased this amp a few days ago to compare it to my old ATI 1807 amp which I'm currently using and quite liking but wanted to upgrade to something better.
However, I wanted to check what it outputs because I will connect it directly to my drivers (using DSP for a crossover).
!!! I've measured ~0,4v (405mV) constant DC voltage on the Left channel and about 0,08-0,12v (120mV) DC on the right channel !!! Clearly cannot connect it to a tweeter!
Is the unit defective? It has a break-in runtime of around 3 days before the test and was warming up for 4 hours but the voltage is similar when cold.
My old ATI amp is outputting between 0,0015v (1,5mV) to 0,0045v (4,5mV) between all 7 channels which I think is acceptable!

P.S. I've checked the test points on the Input stage and saw a difference of around 12-15mV between L and R channels.

P.S.2 If I like the amp I'm ready to explore the way of using three amps for my 3-way speakers but if it outputs so much DC I won't be able to do this...

Looking for a pair of Emission Labs EML 20A mesh driver tubes. Please let me know what you have and what you are asking for them. Thanks

Hi all,

This thread is about alternatives to mica, gold, tin and tantalum. If you want to know the rationale behind this, type the name of the material and "child labour" or "conflict mineral" in a search engine.

Political discussions are not allowed on this forum and the moderators have a fairly broad idea about what is political. That's a bit problematic, because building DIY electronics usually involves buying things and any decision to buy or not buy anything has economic and environmental consequences and is in that sense political. I hope the moderators will allow this thread if we refrain from discussions about the advantages and disadvantages of child labour and armed conflicts. Make sure to frequently make local copies of this thread if you should find it interesting.

Mica insulators for semiconductors:
Silicone insulators, other thermally conductive and electrically insulating foils, ceramic insulators (alumina).
Fair trade mica insulators, if those exist; I've never heard of them.

EUVL once compared various ways to insulate semiconductors from a heatsink and found that Keratherm Kerafol 86/82 works very well, see his article "Design considerations for a class-A amplifier enclosure" in Linear Audio volume 3. I haven't a clue what materials it is made from and how those are sourced.

Mica insulators inside valves:
No alternative I know of.

Gold plating of connectors and switches:
Gold is an important contact material for low-level signals because it doesn't oxidize. I don't know a good alternative, but fortunately, gold is an official conflict mineral, so some manufacturers of gold-plated switches and connectors at least have a statement about the origin of their gold. In some cases, reed relays could be an alternative to gold plated relays for low-level switching; reed contacts don't oxidize because they are not subjected to oxygen.

Tin:
I don't know of any alternative to tin for soldering. Fortunately, Stannol has a range of Fairtin solders. Tin is also an official conflict mineral, so there should be manufacturers with a statement about the origin of the tin.

Tantalum capacitors:
Can usually (but not always) be replaced with aluminium electrolytic capacitors or, if linearity doesn't matter at all, class 2 ceramic multilayer capacitors. Tantalum is also an official conflict mineral, some manufacturers of tantalum capacitors have a statement about the origin of their tantalum.

Tungsten, cobalt and lithium:
These are not used a lot in DIY audio equipment, as far as I know.

Regards,
MarcelvdG

Just like the title says. With caddock im thinking of their mp series with what they call Micronox® film. Cant find any info on what this stuff consists of.

With smd thick films im thinking of generic ones.

I am looking at DC heaters for a phono section and have a few questions.

1. I think it would be more convenient for me to use series string heater arrangement (4x12AY7). Is there any reason that this would not be advisable v.s. parallel heaters?

2.Would it be wise to have a polarity switch to reverse current every "X" hours for even heater wear?

3. Even though the current is DC would it be a good idea to twist the leads to reduce EMI getting into the heater circuit?

4. Does it matter whether one uses 12 or 6V wiring?

I'm looking for a good phone that can double as a portable audio recording device for live situations, specificslly with mics that wont distort early with low end.My old Samsung S9+ has so far served me somewhat ok, but it wish it had variable record level. Any suggestions?

CANCEL

Please don't berate me for buying on Aliexpress, I knew what I was getting into! Inspired by videos from JohnAudioTech and the Imsai Guy, I built a little test jig to test slew rate on DIP-8 dual opamps. A way to experiment and potentially to detect fakes. Have tested various NE5532, LM4562, JRE2168 from official and slightly less official sources, all with plausible and acceptable results. I saw LM49720NA advertised on Aliexpress, which I understand to be equivalent to LM4562 so I ordered a handful for $5. Not a big gamble, and an education. I wasn't expecting quite how spectacularly badly they would perform. Attached, an oscilloscope trace of the output from a 10kHz square wave with 11x gain. Slew rate is 70x worse than the official part and there is massive crossover distortion.

I'm just curious what kind of part this could be, because I guess it would be useless as an audio opamp (I haven't tried any listening test).

I put in a dispute with Ali, attaching my oscilloscope trace, but they want photographs showing how the part differs visually from a legitimate one! Think I'll give up now, and just leave some feedback on the seller's page. Amazingly there are lots of happy customers for this very part.

Rob

just curios, but probably this question has been asked previously by many others DIYers, however I did not find any match regarding this topic.

I would like to ask if anyone of you managed and succeeded to remove the aluminum spindle disc from the spindle motor? Could you share your experience?
thank you very much.

Based on my experience, I will keep the mechanism in the freezer for at least 24 hours, so the metal parts would shrink, and therefore creating a gap between the the spindle and the disc sufficient for me to pull the disc out. May be I need to spray WD-40 to help pulling it out.
I would avoid removing it by heating...

Any suggestion?

wmincy

Hello
I received a nemesis NA-5KD for repair that had already been operated on previously.
The problem with this amplifier is that the audio output transistors get high temperature in a short time of use, with load and without load.
I have doubts if the driverboard is the original and the audio output inductor coil is the original. Install IRFP260N new 10pc
I did tests with a driverboard P/N 14-2QA0016D-00 and the fault persists

Edit : Also replace all 2T and 2X driver transistors

I'm looking at a very first generation 3020 Series 20 with the 4 main caps near the headphone socket (not in the centre of the board) and having great difficulty trying to ascertain what's wrong with it at the point of trying to set the bias.

I cannot get any reading measuring across 0.22 ohm resistors installed at R653 and R654.

Measuring in the collector feeds with a 1 ohm resistor, I cannot get past around 12mV bias without the power transistors starting to overheat and the bias increasing on its own. I found this out the hard way as one channel blew up completely the first time around, but the fault is still occurring on both channels with all new outputs installed.

The unit is otherwise powered on perfectly fine with with both channels reading very minimal DC offset.

The power transistors were tested before installation and should be working perfectly.

The driver stage has been replaced with new ONSemi BD237G/ 238G.

New BD139s have been installed in the power amp section (Q609/ 610 and Q607/ 608)

New KSC1845F have been installed in place of 2SC1400 (Q601/ 602)

The RX resistors have been replaced with Bourns trimmers with 1.2k ohm fixed resistors in parallel. Capacitors C627/ 628 were replaced with Kemet R82 series film capacitors due to the fact the originals were too large to reinstall after the trimmer modification.

All electrolytic capacitors have been replaced (verified correct with untouched NAD 3020 side by side)

I've checked the orientation of the transistors multiple times and checked all resistors and diodes in circuit.

Oddly, I have about 33v on the collectors of the power transistors and not 28.

As far as I can see, there is either something shorting both channels, I've made the same mistake in each channel or it's something to do with the power supply, which I find incredibly unlikely given I have good DCV values on the power supply daughter board.

I have good experience in vintage audio repair and have done one of these in the past. I am at a complete loss at this point as to what to do next. Can anybody advise some useful checks?

Does any-one know the trade-names or chemical-constituent types of the substances that manufacturers use as coatings for their cones and/or soft domes to damp the amplitude of resonances ?
Eg:- such as SEAS use for their CA series of coated paper cone drivers ?

I refer specifically to substances that remain flexible and not to those which dry to semi-rigid , such as the varnishes do {and of which Dammar may be one , though I have not yet seen dammar} .

Guys, hello.
I have NAD c326bee and I see some (as I think) very strange behavior of it.
Before trying to fix it myself, I would like to get some opinions.

The amp has huge heatsink with 4 main transistors on it (2 per channel).
Besides that it has 8 additional small heatsinks (4 per channel) with small transistor on each of them.

When amp is working the main heatsink is hardly warm,
4 of small heatsinks (2 from one channel and 2 from another channel) are warm ,
4 of small heatsinks (2 from one channel and 2 from another channel) are very very hot.

From now lets talk about one of channels. Look at scheme below.
Cold small transistors are Q346, Q350.
Very hot small transistors are Q342, Q344.

I replaced to absolutely new both zeners D322 D323 and both capacitors C361, C362.

My thoughts on a problem.
What causes heating of transistors? High current that flows through them, right?
What dictates the current value through Q342, Q344?
As I understand diodes D324, D325, D326, D327 are responsible for value of current that flows through Q342, Q344.
Probably these diodes became very tired and they allow higher current to flow through Q342, Q344.
So, as a start I want to replace these diodes.

Am I going in correct direction? What else can cause such heating? Maybe transistors themselves got tired?
Anything else?

Isn't it strange that big heatsink stays cold? Looks like amp is working mostly on small transistors..

I attach here full service manual with complete scheme.

Sorry if this is OT, but with so many great driver/speaker people contributing here I thought maybe one of you wanted to apply to this position:

https://www.linkedin.com/posts/seas...=linkedin_share&utm_medium=member_desktop_web

A long time ago I ran across some discussions of using choke loads for low B+ applications so I looked at simulations and of course the higher the inductance the better the low frequency performance. In the process however I discovered (OK I am sure rediscovered something obvious) that carefully chosen cathode resistor bypass can result in response quite close to that obtained with a larger choke. Going to diode bias (and I presume battery bias) provides some improvement but the right cap value (not too large not too small) can be even better. I also noted that group delay in the audible range remained below 12mS in all cases.

Might be something to keep in mind if you find yourself with a marginal choke. I presume that something similar should work for IT too.

Hi!

Is it normal to have black area on Rifa X2 capacitor? It is old power line distributor-filter. Attaced photo.
Thanks.
Rait

I am looking for 18w8535's and 8513's for the ProAc Response 2.5 clone.

Thanks

Greetings,

What are the driver "lookback" impedance curves in XSim? What is most important about them? Is there a threshold value than needs to be held, or does it point to issues with the crossover?

Thanks!

Neil

Hello,

Currently selling two 24V power supplies:

Murr 85352 230V input, 24V 12A output linear power supply - 10€ + shipping
Meanwell S-100-24 24V 4.5A output switching power supply - SOLD

See pictures below.
Any question, feel free to ask.

Hello,



I have an issue with an oscillating line stage, depending on which opamp to use in the DC-servo circuit.

Some details:

Line stage (PCB + circuit is attached)

• clone of the famous CTC Blowtorch preamp
• power supply: CRCRC + LM317 + shunt regulator + Lateral Fet cap multiplier

Servo

• inverting type. Both opamps inside 1 DIL08 used for balanced line stage.
• small PCB connected to line stage PCB with headers.
• Power supply: R + Zener solution derived from line stage PSU. 2x15V zeners bypassed with 100n Wima FKS.

Issue

• Preamp oscillates easily when using AD712 + switching on/off main amp or source.
• Preamp does not oscillates when using LF412. Tried many things to get is oscillating, it remains stable.

Trials to find the root cause:

• 110pF RF cap at input. Between GND and signal. ==> No difference noticed. It still oscillates.
• 100µF elektrolytic caps // to 100nF WIMA’s, close to opamp + and - connection ==> No difference.
• Other AD712 ==> No difference

Does anyone has some experience with this kind of issue? All advice is appreciated.

Just hands on purchased a pair of JBL CS100 for my computer mains channel use and discovered one of the tweeter seems had sound bad ... Any equilavent replacement parts for the CS100 tweeter? thanks

Hello there. I'm planing to build the RJM-Sapphire 4 and conflicted about what VA rating transformer to get. Ill be using the dual mono setup with the X-reg board but the dual 25VA transformer seems excessive.

Hello guys,

I have a pair of B&W Matrix 3 over here.
One speaker doesn't do anything at all.

I checked this with different amplifiers and the problem is the speaker itself.
I already dismantled it but I don't see anything special at the crossover.

I'm wondering why I don't have anything.
I noticed the relay in the circuit, but it has only effect on the HF circuit, right?

Also the inductors seem fine, but hey, what can go wrong with an inductor...?

Seems like I need some advice here. What can be the cause?

Thank you in advance!

See the manual with schematics attached

has anyone got one they would sell me
i know they are on ebay but dont really want to chance getting a fake one as they are from the 1990s
20200724_124941 by glenn jarrett, on Flickr

My daughter asked me to evaluate a speaker I built for her some years ago. Before she pulled off the magnetically attached grill, she said, “This is really bad.” I chanted the Hitch Hiker’s Guide to the Galaxy mantra: “Don’t Panic.”

Seems a visiting toddler ‘explored’ the speaker and ‘modified’ the whizzer cone on this FE206e. (Photo below) I brought both speakers home and closely examined the injured driver. The voice coil, main cone, whizzer cone joint appears to be intact. I connected the speakers to my MiniWatt S-1 (2.5 wpc) tube amp, put on my test CD, crossed fingers, and hit play. Surprisingly, the speaker sounds OK. At least up to the 80-82 dB level I can tolerate before tinnitus rears its ugly head. I’m sure if I measured the response I could find differences between before & after, but for my daughter’s purposes, all is well.

I must say, I’m really impressed by how robust Fostex drivers are!

Cheers, Jim

A lot of my valves come in matched sets but there are others that I want to sell with confidence that they are matched and /or have reliable tested values. Is there anyone close to Carmaux/Tarn that can test valves for me?

Full Korg B1 kit with Silver Chassis $199 + 15 shipping lower 48.


I can post pics or PM them to anyone who wants them but not much to see as they're still in the shipping boxes. Shipping UPS Ground from my office (Springfield Eyecare in Springfield MO) so you know who you're dealing with. I have sold on DIYMA under Pilk, Ebay under Huskerpilk, and GolfWRX under Pilk for references.

Hello,

I am spending hours to put FLT (low latency) on high on GY-PCM5102 card (see attached). As mentionned on the datasheet, I tried to connect FLT on 3v3 but the card stop itself, with 10k resistor nothing change, checked with RTL utility. Do you have an idea of what going wrong ? Thank you

As i understand it, Dolby Reference level set to 7 will give a fixed and known volume of 85dBc using a "dolby pink noise." I have also read that this should equal -31 LUFS.

If we play source material with a loudness of -18 LUFS, on a calibrated system set to Dolby Reference level 7, can we then predict that the SPL will be around 85+13=98 dB(LAS)?

Selling a variety of 6SN7 and 6J5 types as follows, all tested good:

All 6SN7 types £20 each REDUCED TO £18
6SN7GTB RCA
6SN7GTB RCA
6SN7GTB Remington Rand
6SN7GTB Admiral
6SN7GTB Hit-Ray
6SN7GTB HP
6SN7GTB GE JAN
6SN7GTB GE
6SN7? GE
6SN7GTA GE

Also some 6J5 types
Raytheon 6J5WGT x3 £15 each
7193/2C22 £6 each, some new in box. I have several of these.
E1148 £15 pair
Send a PM of contact me directly on performanceandmedia@gmail.com Andy

I know there are a host of descriptions of ways to lower the 405 input sensitivity. They are not all alike, some refer to 405-II's, and some are in the context of other modifications, and others are just different than each other. I have an ISS-9 405, I'm not doing anything other than I've re-capped, replaced transistors, and would like to lower the sensitivity without changing anything else. Some say use a 47k resistor and some say 4.7k. One uses multiple additional components, etc.

Is there a for sure way to do it? Is just the replacement of the C2 with 33uF and the replacement of R4 with 47K the correct solution?
Thanks😉 I have this amp working and don't want to see any more flames🙂

Hello.

As some people and I have said, there is on internet some laser diodes that area announced like Sharp LT022mc that does not do performance like it have to do, and all seems that are a counterfeit. The original has the base plated, and the counterfeit is all golden. The power out of each one is very dissimilar. The power showed in the power meter must be multiplied by 0.73 for 780nm. For example, the best "fake" LT022mc gave 1.64mw(2.25mw x 0.73) for a current of 100mA. That low power with that amount of current shows that the diode is not running like it have to do. This diode was the best "fake", the others was worst, one gave only 87uW for 100mA!
However, one orginal LT022mc gives 4.3mw(6 x 0.73) for 64mA. It's a typical value.

So, avoid these Sharp LT022mc with golden ring socket. They are counterfeits.

There are other diode that are use to be announced like "Sony kss-151A", 3-5mW. Well this diodes are not so bad that fake LT022mc, but they don't feature like it have to do. For to 3mW, the current is betwen 80 or 90mA, this is too high.
Besides, as you can see in the picture, are bigger than original Sony SLD-104 laser diodes, fake diode looks giant compared to original Sony.

The meassures were performed with the Sanwa LP-1.

Fake LT022mc and Sony laser diodes - Google Photos

Building a PP KT120 amplifier, 65 watts Class A, fixed bias (-43V), 450V B+ at 120mA idle each side. Earlier prototype monoblock has been working flawlessly since September, the other monoblock has undergone numerous revisions, mainly power supply tweaking, delay start and circuit protection. Prototypes are on pcb with the HT hard wired to the socket pins to avoid thermal/stress failure. Bias adjustment is by two trimmers: one sets bias voltage and the other balances with LED's sensing off a 10-ohm cathode resistor, with the cathode voltage fed to the bases of differential NPN's that have the LED's pulled through the collector, whose emitters are held steady through a common current sink. The ccs and the collector are off a half wave rectifier from the second secondary of a xfmr; the other secondary feeding the 80V bias circuit. There is a B+ time delay of one minute and the bias voltage is on the grid well before the B+ turns on.

Noticed one KT120 tube burned out on the newer monoblock, but the fuse intact. Replaced the tube, started amp and noticed one LED brighter than the other. After a few minutes, the replacement tube started glowing very brightly and the other tube's bias LED went dark... and immediately shut down power. After two tubes in the same socket, suspected bias voltage loss.

Removed the power tubes and started the amplifier with a variac to keep the B+ to 450V. Measured both pin 5 voltages with the probes in the sockets and adjusted the bias to -50V. The voltage held steady for over an hour. Plate and screen voltages remained constant at 450V during that time also.

Installed the tubes (swapped sockets to rule out tube). Placed a DMM probe on the cathode of the suspected socket and another DMM probe to the grid bias. Started the amplifier. Bias held steady at -50v and the cathode voltages each measured 0.90V (90mA). Corresponds with the plate curves. The tubes were balanced and operating for about three to four minutes when the tube cathode voltage in the problem socket climbed to over 2.00V and the bias dropped to -18V before I shut it down. Couldn't tell which came first, both voltage changes appeared to happen at the same time.

The bias was measured at the downstream lead of the coupling capacitor. Even if the grid pin at the pcb was faulty or lost contact from heat, shouldn't the voltage stay constant at the capacitor? The only other thing I can think of are the trimmer resistors -- they have been pulled from previous prototypes and reused, maybe five or six times.

Can anyone offer other things to check? This is my first build and learned quite a bit. But I'm stumped here. Appreciate any assistance. Thanks.

Ok, time for silly questions/comments, it's Friday.

1. Did Nelson Pass design the Adcom 555II amplifier for Adcom,
if yes, then more questions.

a. What other Adcom models did he design?
b. What type of topology is used ?
c. Since there are so many of these amplifiers on Ebay,
can the design be modified to run lower impedances,
and/or can per channel power be increased, ie paralleling outputs, bigger power supply. Of course this will require major hacking - hehe

I have one of these in the garage for my speaker
testing, it works quite well, I like the mono bridged
mode for 600w.

I'm debating on whether to;
a. build my own amp using "off the shelve" schematics found
on the internet, this will take time - heh
b. or just settle on getting more 555II on Ebay.

I need 6 channels of power, 200-400w per channel would
be nice, and need 2 more channels with 400w-800w,
but after listening to the 555II bridged, I would love to
have 6 channels of 600w - WooT !!

I don't want to get into exotic amplifiers (Krell, etc.)
that cost a bazillion dollars - ha!

The only thing that caught my eye so far was the holton 1kw
amp design I found on the internet.

I'm selling 2 Toroidy Supreme Audio grade transformers with
individual specs,
I planned to build a tube amp that for private reasons,
I was never able to finish... they never really had to work

PRI:230V SEC:

0-370-380V (1,1 amps)
3,15-0-3,15 V (4,5 amps)
3,15-0.3,15 V (4,5 amps)
0-7 V (2,5 amps)

Click to expand...

Toroidy Supreme Version, diameter 17 cm

100€/pc + shipping(heavy weight), payed almost 500€ for both

shipping within Germany 8.50€
shipping EU 20€
other countries, please ask

I have a Krell 402e that is tripping the internal breaker. It will run for about a half hour or so and then the breaker will trip and it will shut down. Does anyone have the schematics? Also any thoughts about what a common cause may be? It sounds perfect up to the point of it tripping. The more it warms up the faster the breaker will trip.

Hi all,

i was using one of the many on line speaker box calculator for a small, battery powered, boom box I’d like to make, but I couldn’t find info on how to proceed when two loudspeakers share the same box. Can anyone help?

I've shared this on the Klipsch Community general Forum and hoping I'd also get some collaborative help and feedback here. Wasn't sure where on which forum to post this as it covers a multitude of inquiries but most importantly setting up the system I have in mind.

Reaching out for help from anyone in the community with knowledge, advice and expertise when installing a system in a commercial restaurant space. Writing this in a beginner-friendly tone because that is where I am now. I've been a lurker taking notes who has finally convinced a friend to splurge on a sound system that will be an exciting feature of his restaurant that I'm collaborating on. A high-efficiency horn-loaded system powered by SET tube amplifiers is the path I've chosen to approach this project.

The restaurant's build is almost complete, with interior finishings currently being applied. I've attached images of the floor plan and sections of the space with coloured markings for the whereabouts of the D.J. booth and speaker placement proposal for anyone interested in size and layout (yellow: booth, pink: speakers). A key with materials used is also included - there isn't much leeway to apply acoustic treatment. Maybe pyramid foam within the waffle spacing of the concrete ceiling. I also feel like the large floor to ceiling windows and wall tiles would create a lot of reflections, especially with how I'm planning to orient the speakers. I have suggested adding thick drapes to help remedy this for the owners, and there would be a few carpet art pieces hung that help in absorption as well.

I'm proposing 2 budget options:

Option 1 / Big-Budget Features:

1. 2-3x pairs of Klipsch Hersey IVs - suspended or mounted on walls/columns upside down with a tilt angle. The horns would point downwards at the customers and the woofer closer to the ceiling to create a similar low-end response when placed ordinarily in a floor-standing position. The speakers will either be suspended by eye bolts and fender washers hung from a concrete beam waffle structure or mounted on french cleats on the structure's columns. They will be powered by:
2. 2-3x Decware Super Zen Triode Amplifier would love to pair the Decware tube amps with the HIVs, but I'm concerned if they have enough oomph to drive the speakers to volume when it's a busy day at the restaurant
3. 1x Condesa Carmen in-house analogue D.J. rotary mixer
4. 2x Technics SL-1200MK7 Turntables
5. 1x DAC/node streamer - undecided [BLUESOUND NODE or the AUDIOPHONICS RASPDAC an option for this budget]
6. (DAC connected through USB or wirelessly streamed via Spotify Connect - Streamed via an iPad through a lighting cable to USB adapter or wirelessly through Spotify Connect connected via a node, respectively (streaming via chrome-cast is not an option because of its inability of gapless playback)). I've also heard that the new YAMAHA RX receivers act as streamers for Spotify Connect and other applications.
   1. Possibility of an independent DAC Schiit Modi 3+ for better sound (as subjective as that is for the setup)
7. 1x Receiver to route all the incoming signal sources to the designated amplifiers and speakers - Need help in this department.

Option 2 / Small Budget differentials:

1. 3-4x Klipsch RP-600M II - also considering fitting them upside down with a tilt angle. The horns point downwards at the customers and the woofer closer to the ceiling to create a similar low-end response when placed ordinarily in a floor-standing position. But the 600 IIs would be mounted on the walls/columns versus being suspended from the ceiling.
2. 3-4x Reisong A10 - I heard great things & felt they'd be a good fit for the more budget friendlier option, but I'm concerned if they have enough oomph like the Decware Zen triodes to drive the speaker in a busy day
3. 1x Vaira Instruments RD20 in-house analogue D.J. rotary mixer

There are a few missing puzzle pieces in the system due to my lack of experience, and I was hoping that anyone could kindly assist me. Looking for a receiver that will take the 3 different sources (in-house D.J. mixer output, DAC-Streamer Spotify output & guest D.J.'s controller output) and send the output signal to all the amplifiers powering the speakers. Would home theatre A.V. receivers work? I've checked the backplate of most A.V. receiver products, and they all have 'surround', 'front', 'center' labels for the different speaker outputs. I'm worried about whether each pair of speakers would get other signals - which wouldn't work in my application.

I've also done my best to map out how the sound system component network would work with a resident D.J. system in a booth, guest D.J. with an external mixer, and DAC for regular musical playlist programming when there's no D.J. performing.

Would love to hear everyone's advice and thoughts on how I've designed the proposed system and mapped it out. I'm not sure if I've got the number of speakers right - it's tricky since where I'm located doesn't have proper HiFi audio dealers in the country - I can't test any components. The purchasing decision must be made based on faith and expertise. As you now learned, a lot would be riding on this

This project aims to bring a hi-fi experience to a population and culture that is not exposed to it and be inclusive in presenting it the best way possible with the budgets at hand.

Your input would be greatly appreciated!

P.S. Any thoughts of anyone who had listened to the active Superwax mini by Pitt & Giblin from Australia compared to Hersey's or other speakers from the heritage line-up?

From the legendary but sadly now defunct Welborne Labs.

Although meant for the Oris Horn, there is no crossover nor EQ but just a direct bypass for the fullrange output.

Bass output is crossed 2nd order at 180hz.

Upgraded with Elna cerafine capacitors and other goodies.

Comes with complete documentation and manual.

USD500 negotiable

I appreciate this might be a bit of an open ended question (and highly driver dependant) but, if you have a mid-bass driver that is better suited to a ported enclosure, is there any significant downside to using it in a sealed enclosure if you plan for the bass frequencies to be handled by a subwoofer?

The specific example is a Scan-Speak 21W/8554-00 8" mid-bass, which has an Efficiency Bandwidth Product (EBP, or fs/Qes) of 92. I understand that values under 50 are generally better for sealed enclosures and over 50 for ported; so this driver is very much in the "port it" range.

The predicted response for the driver in a 40 litre ported enclosure vs an 11 litre sealed indicates that it should be very similar down to around 130Hz, and only differing by ~2dB at 80Hz. If I were to use an 11 litre sealed design with a separate subwoofer crossed over at 100Hz, would this likely "work" (in the sense that there should be no negative consequences over 100Hz, and on the assumption the sub would provide sufficient bass below 100Hz)?

Diaphragm for Ribbon tweeters any size up to 25mm width, length unlimited. With or without corrugation. Thickness 5 microns.
Price up to size and complexity. Paypal payment.

Hi all, i have TDA1541 OS DAC and i need cheap high quality low powered SS amp "kit" for the DAC. I like the sound of the new Harman Kardon receivers, they have very clean sound almost like tube amplifiers with strong bass, is it possible to copy the amplifier, or any kit (high-current, ultrawide-bandwidth) amplifier?

Hi,

I'm looking for a high dynamic range dome tweeter in a standard 104mm faceplate.

I need something that hits 110dB/1m without dynamic range compression. ie. no loss in output when compared to 80dB@1m.
Needs to be able to cross around 2KHz- 2.5KHz with 3rd order electrical filter.

New Emotiva amplifier does not have an AC ground.......OH NO!

Erin's review on YouTube:

Login to view embedded media

Looking Candeias Engineering CC80 balanced amplifier modules.

Looking to buy CDM4/11 transport for my Philips Cd -472 CD player. My player's transport has been broken in transport.

Regards
Sachin

I recently ran an experiment with a small box and a midrange driver. The goal was to test the effects of different stuffing materials on the response. I shot these sweeps on REW and kept all the variables the same besides the materials used for stuffing. I'm not really sure how I should be interpreting the phase response graph and what is ideal.

Test 1: No stuffing, empty box

Both the frequency response and phase response are jagged. The pattern is broken up around 13khz, I'm assuming that is some kind of driver breakup causing a spike in FR.


Test 2: lightly stuffed with polyfill

In this test, the phase response seems to have flattened out significantly. My assumption is that this is a good thing since that means the different frequencies are more or less aligned closely?

Test 3: Tightly stuffed with polyfill

With the tightly stuffed polyfill, the phase response has gotten very smooth and linear. The FR has also smoothed out quite nicely.

So my question is, what is an ideal phase response? Subjectively speaking, what should a good phase response sound like?

I'm thinking of buying or building a simple sealed sub. Building would be fun, but I have other speaker projects that keep me occupied, so I don't absolutely need another one. So the question is this: If I have $500 to spend, to either build or buy a powered, sealed subwoofer, could I do much better than this SVS SB-1000? They claim an F3 of 24 Hz (is that believable?).

https://www.amazon.com/dp/B00AF88C0...82059&linkCode=osi&psc=1&tag=c_1c_a_o-20&th=1

My main interest is music, not home theater. And I'm sure I don't need 300 watts, 100 watts would probably be enough.

I want to end up with a compact powered, sealed, subwoofer. Is there a driver and plate amp I could buy for less that could be much better?

Thanks,
Eric

Greetings!

I got a good amplifier from a friend, the Carlsbro Powerline pro 2000. the main issue is, that the driver boards are missin.
I only have the transformer, power supply, input and output boards and potentiometer boards. I powered everything up, and the outputs work fine.
I dont know where the VAS and the IPS are located, i dont know if they are missing. I would like to kindly ask everybody for a schematic.
Without it i am in complete darkness. I would like to design around these boards, as i could get a really powerful PA amp out of them.

I have some vintage Germanium transistors i want to get rid off to pay some bills.


And some tubes.


I prefer to sell to EU customers because shipping overseas can be prohibitively expensive

Hello All,

A friend of mine wants help building some speakers for his workshop. The space is about 1300ft2 of almost open space.

Currently he is using a Rogue Sphinx to power some Klipsch KLF30sthat are about dead: couple of woofers no longer working, one crossover needs to be rebuilt, one tweeter needs to be replaced. He's interested in building some new speakers instead of repairing the Klipschs and really likes the look of the Liionidas speakers from Lii Audio. https://www.lii-audio.com/product/p...drivers-simple-and-musical-complete-solution/

I'm worried that these won't be able to fill his workshop like his current speakers.

Any thoughts or recommendations?

TIA

I have collected several European radio triode valves from the 1930s with bases like side contact, B5 and B7. Some with added diodes and top caps. They all have a gain (mu) of 30 or over and I have used them as drivers in my 2a3/300b amps. They sound wonderful and are little known gems, typically collected by radio enthusiasts for renovating old radios. Excellent as a driver stage or a line stage.

I will be offering several in this thread like REN904 types, MH4, AC2, ABC1 and so on. Most are 4v filaments, and there are also 13v/200mA versions. All are tested good. Many are very pretty with their gold or silver metallic coats. I also have a variety of bases like original side contact ones, since Chinese ones don't work. Contact me for more details.

So to start with here are some AC2 (4v) and CC2 (13v) plus 4D1 (13v). I have several more of each type.
Pair of 4D1 new in box £8
Pair AC2 Tungsram new looking £22
Pair of CC2 new in box, unopened £22

I will be listing many more in this thread. For details PM me or contact performanceandmedia@gmail.com Andy

Well used but not by me. Large phase plugs (wood), damping goop around magnet. Work fine, great shape.

$100 plus shipping, continental US only

Hi everyone,

i really need some help. I recently was searching eBay for a vintage Yamaha Amplifier. I wanted the A-760 but searching eBay for North America around someone selling an A-6. Well I didn’t do my research and just thought I’d was the same as the A-760 just Yamaha having the same amp with just another model number not realizing it was a Japanese model for 100 volts not our 120 volts. So basically to cut to the chase what do I need to do to it to make it a 120 volt model?
New power supply and a couple other things?
Will parts off the A-960 work? I just want to know what’s different between the A-6 and the A-760. The guy I bout it from said it works fine which it does except if there is a spike in power I can see it blowing. 100 and 120 is a big difference.

Thanks everyone

anthony

Hi,

I’ve tried to understand how to fix the thump when powering down, but I’m a bit overwhelmed from reading through the thread…

The VFet I have is the second version in the offering, and with my Cornwalls, there is a rather “potent” thump when powering down.

Trying to figure out how to best fix this problem, and and help with this would be greatly appreciated!

Thanks!

Per

Can anyone help me with documentation for these Oregon Electronic HV supplies, model D6? I could use at least the schematics and specs.

I saved these two beasts from the trash bin many years ago when my first employer was about to toss them out. They have rested in peace in my garage for 25 years awaiting my attention. I have no documentation, and web searches have brought me nothing useful. This company seems to have vaporized. I wonder if it might have been a spin-out by Tektronix employees. Both units are the same model although the front panels are different colors. One unit has a date code of 1956 on a choke.

Each unit has two separate HV regulated outputs, each adjustable from 0 to +600VDC. The raw +650VDC supply is brought out front too. These two outputs can be used separately or in parallel. There is an adjustable negative bias supply, 0 to -150VDC. A heater supply of 12.6VAC CT at 10A is available on the front terminals too. Meters indicate up to 600V, and 500mA. Tube complement includes six 807, one 6X5GT, two OD3, two 5R4WGY.

They would make useful bench supplies for any tube project up to and including large power amplifiers.

Does anyone know anything about these? Thanks in advance.

Looking for a pair of Tannoy 3833GG drivers.
These where used in the dmt 15 and the Churchill.

EF14 pentode in steel housing

I'm offering 2 pieces of Telefunken EF14 in a closed and sealed box!
The box is sealed with a banderole under the flap which has not been opened.
So these are 2 tubes in the condition in which they left the factory!

Since I don't want to open the boxes, I can't say anything about the condition of the tubes themselves.
But it can be assumed that they are in best conditions.

Private sale: no guarantee, no return.
180€ + shipping

Does anyone have a spare 15vac 100VA+ transformer going spare, ideally something decent such as Noratel.

Based in UK.

A pair of mark audio super pencils with the alpair 12p drivers.

Looking for £325 and will have to be collected from Bristol, UK.

Pair of emoto ultra ribbon super tweeters sitting on top. I am happy to include them in the sale for an extra £40 if someone is interested. I managed to drop one of them since owning these so they're not in perfect condition.

Thanks

Hey every, found this forum quite useful over the past few weeks so decided to join.

Recently started collecting older stereo gear, you know, just for fun and set up a test bench in my basement. Recently scored an audison lrx5 a single din pioneer premier deck thats never been used and a pair of older 5 1/4 pionner coax for $120. Just thought id share that excitment but thats another story.

My current system in my f150 consists of a kenwood dmx7706s
4 6.5 tc sounds tropo
Sundown saz1000d
Hertz hcp4
hertz mpk165.3


The reason for this post is i found what looks to be a decent set of hertz hsk 165xl. He was originally asking $400 but ive got him down to $290cad.

Only issue i can see in the pictures is that the crossovers are missing the plastic snap on covers and 1 terminal screw. Ive been googling for a day and cannot find replacement crossovers for these. Closest i can find are the 2tw10.4 crossovers that 'say' they are for the hsk set but im not so sure. Whats everyone here think of mismatching passive crossovers on sets? Maybe i can use different quality passives? Or should i just rock these without the covers? Worth $290 canadian? How do they compare to the mpk165.3?

Next question is, ive never really used 1 of those external active crossover things. I dont really want a dsp as i dont own a pc at home. Can anyone give me a quick low down on how i can incorporate an external active crossover into my system using a single 4 channel amp. Id love to try out active but this is my first time. Is it as simple as hooking up the rcas the mids and tweeters and then just adjusting the crossover points for each?

I just bought this little amp for a very good price. The first impressions are very positive. It looks nice, it has a 12" speaker, the sound is decent and it's far louder than what is acceptable at home.

However...

It has a very audible hiss. It's irrelevant while playing, but if you leave it on while you do other things it gets annoying.

The guts are a bit disappointing. SMPS and a TDA7294 circuit on the same board. And both channels go through the DSP on the front side.
I am afraid it's one of those devices that are destined to end up in a landfill after 5-6 years (unless you repurpose it or something).

The nice thing is that the chassis is roomy with lots of space for custom stuff.

So the DIY/mod plans so far are

• Add a 1/4 jack/plug so that I can reuse it as a cab
• Eventually change the speaker into something nicer
• Replace the SMPS with a nice lower V chunky transformer (and glass fuses), a normal and properly filtered bridge rectifier, and nice big CRC filters.
• Replace the 7x15 regulators with nicer ones with lower impedance and less noise.
• Replace the TDA7294 circuit with an LM1875 at 20W (or even less, I will have to coordinate the PSU first) and proper beefy capacitance
• Change the crappy plastic switches/buttons with nicer metal ones
• Add a buffered FX loop
• Prepare for replacement preamps or something for when the DSP goes to the big gig in the sky

Any other suggestions?

Hi,
Hope someone can help, I had one channel blown on a sony TA-2650 so replaced the pre drivers and two matching pair of power transistors, powering up with
lamp tester I noticed the bias would shoot up and found SV04F (diode D101 & D201) faulty, If i rapidly cool it with freeze spray the bias shot down again. So got 3x 1N3595 in series mount on the original mounting expoy resigned to the mounting and secured to the original transistor, noticed that the other channel was also fluctuating a bit and very unsteady so replaced that SV04F also, but now the bias only goes to max of about 2mA with the trim pot, the other channel is the same, so the SV04, 3 diodes in series is causing this, as the good channel (fluctuating) on was able to bias higher with old SV04F....does anyone know which resistors I need to up in size or lower in size to compensate please ? Thanks in advance