Has anyone brought one of these. I should get one in the next day or two to assemble. It took a long time to get delivered because the 1st one shipped got bounced back to the seller.

I was looking for a low power reasonable performing 2 channel amp to run my tweeters in tri-amp speaker. The specs aren't the best, but seem ok if you don't push the limits of its power. I doubt if I would use more than 10w peak. The reason for this choice it is seems to have speaker protection that I hope works during power on and power off cycles. Going to use a 100VA 36vct transformer with it. After I bench test it if it works well I have to find a case and heatsink for it.


2018 GC version LM4766 dual channel HIFI power amplifier board diy kit | eBay

I'm not sure what is wrong with this amplifier, it Powers up and has a different curcuit than the cxa amplifiers. There is no output at the speaker terminals.

Hi,

I recently bought a paire of Onken enclosure for Alpair 7.
As I had already built FH3, FHXL , Pensil, I wanted something different and decided to buy a pair of MAOP 7...the last project ;-)
Well, not sure if I want to keep this enclosure or go back to FH3....I may be tempted by a WAW project.
What are the best option regarding the onken enclosure?
Keeping the Onken and build another onken WAW?
Or a brand new project?
Crossing must be analogue
Thanks for your help.

Ok after hooking up my old record player for the first time in 23 years I was very impressed by the sound of it. (using an old pioneer receiver for phono stage).
So I decided to start picking up vinyl. Bought an old thorens td 125 turnable but now I need a decent phono pre.

I wanna build the Aleph Ono with mc part included.

I got a pcb layout and Bom from another forum very kind forum member (sylvian bergeron) . But these are in dns format which I can’t open and even if I could I don’t have any experience working with pcb routing software.

They are mono boards
It is a version without output capacitor.

The power regulator and power transformer are on separate pcb’s so it is’ actually the xono version.
I will make these two relative simpel psu boards just the old fashioned way with a permanent marker.

there ’s a company here in the Netherlands that can make the pcbs for the main amplifier board.

They charge me the following

PCB 220x115mm - finishing with HASL, Green soldermask, White component printing

45 eur for converting DNS to gerber RS274X

2 pieces for Euro 99,42 (per print €49,71)
5 pieces for Euro 136,80 (per print €27,36)

Delivery Euro 6,00

delivery time between 1 and 2 weeks

And underneath the actual questions:

Is there anyone one out there who owns a set of pcb’s that you are willing to sell or know where to by them?

Is this a competitive price and where in the Netherlands do I get a better deal?
would anyone be interested in pcb’s?
(so I can order more pieces to reduce costs)

Ok that is a long story for some simpel questions

Anyhow awaiting yourrespons

I ordered two 2x10" sealed vertical cabinets that will serve as both subwoofers and stands for a pair of bookshelf speakers. I am buying a Minidsp SHD and will be using room correction and active crossover between the bookshelves and the subs. I will be playing around with different crossover points and curves to find what works best for me, but I think I will be somewhere in the 250-500hz range.



Are the Peerless by Tymphany 830668 are a good choice for this setup? Are there better options out there for the price, or will these do just fine? The enclosures are 2 cubic ft a piece, so 1 cubic ft per sub.

Hi, Gang,

I'm redoing my PAS-3X and will not be going back. But - I know someone who wants to keep the tone controls prefer the 3X versions as they are out of the circuit at center position.
I'm including the local caps and knobs, to be fair, the knobs are pretty ratty but I think they should go as a set.
I'm not sure what a fair price is, so here goes - $35 + shipping, or best offer. If these sell today, maybe I was a bit low. And seriously, if I'm out to lunch on my pricing, feel free to let me know.

Thanks,
Frank

FS.GENUINE PETER DANIEL AUDIOSECTOR LM3875 KIT ASSEMBLED BOARDS PLUS HIGH QUALITY CASE.NEVER USED.COMLETE WITH INSTRUCTION MANUAL.JUST ADD TRANSFORMER.UK/EU SALE ONLY.£85 plus postage at cost.

I want to ask about the corona wind type plasma,like the Plasmasonic headphones or the Nelson pass cloud speaker,I believe the Corona tweeter from Lansche is the same type,its corona discharge that is modulated push pull from both sides by electrostatic force,like a Stax but instead of membrane there is plasma.

its different from Alen Hills Plasmatronic /Magnat sphere tweeter/Ionovac,these are glow discharge that makes sound by getting bigger hotter and then cooler smaller.This is picture of the Plasmasonic headphones

My question is,how can this "corona wind" type plasma device work? I learned that the net charge of plasma is neutral,so how can the push pull stators push it with electrostatic force if the plasma is neutral?

When I imagined it in my head,when one stator is negatively charged,and other positively charged,wouldnt the plasma cloud go both ways?! I mean the negative charged particles in plasma cloud go in the direction of positive stator,and positively charged part of plasma goes the other way towards negative stator,my thinking is probably wrong?


Is it possible to make the plasma cloud have net negative charge instead of net neutral?

I have one pair of the SB Acoustics Satori MW16PNW-4 for sale. This is the 6 1/2 inch white cone mid-woofer, 4 Ohm. Asking $150 US; I will ship for free inside the US only.

I have one pair of the Aurum Cantus G3Si ribbon tweeters for sale. Asking $150 US; I will ship for free inside the US only.

Neither of these have ever been abused or over driven. They have never been soldered.

I doubt I have the original shipping boxes but I will very carefully pack them and double box them to keep them safe.

I have a PayPal account; please send me a Private Message if seriously interested.

1 pair gently used, never soldered SB17 CAC35-4 Mid Woofers.

Priced at $86.50 each on Madisound, etc.

Asking $150; will take serious other offers.

Great for a 2-way or even very small 3-way; very low distortion, ceramic coated aluminum cones. These are 4 Ohms; works well in closed box 7 liters and up; works well vented in 18 liters and up.

I agree to pay shipping but ONLY inside USA lower 48!

PM for SERIOUS inquiries ONLY!

Hello,

I'll be building a new set of cabinets, the same as my last set but they weren't didn't fit as tightly together as I would've liked. So I'll be building another pair which will then be veneered and finished by Boesch who usually renovate and finish classic Rivas.

When I was putting together my previous pair and I was fitting the Silent Coat butyl damping sheets I noticed that it didn't actually make that much of a difference at all when I gave a knock on the wooden panels. Do you know at wat sort of frequencies butyl damping is most effective? And what are the most effective damping compound to fit in different chambers of the speaker? What would be most effective in a bass cabinet (20 - 300 Hz) and what would be most effective in midrange chamber (300 - 3.000 Hz)?

Would like to hear your suggestions.

Thread closed.

I have a built SB15SFCR39-8 passive woofer that I no longer require. It was built Jan 2020 to test the woofer and then used in a small 2.1 system. The enclosure has been built with an industrial theme, removable baffle and uses birch plywood coated in clear matt polyurethane. It does not include the isolation feet (in pic) which have been replaced with nail in nylon floor protectors.

This is not a subwoofer but a woofer for use in a small to medium room partnered with small speakers to make a 2.1 system.

Woofer SB15SFCR39-8 which is equivalent to a 7" woofer and has been coated with Visaton LTS50 to protect and dampen the cone.
Vb=23 litres, ø63 port, Fb=33Hz, F3=41Hz, F6=34Hz, SPL=87dB, rated power 60W.

There is no crossover, active filter or amplifier and would be suitable for a builder of electronics who can build a sub processor (stereo-mono mixer, filter, gain, phase) and a small power amp. If a passive xo is required then a filter using 22mH + 100uF 2nd order works well.

Pick up only in the Newcastle NSW area (close to Belmont).

I have had the folly to bid and buy the following turntable but realised (too late) that the output cables may not be at all the standard ones but instead the Hypertac ones. I am not an engeneer and therefore would have no idea how to connect them to my Rogers Ls 5/8.



Can someone tell me whether the unit has normal output or only the Hypertac one ?


Thank you very much !



Having forked out 2200 UKP you can understand that I am rather worried ...



Alexander , the audio fool

Looking for one or two pair Acoustic Elegance Dipole 15. Paying with paypal.
I prefer a seller from Europe. Please PM me.

Thank you!

Andre

Time to break down and upgrade my old Tek scope. It is great, but I really want a storage scope. Don't need it fast. The last storage scopes I used were still phosphor storage (mainframes and 466)

Looking at auction offerings,
Tektronix 2000 series, much older, controls like on my old one.
Tektronix 300 series, circa 93-94 or so. CRT based
Tektronix 1000 series, the newer LCD based
Some HPs, but I know little about them. Always had Tek back in the factory. Some newer off brands, but I know zero about them.

Then there are the PC based USB scopes. We get a bigger screen of course, but do they really do the job of a traditional external trigger, delayed sweep, storage etc? I guess as slow as 20Mhz would be OK.

The "boss" wants me to spend less than $200. Just outbid on a 1002B last night.

I'm looking for a very simple DSP crossover. I have found trigaudio and I am negotiating with them. They normally sell in MOQ 300, and I need maximum 20 (for reselling in my small DIY shop).

Are there any other alternatives. I'm not looking for a MiniDSP competitor, but just a very basic board.

Dear members,

Because the original plate amp from Final S220 subwoofer died, I ordered a Hypex FA251 plate amp. Not knowing there are no filters installed...... I read the manual and searched for tutorials but I haven't got a clue what to do😕

First of all, do i need measurements to design the filter or can i use some sort of default settings for subwoofers?

I attached the specifications from the manual.

Thanks in advance.

Barry

Well, 2 months after warranty has ended my power supply stopped working.
I replaced fuse and found it still not turn on and had a bad smell to it. So I opened it up and found C3 completely burnt out and cracked. Does anybody know the value or has schematics?

Thank in advance
Neville

Hi.I found these drivers on taobao com. Do you think they worth the money ? Does anyone have experience with them?
Here the drivers
https://world.taobao.com/item/528908373538.htm?spm=a312a.7700714.0.0.HxRUd3#detail

https://world.taobao.com/item/531656628653.htm?spm=a312a.7700714.0.0.MLY787#detail
Best regards

Hello, asking for help please in trying to identify a kind of subwoofer I've seen in the past and remember vague details about.

It has like a curve sided V in the front of the driver. Not fully enclosed. I believe it was first worked out by a Dutchman? Used in the 1950s originally.

Thanks!

Hello all,everybody.
I was asked to repair a previously repaired Audison lrx 4.000.
What are its original mosfets? where can I find the wiring diagram ?

Thanks

OB/FR is where I ended up finding myself seeing 'Nirvana' after much experimentation and study. Simply my preferences, not necessarily anyone else's Cup of Tea. Still crazy over Horns, simply no room for them.

I'm an admitted Couch Potato when not online or working so HT is important to me as well as music. My music takes preference regards quality of sound and a year ago I saw myself needing separate systems for each. When I started studying amplification I also saw myself investing bucco dollaro to meet all needs.

Of late I'm wondering if all this is necessary for those of us of meager means.

I'd like to see sensitivity of high 90's for music just because of distortion concerns, not because I'd seek lower powered amps. Subs don't really concern me that much as to my way of thinking I see all kinds of options there that I believe would integrate fairly well for Movie use and I personally don't need to rattle the walls for entertainment when a helicopter flies over. Again, simply me.

Some guys run tubes for both music and HT. Out of the question financially for many of us as well as beyond our DIY skills for many. I'm not seeing GC as a meets all needs alternative anymore and even done DIY properly not an inexpensive task. I do like them as alternatives to standard fare for Office use and plan to limit my excursions there to that purpose for near future. Of late I'm also over at Nelson's page primarily spurred on by Scott Mouses comments regards build difficulty being easier than many GC's in another thread. I'm also impressed as to how many testimonies from guys believing they sound just as good as or even better than tubes. They are still beyond my skill levels without a good deal more reading. Financially appears to be doable.

Stay with me on this, I'm getting there.

Posted in another recent thread I bring into play the multi amp units from Emotiva, Outlaw, Rotel and even used Bryston. You can't knock a 20 year transferable warranty. 3 years old Brystons are fairly affordable and most that invested that initial sticker price likely treated such as the investment they were.

I don't personally know tubes but all that run them claim this is the ultimate. Financially I'm starting to see these above mentioned units as 2nd. best alternative and combined with high sensitivity OB/FR speakers a good bet for both music and HT . I haven't read a great deal about each companies processors but I'm sure there is a Sub out and if not many are versatile enough in hook-up options to get you plenty of power for Subs unless you simply must have 20hz. at 110 decibels.

Adding an active XO and equalizer if individual felt such necessary (I'm not convinced, especially if you used dual Subs, think gain settings likely adequate) should integrate well enough to give you a pretty kick tail music and HT system for reasonable dollars.

Many guys are posting low buck OB efforts of late but some don't meet both needs and several that appear they would aren't telling us how they are powering same.

Moderator - Asking much but could we see a separate gallery section for OB efforts? It's growing rapidly.

I'd like to hear from those of you who have built that are happy if you believe your choice meets both HT and Music needs as well as how you amplified. Kind of a dual topic question but really a combined question I thought answered best posted here.

Move it if you desire.

Show off guys - please. Many of us want the whole story.

Thanks - Bluto

I'm trying to design a sub-sofa subwoofer using the RSS265HO-44 and can get what seems to be a nice enough power response using the LS wizard by tweaking the sliders and adding polyfill etc, but a pretty ordinary power response overall when I go back to the main screen.

And that's after 'saving' the response in the LS Wizard.

Can anyone tell me which is likely to be more representative of the real world response??

Auditorium 23 Hommage Cinema loudspeaker | Stereophile.com

Link above. Can someone explain to me the midrange horn expansion? From the outside it looks like a parallel wall tractrix deal with the compression driver just dumping into the back end, but that cannot be the case, else it would have some high q tomfoolery in band.

Is there an initial expansion that is folded inside that I can’t see? Any guesses?

Edit: oooh is there an expansion that passes down, through the final expansion, into that horn ‘base’ then curves around to the back of the final expansion? Like one of those western electric horns that passes through itself...??

Hi,
I have pondered a more powerful single ended design than the SE El509 in triode or SE300B'

Both the 6C33C and GM70 are capable of at least 15 - 20 watts

The GM70 run at lower B+ say 750- 850v DC appeals to me

I have some 6C33C tubes but read they are problematic to balance and stabilize .

Welcome idea's on this issue and driver tubes used .

I learned from Morgan Jones Valve Amplifiers that the min current required for choke input is approximately equal to Vin(rms) divided by L(H). That means as the current is lower the induction has to be higher. I wonder if this formula still apply if chokes are in series and using the total induction summed up??

Hello

I am looking for the datasheet of this DAC because I want to tweak a Audio Alchemy "Dac In The Box". I want to know if I can supply it with +- 12 V in the analog part.

Thanks

Philippe

CEC (C.E.C) claim by their mostly amplifier models, it's class A (here in Germany even "Pure Class A") The name of circuit topology is "LEF (Load Effect Free). The developer is Mr. Carlos Candeias. Have a look to this URLs: Amp 3300R:
CEC AMP3300R
and Amp 5300R (Amp5300R Amp 5300R Amp5300)
CEC EUROPE WEBSITE
The last model delivers 120W/8 ohms and 135W/4 ohms, as to read in the CEC datasheet
If anybody can posted the schematic of one of both models, I will make an evaluation. I guess, the term "Pure Class A" is concerning the pre-driver stage and driver stage of a push pull complementary CFP resp. Sziklai pair, but I don't know this exactly.
If there really pure Class A by the output power devices, where is a heatsink with the appropriate sizes?
Thank you very much for your posted schematics in advance

You could say this is a self induced nightmare as I knew buying the Shanling cd-t80 on ebay from a seller in China would void the warranty. After using it for very few hours the cd stopped spinning. The lens still moves to try to read the disc. After a few seconds it displays the no cd message. So now I have a nice looking, aluminum clad, rather large paperweight for my desk. I was using a Radio Shack step up transformer to power it up. I wonder if that could have caused a problem as the voltage would still be 60cps not the 50cps as it was designed to run on. I was told this wouldn't be a problem. What is a problem are the audio withdrawal symptoms I'm now experiencing now that I don't have the Shanling to listen to anymore. The upgrade in sound the player gave me was amazing. I'm thinking of buying from an authorized local audio dealer the new cd3000 that Shanling just recently introduced. Anyone interested in a big paperweight? Maybe I'll list it on ebay and chalk it up to a lesson learned the hard way.

Despite lacking expertise, someone asked me to see if I could determine why a Rotel RA-1412 is not working. It has dual power supplies and my first thought was to look there. My skills are rudimentary and with some coaching, it appears that both power supplies are OK.

The amplifier's problem is no audio output. The first thing I noticed was two 8 amp rail fuses were missing on the left channel's power supply board. Replacing them cause a DBT to glow brightly. I checked rectifer diodes, stabilizer transistor and output transistors.

Two of the four left side outputs are blown which are 2SD426. The internet searching I did this afternoon identifed two potential replacement candidates. MJ15022 and MJ21194. Limited quantities of both are on hand at a major supplier.

I am poor at reading data sheets.

Both of those tentative replacements claim audio amplifiers as an application. But most if not all their numbers exceed those of a 2SD426.

I understand that within some parameters, more can be inconsequential or perhaps even better. My hope is that someone here can either vouch for an MJ15022 or MJ21194 as being suitable or suggest an altogether different one.

At this time, my intention is replacing all four 2SD426 outputs on the left channel only. Being dual power supplies, my thought was to leave the right channel's functioning 2SD426 outputs in place.

I opened up my very inexpensive dvd player yesterday to try to look for upgrade options. I noticed that the opamp used for the audio output was an NE5532. Could anyone recommend a specific opamp to upgrade to, or is the NE5532 a decent opamp that I shouldn't worry about replacing for now. I noticed someone talking about an OPA2134 as a replacment. Any suggestions would be apprecited.

Thanks

Rob

Hey guys,
Having a problem with a Sony 5-CD changer. When I load a disc, the mechanism grabs it and starts to spin it, but the disc won't read. No track count, total time etc. Pressing play only shows an attempt to read track 1, but then it goes back to showing "0" on the display. The disc spins perpetually, even if I press the stop button. It will only stop and return the disc to the slot when you press eject.
When spinning, it makes a chirpy sound -- like the laser is trying? Not really sure (see video: Shared album - Simon Cohen - Google Photos ).
I've tried cleaning the CD and the lens with isopropyl alcohol -- no difference.

Other things I've tried to diagnose:
- Laser diode appears to work -- I can see a faint purple light when the diode pops up to read the disc
- Tracking servo appears to work -- when I advance the module on the rail manually, and press play, it returns to the closest position to the hub.

Any bright ideas or is this thing toast?
Thanks!

Hi Everyone

I changed the electrolytics in my friend's Pass Volksamp Aleph 30 based on the recos I received in this thread:

Best choice for Aleph 30 re-cap

I'm now testing the amp to confirm everything is operating within spec. Can someone kindly confirm if following measurements are OK?

1) Both + & - power supply measurements show 25.6V DC with 64 mV ripple.

2) DC offset is 73 mV on one channel and 10 mV on the other; I believe these are fine, but is it unusual for the channels to vary that much?

3) I'd like to check the bias, but I'm not sure where the test points are. The amp is physically a little warmer than I'd expect at 56C.

Thanks in advance

I know enough about electronics to be dangerous, and my forte is old tube radios, so trying to figure out the protection system in a modern-ish hi fi amp has me puzzled, especially since Denon doesn't put voltages or useful circuit descriptions in their service manuals. I guess if I was a qualified service technician I would already know, right?



So, what had happened was:
I turned on the amp, and it hung at "1 Front Large". (I only have 2 speakers and was using it in stereo mode). Front controls were non-responsive. I didn't realize that was the protect mode, but...


(If I remember correctly, it had turned on, but I had a phono pre-amp plugged into the front AV inputs I'd forgotten to turn on, and didn't want to frighten the Denon, so I turned it off to turn on the pre-amp, and when I switched it on, that's when it would no longer work.)



I took the thing apart and immediately recognized 2 very swollen 10,000 uF capacitors. Well I know about caps, and I measured them, and they were about 30 or so uF each. Wow, how did I not hear hum as they slowly deteriorated? Anyway, Mouser has some nice Nichicons, so I replaced those, and a handful of other power supply caps for the helluvit, and...


No change. I was thinking maybe it's the microprocessor, because certainly it would tell me if it was in protection, right?


Anyway, after much futzing around, I decided to connect speakers to it, and noticed it only sends output to the Front B speakers. (Nothing on the front works, so no volume, no speaker selection, etc.) I noticed a loud pop, a brief hum, and then nothing. I then noticed the woofer of my cheap test speakers was being pulled way in. DC! Holy crap.


Disconnected the speakers and put some 10 ohm resistors (about 5 watts) so I could poke around. Yep, DC on the collectors of the front Left and Right channels. Also, wide DC swings on the base of both.


I disconnected the pre-amp board, to see if that was the source of this DC voltage into the power amp stage, and that disabled the protect circuit, the base voltage swung above my scope's screen, and before I could comprehend what was happening, I heard my 10 ohm resistors sizzling and burning.


Now they're 20 ohm's each! OK, so we'll put the preamp board back in.


Trouble is, I can't figure out what would affect both channels the same, and whether the bad caps had anything to do with it.


All DC voltages from the power supply seem normal.


The service manual is available from VinylEngine, but I don't have permission to post a link here. I presume Denon's amps of the mid-2000s are similarly designed, and hopefully someone can guide me.


A good tutorial on how these amps work, and a way to figure out which transistors are part of the amplifier, and which ones are part of the protect circuit would be helpful, as would some basic things I could check.


I have a scope, a soldering iron, and an account at Mouser, so that's enough to make me dangerous, I think. I would like to get this thing fixed and off my bench so I can go back to my tube radios and record players.


Thanks.


Dan

FS: 2x completed LM3886DR [SOLD]

Everything is now SOLD

Update Dec 13, 2020: SOLD

Update Nov 22, 2020: chassis is sold, only boards remain

The pictures show a chassis, but that is not included. Only the completed LM3886DR boards and cables are offered. See post #5 below.

For sale is a pair of completed Neurochrome LM3886 Done Right modules.

I built these about two years ago, see here.

I have since pulled that Connex SMPS for use in another project. I have too many amps and am trying to downsize and declutter!

Asking $50 (USD) for local pickup, or $65 shipped in the USA (USPS flat rate priority box). Domestic only at this time (sorry, can't do international right now).

Thanks for looking!

There are several quantitative measurements for low voltage audio power supplies which are easy to implement -- PSRR, Output Impedance (and transient response), Noise, etc. In the digital audio realm, I would guess that reverse PSRR could also be important. More difficult to measure are regulator error amplifier issues.

Which do you consider to be the most important criteria for vacuum tube power supplies?

PSRR, or "Line Rejection"?
Output Impedance (or transient response)
Noise

cosmetically nice, no lock assemblies only suspension, no cover
1019 has good quiet motor, needs lube job. I cannot change speed, runout return working has Shure M44E cart and stylus. $125 + shipping

Does anyone know where I can get a manual for this meter? I've had it for years and have lost mine. I am not having luck finding one online. I sent a message through the mastech website and got an error message in Chinese...

Hi all,
Just found this place! Looking forward to annoying everyone with, hopefully not-to-stupid questions! 🙂 So far I've built Adire's Kit 281, 81's and did a few Tempest subs, currently a twin Tempest sealed.

So, first up....

I've seen this in the PE catalog and was wondering what they are used for?
Would these "help" a driver that "works best in a vented enclosure" if used in a sealed box?

Pete

I have a XA900 amp with some issues and Im looking for a schematic for it. Ive searched online with no results.

Hello fellow Audio Diy-ers,

I want to install some acoustic panels that can be easily removed, so I started thinking about how to build some standing acoustic panels that can be easily moved around

Basically my idea is to buy some 36"x80" bi-foldable doors (possibily used to save some $$) and glue 2" acoustic cotton on them and then wrap them in acoustic fabric.

In this way, if I keep the foldable panels not fully opened they would be able to stand without hanging them to the walls and I can move them around to find the best placement.

Has anyone tried a similar solution before? ..or is there any reason why this could be a bad idea?
Thanks everyone in advance for your suggestions/ideas

Is anyone familiar with the ting sensor? Our homeowners insurance is offering one for free with 3 years service. It is supposed to sense "electrical arcs, sparks, faulty switches, overloaded circuits, etc. in a home electrical wiring system."

It sounds great but I'm not a fan of all the legal mumbo jumbo agreeing to having them send an electrician of their choice to 'fix' any issues. And things like "We also collect certain information regarding devices that are connected to the same wireless network that the Ting sensor is connected to" bug me.

Does anyone use one?

Just popping ideas about a current drive amplifier driving a fullrange or midrange/tweeter section of a speaker.

What would be the simplest way? An output transformer with a pentode/tetrode output section? As a transformer winder I have the freedom to wind anything. Pentodes would favor high Ls low Cp/Cs OPTs.

But what about linearity? Pentodes are famous for potentially giving more odd-order distortion. Then I should introduce local NFB, but voltage NFB will decrease output impedance, which we don't want. Current FB perhaps?

Just started to build this stereo tube amplifier based on 4xEL84 and 2x6N2P tubes from Die Röhre, Wulfert audio.
www.dieroehre1.com

Stereo PP Endverstärker (Leerplatine) EL84 autobias sym | on eBay (search)

If anyone has experience to build this kit, all tips will be much appreciated... Wondering particularly how to combine volume potentiometer with balanced and unbalanced input (any suggestions...). And if power transformer is not shield, it should not affect the quality of sound?

Hi,

Would it be possible to modify this active crossover circuit with dual ac supply to work with single dc supply?

Linkwitz-Riley Electronic Crossover

24 dB/Octave 2-Way Linkwitz-Riley Electronic Crossover for ICEpower 50ASX2se -
EasyEDA

How to use an opamp with a single supply - YouTube

As new condition. Wires have not been shortened. Stunning amount of low level detail and bass power in my 2A3 amp.

€1000 inclusive of shipping within EU. Not really keen to ship outside EU, so Brexiteers, don't miss your chance 😀

Hi all,
I’m very tempted to build 2 HD15s side by side, like the old Turbosound tse 2x15... to go under 4 Turbosound tse 111s.... HD15s fit my size limits perfectly, frequency wise I’m only after 50hz and up so don’t need anything lower...

2 HD15s look good to me in hornsrep with the driver I have picked, but I’m concerned the driver might not be strong enough and have enough Xmax.. I’m looking for some advise on this driver and weather it will work and if the results will actually be close to the hornsrep predictions

If not I need a neo driver that will work in this design and give a good solid 55hz to 50hz On up.

Driver is a fatial pro 15PR400 4ohm..

Hornsrep result of 2 HD15s and diver attached

Thanks
Luke

The original (now obsolete) relay is the Omron G2VN-237P-US 12V

My candidate for substitution is the Omron G5V-2-DC12

Comparing relay specs makes my head hurt, so I could use another set of eyes.


UPDATE: For posterity, Omron confirmed that G5V-2-H-DC12 (linked below) is the correct sub.

The old classic it worked before the recap! I made the mistake of not checking the polarity of the capacitors and installed C19 backwards 🙁. Its been on a dim bulb since the recap not full mains but alas somethings not right and I just cannot find the fault.

The amp seems to work when the tone controls are switched into the circuit, When they are switched off the amp faults and the relay chatters along with itself for a minute or so then stops with the relay open i.e in protection.

Any ideas what I could have damaged? any of the IC's?

SOLD!
Hello.
I was looking for a single 18W/8531-G00 to mate to this unit, but I found a pair, so here for sale this SINGLE UNIT.

Slightly used and in very good aesthetic and working condition.
No solders on terminals.

Asking 70€ plus shipping and PP fees
Shipping to most EU countries is 16€

Apologies for starting a new thread, but I could only find bits and pieces of info buried deep in other threads and wanted to confirm a few things on a capacitor across the AC line for my tubelab SE (120V North America)



1) The Capacitor I got is an X1 .1uf rated for 530VAC. I believe this would be appropriate, right? I wasn't sure because people were talking about caps rated for 1-2Kv.



2) Any consensus on where to wire it in? Is across the AC switch okay?



3) I read some people have a resister involved as well -- what is the purpose of this? And if I wanted to do that since I'm in there anyway, what is an appropriate value and wattage rating?


Confirmation / help would be much appreciated - I'm nervous to put something that will be touching live AC 24/7 without completely understanding.



Thanks!

SOLD Pair Eminence N314x-8 TeXtreme Compression Drivers

11/21--SOLD

I got these for a project I just don't have time to build. Used for a couple hours on a pair of JBL 2384 horns. Sitting on shelf for months, collecting dust.

Very smooth sounding beautiful midrange with the carbon fiber TeXtreme diaphragms.

$500/BO for the pair + we split shipping.

1. Rifa PEH169 33000/100v. Light use in various prototypes. €50 each. 4 available.

2. Nichicon NT 33000/160v. Practically brand new, used for only a few hours. Surprisingly good sounding. Current Mouser price €110 before VAT. €50 each. 4 available.

3. Rifa/Kemet PEH169 10000/63v. Used. €15 each, 10 available.

Shipping withing EU.

Anyone have a pic of this area ?

I believe the title says it all.

And, as the title will tell you, i am totally new to all this DIY speaker crossover lark.
I have gathered, however, that the hardest part is getting the crossover right.
So i was wondering if i could maybe buy a used cheap active digital crossover (Behringer DCX2496 is most common, and can be modded easily & cheaply to sound better), get the crossover frequencies & slopes right for my drivers+cabinet, and then probably get a helpful soul to assist in the design of the analog passive crossover.
I'd imagine it wouldn't be perfect, but i'd also imagine it would be closer than what i would achieve without the digital active crossover to experiment with.

Now, if it can help, here is my aim:
- tri-amped 3 way speaker that goes down to 25 Hz or so
- flat, neutral
- detailed, analytical (PMC IB1S / MB2 are the inspiration here)
- used as monitors in a professional recording studio
- the amp is a hybrid tube amp, the DARED DV6C, a 6 channel amp.

First, i will probably go for an open cabinet 3 way design with cheap drivers, but the project above is the ultimate aim.

Thanks to all !
Rick

SOLD

Can anyone give any guidance on the question of survival of viruses on surfaces like vacuum tubes? When buying tubes it's possible to be exposed to the risk of virus survival on surfaces like glass, where according to Australian research it can survive for up to 28 days at room temp (20°C), though this drops significantly at 40° or higher.

Unfortunately, cleaning the tube with either soap or alcohol wipes off the label and devalues the tube considerably, so that's a poor option. I've been wiping the base with alcohol and then heating the tube via its heaters, which I assume does the job. But I'm wondering about putting tubes in a microwave, and also doing the same with tube boxes. Or are there other choices?

Can anyone provide any useful guidance on this? Could also be useful to know about metal surfaces etc.

First time only Q6 was shorted between Base and Emitter.

4 Ohm bridge bench test passed.

During 2 Ohm bench test amp gone in protection near clipping point

This time Q6, Q5 and ZD6 failed.

Changed parts and during 4 Ohm bridge bench test amp gone again in protection.

This time only Q281 failed. N Channel Mosfet FQP33N10.

Both, Q281, Q181 changed. Set Bias and test it again.

Heat up amp with 8A Power consumption, clean sine wave, gain works properly.

After heating up, amp was a long time in idle current, maybe one hour. Remove remote, apply remote, Q6 again shorted between Base and Emitter.

Any idea?

So i have built said enclosures form thick cardboard like materials about 1/2" wall thickness. These performed well but I can't get that material anymore. So I would like to know if anyone has ideas on this. I have tried sonotube from hardware store and it just seems too thin walled. Maybe 1/16" wall thickness. Has anyone tried 2 different diameters of sonotube one inside the other and pour concrete between the two? Is concrete non porous enough? Anyway like the tube idea just need to knbow where I can get it with thick enough walls.

Hello all. I am soft of new to this, so please bare with me.



I have a small problem with my PAM8610 amp which I can't for the life of me figure out. I am using this board to connect an external speaker to an IP camera. The actual setup works. I am able to talk to the camera. However, there is a faint humming and sort of popping sound coming out of the speaker. As soon as I disconnect the input line the popping stops. I am not concerned about the fain humming as much as I am concerned about the popping sound.



As you can see from the photo I added a 100k resistor to the speaker output, which reduced the popping by about 90%. Anyway to completely remove the popping sound?


Thank you all in advanced!

I'm rebuilding a McIntosh C27 preamp and I'm having trouble discerning the orientation of eight, small, 2.2uf electrolytic caps in the pushbutton assembly. The schematic is too large to upload completely, so I've enclosed some pertinent pages. It appears to me that the schematic and pcb outline board are in conflict as to orientation. If I'm wrong on that, please set me straight. If there is a conflict, then could someone tell me which of the two exhibits is correct. Thanks in advance.

For sale:
2 pieces of Audax Tweeters TM025F1.

The units are in good condition.
Their terminals have been soldered.
Only the plastic around the 4 front supporting holes need a little attention not to crack (see photo).

Price is 30 Euros for both.

Wanted Pete Millet 6P1 preamp board with Nutube or completed preamp.

This is a CD of Lute, etc. music but I can't seem to find it in the USA or Canada or even the UK online. Maybe it is available in continental Europe or Asia?

The label says INTAVOLATURA GLCD 4001



The title is "Intavolatura Di Liuto, Tiorba E Di, Chitarrone" The artist is Olav Strandberg.

Can those of you into Baroque music with connections to music CD suppliers have a look for me? PM me if you have any luck at all.

Thanks!

Olav Strandberg - YouTube

I found this on YT

Hello guys, I’m desperate to find an original power supply for this amp. It was handed down to me and I listened to it all the time but my partner threw out the power supply by mistake thinking it was for the keyboard we were getting rid of!!! 😡

If they are pure unobtainium would anyone happen to have a circuit diagram or know how to make one?? I have done a little research and there isn’t much online wrt the power supply. What I did find is what it needs a 19v+/- ac supply.

Any help would be much appreciated.

Matt

If you have or have a source that you know has real, not counterfeit parts, let me know.

I know I can order from China, but can't confirm real parts.

THANKS!

Greg in Mississippi

I have put up a wiki page for my SSR03 super regulator power supply group buy.
Picture

Wiki page

If you think it's too complicated to sign up, just send me a message and I'll do it for you.

looking for ideas and thoughts.

I don't have much space for my gear. at the moment its on top of a small cabinet. To free up some space I'm considering building/buying some kind of platform to raise my turntable and place a small dac, media player and phono stage underneath.

can anyone think of a reason why this would be a bad idea, or failing that any tips or ideas before I spend money?

thanks all

I thought I'd start a thread on this subwoofer alignment that you rarely see mentioned. For those who don't know, a "passively-assisted" sealed alignment is basically a basic sealed alignment with capacitance added in series with the driver's coils. Do this right and result is an extended bass response.

Wait, that does not sound right does it - capacitors are supposed to reduce the response at low frequencies....

The key here is the AMOUNT of capacitance that's added. Add the right amount and, instead of reducing bass output at low frequencies, you end up extending it, a bit like a vented alignment, without the vent and larger box. While it's supposed to work best with high Qms drivers, it should be possible to use the idea with any sealed alignment, and the impact of added capacitance on a sealed alignment can be sim'd pretty easily with any decent x-over design software.

For the example I'm providing here, this involves the use of a fairly cheap car audio 12" driver (I purchased it for $100) with a high Le, installed in a sealed box of about 1 cu.ft.. The end result is a sealed alignment with an Fb of 40 Hz and a classic humped FR response that's characteristic of high Le drivers. (first image).

The second image is this same alignment with 1000 uF of capacitance added in series with the drivers coils (two 100V 500 uF NPE capacitors wired in parallel together and in series with the driver's combined 4 ohm impedance coils). The hump in the FR above Fb is flattened and the output below Fb is increased by up to almost 3dB, the equivalent of doubling amplifier output into the subwoofer. Not bad for $15 in parts, eh? 🙂 Note that I could have opted for an even flatter passband response by reducing the capacitance to around 800 uF, but that meant give up a bit of response at 20 Hz in the process.

So, what's the tradeoffs?

Well, small box with low F3 isn't going to be that efficient. In any case, I'm using a car audio driver, which are usually designed to be able to take a bit more power and abuse (using 100V caps means that I drive the sub with up to 2.5kW before they blow up, and I won't be driving them anywhere near that power level.

The second disadvantage is that all the output is still from the driver, so more low bass = more excursion = more THD. Interestingly enough, for my particular test, the driver's overall distortion response seems to have improved too, though I'm not sure why. Another mystery to investigate....

The third one is supposedly poorer GD. Yes, it will worse than a sealed alignment. However, at least for my case, the increase in GD isn't really objectionable - GD has moved from 12.2 to 12.6 ms at 40 Hz, a negligable change. At 30 Hz, GD moves from and 13.3 mS to 30 ms. At 20 Hz, it's at 33.3 ms. In practice it seems to sound pretty good. The last two images show the change in GD when the capacitance is added.

Right now I'm using the driver in a test box, but the intent is to build two of them into two 1 cu.ft. cubes, on for each side of the couch, and use inline capacitance to get the F3 down to 32 Hz. I haven't started the build yet because I haven't decided if I want the drivers down-firing or side-firing.

Note - I suspect the same approach can be used to extend the response of an open baffle woofer or subwoofer. Just take into consideration that the increased response at low frequencies is all from the driver, so make sure that it has enough linear excursion to produce the extra output.

Long story short - I can buy some UK built Quad 989s at a low price ($500). They look great physically, but they arc audibly. Two questions:
1) Is the price actually low, or will I end up spending a fortune to repair them?
2) Can I actually repair them (I'm quite handy in the DIY department mechanically and electronically)? This would be my first electrostats, so I assume there will be some learning curve.

Hi guys.
I'm trying to repair a Luxman MB-3045 monoblock (I have another working MB-3045 to compare).
The power transformer died (exploded or melted), so I got it rewinded and already installed it. Still trying to find the right diodes for the power supply, the original ones are unrecognizable, and the ones in the working amp apparently have been discontinued for a while.
All multi section can capacitors measure ok when disconnected, but I have a short somewhere when I connect them back into the circuit.
Is it possible that the output transformer also died when the power trafo went south?

Thanks in advance.

I have a parasound 2205 amp and one channel is dead.I take it a part and the 2 fuses on channel 4 board are blown.

Now all the cap looks fine, the smaller ones and the 2 big 80v 15000uf.

So I replaced the 2 fuses and plug it in and the 2 fuses blew. This is with no pre amp plugged in and no speakers plugged in, just power.

I hate to send it out for repair since it will cost a ton for shipping and I'm not sure of any repair places locally to take it too.

I'm not bad at fixes thing and soldering components on the board.

So any thought if it could be one of the 2 large caps?

thanks for any directions.

Luxman Integrated Amplifier L550 ("L-550") Capacitor Replacement in the Power Supply

The genuine capacitors are ELNA, "Special Made for Audio". The value are 30000 uF (30.000uF) and 50V.
Now my Problem:
The sizes (ratio between height to diameter) is unusual: 63-65mm diameter, 80mm height (industry standart is 100 mm height by a diameter of 63 until 65 mm).

There are no additional space to use larger types - have a look to the second image of opened amp device about
http://audio-database.com/LUXMANALPINE-LUXMAN/amp/l-550-e.html

Are there any vintage caps with screw terminal from Sprague, Mallory, Rifa or Nippon Chemicon in the size 63x80mm ?
Capacity isn't important (at least 10.000 uF) but the ESR must be as low as possible. The rated voltage shold be 63V or 100V.
Thank you for advices.

Hi all,

On offer is a well cared for first watt B5. Selling for 1500aud plus postage. Drop me a line if you interested.

Cheers

Luke

Got one in very rough condition but has since been serviced to "semi" working order. Any input would be greatly appreciated...

Symptoms:

Loud crackle / pops / noise

- VERY irregular/intermittent... can sometimes use the amp a whole day without any issue
- happens even if there are no sources connected (absolutely nothing plugged in the inputs)
- comes out of both channels
- loudness dependent on volume level (ie: it gets louder/softer depending on how high/low volume is set)

Actions taken:

1. Cleaned volume pot
2. Resoldered some visibly poor solder joints on the preamp board

Questions:

1. Can this type of behavior be attributed to the preamp section or power amp section? I'm hoping to isolate it in order to minimize parts I have to disassemble
2. Are these signs of failing capacitors or perhaps something else?
3. Can this also be caused by irregular current from my wall sockets? The house is pretty old and I'm using a stepdown transformer so I'm considering buying a decent voltage regulator if this is the possible culprit.

Thanks in advance!

Anyone used SPK Audio F02P drivers before? I noticed them on a site that sold markaudio and hivi drivers but cannot seem to find much online about them, couple of japanese youtube videos I think and might be about it