Okay, I found this DIY amp on internet, and it looks kind of interesting with Darlington coupling on each output transistor, so my question is, has anybody build this thing and how does it behave?
Link to site.
Big amplifier-general

I have for sale 2x0,5m verry good digital rca cable in top condition.I buy this some years back over audiogon and used this in my system for now.Back then when I decided to go the way with dac and streamer in my system I have try more than 20 digital cable up to 300 euro,but this was the most musical cable from all of them.Thia cable have verry magical midrange with full of emotion and verry transparent,instruments are verry natural with full body and highs are clystar clear and silky smooth.Bass is strong but little rounded.This cable suits those that have to bright system.Plese see for test results and user opinion in internet.Price would be 100 euro for both cable plus shipping or best offer.

.

Hi All

i recently rebuilt this amp for my son as main caps were swollen ect - it now works great and looks in my opinion very much like the Earthquake early 90's pa2300 models - anyone know what amp this actually is ? or any detail - the heatsink has no markings at all.

i presumed its one of the clones of the various 2300 - but im happy to be wrong - anyone else come across this board before ?

i set the bias at 50ma : anyone able to confirm this would be correct ?

many thanks

Tony (old school fan) 🙂

I've been planning to build a pair of 2-way speakers according to jkim's 'poor man's high end' design.

Link to this design here:
2-way MT: SB Acoustics SB17NRXC35-8 and Vifa DQ25SC16-04 (Poor Man's High End) -

Techtalk Speaker Building, Audio, Video Discussion Forum

In my quest of sourcing the parts I have noticed that the Vifa DQ25SC16-04 tweeter is hard to find here in europe.
I've wondered if I could swap it out for the BC25SC06-04 without much change to the original crossover design.

I could go through the trouble of loading up the data in XSim but as I understand it in the original design jkim used speaker measurements instead of the manufacturer data. I do not have the required equipment to measure this data myself.

Could someone look at the datasheet and design and give me some advice on whether I can swap these 2 tweeters in the design and if I need to make changes to the crossover design?

I make active modules such as line array, monitor, tower.
Behringer preamp chart has been added.
High output and low output level are adjusted with an equalizer according to its own speaker.
I will cancel the Behringer preamp equalizer piece.
And instead I will put 10 equal 2 equalizer bands on the other scheme.
How does it work? Where is the Behriger Opto connector X7 Pin going

(This information ONLY for the people who know the power amplifier circuit.)

Quad's current dumping circuit amplifier is such a simple circuit, good sounding and powerful long lasting amplifier from the past to modern days.

In the Quad current dumping amplifier big family, only Quad 405 is using op-amp in the first input stage. When compare Quad 405 circuit to her big brother Quad 606, it's simple to modify Quad 405 to Quad 606 circuit by replacing the op-amp input stage with a single PNP transistor, change op-amp(use as DC servo control), resistor, capacitor, adding transistor and diodes on the same Quad 405 PCB.

The new component can be place on either side of the PCB according the component space needed and cut one PCB copper trace for the mod job.

I made the MOD and the result is good. Sounding is good and I like the all discrete current dumping circuit.

This MOD is not the last, we can have more MOD like adding one more pair output power transistors as the Quad 520 model which can handle better speaker loading.

direct coupled preamplifier
very linear and pleasant sound
main power switch and source select to come on lather
4db gain more than we need with modern source and cd player

Hi, just to check interest here, to possible avoid eBay sale hassle.
Sony SA5ES tuner, one of the best Sony audiophile tuners, champagne,
fully functional and in great shape. It is EU, 220-240V version.
Asking for 150€ plus shipping ( around 25€ for EU..)
Regards, Davorin

Dear all,

Does anyone have the Breeze Audio DV20A without the dac and would like to comment on the sound quality of it compared to f.i. a good cd transport?

Also does it play NTFS formatted SSD`s?
Any feedback much appreciated!

Best Regards, Veeren

SSR DC protect for 150WRMS into 4 ohms and 300WRMS into 8 ohms max.
Four second power up anti thump delay.
Power down protect mode.
250mS DC protect.
No mechanical relay to go wrong.
Requires 5va mains transformer dual 9VAC secondaries. One transformer per unit !
£9.99 each plus p+p.
p+p is £3.99 to u kand £9.99 rest of world.

Today in a debate over enclosure qualifications, some one made the comment that George Augspurger used a BR for his studio monitor designs....

First of all...I don't know this to be true...MLTL gets confused for BR all the time...when I look at pictures of his designs it looks like BR at first glance...I see the inside being stuffed with dampening material...typical of TL not BR, so I thought.

Is anyone here, knowing whether or not George Augspurger studio monitors were actually BR or TL....if a BR whats the deal with the dampening material...and last, if George Augspurger did all this work on TL....only to eventually design a product using BR...did he come to the conclusion that TL is a waste of time...or is he just another designer cutting corners?

Hello all. I am trying to repair a 12V switching power supply which intermittently works and then stops working. Typically it may run for 20 minutes and will produce about 13V, then it will fail and the output will bounce back and forth from about 7v and up to 12v. It will pulse back and forth about once per second. This may last for seconds, or minutes, up to about 30 minutes, then it will go back to working again and hold a solid 13v. It does not appear to be related to temperature at all. I have changed all 5 electrolytic caps. I have a meter and an oscilloscope for testing. I am a hobbyist but have no experience with switching power supplies. Can anyone give me a hand with this? Thanks

I suspect the title is not terribly clear, so here's the situation:

I am repairing a Luxman L-430 amplifier. It came to me with a blown channel and required several output transistors and an electro cap with a hole in its side replaced. I considered that the electrolytic was the likely culprit and have replaced all electros in the amp as a precaution.

I had it running at up to moderate volumes for several days without trouble (and it sounded very nice).

Source has been a professional CD player with 2V line output, full signal input for the amp is 200mV. This is not ideal but it has been only a minor annoyance with a number of other amps over the last ten years.

Today my partner went to play a CD while I was not home and as she is not used to the new system had not realised that I had turned the amp off earlier (the lamps are all blown and I haven't fixed them at this stage). So without looking she turned the volume up nearly full, realised it was not on and turned it on at full volume. That immediately blew an output device, with just a tiny pop of sound out of the speakers.

That's not the behaviour I would have expected from the amp. I would expect a clipped signal (due to the signal level mis-match) and enough volume to make you wet your pants, but not self destruction.

Am I missing a problem somewhere that higher power may be showing up? Is this actually normal behaviour that I'm unaware of because I don't normally listen at 120dB?

Thoughts are sought, output transistors are a good deal more expensive than fuses and I'd like to rule out doing this frequently.

Hi amigo,

I am looking for a good Android phone, with the best possible DAC un der 200$ (second hand OK).

What about HTC10, LG G7 or LV30 or maybe other ?

I need to drive some floor speakers 2.5 way @93DB / 120W RMS

My setup :

- External AK4497 dual DAC
- TPA3255 Amplifier

Audio Sources :

- Quboz streaming HD Audio.

Could you please help from your experience ?

I have a 10'' sub that I rebuilt using market parts, but there is no info about power rating of the coil. Even why, the actual power rating will depend on how well the coil will be able to dissipate heat during operation.

So I thought of installing a thermocouple in the top of the voice coil and connecting it to a thermometer outside the enclosure, so I can read the temperature in real time.

This temperature, however, is not going to be the actual wire temperature, but the temperature of the aluminum foil.

I think this might be even a better measurement, because I suspect the first problem that is going to happen is the deterioration and softening of the epoxy resin that holds the cone, the coil and the spider together.

I know that, by the temperature limit of the epoxi resin, it needs to be at max 100 ° C, but I'm not sure about other stuff like the paper cone or poly cone (If I decide to rebuild it again). And even if I find some info online about their limits, they rarely will be considering a operating regime of constant stress and vibration.

So, what you'd say is a good temperature for me to set as a operating limit?

Thanks!

Hi I am from Singapore and looking for the below vintage fostex parts.If you selling please email me Leong_kin_pang@yahoo.com.sg

SLE20W
FS70D
FT3RP

I have for sale the following pairs of vintage Dynaudio drivers:

D21 3/4" dome tweeters $100.00 pr + shipping
D28AF 1" dome tweeters $120.00 pr + shipping (SOLD)
D54 2" dome midrange $220.00 pr + shipping

These drivers are used, but in very good condition and sound great. They were used in a large pair of home audio speakers in a room that was
pet free, smoke free, and no children. I can email pictures to interested buyers. If interested, send me a PM or email me at roncjoyner@yahoo.com.

I am investigating using a EL83 pentode as a CCS in a parafeed output headphone amplifier I am designing, since the CCS will need to dissipate 6-7W. I have learned a weakness of the pentode CCS is the g2 dropping resistor cause a shunt, giving the CCS an impedance approximately equal to the dropping resistor, paralleled to the pentode.

In the case of the EL83, dropping resistor is ~79K whereas internal resistance of the EL83 is ~270K in my drafts.

Using a MOSFET as the lower device, I have gathered this will prevent current fluctuations associated with using the pentode alone. Are there other advantages of a hybrid setup over the EL83 by itself? This design is new to me, very limited information from what I have been able to find, trying to piece it together.

My proposed design is below along with the g2 = 170V EL83 curves. I have penciled in the IXYS IXTP08N50D2 depletion mode MOSFET as the lower device.

https://www.mouser.com/datasheet/2/...te_MOSFETs_N-Channel_Depletion_Mo-1623348.pdf

I've been doing a fair bit of reading and searching but there's something which kind of has me at a bit of a loss. I'm hoping someone of the members here with a great deal more experience in these matters might be in a position to comment [emoji6]

In most older (pre 1980) designs that I've seen, mostly British or British based designs, the output stage is either a totem pole arrangement or in the later designs, some combination of complementary szilikai/Darlington arrangement, but where the outputs are complementary they tend to be common emitter with the collectors driving the load.

But at some point, it seems consensus shifted towards common collector complementary output stages in class AB amps.

Can anyone explain the rationale behind both arrangements? And why the preferred arrangement seems to have changed over at some point in the late 70s/early 80s?

I had been using isopropyl alcohol to clean flux off circuit boards. I didn't have any left so I tried some acetone, and it just ripped right through the stuff way easier than alcohol. Is this a good substance to use for this?

Hi,

I have a set of Grado SR80i which I absolutely love the sound of for the price.

However recently the left cup started cutting in and out with the separation between in and our separtated by this awful clapping/slapping sound.

So I've opened up that cup and it seems as though the driver body has separated from diaphragm (apologies if my terminology is wrong let me know if I need to clarify anything).

The noise is the two happening to come back together (the cable mean it can relocate) and it cuts out when they separate.

I can push the two back together and there is a little bit of friction which will hold it there for a bit, but I bet I am going to have to reopen these with a few weeks or months - it also can't be good for it to have it flap around.

So my question is: Where can I apply adhesive to hold it in place and what sort of adhesive should I use so that I don't negatively affect the audio quality.

It looks as though there was a small amount of adhesive on the very perimeter of the drive which has dried and cracked. I could reapply that but I am not sure what sort of adhesive to use.

Pictures attached.



PS: I've traveled with these headphones so they've had a pretty hard life, I don't think my issue should reflect poorly on the manufacturer.

Hi folks,

I will be building a HV DC power supply with current limitation to test the dielectric breakdown voltage between the primary and secondary of my transformers.

But, what should be, a safe current value in order not to carbonise the breakdown insulation spot?

I guess we need to calculate dissipated power per surface here? But what is the surface of an internal arc?

Hello everyone, grudgingly I give the following NOS tubes, purchased, tested and placed in a drawer as I have never started building the amp


2 Sylvania 5814 coupled 60 €

1 JG 6189 original box € 30

+ shipping costs of your choice.

Happy listening !!!

Just got the nad 658 it plays fair with a cheap lepai chip amp, an old g12 tube amp but the main function was to hook up to a pass f6 which every time I try smoke rises from my F6 luckily the F6 still works after several tries. Along with the smoke is a buzzing sound. The smoke seems to come from the cl60 which is only there for slowing start up

Hi everyone,

I'm looking for a "easy" and simple to implement (no programming required) solution for cartridge loading/gain change on-the-fly without having the pop sound from dip-switch or relay switching. Loading and gain adjustment will be a matter of paralleling resistors. A schematic will help a lot.

Can someone please tell me how to fix the power supply on a Threshold S/500 STASIS Power Amplifier? I have some schematics, but they're general overviews for several later designs. I need the specific technical information on this particular model. Hopefully, someone can tell me the voltage, tolerance, and bias.

Hi Scott, Dave & anyone else who reads this.

I haven't been online here in diyaudio.com for quite awhile. I had a good almost 13 year run with the Sachiko cabinets you guys suggested and since selling them I've actually been pretty content with my Beauhorn Virtuosos. However, I just picked up a pair of these exact Diatone P610 clones with Alnico magnets as seen here:

pair 2pcs HiEND 6.5inch fullrange speakerDIATONE P610 CL0N (2019 big Alnico ) | eBay

The trouble is I have no idea what cabinets I want or should put them into. I had one man I met who was really a great guy and he suggested putting them in the Mark Audio Super Pensil 12P.P cabinets, but I have absolutely no idea if that's what I should do or if there isn't an even better enclosure one of you guys knows about that would be even better to use. What I do know is when I decided to make my first journey into the world of single wide-range drivers so many years ago now. Both you Scott and you Dave were a world of help to me by suggesting I use Sachiko cabinets for the Fostex FE206E and FE206ES-R drivers I had at that time.

I cannot help but believe you two can be the same type of help to me now. I received these drivers today and I think they're absolutely gorgeous. At the link to eBay up above, you'll see their Thiele-small parameters as well as their frequency response. I'm hoping this time instead of two separate horns whose mouths open on the front just above and below the driver. Perhaps one of you two can think of an enclosure with a single horn that opens on the rear of the cabinet. But that being said, you two are the authorities, so far be it from me to tell you what to do, I'm just expressing preferences if they can be met. Scott would these work in your Avebury cabinets?

In any event, I deeply appreciate whatever help that either you Dave or you Scott or anyone else that wishes to contribute for that matter, is willing to provide. I have a good feeling about these drivers. I just hope I'm not wrong...

Thetubeguy1954

Does anyone know this novar tube ? similar to 6av5 ? , look a little like a sweep tube but cant find much in detail about it …..perhaps a Euro getter ?

pin 1 ,G1
pin 2 , unused / no connection
pin 3 ,G2
pin 4 & 5 heaters
pin 6 , plate / anode
pin 7 , cathode & G3
pin 8 , G1
pin 9 , unused / no connection

Thankyou , good folk of Diyaudio !!!!!🙂

Hi friends
Barely finished a project (DCB1 mez) I already want to build the next one. It's definitely not only about good gear, it's about the solder-magic...

I'm fascinated by the genius of those project, and right now I want them all. Even if only in my dreams. 🙂

I'm struggling with the GB's, although they're quite clear, I don't get what elements (PCBs/Kits) I need for especially the DCG3 and simplistic phono?

Did I miss sort of a build-guide in the forums?

thank you!
david

I’m trying to find a replacement for this diode. I’ve searched the net but can’t find anything at all. It comes out of a 60’s valve powered projector amplifier.
The only things written on are RC 16K16
[/URL][/IMG]

Does anyone know what I can use to replace it?
Thanks

Hi, I have passed this stage, rockford damaged, what happens is that the Q215 or TC11, came burnt, and try to change it, jump again, when more than half of the course entry level, then your temperature rises in a spectacular way to just frying, but if not exceed that tour, its operation is normal (at low volume, of course) the power, well, I suspect the U1 and U2, to test them any pin negative voltage has given me, any help? Thanks in advance.

Does anyone know what topology was used in the George Wright WLA12/A line preamplifier? It uses a 6X5 rectifier, 6EM7 as a series high voltage regulator, and two 6SN7s for what his old website describes as the "voltage and driver stages."

Does "voltage and driver" stage have a particular meaning?

I'm trying to understand the differences between common preamp topologies (SRPP, mu follower, cathode follower, grounded grid, etc.), and the WLA12 is the only one I've ever heard. Trying to match experience with book learning here.

Thanks!

Jeff

Hi all,
I bought these PT’s 20 years ago on a discount shelf at the local electronics store. I’d love to build amps with them but they have low current and high voltage. I read a little about wiring the transformer to double the current capacity, but not sure how to do this. Any thoughts on how turn these into a nice projects?

I recently acquired a Dynaco PAS 3 that was built as a kit. I brought it up slowly on a variac but none of the 12AX7's lit up, only the 12X4. I tested all of the tubes on my B&K tube tester and they all tested strong with no shorts. I also pulled the 2000 mfd capacitors out of circuit, one tested good, the other not so good. After doing some googling, it seems as though the selenium rectifier should also be replaced.

While I am in there, I'd like to replace the 4-section can capacitor which is 30/20/20/10 mfd @ 450V. The only recommended replacement I can find is 20/20/20/20 @ 475V from dynakitparts.com. Is this a good option?

I want to keep the preamp as designed, with no mods other than replacing the selenium rectifier with the 1N4006 diodes as recommended by Curcio Audio. I will also rebuild it from the ground up since the wiring and soldering of this kit was poorly done.

Thanks in advance.

About a year ago I bought a SP9 octal pre amp kit from tubes4hifi. The instructions were minimal at best, but I got it together by looking at photos of previous builds. The preamp worked but there was unacceptable hum. The grid voltages were way off spec according to the schematic that came with the kit. I got in touch with Roy Mottram who couldn't decide if the voltages at the grids should be 129 as per his schematic, 55 volts as per 4 customers ( including myself) or 12 to 14 and 0 volts as per his email. He then stopped the voltage discussion altogether. After many hours of searching I found a problem on the pcb and advised Roy. His answer "OK, so it looks like you found an error on that board, that's good, that's how things get fixed". No apology or assistance of any kind - he said I could buy another pcb at my expense or have him fix it at my expense - Great service for a kit worth $1000.00 !

I get the technicalities. I'm wondering why the limitations have not been overcome. Imagine a seriously dynamic flat panel driver

So much discussion on "just because you can hear it, doesnt means it's so" and "I cant believe people spend good money on this".

I have to ask; has anyone made a successful audio purchase based solely on another person's stated perceptions?

This means you did NOT go listen to it first. You bought hearing-unheard.

For me, I've had it work out both ways; I've bought because I read someone said it was good, and it was good to me. I've bought because someone else - "well, that's what that guy uses" - and it didnt work out for me.

I'd like to read about such trials and tribulations. Please share here. Thanks!

Im looking into my next project, a set of desktop speakers with some punch.
I like the build method used on transmission line speakers and I got an available CNC.

Can anyone elaborate on why most all transmission line speakers I find online is 1 way? and wont a 2 way speaker have to ability to play louder without distortions, and both being equally good builds the 2 way will sound better?

If I rip of the design for a transmission line speakers I find online, can I simply scale the enclosure up and down in size (internally) based on the speaker size I want to put in or do I have to do the math on this?

Attached there is a picture of the approx. design im going for, and a sketch i was playing around with.

These DD amps seems to fail in strange ways. This one has me scratching my head.

If I apply 14.5 volts the amp will go into protection as soon as the relays engage.

If I bring the amp up at 10 volts and slowly bring the voltage up to 14.5 volts the amplifier stay up and stable.

I was able to check all of the voltages and drives this way and everything looks good in the output section and in the power supply. The amp produces 125 volts rail at 14.5 volts input.

I don’t understand why bringing the amplifier up at 14.5 volts trips the protection circuit but bringing it up on low voltage and running the voltage up does not.

This amp has some 5 leg predrivers in front of the output driver card. They’ve been masked off as well as the ICs on the driver card.

Anyone have any ideas?

David

So I was just a little slow in getting my chassis ordered from the diyaudio store and now it appears I will be unable to get a chassis shipped from Hi-Fi 2000 due to the US-Europe travel ban that goes into effect tomorrow, for at least 30 days.


I am looking for an alternate source for chassis and heat-sinks with milling service to mill the sinks out to the UMS specs in the diyaudio store.


Or, if some good soul from Canada perhaps is willing to be my go-between for shipping through the diy audio store, we can discuss those details and I would add in a small bit of compensation for their time in helping me out.



Thoughts?

Hello,

originally in this phono amp was Electro Harmonix 12AX7. Long years I was using Tesla E83CC or Tesla ECC803S tubes without problem.
I also changed original OPs to AD829. Due to this change I had to change also capacitors and trasistors to make this OPs works (also change PCBs routes etc.).
After years my tubes starts dying and I made decisiont to buy new ones.

First I tried Svetlana 12AX7LPS but it does not work. I return it to shop for test and it works for them. But they return me money and I bought another tubes, Tung-Sol 12AX7/ECC803S gold pins. But also these tubes do not work. Both, Svetlana and Tug-Sol was/are warm, but no light and no sound. When I put back Tesla, it works.

At this moment I dont know whats going on here.

Do anybody have any idea?

Thank you

I am recently relocated to San Diego, and the shift to smaller California homes means that I need to downsize my fleet that I accumulated over the years to better fit downsized housing.

SOLD Wavecor SW223BD02 (x4) - $400/pr
Wavecor SW223BD03 (x4) - $400/pr

ScanSpeak AirCirc D3004/6600 (x2) - $200/pr
* Thread where the tweeters were tested
** I have aluminum waveguides for these (see Augerpro's thread) that can be included for an additional $200/pr

SOLDScanSpeak/Vifa D2608/9130 (x2) - $120/pr
SOLDSB Acoustics SB15NBAC30-8 (x2) - $80/pr
SOLD Dayton Audio RS52AN (x2) - $50/pr

Plus shipping, domestic PayPal is included. If you don't like my prices, feel free to make me an offer. I reserve the right to laugh, though. Most of these are NIB and have been in storage for a while. I'm in North County SD (San Marcos), and I'm happy to deliver within reason (think Temecula down to Chula Vista, but Calexico is not in my travel plans!).

Dear All,

Can somebody help me to identify these connectors ?

Regards,

Davide

Is it possible to strip a power board and amp stage output board down completely, replacing all old parts with new parts? Both blew, was repaired, then blew again after about an hour. Thus other components must be shot. I know it'll be unwise to do this myself, but I want the get rid of them but don't want to give false info to someone else...

Hi
I have put my pair of EAD E60 fullrange drivers up on eBay.
They are a drop in replacement and maybe an upgrade from the Jordan JXR6HD.
They are in perfect condition, as new, only now run in.
Worldwide shipping available

Pair Of Ead E60 Fullrange Driver Speaker 2 Pieces Jordan JXR6HD | eBay

Sold! BK Signal Generator.

Sold!...BK 4005DDS signal Generator. Like new.
Includes cables and a BNC to RCA adaptor.
$150.00 including shipping
PayPal and US shipping only.

Would this be considered a swinging choke?

Well Hello, im new here so please dont make fun of me, I have a Boss NXD3500 mono class D amp hooked to a Pioneer 1000w subwoofer that I removed of my car due to space limitations and the problem of that huge sound.

So now I have it installed in a room with an Onkyo amp, I made a rig with a car battery and a UPS so it can recharge the battery and 3 relays so when the amp turns on the UPS turns off and vice versa (That was made due to interference when charging the battery and the amp turned on)

First, I wanted a house amplifier for my subwoofer but didnt find any.


My problem is:

I cant have too much time out of my battery (it dies) and my UPS cant recharge it fast enough, so I was thinking of those 30a 12v dc power supplys used for LEDs, but when I hook a 12v power supply to the BOSS amp I get a hiss out of the subwoofer.

Anyone knows a hint on what can I do to remove the hiss? a diode? a proper power supply for the amp?

Thanks!!!

Hi,

Anybody knows the S6M4812 ?

This ic is on sure electronics jab2 and Dayton kab KAB-230. This is the 10 pins nearest bluetooth board.
https://www.parts-express.com/Data/Default/Images/Catalog/Original/325-103_ALT_1.jpg

The only informations I can found are in description of
Taidacent Bluetooth Audio Decoder.

"... using S6M4812 pre-amplifier, full bass, high sound, output frequency is not distortion..."

Im looking for 2-3 pairs.
If you are aware of a reliable purchase option, pls let me know.
Thanks

Hi,

I'm looking for a NC252MP stereo module.
Delivery in France.

Thanks,
Mickaël

This may be another daft question of mine...standby....

I have been messing about with CCS anode loads for a headphone amplifier, and it's taken me the last month to notice that the idle current stability isnt all that great 😡

I have been using two different stages, loaded with different CCS; one BJT cascode delivering up to 1mA (BC557 and ZTX558), and another MOSFET cascode delivering up to 8mA (both devices DN2540).

Both circuits use LEDs to lift the cathode above 0V, but I have replaced the LEDs with bypassed cathode resistors of appropriate value to get close to the same Vg.

The CCS performed the same in either case.

The low current CCS biases up and stabilises nicely, the little TO92 packages heat up and stabilise at about 40 C, according to IR thermometer.

The high current CCS biases up quickly, but then
idle current continues to drift ever so slowly upwards from the setpoint.

At this point no heatsink on the TO220, and they read about 40 C also.

Okay, so a temp. co. That I hadn't bothered to think about.

Besides the obvious, adding a heatsink..., what's the best way to mitigate this? Any clever tricks out there? Maybe adding a PN junction between the D-S cascode connection, and bonding thermally with the CCS MOSFET?

So, I added a small 40mm regulator heatsink to eat DN2540... same result, almost.

Temperature seems to stabilise at a slightly lower temperature, but the CCS still drifts, causing Vp to drift higher over a longer period.

So I set about to use a larger heatsink, and due to space constraints, I settled on a piece of 40x110x5mm copper stock, and mounted both DN2540 on the heatsink, insulated of course...

Now I thought that this is going to make the temp co. effect worse, but the larger heatsink may mean the stabilised running temp is even lower.

OK, admittedly part of me thought the two devices might magically compensate temp. co., in the way the bias diode can when thermally bonded to the output transistor heatsink.

And then I thought again.

The temperature did stabilise lower, but I'd still see a drift of perhaps 5V out of a supply of 150V.

OK, only 3.3% drift...but not good enough!

So I could use a much bigger heatsink, and see a small drift.

Do I need a bigger heat sink?

I drop a total of 50V across the cascode pair, at up to 10mA; so 50×0.01 about 0.5W.

Any ideas how I can reduce this drift further?

Can I use a diode or two between DS cascode connection thermally bonded to one device of the other, to compensate for the drift?

TIA

I've got about twelve more minutes (before I need to head to a big band gig), so I'll make this quick. However, I have bunch of enclosure designs for my drivers that should be on my site. Here is a quick overview. I'll try to fill in pics and specs later on.

Betsy: The OB options are fairly straight forward, by herself or with a woofer. You can use her in a sealed box, but I'm not sure why you'd choose to do so. One unique option that came up in discussion is a small aperiodic box. It might be the smallest way to get a Burro speaker into your room, and with it, more sensitivity, dynamics and image size than you normally get in a bookshelf.

BetsyK: Sealed and vented options abound, but here are some more interesting things:

GM posted a 10:1 TQWT that looks great. If you can tolerate a wide cabinet with a decent sized footprint, it promises great performance and a very simple build. Specs to come.

Skinny quasi TQWT/TL: I designed a box for my brother in law after seeing the Zu Essence and liking the size. Mine is about 12x13x44". It is a very easy build with some advantages over a regular BR. I'm listening to a pair right now. I think this cabinet should be very, very popular. My in-laws are thrilled.

MooseBVR: ScottMoose was kind enough to simulate one of his double mouth BVR's for the BetsyK. I'll send you the dims if you want. I plan to build a pair. I meant to this fall, but the Skinny TQWT project got in the way.

BIB: My cabinets stayed in MN when I moved west. However, I can give you the specs I used (skinnier than the calculator produces). They are great fun.

I do plan to do a better, and more complete list than this thread. But, I wanted to get something fun up before folks get home from work!

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

I have a car electronic with some capacitors I need to replace. One is a Rubycon RX-20 63v 47uf 125*c 10mm diamter. I have found a suitable replacement for that on Digikey. The others are 40v 47uf and 25v 47uf, both also 10mm diameter and 125*c. I can't tell the brand, but it has a triangular looking logo with three points (almost looks like Mitsubishi logo). It seems maybe in the last 30 years the 25v 47uf are typically smaller diameter (5-6mm) and if not, I'm having trouble finding the higher temperature rating. Any help finding these or what would be a suitable replacement would be greatly appreciated. I already have something for the 40v.

I'm gradually clearing out my workshop, as I get stuff home and it's up for grabs I'll list it here. No fixed prices, make an offer. My priority is to get it out of here, not make a fortune.

I'm happy to post anywhere at all IF you are spending $20 (AUD - $12USD?) on goods. Want all my 1B3's for $1 because you are repairing an old TV? Sure I'd sell them for that, but if you want them posted you'll have to pay $20 plus the postage. Apart from that pickup is from East Brunswick in Melbourne Australia. Open to trades of good beer if you don't like cash.

This list will grow and I'll update this thread when it does. Soon to come are a bunch of inductors, resistors, more valves, books, etc.

See attached image.

Hi All,

Looking for a little diagnostic advice. I got my TSE up and working about a year ago and it’s been absolutely flawless. I typically run it for hours on end, and while it does get uncomfortably hot, it’s performed perfectly. Until this morning. I was running it at about mid volume when one of the speakers popped/crackled, then no sound. I ran over to it, cut the power, and noticed some carbon burn marks on the base of the left channel output tube. Opened it up and saw R33 burnt to a crisp. Replaced it with another 1/4w 100 ohm resistor, reassembled everything, and turned it back on. I then noticed a puff of smoke (no sound from speakers, despite active input signal). Shut it down, opened it up and this time I noticed R29 burnt. The picture below is after I replaced R33, but before doing anything with R29.



I’m wondering if anyone had seen this pattern of failures? Or if anyone can offer any hypotheses? I wonder if R33 failed for whatever reason and perhaps ruined my left 300b tube? Is that likely or possible? If so, would a bad tube cause R29 to blow?

I suppose my next step is to replace R29, remove tubes, and go through the checkout process again. Unfortunately I don’t have a way to test tubes (short of using a multimeter, if that’s even possible). Any thoughts or advice? Thanks much!

Hello, I have a Jet city JCA100h 100w tube head amplifier that has some noise and a weird hum. The hum is present as soon as I put the standby on, the hum is very high (100Hz) and will gradually disappear until it is completely silent after about 10-15 minutes of normal use.
What I know:
With the master volume at 0 there is still some hum, and increase if I increase the master.
If I remove the PI 12ax7 the hum disappears, so the noise has to do with the preamp.
I verified that the heaters ac current is about 7v, above the recommended 6.3v. I'm using two 0.15r resistors in series to lower the voltage, but that didn't solve the hum problem.

What can cause this hum?

I've already checked all the solder joints, I can't find anything wrong, I'm thinking maybe to change all tube sockets to something with better quality, but I don't know if this will be the problem.

Sometimes I hear some noise like pops, it happens even without PI tube, but they are also amplified by the preamp. I heard it may have to do with charging the capacitors ... does that make any sense?

Some help please 🙂

No rush. I have TAD 4003 & at some point in the future want to have 2002 8 ohms if available in good condition at good price.

Please PM. I can arrange for global pick up.

Goodnight,

Someone will have the soundstream tarantula tx2.1500 diagram because the entire source is burned and I cannot recognize the drive transistors

Technically speaking, is it possible yet to make a stereo system with the following criteria:

Harmonic distortion 80db below signal at say 100db output. (not quite 16bit but 0.001% from 20hz-20khz.)

-Flat on axis and even horizontal off axis response within 0.5db

-110db output.

The Polish magazine Audio has just published test and measurements of the flagship 101-Xtreme. I haven't had the opportunity to hear any MBL's. The article is in Polish, but we have Google translate!

MBL 101-Xtreme - Zespoły głośnikowe | Testy w Audio.com.pl



Response show considerable interferences above 1kHz, but looks like room response might be adequate. Sad that this concept is extremely difficult to DIY.



Stereophile has tested and measured an earlier model 101E MkII
MBL Radialstrahler 101E Mk.II loudspeaker | Stereophile.com

A few years ago, Burr-Brown propagated the use of a GIC low pass filter at a DAC's output or ADC's input instead of the more common Sallen-Key and multiple feedback configurations. Advantages were supposedly lower distortion and noise.

In the newer data sheets, even that of the PCM1704, they have converted to mulitple feedback. Why is that? Lower component count? Were there unknown disadvantages to the GIC topology? Anybody tried it?

Eric

P.S. the attached app note is really pdf format and should be openend with Acrobat, but the forum insisted it does not like pdf file extensions...

Hi I'm a little new to subs and amps i just bought 2 Alpine Type-R R-W12D4 750w rms. I plan on wiring them at 1ohm but what amp would be recommended to push these budget friendly. Also Should i get a second battery or a capacitor?






I seen a few below



Memphis PRX1500.1

Skar RP-1500.1D
Audiopipe APCLE15001D
HIFONICS BXX1600.1D BRUTUS
Rockville RXD-M4

So currently I am working on a EL34 25-35W push-pull amp, HT around 280-320V
(I don't wanna use a PPP EL84, maybe 6L6 PP is also possible).

For this project I still have a transformer laying around that is a perfect candidate for this.
The transformer only has a single HV output plus a 6.3V heater tap.
Since I have some current (power) "left" on the heater tap, I thought that it would be a nice idea to use a tube rectifier as well.

The DC bias point of the EL34 is going to be around 35-45mA
So I think the EZ81 (6CA4) or maybe even a 6AX5GT would suit this just fine with some tweaks and tricks.
After some tinkering I came up with the following idea.
Some kind of hybrid.

To prevent inrush current, I think I will add a NTC somewhere as well.

Besides just sharing the idea, do you guys have any further thoughts?
Obviously the bridge rectifier will see a uneven load at one side, but I don't really think that's a huge deal.

I am also a little confused about the maximum output current of the EZ81?
The datasheet says 150mA, so for a push-pull EL34 pair that will be just fine.
Maaaybe I can even add the G2 to it, but that's going to be very close?
However, as far as I understand, this is without the ripple current?

Obviously care will be taken to prevent noise and other things on the heaters, but that's something for later.

Up for sale 3x Anaview AMS0100-2300 boards

SOLD

Hi I have a Blaupunkt Montreal SQR 48 cassette radio on the bench.
There's an issue is with the fader, it works fine full front or full back setting but reduces the vol output to zero when centred? So it like it's working in reverse?
Any thought on what could be causing the issue?

Any help appreciated.

Hello !
I got, a few days ago, a pair of Wharfedale Diamonds 9.6, a 3,5 ways with 4 speakers : a dome tweeter, a dome medium, a medium-bass speaker, and a... boomer-woofer (?).





From what I could read online about the crossovers, there's first and old thread on diyaudio :

Modifying Diamond 9.6 crossovers.


It seems that the crossovers frequencies are :
150 Hz, 1 khz, and 6 khz.
On this thread, system7 draw the crossover schematic, here it is :






Derwhalfisch, who begun this thread, created a nice infographic for the crossover boards :









And now, the problem :

I find the trebles on these speakers... Difficult to find ! 😕

The tweeters are working, it is not the problem.
But it sounds like with a curtain covering the tweeters... The cymbals sounds as if there was felt glued on it, the triangle like recorded from the backstage. There is not this high treebles giving "brillance" to the percussions, or a hint of acidity to the violins... And the medium is powerfull. So, on a small jazz formation, or with electronic music, you can forget these defaults for a time. But on a symphonic orchestra, no high on the violins, and a medium making all the stringed instrument...Messy, not clear.




So my questions are :

- is there a owner of these speakers, or of on floor speakers of the same line, who could make the same constatation about the trebles of these Wharfedale ? Is this sound the original sound of these speakers ?
- If it's not, is it possible that the components of the crossover have suffered from an overload in their past, with all the speakers in working order ?
- And, if this is the normal tonality of these Diamonds, is it possible to improve a little the highest frequencies in changing slightly some values in the crossover, to give a little "shine", a little more relief to these trebles ? I find that this tonal balance, with emphasis on the mediums and weak trebles, is disapointing...
Thank you ! 🙂

I coded this last summer. It is comparator of mp3 coding quality. So basicly a tool to compare encoders. It comes together with tutorial on the webpage in the folder. However you have to guess images as google drive doesnt allow for direct images link sharing. Or download the webpage with pics into one folder. There is exe, o, and there is a source code either. Also some literature is included, enough to make your own decoder.
Have fun.
Mp3ext - Google Drive

Hello everyone,

I'm posting here after long time and again this time I have a query about music and amplifiers. I recently built a music system with a usb-mp3 module with Bluetooth function and a audio amplifier board based on LA4440 chip. I used a common 12 Volts 3 Ampere transformer for powering both the module and amplifier after adding a 5 Volts regulator for powering the module. I assembled the whole system in a metal cabinet. But on powering up the whole system I found a high frequency buzzing noise (same as sound of continuity buzzer sound of digital multimeter) from speakers which I suspect is coming from the Bluetooth module and being amplified by the amplifier. When I play music from the module using flash drive the noise appears to be suppressed by the music/song but when I pause the music, the noise can be heard again. I think the noise is actually continuously coming from the module but gets hidden when something is played. I want to know why this module is making this type of weird noise ?

I also have a usb-mp3 module without Bluetooth function but that doesn't make any noise like this when connected to the same system which I built.

If anyone has a 2 which I would prefer but still interested in a 1, thank you Paul, you can also call if you like 318-623-1400

I am selling a used Behringer ECM8000. This does not come with the wind cover or mic attachment for stands.

I've owned this mic for approximately 10 years now. It's kind of been my "fall back" and travels with me when I go to shows and whatnot. Physically, it's worn. Not terrible. But it shows signs of age. See photos.

It was calibrated in 2009 but certainly would need a re-calibration if you wanted to use it for total accuracy. That said, I've attached the calibration info from what Herb @ Cross-Spectrum Labs provided me and can provide that data to you in a txt file as well.

I'm asking $40 shipped, CONUS.

PM me if you're interested.

- Erin

I guess its an OCD thing but I want to archive my music somehow for long term storage in a remote location.

The library is now around 600Gb containing lossless m4a apple and some MP3.
Not worried about the format as m4a is open source and BSD/Linux will be here a thousand years from now.

As an experiment I have burried a couple of flash thumbs in back yard and dug up after one year. They were wrapped in aluminum foil and suspended in a glass jar, embedded in unscented paraffin. Yes bees wax is better.

They worked perfectly after I retrieved and downloaded. The foil helps even out temperature when melting wax. It keeps the wax out too.

Maybe a public wilderness preserve is the best location. Natural landmarks required as GPS may not work properly.

I lost a camping cache once as the terrain had drastically changed and when I tried to locate, no avail digging many holes. Metel detector could not pick up because it was around two feet down.

Like I said, OCD? maybe.

Any better ideas? Please do not say 'icloud'😡.

OK, so this is going to be a bit of a loaded question and just might open a big can of worms but I really want to try to stay open-minded on this before passing judgement.

I was just reading a huge review of rectifier tubes over at a popular headphone-listeners forum and I have to say I am skeptical.

I'm a tube newb, but as I understand it, a rectifier is just what it sounds like; it converts AC to DC which is then filtered. The result is the B+. The audio signal does not flow through the tube at all.

I do understand that different rectifier types work and behave differently. A classic example that I have seen many times (typically on guitar amp forums) is that a 5U4 tube will cause more "sag" vs. a 5AR4 tube and in some cases this is desirable. Either way, changing the rectifier type can change the character, quality, or "speed"? of the rectification in such a way that it is audible.

However, I find it doubtful that a specific 5U4 tube (as compared to other 5U4 tubes) can provide "Hauntingly beautiful tone, lots of air, great layering, transparency above the rest, and just perfect extension in both the highs and lows, deep bass, palpable, lucid midrange, holographic 3D staging and imaging ... amazing! Overall balance is great as its neither overly warm nor bright, transients and PRaT are as good as they get with tubes (like seriously, beautiful liquid transients!)"

Again, the audio signal isn't passing through this tube. Its job is to convert AC to DC. Am I crazy for thinking the above is 100% bollocks? I wonder what DF96 would have said.

I am thinning out my collection of tubes that are extra or that I have no use for due to changing gear. I don't have a tester but they all worked in my amp the last time I used them. I will send pix before any purchase. I can only ship to the continental USA. I purchased all of these as NOS.

Reflektor 6P3S-E one quad dated 1975, about 200 hours use, no boxes $40 + shipping

Reflektor 6P3S one quad, early 1980s?, less than 8 hours use, in original boxes, part of base ground to fit amp $22 + shipping

Foton 6P3S one quad, 1965 in original boxes,less than 8 hours use, part of base ground to fit amp $28 + shipping

RCA 12AU7 clear top in box, less than 100 hours use, $15 + shipping

NOS 12AU7 of unknown origin, less than 100 hours use, 3 tubes, $10 + shipping

Electroharmonix 12AU7A less than 400 hours use, $10 + shipping

I am open to offers.

Thanks

Bought a old REL Q400E, first use I noticed a tiny hum in the driver but didn't take much notice until a few weeks after use it annoyed me, so I popped the backplate off, all seemed ok but the last main electrolytic capacitor was all buldged on top.

So it'll need replacing, but I think it's best to do all 4 at the same time.

Any thoughts on replacements?