Hi all. My family and I are going to moving to a new house in January.

In order to prepare for this, I am going to stop taking orders on the web site starting December 23rd, until I can get settled in (likely early February).

Once I am able to fill orders again, I will re-enable sales. I will continue to accept orders until the 23rd.

Thanks for all your support over the years, and here's to a happy new year for all!

LPA-2
http://funk-tonstudiotechnik.de/LPA-2 englisch.pdfUsed but in very good condition.
60€

LPA-2s
http://www.funk-tonstudiotechnik.de/LPA-2S-englisch-300.pdfLike new, only briefly used.
70€

PSU PWS-04a V2
Manual only available in German
http://funk-tonstudiotechnik.de/PWS-04a_V2-2011.pdfUsed but in very good condition.
60€

I have only one Potentiometer.
ALPS RK18 AX 21-Detent

Each HPA comes with SIA-5 debalancer.
This allows the HPA to be connected directly to a balanced source.

The prices are plus shipping from Germany.

I prefer shipping to EU (because of customs).
But worldwide is also possible.

This are 100% genuine kits I´ve bought "some" years ago from tech-diy.
IDss range 2SJ74/2SK170 from 8 to 10mA.
2 for €100,-
4 for €180,-
plus delivery fees. I would prefer shipping in Europe

Hello
My name is Alessio, I write from Italy, I apologize in advance for my basic English but luckily there is google translate 🙂.
I hope someone can help me or give some advice. I'm building an aleph 3 to measure the 5V reference voltage on R120 I had to increase the R113 resistor to 150K
Do you think this is normal? Can I perform some checks before continuing with the construction? do i have to check the hfe of the mpsa18?

Hi
I bought two plates of this amplifier (ebay chine)
I've ridden and I've fed AC35+35 (DC50+50)
I have been burned when ignition resistance.
Turn repidamente.

I have not tried the other channel because I have fear of burning.

As I can find the problem.
Thank you.

Just watching a YouTube video form Paul McGowan of PS Audio and spotted this in the corner of his room. Good to see that Paul recognizes or appreciates another manufacturers product.

Good afternoon good people of the DIY world.

I've a query I'm hoping I can get help with.
I picked up a suitcase record deck with built in amp a few years ago and I've only just got round to having a look at it.

I sold off the record deck and didn't want to throw the suitcase/amp part of it because I thought it may make a good project at some point.

So now I'm at the stage where I connected it up this morning and kept blowing fuses if I wired the amp up bypassing the switched part wiring of the I/o pot, going straight to the voltage selector wires.
Attached is a pic of the pot, could some enlightened individual please explain to me which of the white wires go to the voltage selector and which go to the mains ground?

Good evening everyone,
I'm selling the following: 2x VTA M-125 chassis, 2x VTA M-125 Noval driver w/components & tubes. Just received a few days ago from Roy and decided I'm going in a different direction. I believe I paid close to $500.
Selling for $275 and I'll pay shipping. Just don't need the stuff lying around.
Need pictures, just ask.

Thanks
Ray
compcar59@outlook.com

I bought a d03 open box from a seller on ebay, and it "skips" briefly while playing music. It does it just often enough to make it a nightmare to listen to. I tried multiple inputs and power supplies, and ran it with and without a preamp. Ive already had my money refunded, as i suspect they knew of the issue when they sold it to me, but im curious if theres any chance it might be something i could fix. I already took it apart and visually inspected all the solder joints and cleaned up the ones that looked a bit shoddy, and it didnt help. Any ideas?

Hi All,


I have recently acquired a pair of Arcaydis EB2s speakers.. Slightly unconventional in their configuration, with a 20l sealed box design.

EB2S – Arcaydis

I was thinking of upgrading the mid/woofer to a higher-spec unit, but I am still learning about driver parameters and their effect on the sound.

The woofer used is the visaton W 170 S --- crossed over at 2.3kHz

187mm / 148mm

W 170 S - 8 Ohm

This has a pretty flat response, high .QTS and a 86db/1w sensitivity... I was hoping to find a unit with similar specs to avoid having to re-do the crossover, but finding a unit with high QTS for use in a sealed box ain't easy!

The closest I have come so far is this driver; The WaveCor WF182DB10

http://manuals.audiomania.ru/data/wavecor_wf182bd09-01.pdf

Seems to behave similarly and has the right sensitivity - but QTS is down at 0.37

Can anyone suggest the effect this will have on the sound? Right now the speaker is a trifle fierce across the mids, not harsh but without much warmth

Thanks for any tips

Hi Guys
I have a pair of nice Zingali Client Name EVO 1.2. They are 15 years old. It is a 2 way design, with a horn mid and treble, and a 12 inch woofer.

I wanted to upgrade / update the crossover caps and tweak up the sound a bit. I have some Mundorf Silver/Gold Oil Supreme's ordered, some Duelund silver bypass caps and some Mundorf resistors 5W.

I need a bit of advice on how the crossover is configured. See photo.
1. Which caps control the mid/high horn?
2. I wanted to look at adjusting the horn, upping the volume slightly v the bass. I think the 4 parallel 20R 5W resistors do that? Or is that controlling the bass driver / filter slope?

Any help would be greatly appreciated.
I would love to build the crossover from scratch, but don't have the specs or schematic.

Friends, good day to you and good mood!
I just want to apologize for my terrible English.

I need your help again! I currently have a Diatone DS-90C system. These are very large and heavy speakers.
Not long ago, I was talking to a friend of mine who builds his own speakers. And I love to do everything myself. And I got hooked on this idea.
I've studied various speaker layouts and settled on D'Appolito speaker placement, but I want to go a little farther. I want to have the same wide bass range as my existing speakers.
I want to make the following layout (bottom to top):
1. Subwoofer at the very bottom, with a diameter of 18 inches, and with a frequency range of 18-20 Hz (yes, I know that there are few such speakers, but my diatons have speakers from 20 Hz and I don’t want the new ones to be worse) - I can't decide on a brand
2. midrange and woofer - I can't decide on a brand.
3. midrange speaker - I can not decide on the brand.
4. tweeter - I will be using a Viawave GRT-145W-8.
5. midrange speaker - I can't decide on a brand.
6. midrange and woofer (I don't know how it will be in English and the mid-range and low-frequency speaker in one case 🙂) - I can't decide on the brand.

I really need your help in selecting speaker models. Can you please advise which speakers should I choose to make them sound better than my Diatone DS-90C? I know the project is crazy. Instead of a passive crossover, I will use an active crossover, I have not chosen it yet. I will design the case myself, taking into account the parameters of the selected speakers. I really need your help.

I have a pair of date-matched NOS GE 6BL7 tubes. I ran them in a amp I'm working on, and noticed one illuminated much more quickly than the other. I swapped sockets, thinking I had a voltage mismatch, but the issue followed the tube, not the socket.

Is this normal variation? Does it indicate a problem with the tube?

Hello everyone, I'm glad to be here.
My name is Giannis and i am from Greece
I am a fan of electronics, and DIY constructions

I'm trying to build a simple volume controller that receives a balanced stereo signal (L&R XLR In),
for example from mixing console output,
control the volume with Digital pot,and go out to amplifier with balanced signal again (L&R XLR Out).

After research and effort, I have been able to control and use digital potentiometers.
I use the arduino to control potentiometers like AD8402, MCP4231, DS1803 etc
Αfter research I see that need a circuit of OpAmps to make it work but I do not know
which OpAmp & materials to choose and which schematic to follow.

If you can guide me and help me it will be a great pleasure.
I know that some or most of you will laugh about what I am asking because
it is simple for you but it is about to drive me crazy 🤣🤣🤣

Sorry for my English
Thank you very much in advance

L3-3 vacuum tube/valve tester sn#2946 manufactured in year 1976, in very good condition for its age.

Can test emission, transconductance, leakage and reverse grid currents.
Working fine, tested and calibrated by professional technician.
Includes full set of perforated cards and power cord (no extra adapters).

On the DVD archive you can find PDF copies of perforated cards for testing hundreds vacuum tubes, including most popular like 6Fxx, 6Jxx, 6Nxx, 6S/6SL, 12Axx, 12BHx, ECC8x, 6P1xP, EL8x, 6P3S, KT66/KT88/6550/5881, EL34/6CA7, 300B, 5U4, SGxx...
You can also make your own card for any vacuum tube/valve, which can be test under these condition: - Ua(AC) = 350/400/500V, Ua(DC) <= 25 ... 300V / 100mA, Ug1 = -0.5 ... -65V (-100V), Ug2 = 10...300V, I(f, AC) = 2.5...17V / 3A, I(f, DC) = 1...14V / 1.2A.

Price 395 Euro, or best offer.

Shipment (from EU country) only within territory of European Union approx. 49 EURO.

p { margin-bottom: 0.25cm; line-height: 120%; }

FU50 + 6N8P + 5Z3P Amplifier


I built my first 300B SE amplifier nearly thirty years ago. Back then SE OPTs were very difficult to find so I contacted Sowters and asked them to build me two. At first they refused, saying that SE OPTs were of antique interest only and too technically compromised for a modern hifi application. After an exchange of several letters they finally agreed to consult with their founder and technical advisor Dr G A V Sowter (then retired and in his nineties) for a design which he duly produced. From today’s perspective the OPTs and the 300B tubes I sourced were very cheap, although at the time I thought them very expensive. I bought a quantity of WE300B tubes for the steep price of $15 each. These were from the UK factory and branded STC4300A.


Some years ago I thought I would build another 300B amplifier and began searching the net for the iron and tubes. Severe price sticker shock followed. There is a very strong interest in diy hifi in China and following Chinese sources for OPTs I found the FU 50 and an amplifier kit. The price of the FU50 kit with all its iron ($130) made it much, much cheaper than buying parts separately from UK and US sources. So I took a punt and ordered the kit. It came as parts and a circuit schematic. I wired it up following the classic tube amp wiring rules. Initially there was too much hum. I had used a star earth system but for convenience I had brought the two sides together using the holding screws on each side of the rectifier tube base and about an inch apart. Bringing the two sides together on the same screw solved most of the hum problem. There was some residual hum which I thought came from the transformers. Tightening the bolts made little difference but, over about 6 weeks of operation, this hum too disappeared.


I have used this amp for some years now and I am very happy with it. I rate the FU50 as better than the 300B.


So, how does the amp sound? Like all the best amps I have ever listened to, built and/or owned, it recedes into the background. It has no character in the same way that the Linley Hood 10w and the Sharp DeltaSigma amp (SM-SX100) have no defined character. One simply listens to the music – the amp does not “impress” the listener at all. If there is any character then it is simply a slight overall grey tonality, when compared to the real thing live. All the other amps I have listened to have had a bit too much "character".


I use the FU50 amp with a Sharp DX-SX1 sacd player and a Kenwood KT990D tuner. For speakers I use a pair of probably 50 year old Australian or New Zealand made Rola 12” AlNiCo speakers in a cabinet made by AWA for broadcasting monitor purposes (AWA Studio Monitor Mk3). For the top end there are some Fostex (Foster) horns and a capacitor. This gets me close to the sound of the Altec Lansing model 19.


This FU 50 amp is still available and now can be purchased as either a diy kit or built up.


Vailala

Does anybody have models in pentode mode for these valves. I would be grateful.

I don't think this project will ever get to the front of my queue so time to share the joy with somebody.

I'm offering a pair of the PCBs from the group buy listed below, a pair of TDA7293V devices (still sealed) and a pair of xrk971's power supply boards (as featured in xrk971's verification build, fourth image in post #1 of the link below).

£15 plus shipping at cost, payment via payPal family and friends.

https://www.diyaudio.com/community/threads/dibyas-tda7293-xmas-amp-by-jhofland-giveaway.366075/

​

This is SOOO annoying. I was about to order a coupla SST404 N-jfet as used in the amps designed by Susyj from Futurlec (german branch)
AEM6000 Based 50W Amp

Due to a rough Covid infection I was out for a few weeks and now when I got around to order, they are all out of stock ,and not expected until end of 22. And nothing about intra-EU sales anymore...

Anybody out there that has a few spares they could consider parting with?

Regards

Rickard

**

I have several items listed below. Would love to move the whole lot, so make me an offer I can’t refuse. Also, if you want, you can pick a-la-cart. All products are in working order, some new, some used. The most valuable piece is the pair (Qty: 2) Rod Coleman V8 regulators kit.

Qty Description
2 Rod Coleman V8 regulator kit (NEW)
8 yellow mojo 4.7uf caps (NEW)
2 Antek transformer: model AS-0507
2 Antek transformer: model AS-2220
8 Russian caps (brown) (NEW)
2 Red audiophiles 3.3uF caps
3 Jupiter condenser 0.47uF caps (top of the line)
2 Wima 2.2uF cap
4 Wima 4.7uF cap MKP4
4 Wima 4.7uF cap MKP10
2 Rike Audio 0.033uF
2 Rike Audio 0.068uF
2 Hammond 166 transformer (NEW, sealed)

Hello guys, time to do some spring cleaning and move some drivers that I have collected for projects that i will not complete..

First up is a pair of new Alpair 10P. These have been EnAbled in gloss black, which reduces distortion. These sound great, I have only tested them. The labels on the back look a bit rough as they had sound deadening material on them which i peeled off to show the original label.
175 euro for the pair.

Next is a pair of Mark Audio Sota 11R speakers. These are also new, I got them last year from a guy in England. These have some sound deadening material on the baskets as they are stamped steel. Awesome drivers with unbelievable bass capabilities. 160 euro for the pair.

Then lastly 4 Peerless TC9FD. These have also just been sitting on the shelf since I bought them in 2018. Tested and working fine. There is some glue residue on the frames which was there when I bought them. All 4 for 35 euro.

These are located near Vienna, Austria. For a shipping estimate just send me a PM. Thanks!

Looking at a new project for next summer and one option would be to modify my current DIY speakers to accept new parts.


They are 2-way with top part ~7l sealed in 210x210x300mm, currently housing Alpair 10.3 but the upgrade would be Seas C18EN002. I need to route a bigger cutout but that should be no issue.

The bottom part is 900x210x300 ~40l vented ~25Hz tuned enclosure with active subwoofers. I will probably update these with Ultimax 10-22 or similar.


I would need to cross the Seas at around 80Hz, will that have any issues?


Looking at the simulations it should work nicely even though Seas Fs is 98Hz, room gain will raise the low end more than enough.
Currently if I raise the crossover higher the sound starts to localize to the subwoofers and there is a clear difference in tone. Maybe with the new parts that won't happen...

So, I'm kind of stuck with my Ditton 332 and 442 trying to remove the tweeters.

They are completely stuck to the cabinet! Many of you have removed drivers form the Dittons, what's my best option?

Tried to remove the mid-range and push the tweeter out, but the mid-range drivers are also firmly stuck to the cabinet.

Any suggestion is more than welcome! 🙂

Hi, am out for a regulator to switch with my LF50 for my DDdac1543.

Anyone tested the two, lets say in a dac.

Frank

Hi, I'm working on designing a small class D mono amp for a portable radio project. The current design is based on a number of other projects, so I need some clarification and advice.

The audio signal is amplified and converted to differential signals using a BJT NPN transistor as a Class A amplifier. the Vcc is a fixed 3v. The signal is then amplified by a small class D amplifier chip (PAM8302) which is powered by a single li-ion cell, so the voltage ranges between 3.5 and 4.2V.

My main questions:

• I'm using a 4.7 uF ceramic input cap for the NPN transistor. Is that an appropriate value?
• The output caps are 1 uF ceramic. I know those caps set a high pass filter and I think they need to be larger to ensure good low end response (ideally 40 Hz), but I'm not sure how to calculate the necessary value. Can I use a large electrolytic cap instead of ceramic?
• I'm using two bypass caps for the supply input on the class D amp; one small ceramic and one 470 uF electrolytic. Will this work for accurate low end response?

Thanks for the help and advice!

Minidsp has updated their 8x12 kit with new AKM 4456 output DACs and specified 115db SNR. Maybe this will finally make them transparent and quiet enough for high efficiency active speakers? Anyone tried them yet? Promising update, and waiting for the last step of firmware upgrade to allow FIR on the sharc processor.

C-DSP 8x12 - 12 channels High Performance Automotive Processor

Hi, I'm building a simple dual rail power supply using a center tapped 15V transformer and currently have issues with a Lm 317 regulator - to cut the story short - there's no voltage drop across it.

The supply output reads +20V/-15V. Tested with no load on either rail. I've double checked used resistors, solder joints and schematics, it seems to be in order. The other regulator, Lm337, is doing a fine job at 15 V.

Does anyone have a recommendation on where to start troubleshooting?

Regards,
Stefan

Hi I just bought an Apogee Jam on ebay and it come without cable whatsoever 🙁 I looked up and it's a proprietary connection which Apogee charges a whooping 24.99 for each cable and ideally you would need 2 or three depends on your needs (Lightning, USB A and USB C) - I think this is way too much for a USB cable so I opened the JAM and looked inside. There is a 10 ways jumper and the connector is very tiny soldered with maybe 10 cables going in... Knowing that USB A is only 4 cables I would be happy if I could make a cable, I don't mind to solder directly on the board.


Does anyone happen to know what the connections are?

would it be possible to solder the cable direcly from the jumpers maybe?


It's a shame otherwise as I can't afford to buy a cable at those prices and you can't find on ebay as it's quite rare and proprietary 🙁

I read somewhere that's the same cable as the Apogee Mic,
any help will be gladly apprecited, thank you

Stay Safe

So, went to update the Garmins in our cars. The new map bricked both of them. Went to Garmin support and "will get back to you in 3 to 5 days"
Great support.

Anyway, I was able get them off finally and powered back up. At least the 61 said "map corrupted" Nothing on the 50.
But as they would at least be recognized by the USB again, went to see if a different or older map was available. In that menu, it did say "map too large" Gee, could have told me that in the normal update! So it did load just the SouthEast map. I have to buy a micro SD to load the full 49 state map. ( But paying $8 for card and SD adapter from Amazon, not $35 from Garmin)

They may have fixed something overnight as my 61 succeeded in loading this morning, though it took forever with data rate as low as 1MB.

Yes, I like my Garmins. I make phone calls on my phone. Garmin's are installed as part of the car. Phone is in my pocket.

I was updating as shifting between cars. The wife's 57 failed totally. Unresponsive or unpredictable actions on the touch screen.

I was wondering if there are kits of resistors and capacitors in 0402 or larger sizes, as I'm interested in learning dead bug/Manhattan construction techniques. I'm looking for a decent range in values with cheap bulk pricing if such a beast exists. Or do I need to just order 100-1000 pieces of common values?

I would also like to get more parts for the Learning Art of Electronics lab manual, but I think that's probably best pursued with through-hole parts in a breadboard.

Hi,

This circuit is from LT3045 datasheet. However, I don't understand why LT's engineer would propose this as the LTC6655-5 isn't quite a low 1/f noise reference. From the diagram, the LT3045 shows 20nv/sqrt(Hz) @ 10Hz (22uf Cset) whereas the LTC6655 is 90nv/sqrt(Hz) @ 10Hz. Any one?

Poting

Hi all

we’ve finished with a friend a pair of bass reflex columns (similar in proportions to pensils seen on this forum) with an alpair 10p in each.

Have gone through hundreds of mails to read about experience with passive equalisation, baffle step compensation, equalisation, notch filter, BSC or whatever it’s called. Can’t get a real picture of what end values are giving satisfaction.

I would appreciate a quick feedback from those who have kept such a passive equalisation and what values are used for an LCR or LR circuit and possibly impedance correction (R or RC) in parallel. Thanks a lot in advance!

Hi. I'd really appreciate some advice please. I have a dud vintage Citronic PPX900. One channel doesn't work at all and the other distorts at 30% volume. Fuses are all fine. I have learnt how to check the 12 Hitachi MOSFETs and it seems they're pretty much all shot. Replacements, even BUZ and Exicon substitutes, are about £15+ each, so more than it's worth. Is there any way I can use much cheaper replacements even if just to check that the rest of the circuitry works before committing to the full expense? My electronics know-how won't stretch to testing the rest of it I'm afraid. Thanks!

Hello everybody.
I present to you these recently made PC loudspeakers.



The Annapurna are small size and self-built loudspeakers, conceived to be placed on the desk and reproduce the sound of the personal computer (to amplify the sound of the PC I use the "Mount Fuji Amplifier V2"). They stand out for their slim design (small tower type) and for their outstanding sound quality thanks to the high quality of the drivers and the rest of the components used.

The tweeter:
As the treble unit I chose the Scan Speak Illuminator D2004 / 602000, a transducer with a 2.4 cm diameter dome-shaped textile diaphragm and a frequency response of 450 - 20,000 Hz +/- 3dB. Scan-Speak A/S



The midwoofer:
The transducer in charge of reproducing the bass and mids is the Wavecor WF120BD10, a unit with an 8.3 cm diameter paper and fiberglass diaphragm with a frequency response of 55 - 5500 Hz +/- 3 dB. Wavecor speaker innovations



The crossover:
I designed a 2-way parallel passive filter based on a second order Linkwitz-Riley (12 dB / oct) with the polarity of the tweeter reversed, and a cut-off frequency slightly above 2 kHz, assembled on a printed circuit board.





C1 = 12 uF
C2 = 6.2 uF
L1 = 0.33 mH
L2 = 1.2 mH
R1 = 1.2 ohm
R2 = 2.7 ohm
Both capacitors are SCR-Audio Smartcap metallized polypropylene, 450 V and 3% tolerance. SCR Audio – Manufacturer of high technology film capacitors
The two coils are Mundorf Mcoil air core (L140, 1.2 mH, 0.31 ohm, 1.4 mm and L100, 0.33 mH, 0.26 ohm, 1.0 mm). High quality HiFi
The resistors are 10W metal oxide film Mundorf MR10 (1.2 ohm and 2.7 ohm, with a tolerance of 2%). High quality HiFi

The enclosure:
The enclosure is bass reflex type with a C4 alignment (4th order Chebyshev) that presents a very slight ripple of only 0.05 dB. The net internal volume is 9.6 liters, and using the unmodified Monacor BR-30HP tube (this tube, with a slightly conical profile, can be considered equivalent to a cylindrical one 11.8 cm long and 3.2 cm internal diameter) I achieved a box resonance frequency of 42 Hz and a cutoff frequency below -3 dB of just 38 Hz. https://www.monacor.com/



For its construction I used 1 and 1.5 cm MDF boards, which I would later veneer with natural american walnut wood. I filled approximately 20% of the internal volume with Monacor MDM-2 uncompressed polyester fiber, the cable used is standard 1.5mm2. The external connection terminals are Monacor BP-405G that are recessed in a recess made in the lower part of the rear wall. https://www.monacor.com/






THE FINAL RESULT
Specs:
Frequency response: 38 - 30,000 Hz
Sensitivity: 84 dB (2.8 V - 1 m)
Nominal impedance: 8 ohm
Maximum power: 60 WRMS
Weight: 5.0 kg
Dimensions: 42 x 14 x 24 cm



https://www.academia.edu/49231656/Cajas_acústicas_para_ordenador_Annapurna
https://issuu.com/jesus_losada/docs/cajas_acusticas_para_ordenador_annapurna

Hi,
having built a lovely Ale Gyrator loaded 2p29l /filament bias preamp, (Thanks Ale) I would like to use the same power supply for some old cv1045 DHTs I have. Old bright tubes for"special occasions". Though meaty enough for the 440mA filament of the cv1045, the 15v (14v at 440mA) wont be enough headroom for the Rob Coleman regs, 2V filament and -10v grid bias needed. Could I use this filament supply to get say 8v of the -10 needed for the grid, then add a couple of diodes to ground to get the rest. A sort of hybrid approach, or would this suck? Thoughts?
Thanks.
Nick.

I want to run a quad of EML 520b in push pull clAss AB1; what input/driver tube would be ideal? A 12ax7, or 6sn7?’ Could I B use a 12b or 20b?
And could a pair of 5965 work as phase inverters? Or a pair of B 6sn7 ? I prefer lower power consumption, so i’d like maybe 5751, or Maybe a pair of 12at 7 , or e80cc? Any suggestions ?

Hi guys,
Planning to build a subwoofer, specifically an Infinity Reference 1250W in a sealed enclosure (300WRMS, but don't really need all of them).
I was looking at some plate amps, but I taught that would be a nice learning experience to put it together with separate pieces.
I'm planning to power it with an IRS2092 (open to alternatives), what other modules do I have to add?

1. A power supply (dual rail), 2 options there:
   1. Toroid and a rectifier (is 300VA ok? or can I go smaller?)
   2. Power supply board (Example) do I still need a rectifier or can I go with the one on the board alone?
2. An op amp module for the crossover, (Not really needed as I have it already in the AVR, but will eventually add it for completeness with the possibility to exclude it),
3. Soft start module?
4. Any way to add standby mode? couldn't find any module boards around,
5. BT not needed,
6. various connectors, pots, etc...

Anything else?

I don't exclude in the future to add DSP.

Thanks!

Edit: Typos

Hi , I am planning to builld a custom high power tube amp.I am looking at using 520b or 1605 tubes, 2 per channel operation inclass AB1 push pull. If I chose the 520b, they will run a bout 120ma each, with anode voltage at lleast 580V. To supply the DC current, i figure on using 3 parallel rectifiers . If I chose 2x274b I can B expect to have 3x 160 ma @550 to 600 v ( total 580 available ma current; or I could try 3 x5Z3 , which would produce 3x 260= 780 ma, but only a maximum of 500 to 550 volts. 3 /‘274b heaters would need 6 amps. While : 5Z3 would ned 9 Amps Im leaning towards the 274b , withlower heater draw, and the reqquired 600 V on the anodes. I also see advantages as 3 parallel tube rectifiers would lower te voltage sag a cross the rectifiers substantially and see 6 amps at the heaters much less problematic that 9 amps if I chose 5Z3( or 5U4). My questions are : 1. Does using 3 parallel rectifiers make power supply
Filter easier or more difficult? And the data sheetd for 274b ?(and 5Z3) dont say whether 3 paralleled rectifiers need enable more ir less filter and/or reservoir capacitance? The rectifiers are all Emission Lab mesh plates. I ran 2 paralell 274b on my last amp, and it worked great. All EML woud say was I could double C1 from 4 if to 8uf. That was with capacitors loaded powersupply. But now tohit 600v, I must use choke loaded power supply. Wirh a Llundahl 1673 dual choke. Can anyone offer advice? I know that I will need a helluva power transfrer. The EML tubes Can be ordered a 6. 5 V 1.5 amp heater, a 5V 2 amp Heater or a balanced 5v ( 2x2.5v 2 amp center tapped B heater. EMLrecomnends the6.5 v 2amp heater for push pull amps .this means 8 amps juzt to heat 4 ppower tubes. Or i could use the more muscular 1605 . It can delivrre almozt 30 watts per tube. It had two heaters options 5v 2.1 amp or 5 v ( 2 x 2.5v) center tapped 2.1 amps. K Ty s wuite s challenge with either power tube, im leaning towards the. 520 b
I welcome all comments. Cautions or advice I am most interested in power supply, filter and power transformer .

Is it a 1khz sine wave I need or what hertz sine wave do I need to measure the preamp output voltage of a head unit ?

Hello there,

I am finally building my own soundsystem. I have already decided on the subwoofer design. However, when designing the tops and selecting drivers I came across a problem: There are 4 and 8 Ohm versions of one driver model and now I have to decide. I did research but couldn't find what I was looking for. There are tons of comparisons between the 2 "technologies" in general but I have not been able to find a comparison between 4 and 8 Ohm drivers of the same model. Can someone elaborate the pros and cons of each? Thanks in advance!

Blessings,
Domme

https://www.google.com/url?sa=t&rct...loudspeakers&usg=AOvVaw2n-Z2LqGkdtRY_tO_BG7ti

https://www.google.com/url?sa=t&rct...ing-speaker/&usg=AOvVaw0dil_eohWMzrph3EHSrOju

Sale!!! Birch Acoustics Raven Fullrange Speaker - Silver Flute Edition For Sale - Canuck Audio Mart

“This is a special version of the Raven speaker that uses the Silver Flute fullrange driver. The Silver Flute driver has a unique wool cone composition that gives a very pleasing sound. This driver is excellent with its tone; it has a very smooth response and a gentle blending of the bass, midrange, and treble when correctly implemented. We have always liked the Silver Flute and have thought about building a speaker around it. Now that we have, we knew it was too good to keep to ourselves and are thrilled to offer it to discerning audio buffs. The sound; price to performance; and quality of this Silver Flute Edition will absolutely floor you. But act fast, there are only a small number that have been built and they will go quickly.

Raven description:

The Raven is 767 rings of birch wood; machined into a stiff, light enclosure that compliments its quad of filterless fullrange drivers. The multiplying of drivers greatly increases efficiency and decreases distortion. The quad of drivers launch larger cylindrical waves which are more impactful and dynamic. The Raven is best suited to larger rooms or owners with a desire for large crescendos of music.

Specs:

Drivers: Quad 5” Fullrange Wool/Paper
Response: 40Hz-18KHz
Sensitivity: 94db @ 1 W
Impedance: 8 Ohm
Dimensions: H W D 42” 9” 12”

All speakers come with a 40 day money back guarantee policy. It's easy listening knowing that if these are not to your taste, or don't play well with your room or other equipment, you can return them for a full refund.

Also feel free to ask any questions, we are happy to help!

BirchAcoustics.com”

I’m not really sure what to make of this.
I see the angle so there is less combing at listening spot ? like slightly bottom of concave array ?

For me, an 8” at 7’ = 1 pair of ears, 12’ = 2 people on a couch.

A 3” at 7’ can cover a couch.

So based on that, a 5” can cover a couch at 12’ just fine ?

I have a pair of magi 3.7i and would like to convert the crossover from serial to parallel.
So I can bi-amp them and play around with better parts.

From the schematic it looks like, and I am guessing 😊

12 db on the tweeter
6 db band pass on the midrange
6 db on the woofer

Am I right? I have never worked with a serial filter before and it looks wired to me

I'm thinking of building a little portable PA system for our theater. I say building because I have zero budget and a truckload of components and MDF and lumber sitting around that I can cobble together.

I'm thinking of basically building a sub box on casters with a horizontal rackmount for an audio desk on top, then a couple extending poles on the side for some full range speakers. I actually have a rolling rackmount case but I can't fit an amp and a sub in it, so I was going to just build it from scratch. (it also has really annoying rattly metal hasps on the covers.

The uses will be for PA when we have an outdoor performance, when we have a sitzprobe, mobile music/DJ for events, or for rehearsal tracks at dance rehearsals. Roll it out, plug in laptop/phone or a few mics and go. Right now I have to pull Eons from storage, pull the aux desk out of the booth, set up a table... blah blah. Just thinking it might be nice to have a little box-o-sound I can roll around.

If I build the sub as part of the case, how awful will the vibes be on the mixer? Am I asking for trouble with a massive magnet and 350w bouncing around that close by?

I am looking to dig into the electrical aspects of my listening room such as the the supply wiring from the house panel to and including the receptacles in the room to see if there is room to cleanup any potentially dirty AC. I do not have any equipment beyond a traditional multi-meter, so I was curious about purchasing or renting a clamp on power quality meter such as the Amprobe ACD-41PQ which has the capability to provide THD readings on a line.

I figure I can measure the THD on the AC line into my listening room and then decide if I need to or want to take steps to improve the AC. Does anyone have any thoughts on my proposed process? Thoughts about the qulity and reliability of a clamp on unit like the ACD-41PQ to provide THD measurements? Is there a better way to go about determining the THD on my AC line?

Good evening.

As we all must have noticed, tubes are getting more and more expensive. Instead of stockpiling spares for every new project, how about building one amp with two or more different sockets in every position, wired in parallel to allow different tubes to be used (only one at the time for each position, of course)?
This idea struck me a couple of years ago when I couldn´t decide whether to use 6L6s or 807s in a project, I had both types on the shelf but only in small numbers.

I´ve mostly been building guitar amps during the pandemic and lately I´ve been thinking about an amp with one row of 7 pin miniature sockets (6AU6 input stage, 6J6 phase splitter and 2x 6AQ5 outputs for example) and one row of novals (EF86, 12AT7 and 2x6BQ5). Grid and plate connectors would be common for both rows but at tleast the output tubes would require separate cathode bias resistors.
Any thoughts on this?

I hope that this is not against forum rules but with how rare 2sk389 are I thought maybe people would want to know about it.

http://ebay.us/6CZmp9?cmpnId=5338273189
We use them in front end of a sensor but the quads ended up not being worth it over a dual due to the capacitance and they have been sitting in a box for 10 years.

I will open with the usual apology for my ignorance. I don't know much about chip amps since most of my audio hobby has been older stuff. So I am unclear on the variations in technology and terminology in this space.

I picked up a pair of Scott Nixon 40 watt monoblocks somewhere in a batch of other stuff I was looking for. I hooked them up in the master bedroom. The source is an Echo Link and the speakers are Spica Angelus. I was thinking a nice convenience system. With the Echo functionality it is a nice alarm clock. And the Spicas have good WAF mixed in with the MCM décor. I am hoping they don't draw much power while idling (is this true?) compared to my class AB stuff.

I was surprised how good they sounded. They are certainly not the weak Link (see what I did there?) in the chain.

Can someone point me to the contemporary version of this amp technology so I can learn more?

Best,
John

Correct slo blo fuse blows instantly when unit is turned on. I removed the lower panel and observed that the amplifier was previously worked on . I suspect that the original resistors across one of the big power capacitors ( 400v 3300uf) were changed ( might have burnt ?) as they do not match the other resistors in the same amplifier and also when compared to the other good good amplifier. Also the weep hole at the bottom of the capacitor was covered with scotch tape. Another observation was that there was evidence of a leaky capacitor due to sticky residue on the bottom panel. I looked at the circuit board carefully and did not see any burnt components.
So would a leaky capacitor of this kind cause the main fuse to blow?

Bought Rogers. So all set for now.
Don

Hi
New to this site; hope I'm posting in the correct location.
LF a Heathkit #54-77 transformer or parts unit IP-32 or PS-4.

Hi ! I want to build a "copy" of The voice of the theater but without the budget to buy GPA copycat of Altec.

Anybody here found a 12-15 inch woofer how sounds like Altec pro typical sound ?

I search a low budget woofer with very high spl
extremely stiff and thin paper cone
with detailed midrange sound that gives you goosebumps.
FLH configuration

I even had it made by a company on alibaba company a copy of woofer with the spec and all data sheet, but the result was terrible and I put that to the garbage !


thanks in advance ! 🙂

nicK

Hey Guys

I was wondering if anyone on here had experience with the kits offered by AmpsLab.com? I have built a pair of Dynaco tube monoblocks and I'm in the process of making another pair of Decware kits. I was looking to make a 2 or maybe 4 channel solid state amp for another project but most places don't offer anything with enough power to drive my Martin Logan ESL panel.

These guys seem to offer a good variety of kits that get into very high power levels and I'm very curious. I have sent them an Email with a few questions but haven't heard back yet.

Here's a link to the website for those wondering
https://www.ampslab.com/products.htm

Hello.
Integrated amplifier MARANTZ PM 700 DC.
Left channel no problems BIAS adjust 14 mV.
Right channel distorted and impossible adjust BIAS......1.5.......1.6 mV max.
1v DC voltage on right speaker terminal.
Trimmer is ok .
All voltages are OK

Thank you

SM.
https://www.google.com/url?sa=t&sou...8QFnoECAgQAQ&usg=AOvVaw1Zn33xMt46LyUGVnLXXf_j

Hello,
I use a TPA3116 amplifier board to have surround sound on my pc. At the moment I use a USB sound card with 3.5mm jacks as output. Since my mainboard also has an optical (SPDIF) out, I would prefer an amplifier board directly with optical in. Or, if that doesn't exist, maybe a small DAC board with output pins similar to the input pinstrip of the amplifier (at the bottom of the picture). All I found was big DAC boards with Cinch output which wouldn't really be a step up in my situation. Does anyone know of such boards / modules?
Thank You!

I am in need of the electrical schematic diagrams for a Mark Levinson ML-11 amplifier and ML-12 preamp. Does anyone have those, or know where they can be found? Thanks.

I don't see the specs yet, but this looks interesting for the price...
Zoolark

I have thought to be quite intelligent to start with a new program, but with VituixCAD in the version 2 i have a very bad learning curve.
I am stuck already with this:
1. managed to open the Trace SPL tool and obtain the SPL and impedance files from screenshots of the measurement curves
2. opened VituixCad2 empty project and tried to import the stuff from 1. for the driver and get all the time the curve imported here - obviously wrong:

i just want to get the values imported in the correct graph for the on axis frequency plot and not in the group delay and phase graph... should be a piece of cake - embarrassing to have to open a thread for this - sorry!

Two years ago in approximately the same time I bought two pairs of lodspeakers. Delta 12 LFA in 30 l bass reflex boxes and EV SH1502. They were OK when brought home, but in a week or two, always the left speaker, started playing softer and with distortion. I could hear the difference in sound. The Delta and DH3 drivers showed the same symptoms - very different impedance from the healthy one (no pronounced resonance peak, just some wiggle higher in frequency and there was like 5-10% distortion even at very low levels. The coils were intact and measured normally at DC.

I wonder what could have happened? The room is always dry and temperatures between 18 - 25 deg C all year. Both failed in their boxes, so the naked drivers were not dropped. Does anyone have any explanation? Could it be e.g. magnetic splinters in the gap (found none visible)? The magnet holds on to iron (in both cases) as strongly as the healthy units. I could not find any mechanical damage while dissecting the Delta and tried brand new replacement membrane in the DH3 - amd it measured exactly the same way as with the old one (which I had to fix with superglue). This has luckily not happened since...

I have inherited a pair of John Bowers Active 1. These appear to be active/passive hybrid speakers with a good reputation. 2.5 way with a passive crossover on the bass unit at 350hz.

The dual amps actively power the tweeter (at 3khz) and the mid run from 3khz down, via the passive low pass for the bass. Unfortunately, both boards are not functioning. I won’t go into detail on the state of the PSU and Amps here as they are doing a number of strange things and have not been stored in good condition. The passive crossover, tweeters and two of the four drivers are functional. I’m happy to source two new drivers. The cabinet and grilles are in good shape and its very well built.
I’ve attached some of the service manual. The schematics seem relatively simple, in modern terms, but I do not have electrical expertise.

I’m in two minds about whether to turn them active with minidsp and new amps, or to take a piecemeal approach with the crossover and to make them passive by taking the crossover from a pair of DM10 speakers, which apparently have a very similar (identical?) dome tweeter (TP26 vrs my TZ26). Both models cross over at 3khz.

I guess I’m wondering if forum members would guide me towards the best approach. I believe in good condition these units are worth about £900. I’m happy to spend £2-300. I’m intrigued by their reputation and it would be a shame to see them end up being thrown. However, if without the amps they will never sing, then dumped they indeed will be!






Local pick-up is preferred. If no one locally wants them I may consider shipping later. If you are in the San Francisco/Bay Area, I am in the East Bay near Ashby BART.

A pair of black ACA V1.6 Batch 2 that I built with power supplies. They work well and I have used them with satisfaction but I'm moving and need to clear out much extra stuff.

$500

My young son has just been building a two transistor bistable (set/reset) flip-flop and the standard two transistor astable flip-flop (flasher) with a couple of LEDS in each. All as first steps into electronics.

His question now is how to make a bistable flip flop with only one switch as input that toggles on/off each time the switch is pressed. Obvious question but it has stumped me.

Years ago I did this by using two flip flops wired as a master and slave but this solution required many transistors and I'm not sure I could reproduce the thing anyway having hacked it on the fly at the time.

I have seen toggle flip flops built with two transistors, caps accross the base resistors and a parallel switch resistor connecting the emitters to ground (as here http://ourworld.compuserve.com/homepages/Bill_Bowden/page9.htm) Fine but I would prefer the input to go into some more normal place rather than brute forcing the negative rail up and down. Also we loose 1 volt from the suply.

So the challenge is, does any one have any nice discrete transistor toggle circuits that:

a) Use minimal components as my sons patients for building things is a bit short at the moment.
b) Uses a more "logical" input method.
c) Runs from a 5 to 6 volt supply, dictated by our rechargeable battery pack.
b) Can be easily understood by a 12 year old beginner. (Or me for that matter)

Extra caps and diodes allowed.

Cheers all.

Hello everyone.

Didn't know exactly where to post this thread (as it is about power supply/transformer), so excuse me if it's not the right place.

I bought for a few tens of euros, a long time ago, a Teac VRDS 9 CD player, described as non working. Didn’t know what was wrong with it. All I knew was that the device came from Japan to my seller, broken. D)It didn’t light on. Period.

I initially bought it for its mechanics (Teac CMK 4,2), being the same than the one used in my Krell KAV 300CD, in case I should replace it…

Recently, I decided to lean on it and try to figure out what could be faulty. I often read it’s a good drive, and I like my machines better when they are fully functional. I'd like to be able to use it as a drive someday...

I quickly saw that no voltage was available, right after the transformer. No secondary winding was delivering anything. So I went onto the primary windings and measured no resistance between pin 4 and pin 5 (pin 5 responsible for 230V operation). Other trouble, the (internal - thermic) fuse seems broken. It should be between pin 1 and pin 2, as on the schematics, but no continuity between the two pins.

Then my thought is: for a reason that can be discussed, the wire that goes from the 120V input (pin 4) to the 230V input (pin5) broke, current delivered rose, temperature too and the fuse broke (maybe the other way round?).
Could I be right?

Then, I face this problem: as it is very unlikely that this transformer can be repaired, I’ve got to find a way to make the different voltages (AC) brought normally by the secondary windings available for the power PCB.

As I can’t read anything on my DMM out of the 10 different secondary windings since the 230V input is unavailable, I thought I could try this: have a 120V source to feed the 120V inputs of the transformer (AND shunt the pins 1 and 2 to replace the broken fuse so that continuity is OK from 1 to 4, if it is safe enough). Just during the time necessary to read the voltage out of each one of the secondary pins. A Variac could do, probably. Though I don’t have a Variac, I can borrow one.

Then I’d find the adequate transformer (or transformers if necessary) to provide the necessary voltages to the Power PCB. Unfortunately they do not figure on the schematics, and the reading of the Power PCB schematics doesn’t allow me to guess them precisely (maybe some experts can do that but I’m not an expert…).

So, briefly:

• does someone know the normal voltage values out of this particular transformer? (9 different values, pin 5 is a ground)
• Or can someone who owns a Teac VRDS 9 take the corresponding measures from his own player?
• Or can someone give an idea/advice/method to help me measuring these values?

Thanks for reading, and even more for help if possible. I join a small drawing taken from the schematics.

Of course I can provide all schematics I have and pictures too.

Have a nice day/evening 😉

I'm not selling anything and this ain't spam. I just came across this and thought it was pretty nuts thought some of you might want to see it. It can be yours for a mere $25,000.00 USD but you will need two so you might want to bring $50,000.00 and a Ryder truck with a lift gate. They are the size of a closet and will heat your house like a pot belly stove but think of all the bragging rights you will have. It's like a whole jigiwatt of pure tubalisious power. I have no idea what they would sound like but I'm pretty sure two of these could power the next Oz Fest.

https://www.surplussales.com/Microphones-Audio/MicroAudio-7.html
Here is the manual for the beasts.

I just bought a pair of these off of Ebay. Do you guys know anything about them?
Thanks!
Pics:












and here is a picture of my Ixtapa armadillo for good measure 🙂

Hi! I have used this for quite a while, purchasing this before they were “cool” (and many years before the lot resold by PcX).

It is in good condition, other than the front of the bottom plate “sagging” down a bit and some marks on the top that are visible in the pictures. The plastic display cover and the VFD display are perfect. The GPIB interface works great, I used a USB converter and some native Python libraries and things worked super well. I imagine the serial interface works, but I never tried it.

The unit also works well as a DMM, and includes a 4-wire interface. I haven’t checked absolute accuracy in a while, but when I originally bought it, it was within spec.

It ships in a Keithley box, though not the original box (it says Tektronix on the box).

Looking at prices on eBay, I would like to net $575, so that plus actual shipping in the US from 78739 I accept PayPal. I will ship it whichever method you like - It’s packed and ready to go.

Thanks!

I powered up just the heater supply for this board with no tubes as my initial test. I'm getting ~7.6VDC from H+ to G, and 0V from H- to G. The transformer is a Triad VPT12-2080: https://www.mouser.com/datasheet/2/410/VPT12_2080-781423.pdf. I've wired the inputs in parallel as per the data sheet as I have 115VAC power. I've wired the output in series for 12VACT CT, as per the data sheet. I'm getting 6.8VAC between the Black or Yellow secondary wires at the Red/Orange pair, and 13.6VAC across the Black and Yellow wires. Input power is set to 115VAC with a variac.

I configured the power supply in the Full-Wave Center-Tap configuration in the attached scan. Black and Yellow transformer secondary wires go to the A C connections, and the Orange/Red wires go to the CT position. I omitted D10, D9, C11, and C12, as per the diagram for the Full-Wave Center-Tap configuration.

The fact that I am getting a stable voltage that is approximately 1/2 of what I am expecting makes me think I have misunderstood some aspect of the power supply / transformer configuration. Either wiring the transformer incorrectly, or configuring the power supply incorrectly. But, I'm not sure what exactly I've done wrong.

SOLD on 2/25/22


Excellent condition, fully tested PAIR (quantity 2) Tentlab filament regulators. About 6 months old. 1 owner.

2.5A units

https://tentlabs.com/Components/Tubeamp/Tubefilament/index.html
Make me an offer (no low balls).

Just an idle idea, and I was wandering if it has been done already.

Simply, using the average time of an lp side, say 20 minutes. Then moving the tonearm base (with a constant speed motor) to maintain approximate linear tracking.

This would be a very simple thing to make (true linear trackers are always incredibly complex) and could be structurally very sound. It could even perhaps use an existing favourite tonearm.

Is there an intrinsic fault in this idea that I have missed?

Yesterday I upgraded my disc player. I bought an Audiolab 6000CDT transport. Paired with my Topping D50s. All I can say is WOW. Anyone ever gives me that old line "its just digital data there's no way it can be any different." I have a life changing A-B comparison to play for them. You would have to be half drunk and semi-conscience to not notice the difference. Its a long way from subtle. My La Scalas have come alive and the sound stage sounds like you turned the focus ring on a telescope. Best $470 I have spent on my sys in a very long time, if you are on the fence about buying one dive in. You will not regret it.

Jeff

FS 4x E180CC Valvo NOS

Price 80 euros (4 tubes), not sold separately.

FS - new - not used

XO Tent Labs 11.2896 MHz crystal Low Jitter for audio DAC

i have for sale this

Jensen JT-11-DMCF Premium Line Output Transformer 1:1

asking 130 € for the two shipping registered in Europe.
They are very good for balanced voltage output dacs.
thks.

For Sale as one item (UPDATED).

6x OP275 PMI
2x LME49710HA metal housing
2x LME49710HA metal housing to 8-pin
2x OPA627 BB
2x BUF634 BB
1x OPA2134 BB
1x CS4390 KP Cirrus Crystal 24bit DAC
8x EL2020
4x TDA1543 Philips DAC
1x DIR9001 to CD8412 interface adapter board new unused
1x ISO485 BB isolated RS-485 differential bus transceiver
2x SUMLINK ST-DV709 digital audio transformer

Hi all.
As the heading says, just a pair, (possibly more if available) please. I do have DIP8 LME49710 to swap four off for the two T0-99 type if required.
My chips are old (the op amps also) so are original.
Many thanks.

Given the traditional mica thermal pads and thermal paste for isolating FETs to heatsinks...

Any reason one couldn't cut their own out of the clear plastic sheets like you sometimes get at a craft store or with notebooks? Is that a common thing?

I've also recently used silicon pads without grease. No muss, no fuss, but I assume some paste would help conduct heat better regardless. Yes/no/I'm a fool?

Hi everyone,

I am looking for an nice great pre-amp to boost my Philips IS-5021 output , before my F6.


The DAC analog output is about 1 v rms , impedance is 200 ohms.


something simple , one in one out , dead quite , some noble stuff that some of you guy's know's about 😀


Tanks in advance


Fabrice


.

Hi There,
I am designing a mono channel pcb for myrefc with following key concerns.

1.Will be using commonly available components.
2.No use of overrated parts to keeps the cost low.
3.Singal caps will be mica or polyester.
4.Common square bridge rectifier.
5.All through hole components.

I have created a video in youtube presenting the design---> link

I am ordering the pcbs from JLC. If anyone needs it in india you can contact me.
i wouldn't mind open sourcing if anyone can make it better and then share again here