diyAudio

zman01 · 2023-04-27 4:47 am

For sale have 2 units of Nuvotem Talema toroidal power transformers, 500VA, 2 x 35V AC secondaries:

https://sg.rs-online.com/web/p/toroidal-transformers/2238910

The transformers are encapsulated (potted). Primaries are for 230V AC.

If interested, please make an offer.

johnreeve · 2023-09-26 4:39 am

I am trying to learn how to repair trickier things... previously I've just stuck to soldering physical connections.

However, a music school asked if I could fix their little powered mixer, a Yamaha EMX66m

On of the input channels distorts quite badly. I have narrowed down the issue to what I think is a pair of transistors that work as a buffer right before the first stage of opamp amplification.

I'm not totally sure how to diagnose problems like this (and while I have a vague idea about how transistors work, I am not 100% sure I understand), but I am doing my best. I figure this kind of goofing around is one way to learn. Anyhow.

The other channels work okay, though and there isn't anything else wrong with the amp, so I compared them. It seems like the signal is rectified after Q101, but I am not what would cause that. In the other channels, I get the full signal at that point. I have a little signal generator with a 1k sin wave to provide a source signal, and that is going into the line in on the channel. I haven't verified that the XLR side of this channel does the same thing, but that didn't seem likely to me.

Anyhow, this is the part of the circuit where that is happening:

If I look at TP5 with an oscilloscope, this is what I see:

On the other channels, I think that is not rectified.

And this is what is on pin 7 of the opamp IC101:

Anyhow, any pointers or things I should look at would be greatly appreciated, as I am not 100% sure where else I can look to see why this is working as it is.

Thanks!

TroelsM · 2023-04-27 8:48 am

Hi Guys.

Looking to restore and old screw-driver that originally ran on 2 NiMh-cells ( so around 2-2.5V).
Its low value and I´m not really sure how much use it will ever get, - but I would like to give it a try.

I would like a bit higher speed and I´m willing to sacrifice some torque ( and lifetime...).
No-load current at 3.5V is around 3A. assuming that peak-current will be 5-10A (very short)

So replacing the 2 cell with a single 18650 and a USB-charger seems like an "easy" solution.
BUT, I cannot find the right (cheap) components on ebay for this. Theres plenty of single-cell USB chargers that will work up to 3A. There is some charge/protection-boards that will tolerate 10-15A, - but without USB-interface for charging.

How would you tackle this?

Its not this exact model, but very close:

Kind regards TroelsM

vemsom · 2022-05-07 7:39 am

Im looking for a (preferably free) solution to stream Qobuz to an RPi.
I've been using Roon using Ropiee, works fine exept for buggy Andriod app, but i'd like to go with a freeware instead if i can.
RopieeXL works for Spotify and some other services, probably Tidal to but Qobuz seems to only work with chomecasts for there Qobuz connect as far as i get it working.
Perhaps Volumio works, i have that in my other music room. I have Volumeo integrated in my MiniDsp SHD, but i think that also costs money like Roon if i want to get it on my other streamer.
Another solution would be to go with Tidal.. but i've been liking Qobuz better (no forced JayZ-commercials and better focus on jazz

Any suggestions on a free streamer that supports Qobuz connect?

Dneu2011 · 2023-09-27 4:07 am

I need to thin out my audio collection of stuff I built, Fostex headphones, and some Minidsp units. If you need any more pictures or info about any items feel free to PM me. All ships from Houston, TX.

- Wayne’s Preamp in silver 1U chassis with Academy audio muses volume control, LPS9 PSU, 2 inputs and 2 outputs. - $400 plus shipping

- Wayne’s preamp built into repurposed Anthem preamp chassis with new Modushop 10mm black faceplate, dual mono PSU supplies, built in Khadas tone dac, 5 other inputs, fixed output, two variable outputs, headphone output, silver coated mil spec wiring, and Alps blue RK27 volume pot. - $600 plus ship

- F5 amplifier built into repurposed Anthem chassis with 37600uf capacitance per rail, genuine JFETs matched by Punkydawgs, and Antek 300VA torroidal. - $700 plus ship

- Minidsp DDRC-88A with Bass management and Dirac - I’m the second owner of this unit. I paid $800 and only used it for 2 months and realized it wasn’t necessary for my 2 channel system and use a DDRC-24. I updated the firmware when I first got it. It does have noise issues with XLR out on output 1 and 2 as mentioned from other owners of this dsp, but I just changed those channels to my subwoofer 1 and 2 and it worked perfectly. No issues using RCA on those channels. I will also include the remote but not the microphone. Asking $650 plus shipping.

Minidsp DDRC-24 - works great and has Dirac. I have the original box I can include - SOLD

Fostex Th-X00 Massdrop headphones - brand new Sheepskin ear pads. There are a couple small scratches on the lacquer but very small. - SOLD

Mofo Amplifier with dual 19Volt Dell laptop supplies, 193T chokes, and built on nice Peruvian Walnut. I used the original mofo boards from DiyAudio. Amps need to be powered on and off with a power strip or power bank. Adding switches between the power supplies caused loud thump which is why I didn’t include them. SOLD

Nelson Pass Front End preamp - built into a small chassis with silver faceplate. Has 2 inputs, mute, one output, and Mark Johnson’s SMPS filter. Panasonic caps with Sonicap bypass caps on the outputs. A nice Dact21 stepped Attenuator volume control included. Asking $125 plus shipping. - SOLD

Robert_B · 2023-10-19 10:21 pm

I'm looking for a Stancor P-6011 power transformer, or an equivalent Thordarson one.
Robert_B

RobertS61 · 2023-09-14 3:16 pm

I found this information on the Internet about 5 versions of FET TEN 'e' Series preamps.
Is this correct (Wayne?):
For reference, the variants of the FET-10E are listed below:

FET10 E -T special end of model, super version with hand selected and tightly matched parts, upgraded power supply, heavier gauge power supply cord, unique control knobs, ... .
FET10 E v4 - most highly evolved FET10 E production series with DC servo pot, polystyrene stacked film bypass, metal military package input FETs, etc.
FET10 E v3 - Same as V4 without the metal, military package FETs.
FET10 E v2 - Same as V3 without the DC servo pot.
FET10 E v1 - Lacks DC servo pot, polystyrene bypass caps, etc.

My unit inside:

Any idea which version I have if these versions exist?

Is it possible that the Noble Black pots (used for Volume and Balance) can get dirty and scratch a bit?

daavelovesvinyl · 2023-10-15 4:09 pm

Hi all,

Long time since I've posted here, I went off and wrote TcMenu Arduino framework that I suspect a few here may have used to build their menu systems. However, instead of helping others build their firmware, I now find myself needing a bit of help with PCB design.

Background:

I have this long-term project that I've been trying to start on for a while now, to build a high-quality but small system for my office. My plan is to do this in phases, this amplifier was the first phase, and also my first attempt at building my own PCB. For context this amp was designed for desk based sattelite speakers with a separate sub.

Before building I checked the schematic carefully against the reference design (several times), I believe it to be correct. Then, after building the circuit board, ensuring all devices were in the right way around, all wiring was correct, etc.

Situation:

I failed at the first hurdle but as the saying goes, but the only real failure is one that you don't learn from. So, I'll explain what happened here and what I've drawn from that in the hope anyone has any other ideas that could have caused this issue. This is all a case of closing the door after the horse has bolted but I wanted to discuss this before another cycle.

Known Mistake 1: So firstly, and rather embarrassingly, I embarked on this with the soldering iron tips in bad condition, they had all slightly tarnished at the end, and instead of replacing them, I tried to push through, I believe was mistake #1.

Known Mistake 2: Layer 2 (back) was a ground layer, I did not leave any thermal relief around the pads, which resulted in great difficulty soldering, combined with mistake 1, I believe this really compromised the build, and I think this renders the PCB useless. No matter how much I tried to resolder the joint at higher temperatures, I could not get a good result.

On powering up the board, with the chip in standby all seemed to work and voltage read off as expected, but on activating standby and mute pins, the device it basically kept tripping my bench top PSU into over current mode (24V, 3A) . Further, whenever I pressed on the board with a plastic stick near any of the ground connections, a distorted signal was output through the speakers and then it would trip again. I was using a pico scope to output a 1khz signal, and looking at the output on another channel, when I pressed on the ground, a somewhat distored output appeared for a short time.

Here are two screenshots, one of the schematic, one of the errors I immediately noticed on the PCB, unless someone can see an obvious error that I have missed, I think the amp is very close the reference design.

Many pin holes had no relief.

I've since made sure that all fill areas have proper relief, and I've also taken the opportunity to do a bit of other re-routing to reduce feedback/bootstrap loop length (as I am pretty confident the first PCBs are not usable). But please be honest, is this design even worth continuing with?

BTW if anyone else was interested in this project, I'd be happy to put it onto GitHub and collaborate on it, eventually I'd like to get it to a point where it had small sattelite speakers, a sub, both analog and digital in with USB Audio, and a TcMenu/EmbedControl based control system.

Thanks,
Dave

Windcrest77 · 2023-07-25 2:56 am

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Sunsun22 · 2017-11-19 11:40 pm

I built my first DHT preamp 30+ years ago without success because of hum. Recently, I built a DL92 preamp with very good result; low noise, great sound that outperforms all my preamps - ML38S, ML380S, Herron Audio VTSP-3, DIY WE437A. With this success, I am going one step further trying to build a 2A3 DHT preamp using cap output.

Yet, after searching this forum, I can't find any discussion in this topic. Is there anywhere that I can look for more information about this?

Yuriy62 · 2023-10-23 5:53 pm

Sale IN-18 - 20 pcs. for $70 ea.

jccart · 2023-10-22 12:17 pm

hi I'm trying to find some replacement faders for a bss fcs966 . a few of them had broken off knobs what i should have done is glued a piece of metal in there for a knob to sit on instead I tried to take one apart to see if it the glue idea would work . now I can't put it back together and can't find a replacement online . it has four pine while most I find have three . anybody know where I should be looking please . learned a lesson anyway check availability of parts before buying or taking parts apart incase you can't get them back together again .
thanks

wanderer47 · 2023-04-02 4:50 am

Looking to spend under $500 per driver. Haven't decided on cabinet yet. I have 2 full martys with dayton um18s that i love for my HT but I read that the pro audio drivers are better for music for their greater mid bass out put. The space is 32 x 34 x 8 feet. Looking to build 2 subs. As for why big subs I just like bigger subs but wouldn't be against 4 x 15 inch spread throughout my space.
I am in canada though so getting flatpacks is tough and I may have to get a speaker builder to make the cabinets for me.

Ghoostknight · 2023-10-16 6:32 pm

Hey

some time ago i posted a thread where i wanted to mod a CM4 Carrier board but it never happened so far
im wondering if a better idea would be to create my own carrier board... the cm4 io board schematic doesnt seem that hard but i definitely need some help to optimize things
i have some basic electronic understanding but its very limited
i started re-creating the cm4 io board but stripped down in EasyEDA, the hardest part so far seems to decide on what parts i use (quality connectors? what kind of resistors/capacitors etc...)

the cm4 io board is wired quite straight forward but im wondering if additional big capacitors could help on the power lines and near some end-devices like usb/hdmi/sdcard/gpio (something like 500-2000uF)

what should i implement to reduce noise ?
the power source will be seperated (probably some LT3045 implementation) power input will be +5V (and potentially +3,3V and +12V)

the board has:
40pin gpio
1x hdmi
1x ethernet
1x usb OTG
1x pcie (this will be used for a usb hub, like on the rpi4)
1x pinheader for some jumper settings
1x power and activity led

everything else was scrapped, its pretty straightforward specially because the usb hub will be external

How would you approach improving the cm4 io board design ? (just add more capacitors and call it a day?)

cm4 carrier board schematic (you need to scroll down): https://cdn-shop.adafruit.com/product-files/4787/4787_cm4io-datasheet.pdf

pjf610 · 2023-10-23 5:05 pm

Hi all, I have a CT F-1250 that I have been working on, I just replaced the belts but when I push the play button it starts to play then stops, I have to hold the play button in order for it to play but once I let go it stops.
Help
Pat

zoom777 · 2023-10-22 7:57 am

SOLD
One set of Miro AD1862 DAC + JLSounds i2sOverUSB stack.
In my opinion, this is the most direct and best combo for the gem, AD1862.
Sounds wonderful. It is a full, completed DAC, a pair of OPA627 op amp is included on board the IV stage.
You need 5Vdc for the USB part of the JLSounds card (red and green wire installed), +5/-5V and +12/-12V directly to the DAC board.
Case it up with transformers, PSU, connectors and you are ready to rock and roll.
If you are wondering why I am selling this gem - I think some members here are aware that i usually buy enough parts to do up a few boards.
I am keeping one set for myself.

I am asking USD$285 for this DAC , and i will cover the worldwide registered shipping with tracking available.
I am only ready to accept Paypal Family and Friends as payment.
I have shipped 30+ packages to US, UK , asia and Europe, not a single glitch so far.

More information of this DAC here :
https://www.diyaudio.com/community/threads/dac-ad1862-almost-tht-i2s-input-nos-r-2r.354078/
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-128#post-6836256

Hayden · 2023-10-23 4:29 pm

I have an old Pioneer A-656 Stereo amplifier and it has a busted main transformer, all I kneed to know is what would the voltage be of the secondary windings?
I have a powersuppy that may work.
I'm assuming that the secondary is about 70vac
I have the schematics for the A-656 but the Australian one is not listed which I think all of the variations are the same execpt mine has the voltage selector, which shouldn't matter what voltage you select the secondary outputs the same?
Just need to know the output voltage, 2 wires off transformer numbered 45 and 44
Thanks guys

wdecho · 2023-10-08 11:47 am

Any word when, or if, the videos of the event will be available as in the past?

Pano · 2023-10-23 3:53 pm

I have seen a lot of record making videos, but never one as thorough as this. Fascinating to watch!

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Lenin89 · 2023-10-22 12:02 pm

It's a type 2 class D amplifier.

I've rebuild the whole driver board. New transistors, new caps, new ic, new diodes.
Even with no output mosfets in at the mainboard, the high side parallel emitter follower pair on the driver board are getting scorching hot in seconds and destroyed. No issues at the low side.
I've noticed also the cap in the red circle is getting bulged every time i power up the amp. I'm using 35v 47uf low esr cap, and there should not be so much voltage across it so it would bulge.
Driver Board Pin-Out are as they should be comparing it to the Perry's Manual.
With the driver board out, rail voltages, +-15, everything looks fine, i do have the proper sinewave at the +In:Audio input to the driver board.
I haven't changed only the ZD6, as I don't know what it is, but it measures just fine.
Any ideas where to look ?

Barsk · 2023-10-23 3:18 pm

I have a Ariston Qdeck with a 12V motor that is toast due to my father using a AC adapter for it...
So, trying to find a spare is not going well, the motor has the marking SHR2R - 50-8Y11B, and I cannot find anything regarding this motor, no specs nothing. If anyone has any info on this it would be most appreciated!

I may be able to fit some replacement motor I guess, possibly with som DIY addings as neccessary. But for starters I need to find out what rpm the previous engine was running at.
The pulley is 5mm, and the turntable belt wheel is 180 mm. This calculator would suggest the motor speed rpm is 1188 for a 33 rpm output.
http://mgfic.com/rpm_calc.asp

goviboo · 2023-10-22 8:51 pm

GE folks,
A friend passed on this unit to the shop, can’t seem to find any info on the web for it. It has USA100 REV05 printed on the underside. The few models/pics I saw of the USA100 don’t have dual RCAs and have two potentiometers.

I cleaned it up and populated a few parts in the pre section, injected +/-12v and I have a clean sinewave throughout the preamp section.

The pcb uses transistors for switching, small signal -A06 and -TIP35 for the higher current.
Again I populated a few parts and powered up but it doesn’t switch.

Anyone got info on this pcb?

SNIRAVIV · 2023-10-21 6:24 pm

Hello,
Dose it make sense to use a RCA cable as a speaker cable ?

Can I use just one RCA to send power from an amp to a mono speakers or do I have to use two - one as the "+" and the other "-"?

manniraj · 2023-10-05 5:38 pm

Clearing some more stuff and the SCG full built preamp needs to go. Made with very high quality parts from Mouser, Parts-express and per the original design. The Antek toroidal (AS-05T120 - 50VA 120V TRANSFORMER) too is included in the sale. It is built to the original schematic from this thread by Rahul - https://www.diyaudio.com/community/threads/schade-common-gate-scg-preamp.380487/ with no modifications. I had this in a case but repurposing hence case is not included. Expecting $300 plus shipping in continental US only.

Jan Dupont · 2023-10-23 9:07 am

Hi All,
I´m in need of a copy of the schematic or service manual for an old Nikko NR-1015 receiver.
Could someone please help?
Thanks in advance 🙂

DBB2 · 2022-08-31 6:49 pm

I bought a Gustard p26 preamp and plan to swap op amps. The problem is, after removing a few screws that appeared to be securing the top, it won't budge. I'm assuming the top aluminum plate is snapped in, but I see no way of getting a tool in to pop it out. I don't want to scratch it up by forcing a knife or screwdriver in. Is there a trick to this? Help.

patriz · 2023-10-17 10:04 pm

Selling my DCB1 Hypnotize Salas version with shunt regulated supply, Talema transformer. 200€

asanden · 2023-10-21 6:29 pm

I have 8 amps…, I have to to let this beauty go

500va toroidy trafo 230Vac
Teabag PSU board
Thf51 matched
400 deep amp 3U modushop
Cinemag CMOQ-4 high nickel trafos
Sounds great

Since I build the SIT-3X this amp gets less usage, but sounds actually equal
Hope It finds a good home
Open to acceptable offers, or a nice Fender Stratocaster to swap😉

JMacII · 2023-09-16 6:58 pm

I've been using Zu speakers for about three years, and they've opened my eyes to the beauty of high efficiency, dynamic speakers, and full range drivers. With help from this board, I built an Aleph J to run them. But...I'm looking for more soundstage and imaging than the Zu's provide. I was watching Steve Guttenberg's review of the Pure Audio Project duos and what he describes is I think, maybe, the sound I'm after. Plus, open baffles look easy enough to build with tools I have...no cabinet maker here! So...if I eventually wanted to work up to a PAP type clone, where should I start? What's a simple way to get a taste?

ReinoutdV · 2007-11-15 8:03 pm

Good evening DIYaudio,

after constructing the 833A-amplifiers (see the thread "where are the 833 amps"; i've included enough pictures and text) which works great i found a whole bunch of old European transmitting triodes.

Philips TB 3/1000

Although the filament is somewhat different to the 833A (12 V / 8 A instead of 10 V / 10 A) the other characteristics are quite similar.

So i changed the 833A-amps to take the TB 3/1000. Why: because the TB 3/1000 is VERY neatly made. Not like the 833A where the plate simply hangs on the top-connector. No...with the TB 3/1000 the structure is made from bottom up. And any expansion through the heat is being taken care by letting the plate slide on glass rods !

See pictures......it works.

And soundwise.....after 5 hours of playing......musical delight.

I'll add some pictures.
The first a comparison picture of a 833A and a TB 3/1000.

Regards,
Reinout

tbaashus · 2023-10-15 2:43 pm

I'm looking for a set of Tucson boards for the M2X amplifier. I offer three sets of IPS7, IPS9 and Cedarburg boards. I'm located in Norway and will send anywhere there is a postal service.

Send me a PM if interested in a trade!

nigelwright7557 · 2022-05-17 8:42 pm

Bought a new motherboard and cpu for my PC.
Had it 2 weeks it has died.
I really hadnt realised how much I use it or need it for home and work.
Having to try and use an old slow laptop in the meantime.
Took me half a day to download software to access the internet and email etc etc.
It really is dreadfully slow.
I need a back up desktop pc rather than a laptop.
First time in 30 years I have had a PC die on me despite building them all myself.
Tried a new power supply but still dead.

Today tried to program a PIC microcontroller.
Too 2 hours to download MPLAB X and get it running.
Then project file was empty and so was code file.
Turns out my flash drive is playing up.
The files are there but empty !
So need to bin it and buy a decent one.

Just to add to my problems the laptop turns it self off after a while.
Looked at power settings and they are fine.
I suspect its getting hot but fan isnt always going fast when it powers off.

Will appreciate my desktop pc more in the future.

zoom777 · 2023-10-23 3:17 am

SOLD
50K Stepped attenuator with remote control and display.
128 steps shunt attenuator. Resistors are a mix of Dale brown and blue high quality ones.
Just supply 6.5 to 7Vdc and it works as it should.
Simple and straightforward.

Hooked them up to test and they worked perfectly.
Was then placed into their boxes and stored.
Decided that I may not want to build another preamp.

58USD shipped.
Paypal Family & Friends only please.
Thank you.

saoaaa · 2023-10-15 8:07 am

just trying my luck here need at least 4pcs of either K246 or K373, maybe K117 too

thx 🙂

Jaytor · 2023-10-21 1:05 am

I've been thinking of building a 6SN7 LTP for a balanced input line stage using a choke as the plate load. I haven't seen much discussion of this approach. Anyone tried it?

What I'm considering is a Lundahl LL1667 which has two windings, one for each plate. I plan to use LED biasing, setting the bias point around 7ma per triode. Lundahl indicates that this choke is available with different air gaps to increase inductance for lower DC current. I'm hoping I can get up to 200H per winding based on my DC current requirements.

Based on simulations, this will start to roll off below about 200 Hz, but it's only down a small amount. I have a separate SS line stage for my subwoofer outputs which crossover to my mains at about 180Hz, so I think the low-frequency roll-off shouldn't be a problem. Anything else I should worry about?

The LTP plates will DC couple to a balanced mosfet source follower stage, so the next stage load will be negligible (except for the modest capacitive load).

I'm also open to other tube suggestions. I am thinking about the 6SN7 because I've heard that the new-production Linlai Global Elite tubes sound quite nice and I like the idea of being able to get new tubes.

Coyoterick · 2023-10-23 1:03 am

I'm looking to buy a rack mount faceplate for a Hafler DH-200. I know they're rare now!

JoeHollis · 2023-10-22 9:18 pm

Brand new TS400 15" 4 Ohm subwoofer with brand new Hypex DS8.0 800 watt plate amplifier. Sold together only. $250.00 - offers not considered. Local lower mainland Vancouver area pick-up only. Must be picked up by Saturday, January 6th at 6:00 p.m.. They both go to the landfill the following morning if unsold. I gotta move and can't wait longer.
JH

Unicycle3044 · 2023-10-18 3:24 pm

Anyone seen a DIY project like this?

E.g. STM32

i2s in and out,
with analog pot as volume controller,
with log volume profile in software.
an extra would be a compressor using DMA

The goal would be to eliminate extra OPAs after DAC, and noisy pots.
The amp should be hiss free anyway at low volumes, so why not do it in digital domain.

bwolverton · 2023-10-19 8:26 pm

Hi everyone... I have a Fender Passport Venue PA system, and it has been acting very strangely. It works perfectly when it's working, but then occasionally just "shorts out" or something, and just creates the loudest most shocking sound I've ever heard. Sometimes the "Protect" red light comes off and on, but that doesn't seem to 100% correlate with the sound issue. It can work just fine for a while, and then BRRRRRRRRRR. And it'll do it even if there's no inputs plugged in. And the "Protect" light sometimes comes on even if no speakers are plugged in.
Any ideas? Transistor? I'm not an electronics guy so I'm trying to gauge whether it's worth taking it in for repair, or if I should just sell it for parts. And I have no clue what these kind of repairs might run for. I called Guitar Center, they said all the local places around me are seriously backed up, so might be a lost cause anyways. But I still want to hear what folks think.
Thanks!

ceulrich · 2023-10-22 5:32 pm

Hello All,

I have three never used rolls of copper foil tape intended for EMI/RFI shielding (see attached photo and data sheet). The tape is 1.75” wide, and about 36 yards long. Each roll weights about 1.5 pounds. These were purchased back in the late 1980’s. I just tested the adhesive on a roll I have been using low these many years, and as far as I can tell, it is as good as when originally purchased. I am selling these for $25.00 each plus postage, continental US only please. If you are interested please pm me with your e-mail address.

Cheers,
ceulrich

MrJoelR · 2023-10-22 6:10 pm

2023-07-15 6:39 pm

Hi.

Got a pair of monoblocks from Advom that had issues when i bought them , and after some research i found that the main reason they fail is due to leaky capacitors on input board.
I opted to order new boards fom Hoppes with matched transistors , and then built / populated the rest on my own.

First amp had an offset of - 166mv , and after some reading on hoppes brain notification notes i found that the input board i built was working as intended.
Dc servo was well within specs along with pin 3 and 4 , so the issue was likely to be downstream.
Took out the output assembly where i checked all components , and only found 2 resistors to be drifted slightly....one that was 8.5 ohm (should be 7.5ohm) , and one that was 66 ohm (should be 68 ohm).
Changed the 2 resistors , cleaned it up and put it together...worked perfectly now with dc offset around single digits millivolts 🧐.

Did not really feel i found the issue on that 🤷

On the next monoblock i powered up slowly with dimbulb / variac (did same on first monoblock) , and had dmm on testpins looking for bias current and dc offset as i increased.
Seeing bias current but also alot more dc offset than the first amp.
Tried with full current on dimbulb to see how mutch offset , and it was - 3.2v.
Pin 3 and pin 4 on input board show correct voltages along with dc servo current.

Took apart the output assembly on this amp aswell ,.and found 2 resistors (same as first amp) to be slightly off and changed them.
Seem one or more of the output transistors is weaker than specs suggest (2sd424) , having hfe in the thirtys (hfe 34).
Could some weaker transistors be the reason of the offset i am seeing?
Datasheet say minimum hfe of 40

Kev06 · 2023-10-21 11:12 am

I'm running Debian in a virtual machine, with a passthrough to a USB port, playing to an audio gadget as the output device. To avoid clipping (regardless of what application is playing sound), I've set Debian's 'maximum-volume' slider to 50%. The output-volume slider then correctly says 50% as its maximum setting. It mostly works well... but sadly isn't proving trustworthy. Glitches cause Debian to forget about the 50% limit (even though the output slider still claims that is max) and I get full volume output. I have my amps set to assume 50% at max, so that is quite loud!

Unfortunately I'm not very experienced with Linux yet, end even less so with its audio chain. Is there a method of setting the maximum output level such that Debian won't overlook it? Perhaps on a similar note, it would also be handy if there was a way to stop Debian swapping to other output cards, when the default audio gadget is temporarily absent?

Thanks,
Kev

andb · 2023-10-22 12:51 pm

I've got a pair of FostexFE126e from Planet 10 that I wont being using. They are a light natural brown and have the dark brown "enabled" markings around the edges. Unused and in new-in-box condition.

They are in Czech Republic, it will be a lot easier to ship to someone in the EU. Make me a reasonable offer and they are yours!

Dibbers · 2023-10-22 5:14 pm

Hoping I can get some help with a faint hum that's coming from one of my Adcom amps. I'm currently using a GFP-555 preamp to drive three Adcom amps (GFA-545II, GFA-555II, and GFA-2535). Everything is being powered through a pair of Adcom ACE-515 AC enhancers plugged into separate outlets (on the same circuit though). I'm splitting my norm and lab outputs with Amazon Basics heavy shielded RCA splitters and cables. The 545II and 555II have zero hum.

What I've noticed on the 2535's hum is that it doesn't change as you increase the volume on the preamp. It's a constant hum. Thing is, as soon as I unplug the RCAs from either side, it's gone. This made me initially think it was my preamp, but even when plugging my bluetooth receiver directly into the 2535 it produces the same hum. It's almost as if there is something coming in on the RCAs that is causing this.

I've tried various cables, different sources, etc. No change. I have eliminated most other devices on this circuit, save a couple deep freezers that I can't move off this circuit just yet. I even removed the coax coming into my TV to ensure that was not the culprit. There are also no fluorescent lights or dimmers on this circuit.

The most recent thing I've done to try and eliminate this is connect the grounding posts of my ACE units together, along with the post on my GFP-555 (following the ACE-515's manual). No change.

Any help is greatly appreciated. While I've read this hum isn't "bad", and it's only noticeable when you're close to the speakers being driven by the 2535; it's quite annoying.

-Dibbers

jazzyj · 2023-10-20 3:40 pm

Dear every body,
I just receive eval board mediaworks with ADAU1467.
I seen many thing for my project in Delta sigma studio.
Now with a very basic design i'm trying to load program with TinySine USBI. But something is missing.
My project (to begin) is to use the SPDIF input (with a 44,1KHz signal) and transfert it directly to the analog output1 channel 0/1 as below.
But i'm unable to confirm that the program is inside the DSP and then the systeme is not working...
Maybe some one can help me to start this first step of project?

Thank you...

RubenDeSmet · 2023-08-14 8:00 pm

Hi, A couple of months ago I built the elekit tu8600s. The amp worked well for a while but then suddenly one of my 300B’s stopped working. After a while it worked again but then after some weeks it didn’t work again for a little while, this repeated a couple of times untill ik broke down for good. I then looked inside the amp and checked the voltages and found that tp 13,14, 23 an 24 are double what they should be. I checked if all the parts where in the wrong place and redid some soldering, but I can’t seem to find my mistake. Is there anyone who had a similar problem and can help me?

paalj · 2023-10-15 6:37 pm

Continue here from the camilladsp thread starting on post 4333 due to way too much off topic:

I am trying to install camilladsp on this board. The camilladsp install went ok until I came to the loopback interface. There was no snd-aloop module in the kernel.

Bash:

 This is a boot script for U-Boot
#
# Recompile with:
# mkimage -A arm64 -O linux -T script -C none -n "Boot Script" -d boot.cmd boot.scr

setenv load_addr "0x9000000"
setenv overlay_error "false"

echo "Boot script loaded from ${devtype} ${devnum}"

if test -e ${devtype} ${devnum}:${distro_bootpart} /ubuntuEnv.txt; then
        load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} /ubuntuEnv.txt
        env import -t ${load_addr} ${filesize}
fi

load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} /dtbs/${fdtfile}
fdt addr ${fdt_addr_r} && fdt resize 0x10000

for overlay_file in ${overlays}; do
    if load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} /dtbs/overlays/${overlay_prefix}-${overlay_file}.dtbo; then
        echo "Applying device tree overlay: /dtbs/overlays/${overlay_prefix}-${overlay_file}.dtbo"
        fdt apply ${fdtoverlay_addr_r} || setenv overlay_error "true"
    elif load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} /dtbs/overlays/${overlay_file}.dtbo; then
        echo "Applying device tree overlay: /dtbs/overlays/${overlay_file}.dtbo"
        fdt apply ${fdtoverlay_addr_r} || setenv overlay_error "true"
    elif load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} /dtbs/overlays/rk3588-${overlay_file}.dtbo; then
        echo "Applying device tree overlay: /dtbs/overlays/rk3588-${overlay_file}.dtbo"
        fdt apply ${fdtoverlay_addr_r} || setenv overlay_error "true"
    fi
done
if test "${overlay_error}" = "true"; then
    echo "Error applying device tree overlays, restoring original device tree"
    load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} /dtbs/${fdtfile}
fi

load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} /vmlinuz
load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} /initrd.img

booti ${kernel_addr_r} ${ramdisk_addr_r}:${filesize} ${fdt_addr_r}

boot.scr

Bash:

^E^YVM^A^[Ze^Cw�^@^@^Gc^@^@^@^@^@^@^@^@^Q�:K^E^V^F^@Boot Script^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^G[^@^@^@^@# This is a >
#
# Recompile with:
# mkimage -A arm64 -O linux -T script -C none -n "Boot Script" -d boot.cmd boot.scr

setenv load_addr "0x9000000"
setenv overlay_error "false"

echo "Boot script loaded from ${devtype} ${devnum}"

if test -e ${devtype} ${devnum}:${distro_bootpart} /ubuntuEnv.txt; then
        load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} /ubuntuEnv.txt
        env import -t ${load_addr} ${filesize}
fi

load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} /dtbs/${fdtfile}
fdt addr ${fdt_addr_r} && fdt resize 0x10000

for overlay_file in ${overlays}; do
    if load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} /dtbs/overlays/${overlay_prefix}-${overlay_file}.dtbo; then
        echo "Applying device tree overlay: /dtbs/overlays/${overlay_prefix}-${overlay_file}.dtbo"
        fdt apply ${fdtoverlay_addr_r} || setenv overlay_error "true"
    elif load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} /dtbs/overlays/${overlay_file}.dtbo; then
        echo "Applying device tree overlay: /dtbs/overlays/${overlay_file}.dtbo"
        fdt apply ${fdtoverlay_addr_r} || setenv overlay_error "true"
    elif load ${devtype} ${devnum}:${distro_bootpart} ${fdtoverlay_addr_r} /dtbs/overlays/rk3588-${overlay_file}.dtbo; then
        echo "Applying device tree overlay: /dtbs/overlays/rk3588-${overlay_file}.dtbo"
        fdt apply ${fdtoverlay_addr_r} || setenv overlay_error "true"
    fi
done
if test "${overlay_error}" = "true"; then
    echo "Error applying device tree overlays, restoring original device tree"
    load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} /dtbs/${fdtfile}
fi

load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} /vmlinuz
load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} /initrd.img

booti ${kernel_addr_r} ${ramdisk_addr_r}:${filesize} ${fdt_addr_r}

Chasmo57 · 2023-10-10 4:19 pm

I have a pair of 12" woofers I'd like to use with some small (1.45ft3) cubic enclosures on hand. The recommended
enclosure volume was ~3ft3 for a low (38Hz) Fc and Qtc of ~0.7. The small cubes seem to give an Fc of 49Hz and Qtc is~1.1 .

These woofers are to supplement the lower base of my 8" towers, which have limited output below 80Hz.

I have read that using DSP, one can 'fix' the smaller system to act like the larger one at resonance and cutoff. How does this work
and how would I accomplish it with my P.E. Dayton SPA250dsp plate amp (anyone doing this already)?

Also, would the resulting equalized woofer system be as well damped as one in a 3ft3 box, Qtc=0.7?

Thanks for any advice(other than box redesign) ;-)

-C

mo7ies · 2023-10-14 7:33 pm

I was forced to put a 33 Ohm resistor in series with my tweeter in a 2-way speaker. (Same arrangement on both L and R speakers in a stereo pair.)
Otherwise, the tweeter was dominating like crazy.
The tweeter is 4 Ohm in resistance. So it seems I'm running it at 8.5% capacity (!) This is unbelievable to me, losing over 90% of tweeter efficiency to balance out the sound.
How normal / usual is this?

jayme · 2023-08-13 1:43 am

Has anyone experimented with a gimbal bldc motor for a direct drive turntable?

My belt drive turntable DIY experiment is working well. I am finding different belt materials have huge impact on speed stability/ wow and flutter. (Silicone belts are terrible for this btw. Standard butyl is ok, but needs a second pulley opposite the motor to reduce lateral stress on the platter. My next experiment there will be with surgical silk for a custom belt.)

But I would like to compare it to a direct drive platter to see if there is further improvement. I ordered an 11pole pair hollow shaft gimbal motor. I have several FOC/sinusoidal /vector controllers to play with to see how well I can spin ot at 33.33 with a weighted platter.

nigelsook · 2022-08-22 11:11 am

need transistor numbers fet 191 fet 192 fet 401

edbarx · 2023-10-18 2:15 pm

I would like to ask whether a capacitance multiplier circuit can suppress interference, more precisely, ringing, from a switching power supply. The latter is a laptop charger power supply which supplies power to a laptop which I use for a USB oscilloscope. Interference signals are showing superposed on whatever signal I happen to examine and view. These are in the form of decaying ringing. Their effect also prevents whatever signals are viewed to lock into view.

Yuriy62 · 2023-10-22 9:12 am

Sale GM-70 (graphite) — 60 pcs. for $35 ea.

audiorado · 2022-08-24 7:23 am

Nos, never used. Quad of tubes. Look for data on the boxes. Price 100 eu including shipping in EU.

Ixnay · 2023-10-16 7:41 pm

This happens again and again. Simple question. What leads are to be connected for a dual primary transformer if the polarity of the windings is not stated. This is an R-core transformer if that makes a difference. The transformer clearly states '115 volts Black-Red and Grey-Orange' are the 4 wires of the primaries, but there is no indication as to what leads need to be connected together for both primaries to be connected in parallel. I know that if I connect them out of phase, I am screwed. Here is a photo. To be clear, my home is 120 VAC and not 220 VAC.

linuxguru · 2011-03-01 10:41 am

This is a first-pass attempt at building a scaled-down, value-oriented version of a nested gainclone similar to the Mauro Penasa MyRef design. It differs from the MyRef RevC in several ways:

1) LM1875 chipamp as the Howland current pump offers more component flexibility - can be interchanged with TDA2040, 2050, etc.

2) Lower output power of 20W + 20W makes it suitable for bookshelf and HT setups.

3) Two channels/board to reduce overall system costs. The board is only ~15% larger than a single MyRef RevC version 1.3 monoblock.

4) Op-amp flexibility - it will work with numerous commodity (NE5532, etc.) and premium opamps (LM4562, OPA2134, etc.) for the outer voltage-feedback loop, with slight changes in compensation in some cases.

5) Outer loop uses Walt Jung's nested schema, which differs slightly from the MyRef.

6) Compensation schema is much simpler, with a single modified DeBoo integrator per channel, greatly reducing the component count of premium capacitors compared to the RevC.

7) Speaker protection circuit is identical to the MyRef RevA 2-channel schematic.

8) Shared rectifier and PSU caps to reduce board area and costs.

I'm calling it the MyRef Mini because of its close similarity to Mauro's MyRef series. It still needs to be built and validated, but I expect it to be comparable to or better than the MyRef Rev A in audible sonics (with the components shown in the schematic). In audible sonics, it should comfortably crush the Yuanjing and similar EBay gainclones based on the LM3886, LM1875, LM4766, TDA7294, etc., at a slightly higher price point for a 2-channel board.

Here are the exported images of the Schematic and Board Layout (warning: although completed, this is only a first-pass attempt and may have undiscovered errors in both the schematic and layout). The dimensions of the PCB are about 5.5 x 3.2 inches. The BoM should be sub-$50 for the PCB and all the components on the PCB. If there's sufficient interest, I'll eventually have a small batch of bare PCBs fabricated and offered here.

Elvee · 2023-10-19 8:40 pm

This is the article:
https://www.edn.com/adjust-op-amp-gain-from-30-db-to-60-db-with-one-linear-pot/
Very nice, as usual, but something bothers me though: Stephen recommends the use of low excess noise resistors in the feedback divider, but I don't see why: these resistors do not see any static bias, except that caused by the input current and offset of the OP37, which are normally minuscule.
The signal itself, if large enough, could cause excess noise on high-amplitude excursions, but it should remain moderate and drowned in a much larger signal.
It would result in a noise component having its enveloppe modulated at twice the signal frequency, thus excess noise from a frequency-domain perspective since the modulation should change nothing there, and maybe a kind of "breathing effect" for large, VLF signals in the time-domain.
To summarize, poor resistors would not affect the noise floor of the system (it would be quiet), but it could degrade the THD+noise distortion figure, but I don't think it would be relevant because of the low amplitude, even for carbon-film resistors, and because the noise would be random, uncorrelated to the signals processed.
Did I miss something? Can a poor resistor have a hotter virtual temperature than its physical temperature?

fernfrost · 2023-10-21 11:12 pm

Does anyone know of a 38 kHz IR receiver that can be panel mounted?

Something like this perhaps:

presscot · 2023-10-20 1:10 pm

I have an a/d/s/ DA20e. It still works fine. Today, I have opened the top cover to check the unit by sight. I found the condition is like new. I also found there’s a vacant socket labeled 9V, as shown in the red circle on attached. I wonder is it possible to modify this DAC? There’s very little info about this DAC. Has anyone ever experienced?

Windcrest77 · 2023-10-21 10:56 pm

I've been using PSUD over the years but still some gaps, if someone can provide answers or anything I need to learn, here is where I'm at with the unregulated supply for a Papa Rusa...

1) For the DCR of the transformer I measured the DCR of my secondary to be 67 ohms. Should I also add in the DCR of the primary? Or is this setting mean the DCR of the secondary only.

2) In the simulation below I went with the default 2 ohms for the capacitors. These will all be DC link capacitors, what would be a common resistance to use here for film caps instead of 2 ohms, (which I assume are electros)?

3) I want to test how "fast" my power supply can recover from a 5ma upward transient draw. I want it to be "fast" so using as little capacitance and resistance as possible. This PS will be for a parafeed headphone amp (Papa Rusa link below) so I dont think the draw will be bouncing around much as its only driving headphones not speakers. So thats why I only tested a 5ma jump from 60ma to 65ma. As you can see it recovers pretty fast to the lower voltage and with no "bounce" or thrashing around just the downward dip, at the 2 second mark. I experimented with more capacitance but it was slower and the waveform hilly. It recovers in .4 seconds. Did I do such a transient simulation properly, or is my thinking way off here? The PS comes to full voltage in .6 seconds as well. I'm assuming the bounce at the beginning is just inrush because using solid state rectifiers, it seems to settle in fast though. Maybe the speed has to do with using a choke too instead of a resistor after C1, because chokes hold magnetic energy I would think thats better than a resistor right?

4) I want the ripple under 3mv, as you can see it achieved 2.8mv. This headphone amp uses a plate CCS so that will scrub even more ripple. So I think I'm happy with compromising ripple against speed.

5) Also note, the first choke is a real choke Hammond 14 H; 75 ma; 429 ohm model. But the second choke is a MOSFET gyrator set to simulate 30 H at 30 ohms. This headphone amp calls for 275V B+ @ 60ma so I think I nailed it with getting 280V. This transformer gives me exactly 236 volts from my home mains.

6) I took advantage of the highish DCR of the first choke to go with a smaller C1, much smaller than this and the PS seemed not stiff enough, I experimented with the middle capacitor but found that 1uf in the middle gave the best transient timing, the third cap I experimented with judging ripple against speed and settled upon 50uf which keeps me out of using electrolytics, the final 1 ohm and 3uf stage will be doubled for left/right channels.

This has been fun trying to make a power supply with as little resistance and capacitance as possible competing ripple against transient speed, it was good PSUD practice.

5ma upward transient 60 to 65ma at 2 seconds (looks good to me but I'm a newby):

No bouncing around at 2s just what seems like a nice smooth drop.

Ripple of 2.8 mv achieved:

The project:

Papa Rusa

https://wtfamps.com/papa-rusa-headphone-amplifier/

PeteMcK · 2023-10-22 12:14 am

I was working out the cutoff freq of an open back Guitar cab, when the following Q. occured to me: If you diminish the size of the opening on the back, when does that opening turn the cab into a helmholtz resonator? It's probably a 'how long is a piece of string' question, i.e. there's no sensible answer...???

mrmalace · 2023-10-21 8:54 pm

I found this tube tester in mercaplace, it has some problems, one of them is damaged rheostat-potentiometer 200 ohm 25 w, which I already ordered, it also has 9 loose cables that go to the sockets attached photo, I have tried to read the diagrams but I have not been able to find the position of the cables, I know that most of them go to the noval socket, I am new to electronics hoobie and I am learning.
some information or photo of the 9 pin socket would be of great help.

ampexperts · 2023-10-12 7:45 pm

As can be seen, the nylon part is broken and wet with oil and cannot be reliably fixed.

I am looking to find an exact replacement.

Appears to be a 100K (probably audio taper) pot.

Can anyone recommend part numbers for a suitable replacement that will drop in?

bigaudioscotto · 2023-02-10 5:47 pm

This is a fantastic sounding Pair of EL84 Mono Blocks
They were Built by John Miller of Tomcat Audio
They use a pair of EL84 or Russian 6p14 and a single 12at7
Mundorf Power supply caps, Miflex copper input coupling caps
They are 22 watts in push pull. with Hammond Transformers
$950 local pickup in Huntersville,NC

cwujek · 2023-10-21 11:07 pm

Looking for a couple drivers, but would take up to 4. Thanks!

spedmetal · 2023-10-19 11:10 am

Hi all.
Im looking for plans to build from. Synergy tops for small to medium outside use. 130+db@1m(more is more), 90 degree horisontal would be nice and usable to 100ish Hz. For subs im planning a pair of Skhorn double 21”s. If somebody has the plans for these, id be gratefull for those also.

I know there are lots of builds around, but has anybody drawn any plans to build from?

Thanks

Tibetan · 2023-10-19 4:15 am

Searches confirm that this should be a SPST on-off switch but I didn't see the switch rating mentioned. What is recommended?

DrRobocop · 2023-10-21 12:42 am

Hello,

I’m interested in purchasing a prebuilt sun audio SV300BE from Japan. However the unit is 100v and I need a 120v for operation in the United States. Is it possible to convert the 100v to 120v without a separate step up (step down?) converter?

Is this a matter of swapping and soldering transformer wires? Or are the transformers themselves different? According to the sun audio website there are 3 versions: 100v, 120v and 240v which you must specify before ordering the kit. So I assume it is a whole different transformer. I hope I’m wrong.

Surtsey · 2023-10-20 12:45 pm

I get the basics but a debate on another thread regarding Sony SS-S9s has got me wondering about cabinet volume. Why does a driver need a certain cabinet volume and when does it need said volume?
They were discussing 2.5 systems which bring me back to an old question: A sub-woofer and woofer sharing the same air space in a ported cabinet. Some have suggested that all calculations be made on the mean value of the driver's T/S parameters - makes sense. But what happens at high power levels? When the woofer becomes affected by the sub's response to frequency it doesn't 'do'. Effectively offering passive radiation and robbing the port of input ?

jacksomprates · 2023-10-21 8:30 pm

Preciso do esquema desse mixer, ele tem vários problemas, é muito antigo e já passou por muita manutenção.

MrLazy · 2023-10-21 8:30 pm

Hi, can you please school me on today's plethora of these power supplies.. ?
Looks like clones of the Tektronics from some years ago.

Noisy ? good regulation, tracking, V droop with pulsed/ fast rise time loads, etc. ?

I am going to need one soon enough, though the Voltage and Current are under what I would prefer.
Currently have a feeler out to a local PS repair shop for an adjustable dual 50V 10A, but I probably wont be able to afford it.
As a mid-choice lets say a 36 - 38V 5A, Dual tracking adjustable bench supply would be great.

thanks very much for your advice!

cibo · 2023-10-21 5:30 pm

ISO F3 UMS.

VS · 2023-10-21 7:28 pm

Hi All

For sale:

3 x MAX3223CPP+ Analog Devices
3 x MAX3322EEUP+ Analog Device

4 x SI9110DJ Vishay - Siliconix
1 x UA741HC Fairchild

2 x SG3524N Texas Instruments
5 x LM2675M-5.0-NOPB Texas Instruments
5 x LM2675M-12-NOPB Texas Instruments
5 x LM2675N-ADJ-NOPB Texas Instruments

100 x 4608X-101-104LF Bourns

1 x ICL7107CPL+ Analog Devices
1 x ICL7117CQH-TD+ Analog Devices
1 x ICL7126CPL+ Analog Devices

1 x MAX232CPE+ Analog Devices
1 x MAX691CPE+ Analog Devices
1 x MAX791CPE+ Analog Devices

Please PM.

Regards,
VS

rif · 2023-10-14 1:13 am

Excellent condition 103r. Unmodified.

Sounds and looks great. If you're into tinkering, there are many diy and commercial upgrades for it. I left it in its original configuration.

Comes with original box, test results. please see pictures.

$250/negotiable

Nicole* · 2023-08-08 10:20 am

Hello Guys,

A few days ago i bought a Sony TC-K770es deck. Apparently it has been serviced not long time ago. I noticed that when rewinding, after several seconds it starts forwarding itself without any reasons, and keeps on forwarding. It looks like someone presses the FF button when rewinding. Does anyone have any idea what the problem is?

Thank you in advance!

talaerts · 2023-03-11 9:03 pm

In the new issue of the German magazine Hobby Hifi (2-3/2023), mr Bernd Timmermanns offered an update to his Jericho horn, this time using the Dayton PS220-8 fullranger.
The measurements are promising. You can also see the effect of the correction filter. It looks like an interesting project.
The magazine has a 14 page detailed article including a step by step construction guide.

.

.

jdg123 · 2022-05-18 5:50 pm

I have a complete set of the recommended Sonicap Gen I poly caps (including recommended bypass caps) for building the Al Klappenburger Universal Crossover for Heritage series Klipsch speakers. If you are thinking of building that one very good crossover to service any of the Klipsch Heritage Series speakers, this is a huge first step. See images for the exact schematic and the caps you would be buying. $50 takes all.

Items sold: thank you.

stellavox · 2023-10-05 4:59 pm

I've just come across this concept and haven't seen any discussion of it or the theory involved. Apparently you "drive" the inner shield (somehow) to keep it at the same impedance as the source thereby eliminating any leakage current or capacitance seen by the source.

Any one provide any "light" or references on the subject? And how would you do this - what kind of driver and how should you CORRECTLY connect the cable on both ends. Make any sense to use in a preamp?

Elektroniklurch · 2023-10-14 7:11 pm

Hello,
I absolutely need data on the following transistors. SJ2517 / SJ2518
Does anyone have a data sheet, specifications and/or can tell me replacement types available from Distrelec, Mouser or others? Because MJ21193 / MJ21194 would fit (as claimed in another forum) I can only get them from Chinese dealers.
Thank you very much in advance and kind regards from Germany

Attachments

For Sale Lots of Gear for sale - DIY builds, Fostex headphones, minidsp units with Dirac

Attachments

WTB Stancor P-6011 power transformer (or equivalent)

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For Sale MIRO AD1862 DAC & JLSounds i2soverUSB stack

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Locked For Sale Schade Common Gate (SCG) Preamp

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For Sale SissySIT amp

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For Sale Stepped Attenuator with RC and Display

WTB 2SK246GR/2SK373

WTB Hafler DH-200 Rack Mount Faceplate

For Sale Brand New TS400-4 15" Subwoofer - $200.00

For Sale Copper Foil Tape

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Locked

For Sale Schade Common Gate (SCG) Preamp