updated with a few fixes

halo acoustics eha-1pro.PDF

push pull output stage, +/-250 volt power.

not enough

i'm getting slow in my old age

input balance not done yet. (thing with the thumb wheel)

halo acoustics eha-1pro.PDF

those were the caps from the group buy?

they turned out to have significant longevity issues.

there were no output caps on the switchers. there is a input cap, not labeled, 47 uf tantalum 30 volt is what goes in that spot. or anything else that fits.

yep exactly. on the back of the board as close to the output pins as possible.

you can also try a cap something in the range of .1 to 1 uf ceramic soldered to the switcher power supply outputs.

nothing with 60db of gain is going to be completely noise free. unless you want to move to a much colder climate. and even then maybe a couple of extra db of s/n. without a volume control in front of the input stage you have no idea how loud, loud is. that residual noise is undetectable when playing music.

you can try say 10pf instead of 5pf. anything higher and the frequency response will change.

the 470pf cap is on the power supply right?

the reason for the 1 meg input caps is to give a minimum stable bias for the input stage. its expecting you to put in front of it a pot, or other much lower impedance resistor.

at 50k the remaining noise is far below any possible music at that level that does not significantly lower the input impedance.

the resistors are just there to make sure its stable with nothing plugged into it.

change the input resistors to as low as possible compatible with what is going to drive it.

10k is probably what i would do.

at least the cary has no flammable wool tuning elements.

miloz never contacted me. i would likely not respond if he did.

get one of each of these from ebay.

keithley 2015 6.5 digit thd multimeter and a hp 82357b (or later) usb to gpib adapter.

yes, the 82357b is a fake coming out the wrong end of the agilent factory (no shielding on the plastic) in china. but work absolutely identical to the real one which is about $600 new. unlikely to pass fcc radiated noise tests

and a windows 11 laptop.

then contact james king for the software package.

ebay price about $600 total for the 2 pieces.  (about $7k brand new)

have at it.  rated for 2000 volts peak to peak. no attenuators or other hacks needed. 

many of the used 2015 will require replacement of the display for about $75, and unsoldering about 100 connections. but the software does not require a well lit display except to put it into the right mode after you turn it on.

accurate to .002% Thd+N. built in balanced signal generator that matches the same specs. single box solution.

better than any stax amp with 50 to 60db of gain. the Noise component overwhelming the signal.

no way i would pay $35k for an audio precision and then pray that the required attenuator does not cause trouble. I would much rather pay that much for a set of CCB brakes and wheels.

retired 9 years now. i only do things that are fun.  like 30 to 130 in the Z06.  over and over and over. and yet no tickets (yet).

knock your socks off.

many different versions.  a couple of different sizes. i don't pay attention to such things.

edit:  here is list of boards by date

04/11/2015  05:43 AM           103,192 cfp2c.zip
04/11/2015  05:44 AM           104,260 cfp2cm.zip
05/29/2015  08:20 AM           462,573 cfp3rs.zip
08/09/2015  02:25 PM           156,813 cfp2dmt.zip
09/06/2015  07:45 AM           158,031 cfp2emt.zip
09/20/2015  04:37 PM           402,743 cfp3rss.zip
02/07/2016  11:11 AM           159,746 cfp2fmt.zip
02/28/2016  06:04 PM           159,406 cfp2gmt.zip
11/06/2017  07:26 PM            55,189 cfp2gmt - CADCAM.ZIP
11/30/2017  09:07 AM            66,091 cfp2hmt.zip
05/24/2020  11:29 AM           131,243 cfp3rssfixedss - CADCAM.ZIP
10/31/2021  07:41 AM           141,717 cfp3rssfixedsssw - CADCAM.ZIP
02/02/2022  06:19 AM           126,329 cfp3smt2 - CADCAM.ZIP
02/07/2022  06:54 AM            78,922 cfp3smt2splitpre - CADCAM.ZIP
02/07/2022  06:59 AM            63,188 cfp3smt2splitamp - CADCAM.ZIP
01/11/2023  08:18 AM            43,551 cfp3largeT.ZIP
08/05/2024  01:40 PM           125,671 cfp3smt2splitampdual2024-2-mosfetdualps - CADCAM.ZIP

 

12/28/2014  11:06 AM            77,647 cfa2.PDF
12/01/2017  08:48 AM            55,404 cfa2cmirror.PDF
05/24/2020  06:47 AM            53,387 cfa3production.PDF
07/23/2020  04:34 AM            69,492 cfa3productionss.PDF

you mean this grossly overpriced piece of antique design. unbalanced and lots of feedback.  clone boards were available somewhere at diy audio. chassis filled with many audiofool components. like bybee's and fancy caps.

if 50 watts into 8 ohms is what you really want then build my pioneer a09 clone. lots better in many ways.

i could publish pictures of the zahl boards, or the mass kobo. both of which are also grossly overpriced pieces of garbage. 

 

speaking of fucked, here is the latest highend.de stupidity. tube current source added to antares v3.5 board.  6sn7 has a max cathode to filament voltage of +/-100v which means that anything over 400vppss at the output is slowly destroying the current source tube. god damm how hard is it to read the 6sn7 datasheet. even worse the filaments of both current source tubes tied to the same transformer winding. sure does not look like srpp.

how fucking stupid is this idiot.

edit: this may have been done by someone else using the highend.de board.

wiring the filaments together for the output tubes causes all sorts of trouble. essentially a differential output amplifier with no differential cathode resistors resulting in what should be infinite gain, except not.  current sources for the output tubes sure seem to be a 6ca7 with a dn2540 or similar as a cascode current source. first time i have seen a tube and solid state together as a current source. and the input tubes wired as differential amplifiers do not have anywhere near enough gain

should a chassis like this show up, i'm absolutely sure i can make a megatronxl custom board fit.

edit: this is the current source

CCS Circuits | Tubelab

 

1 metric boatload of labor goes into building stuff like this. And then making more and more. compared to a bunch of other stuff at this price level this is actually worth the asking price.  No idea of performance. Highly similar to megatronxl.  In 10 years when the electrolytics need replacing its going to be a multi day project.

so the idea is to keep the voltage going to the 10m90s that drives the zener string  between 600 and 900v.

depending on voltage input, just a standard voltage doubler will push the voltage well above 1kv. and no reason for this. so in the very original spoilers, a pot was added to spoil some of the voltage that would normally have been generated by a standard doubler.

 

2 current sources now.  1 between unreg caps and passfet. other current source between regulated caps and output.

kgsshv600vpowerv2 - CADCAM.ZIP

circlotronpsupdated2cs.pdf

i use the 47uf non polarized ceramic.  performs better than the electrolytic, and lasts forever.

edit: removed, looking at the wrong schematic.

 

board updated with extra diode.  in the stax mafia google shares

 

the power of that part is 170mw.  so the stn0214 should work. make sure the pinout is correct.

mouser has thousands of ksc5026 in stock.

the extra diode cannot hurt. not sure what it is supposed to do.

 i know how the one error got there.  the other errors may have been there for a very long time.

will go and look at the original circlotron file later.

updated schematic

 

circlotronpsupdated.pdf

new board in the stax mafia google drive has the orientation of the ttc004b fixed.

edit:  current limiting on CS LED???