kevin gilmore
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Posts posted by kevin gilmore
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you do not have the jumpers in the right position for the voltage you need.
the voltage rating on the fuse is meaningless.
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are you sure of the jumpers for the voltage you are using. if jumpered on 100 or 120v and you put 220 in it, fuse will blow instantly.
but you do need a slow blow fuse.
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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.ZIP12/28/2014 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-
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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.
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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.
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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
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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.
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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.
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2 current sources now. 1 between unreg caps and passfet. other current source between regulated caps and output.
kgsshv600vpowerv2 - CADCAM.ZIP
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i use the 47uf non polarized ceramic. performs better than the electrolytic, and lasts forever.
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edit: removed, looking at the wrong schematic.
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board updated with extra diode. in the stax mafia google shares
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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.
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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
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new board in the stax mafia google drive has the orientation of the ttc004b fixed.
edit: current limiting on CS LED???
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you can certainly set the bias at 2 amps, then into 8 ohms its 32 watts class A and the rest is class B or bridged 4x
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amp board for single ended. you can run this as low as +/-24v and as high as +/-40v
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clever huh? first time i have seen this. what it really is, is some local feedback around the current mirror. the lower impedance load forces the current source to supply more current to the drive of the output transistors. all those output transistors in parallel really form an extremely stiff drive current without global feedback.
in single ended form, perfect for low impedance ribbons. and 30v/10a switchers are cheap. lot of heat however, 1.5 amp bias current. (total) i have a single ended gain stage to go with it. basically half of the balanced version with a cfa capable input section.
input section can have local feedback as shown. or remove that resistor. updated to current version
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Saw some talk about this and decided to make a new version.
use either the tube unbal/bal to bal board, or the solid state version
result is about 125 watts rms into 8 ohms at thd of .005%
will definitely drive 4 ohms with suitably large power supplies.
transistors are standard pinout, so pick your favorite output transistors.
the to220 transistors are mje15034/mje15035
perfect for so many things, including esl boost transformers.
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you should see some of the chinese cfa3 ripoffs for around $1600. one in particular is fairly decent, the rest are trash.
just wait till the chinese start selling the D&G clones. running with multiple >1kv power supplies. what could possibly go wrong.
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being retired means i get to do what i want to do and when.
so the new thing based on the pioneer a09 (no not the a9) is also zero feedback, 120 watts into 8 ohms, damping factor of 100 and a thd about .001%. the absolute perfect thing to drive your lundhal electrostatic transformers.
basically the exactly same ubal/bal to bal board in the cfa3, and then the high power buffers. pair of 30v 20 amp switching power supplies.
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10 hours ago, philodox said:
Love it. How are you doing sir, still teaching? Any chance you'd take a glance at my McAllister mess/amp? I'd love to give it a refit.
i am retired now, 7+ years. And loving it. Due to arthritis issues i am no longer working on any more equipment. including my own. going to pay a couple of high-school kids to stuff and solder boards and chassis etc for new projects.
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has to be one of the ones that can be set to 12v like this
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at the moment, do what i did 30 years ago. srm212 plus 12v 7ah gel cell. its portable. kinda portable.
or buy 4 x apex opamps and run them class C with the dc to dc converters.
i wish i had a better solution. getting all those transistors to touch the heatsink at the same time is not easy.
even the koss box requires a decent size battery. (6 x D cell)
my stax 717 blows the fuses at the input of the transformer 220v 1.5 fast blow - do i need test slow blow or fast blow 30A fuse?
in Headphone Amplification
Posted · Edited by kevin gilmore
that is not one of the available options.
the options are 100v, 120v and 240v
some people think the 120v option is 115 but it is not.
for 240v the 120v windings are in series.
if you really want the 120v in series with the 100v for 220v, you have to wire remove all the jumpers and wire by hand