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Rod Eliot project 88 question
Rod Eliot project 88 question
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Old 19th October 2019, 03:15 PM   #241
Hicoco is offline Hicoco  France
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Rod Eliot project 88 question
Quote:
Originally Posted by rabbitz View Post
100nF Monolithic 50V X7R. IIRC all the capacitors on the P88 PCB went across the rails and not to ground. I can't remember the section with the 2 electrolytics as I only have the first stage PCB left.
With LME49720 i use 0,1uf and 10uf cap see datasheet...page 37 http://www.ti.com/lit/ds/symlink/lme49720.pdf
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Old 19th October 2019, 03:43 PM   #242
Hicoco is offline Hicoco  France
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Rod Eliot project 88 question
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Originally Posted by Mixi View Post
So here's my version of a 317/337 power supply. Very much inspired by the rod elliott / doug self / muffsy designs of course. i'm very new to pcb design so any feedback would be welcome.
PSU for P88 and P06
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Old 25th October 2019, 10:03 AM   #243
Sadface is offline Sadface  New Zealand
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Quote:
Originally Posted by Mixi View Post
Sadface - you mentioned going for a dual LT1086 design for lower noise. What kind of noise figures are you expecting?
I don't have any equipment to measure other than my ears.

I'm working off the idea that I may as well start with the best theoretical base and then try to build something that approximates best practice in implementation.

I had developed a version 1 of a bipolar LT1086 board.
lt1086 top side.jpg

But then I had a read of the denoiser thread and decided I might design a board that essentially grafts a denoiser onto a ESP P05.


Here's my latest version of the preamp pcb also.
mono top side v4.0.jpg

Last edited by Sadface; 25th October 2019 at 10:05 AM.
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Old 25th October 2019, 02:29 PM   #244
dotneck335 is offline dotneck335  United States
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Originally Posted by Sadface View Post
But then I had a read of the denoiser thread and decided I might design a board that essentially grafts a denoiser onto a ESP P05.
If you incorporate Elvee's denoiser (a GREAT idea!), then you MUST base it on LT317/337s rather than the LM78/79xxs depicted in Rod's P05. If you design a PCB doing this, count me in---I'll spring for a few. I think Elvee's idea is the easiest, most economical, and best performing concept for a regulator I've seen.
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Old 25th October 2019, 11:37 PM   #245
Sadface is offline Sadface  New Zealand
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Originally Posted by dotneck335 View Post
If you incorporate Elvee's denoiser (a GREAT idea!), then you MUST base it on LT317/337s rather than the LM78/79xxs depicted in Rod's P05. If you design a PCB doing this, count me in---I'll spring for a few. I think Elvee's idea is the easiest, most economical, and best performing concept for a regulator I've seen.
That is my conclusion as well; simple, cheap and with a theoretical noise floor so low that as long as I implement a half decent board design, the community should have something high performance, modular and adaptable to various voltages.

My idea would be to release the gerber files so that all and sundry can order their own. JLCpcb is all of $2 for 5 boards + shipping and that would save me the tying up my own money in a large order of boards and the bother of shipping them out everywhere.

Last edited by Sadface; 25th October 2019 at 11:42 PM.
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Old 31st October 2019, 07:41 AM   #246
ivanlukic is offline ivanlukic  Serbia
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Quote:
Originally Posted by Mixi View Post
So here's my version of a 317/337 power supply. Very much inspired by the rod elliott / doug self / muffsy designs of course. i'm very new to pcb design so any feedback would be welcome.
I wouldn't recommend transformer on the regulator PCB. Ideally, transformer should be as far as possible from any active circuitry, including regulator circuitry. The best place for the transformer would be outside of enclosure, or inside enclosure as far as possible from all active circuitry.
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Old 31st October 2019, 07:44 AM   #247
Mixi is offline Mixi  Europe
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there‘s no transformer in my version (post #240).
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Old 31st October 2019, 07:52 AM   #248
ivanlukic is offline ivanlukic  Serbia
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OK Mixi. That was Hicoco's PCB.
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Old 31st October 2019, 08:13 AM   #249
Hicoco is offline Hicoco  France
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Rod Eliot project 88 question
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Originally Posted by ivanlukic View Post
I wouldn't recommend transformer on the regulator PCB. Ideally, transformer should be as far as possible from any active circuitry, including regulator circuitry. The best place for the transformer would be outside of enclosure, or inside enclosure as far as possible from all active circuitry.
You should advise xrk971, they have 2 transformers on the same board for Yarra Preamp
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Old 31st October 2019, 08:18 AM   #250
prasi is offline prasi  India
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Rod Eliot project 88 question
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Originally Posted by Hicoco View Post
PSU for P88 and P06
Hello Hicoco,
Nice professional PCB.
In my opinion, trafo on PCB shouldnt matter much atleast in terms of audibility.
Also, since you have dual seconday trafo, better to make dual bridge rectifier section.

However with lm317/337, all its grounds should be connected to the out put for lowest noise.

look at the example here.

Juma's Head Amp

regards
Prasi
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