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Old 23rd April 2009, 01:31 PM   #1581
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Default Tread PSU OK?

I've got my B1 board and chips (thanks to Colin at PassLabs!!!)... I've got the parts on order. I got the AXON caps from a seller on eBay (audiograde).

But, I'm wondering about PSU. I have a Tread (from TangentSoft) that I'm not using for anything else. Will it work OK in B1???

NOTE: I saw some discussion on PSUs a few pages back and searched the forum and found nothing... So, please the noobie dumb question.

Thanks,
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Old 23rd April 2009, 02:19 PM   #1582
troystg is offline troystg  United States
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Default Re: Tread PSU OK?

Quote:
Originally posted by sandbasser
I've got my B1 board and chips (thanks to Colin at PassLabs!!!)... I've got the parts on order. I got the AXON caps from a seller on eBay (audiograde).

But, I'm wondering about PSU. I have a Tread (from TangentSoft) that I'm not using for anything else. Will it work OK in B1???

NOTE: I saw some discussion on PSUs a few pages back and searched the forum and found nothing... So, please the noobie dumb question.

Thanks,

If it is 18 - 24 DC it should be fine. Mr. Pass said he used "higher" voltages than the "stated" 18 VDC so I would feel safe assuming anywhere between 18 and 24 would be good.

I still have PLENTY of 48VDC power supplies if anyone is interested in making regulated 24 or even 18 V pwr supplies.

Last count I had ~50 of them.. I just can't find the heart to throw them away....
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Old 23rd April 2009, 02:36 PM   #1583
Salas is online now Salas  Greece
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I have found +/- 10V to be optimum subjectively in my non coupling caps version. I have started from +/- 8V, gone up to +/- 15V. It will not be surprising for +20V to be so for the normal version too. Just listen to voltages between 18-24V if possible.
I attach an FFT of my version at half volume knob rotation. Some high frequency minute spikes are present in my card's loop too.
Input=1VRMS=0dB.
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Old 23rd April 2009, 06:42 PM   #1584
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Quote:
Originally posted by Salas
I have found +/- 10V to be optimum subjectively in my non coupling caps version. I have started from +/- 8V, gone up to +/- 15V. It will not be surprising for +20V to be so for the normal version too. Just listen to voltages between 18-24V if possible.
For every JFET circuit like this, signal level and load there is a "sweet
spot" of rail voltage value. It is easy to find if you have a distortion
analyzer.

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Old 28th April 2009, 05:16 PM   #1585
crt is offline crt  Indonesia
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Halo
i have finished build B1 buffer. Not Tested Yet.

B-1 Buffer picture

BUT i have a big problem.
the transformator i have buy is not 0-24V but only 0-14V.
after diode (rectifier) the voltage is 19,XX V
and after LM317 reg. the voltage MAX only at 18,3V.

can i use a lower voltage than a suggested (18-24V) ?
maybe around 15V or 17 V ?
with this lower value, should i change the another component maybe resistor value. because i can not buy another transformator again.
i will stick on this transformator

Thank's
La Ode

Sorry for poor english
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Old 28th April 2009, 09:40 PM   #1586
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Nice PCB but just a question: are the input and output caps not too close to eachother ? Or it could be that the yellow ones are input caps ?!

BTW You could have omitted input/output caps if you would have used the schematic of Salas ( symmetric B1 ).
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Old 28th April 2009, 10:16 PM   #1587
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Regarding your transformer.
Why not try a Notebook switchmode powersupply (ie most are 19.6 V). If it is good enough for Nelson's retail product, then it is definitely good enough for me.
Anyway go ahead and try the transformer, and if you have any doubts about the sound quality after listening to it, then try the external switch mode power supply and compare.

Anyway, I think nelson originally specified 18V, so I don't see a huge problem.
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Old 28th April 2009, 11:00 PM   #1588
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No, it's not a problem. Switchers work fine if you use the passive RC
filter in the project and the ferrite collar on the supply wire so that residual
noise doesn't make it to the FETs.

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Old 29th April 2009, 09:01 AM   #1589
crt is offline crt  Indonesia
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Quote:
Originally posted by jean-paul
Nice PCB but just a question: are the input and output caps not too close to eachother ? Or it could be that the yellow ones are input caps ?!

BTW You could have omitted input/output caps if you would have used the schematic of Salas ( symmetric B1 ).

yes maybe thats caps to close, but i think it will not make any problem. the yellow caps for input and parallel 3x 3u3 (red WIMA) for 10uF for output.

i use ariginnal Article in B-1 Buffer. can i remove the caps ?
salas version ?
sorry this is the first time i posted in Pass Labs discussion.

Quote:
Originally posted by thanh1973
Regarding your transformer.
Why not try a Notebook switchmode powersupply (ie most are 19.6 V). If it is good enough for Nelson's retail product, then it is definitely good enough for me.
Anyway go ahead and try the transformer, and if you have any doubts about the sound quality after listening to it, then try the external switch mode power supply and compare.

Anyway, I think nelson originally specified 18V, so I don't see a huge problem.
I buy this transformer is "second hand" not new tranformator.
i though this is 24 V but i was wrong.

the notebook PS is quite expensive to me.
with those transformer only take US$ 3.

Quote:
Originally posted by Nelson Pass
No, it's not a problem. Switchers work fine if you use the passive RC
filter in the project and the ferrite collar on the supply wire so that residual
noise doesn't make it to the FETs.

So, I will stick with 18 V.

Have Tested today. and no problemo.
SOUND , ABSOLUTELY SUPERB FOR ME !!!

THANK"S NELSON PASS! for your design.

Regards
La Ode
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Old 29th April 2009, 11:02 PM   #1590
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Great to see you have finished.
I am still casing mine up.
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