Building a symmetrical PSU B1 buffer

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sutantoroy

Member
Joined 2008
Upgraded the supply caps from elna for audio 4700uF/45V into Silmic II 3300uF/50V. My transformator out is 15-CT-15.

Will it goes significant better when using 4700uF instead 3300uF?
Is it a good idea to paralleling the caps using MKP or oil caps with small value (under 1uF)?
I am using 1N5819 diode, Is it okay paralleling each diode with 1nF to make into a soft recovery diode?

Thanks :)
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
sutantoroy said:
Upgraded the supply caps from elna for audio 4700uF/45V into Silmic II 3300uF/50V. My transformator out is 15-CT-15.

Will it goes significant better when using 4700uF instead 3300uF?
Is it a good idea to paralleling the caps using MKP or oil caps with small value (under 1uF)?
I am using 1N5819 diode, Is it okay paralleling each diode with 1nF to make into a soft recovery diode?

Thanks :)
Click to expand...

Those are Schottky just 40V. Soft enough naturally. Stressed for reverse voltage with 2X15VAC Tx. Use 8, 2 in series for each side of the rectification bridge. Personally I don't prefer paralleling small caps around, but those are harmless experiments you can try, maybe you get lucky. The main filter caps value is adequate, look for quality mainly.
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
sutantoroy said:
crt changed 220R into 1K and the sounds is suit his taste. I just worry about the safety operating within these value.

I already added heatsink into the transistor, seems like they 'didn't do their job effectively', its not hot yet :D
Click to expand...

You up the output impedance that way. In experiments done by some users in the regular B1 thread they preferred the less value they could get away without oscillation when driving their cables. The same was my experience. Now if when changing to 1k, type was changed too for better, or there was some little oscillation driving the output cable and main amp before, then it could go better. Did it subjectively smooth out in the highs? 1k is safer even, no technical adversity.
 
Tripmaster

Tripmaster

Member
Joined 2008
Hi

I am in the process of ordering the parts for a Hypnotize board. Ive been following the DCB1 V4.2 BOM and Ive noticed Farnell Part No.1003207 refers to a Red LED rather than the Green on the BOM PDF.

If it is OK, I was going to order some for a friends board. How many would you roughly say I need to buy to get four matched rails?

Thanks
 
A

AndrewT

R.I.P.
Joined 2004
two DCB1 boards need 32 LEDs. That's plenty to choose from and get your voltages close to an exact match. A bigger difference will be due to small differences in the current flowing through each of the LED strings.

However, LEDs are so useful and so cheap you should be buying them by the 100.
 
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