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GB for DC coupled B1 buffer with shunt PSUs

diyAudio Chief Moderator
Joined 2002
Paid Member
Blue bom

Here I edited the BOM. Small differences, have to do with snap in main filter caps, *film caps for the 5 leds bypass, TO-220 rectification diodes, and 10R 5W for hot rod current. The PCB still has places for small diodes and 68R//68R 1/2W current set resistors for anybody wanting to run it on conservative current. Using big or small diodes excludes sourcing/fitting the other type.
The power trafo recommended is 15-0-15 VAC secondary, 50VA power. EI, toroidal, R-Core, whatever you fancy.

I attach the specs for the relay, just 1 needed for delaying the output, and releasing fast, so to avoid turn on thumps and DC offset power off cycle. Either a 5V or 12V Panasonic TQ2 or Omron 6GH or similar. Get 12V if available so to avoid voltage dropping and some heat on its feeding circuit. Example.

Remember, just an input rotary switch makes the Blue edition a multi input unity gain pre amp. Your volume pot should be 10k-20k log stereo. Switched type with fixed resistors or even LSPD are superior.

*The film cap mod has a nice space in this PCB, to take almost anything you wanna subjectively try. From 0.1uF to 10uF plastic or even 10-100uF 5mm electrolytics. 0.22uF MKP-10 Wima is suggested as a good indicative one as found by early testers. YMMV.
 

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Disabled Account
Joined 2002
Hi Salas, please advise to use 12V versions of the relays. That is better technically and there is no need for turning power into heat for no reason. All power loss will be a large number when added up. Simple but true. The 12V version can be found on Ebay, Farnell etc.

BTW maybe the PCB can be changed in another run to cater for both the TQ2-12V and the standard telecom relays like Takamisawa RY12W-K and all the variants of literally all relay manufacturers. Those can be found everywhere at lower costs and there are made very good versions of those.
 
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Disabled Account
Joined 2002
Either a 5V or 12V Panasonic TQ2 or Omron 6GH or similar. Get 12V if available so to avoid voltage dropping and some heat on its feeding circuit. Example.

Just mentioning the less optimal part will result in people buying that part as we have seen in the past. AFAIK that is why there is provided in voltage drop resistors on the PCB's....
 
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Hi Tea-bag

Not sure if we are supposed to alert you here on diyaudio about payment.

Are we?

Well anyway, just paypal'd for one Blue edition and one set of PRP resistors.

Originally had two blue edtion pcb's on the spreadsheet, but decided in the end to just buy one board, so I updated the sheet just now also.

Thanks very much

Curt
 
Member
Joined 2006
Paid Member
Hi Tea-bag

Not sure if we are supposed to alert you here on diyaudio about payment.

Are we?

Well anyway, just paypal'd for one Blue edition and one set of PRP resistors.

Originally had two blue edtion pcb's on the spreadsheet, but decided in the end to just buy one board, so I updated the sheet just now also.

Thanks very much

Curt

Curt, got it, thanks!
No problem on payment alerts. Sometimes someone will pay the wrong address, and there is no verification:).