DC Voltage Reg PCB Group Buy Notes

[Andrew]

I promise this for several folk, including Neal who purchased some spare PCB off me at Owston.

If using the specified parts, insulation washers and tabs on the heatsink are not required.

For 6.3v use a 9v AC TX operation R5 = 120R, R6+R7 = 560R + 68R (ish) depends upon the reg and Darlington used.

For 12.6v operation, if you have the kit, you need to up-rate the input cap to something like 6800uF @ 25v, watch out for the part's diameter. A 25mm diameter cap is a very tight squeeze and obtaining a 10,000uF at 25v at 22mm is quite a challenge, however 6800uF 25v 22mm is fine. R6 + R7 should be 1.2k + 56R (ish). At a minimum a 12v AC TX should be fine.

As always watch out for cap polarity when stuffing the PCB. The Tantalum cap is marked, but typically on a small Tant with the writing towards you, the positive is on the right.

Code: Select all

Part                                   Farnell               Rapid              Notes
STMICROELECTRONICS - LD1085P TO220F    1       1087151       0              
SK 129 50,8                            1       1319813       0              
TIP122 , NPN, 100V, 5A, TO-220FP       1       1084454       0              
2kbp02 2a 200v In-line Bridge s203l    0                     1       47-0902       
470nf 63v Mks2 Min Poly Capacitor 5mm  0                     3       10-2224    Bend Legs to fit or find 10m part
4700uf  16v 7.5mm pitch 16mm dia       0                     1       11-3746              
10uf 35v 5mm Tantalum 5mm pitch        0                     1       11-1022              
10000uF  16v 22mm dia 10mm pitch       0                     1       11-2990     No longer stocked
1N4001                                 0                     1       47-3130              	

Andrew

[rdowdall]

Hello Andrew - I would like to introduce myself, my name is Rick Dowdall. I recently posted on DIYAudio regarding interest in a 300B OTL schematic. A friend of yours Ray replied to my post and recommended that I build a modified version of Bruce Rozenblit's amplifier published in his book Tubes and Circuits. Ray also suggested I contact you regarding the purchase of DC heater board that you sell. I would be interested in more information about these if you still have them for sale.

I live in the US, close to Atlanta,Georgia.

Regards,

Rick

[Andrew]

Hi Rick,

Nice to talk to you, by now you will know Ray has closed the loop and we have been in contact, but I'm sure I speak for all of us on this forum when I say a) welcome and b) we would love to hear more about your build over the coming winter.

PS there are two PCBs types (I'm sure Ray has explained) this thread is for indirectly heated type valves (I believe they are also used by both Ray and Wolfgang in their builds for the driver valves) the others are specifically for DHT like 300B and are in this thread. http://www.audio-talk.co.uk/phpBB3/view ... =19&t=5500

cheers,

Andrew