General Category > VALVE archive

C/4s original SEX ,voltage questions.

(1/6) > >>

najo49:
Hi I just put a set of the c4s boards in (I built them up myself). i have many of the Brainiac changes to the circut as well. I am getting just 200 v going in to the board and 116 going out. I plays fine,the voltage in the old valve mag says a considerable larger voltage. the 1k resistor is removed in the PS. Any thoughts,this may take paul or doc to comment. Thanks

Paul Joppa:
Unfortunately, I can't locate any information on the C4S installation and my memory does not include any details either. Do you have a manual or circuit?

The voltages ae quite acceptable, however. I would speculate that there is a series resistor between the power supply and the C4S input, which drops a substantial voltage. But changing that, and thus changing the input voltage, won't change the plate output voltage, so it won't affect the performance.

najo49:
Thanks Paul, I did all the work according to the Valve schematic,and docs schematic on the c4s board. In that he says there was 300 V going in .  then  a resistor 60 ohm,then the 2907 ,350 b and and a 60k resistor to gnd. after the leds. but I only have 190 going in not 300v. But as you say ,and the fact it works fine may be I should just consider it a success,and for get about it. The rest of the mods were done according to a valve piece you wrote on SEX changes in valve. In fact the original schematic contains no voltages ,if I had them, perhaps I could have figured this out. Thanks again, let me know if you have any further thoughts. I love these amps,but i thinks i am pretty much alone in this, I guess all the bottleheads did this 16 years ago and have moved on. Jan

Paul Joppa:
If you tell me what issue of VALVE has the C4S schematic, I'll look it up and estimate the voltages. If you can find Doc's post of a schemo, I'll look at that too. There is probably some reason fro the 190 volts!

najo49:
Paul, It was in vol. 6 no. 1. Jan

Navigation

[0] Message Index

[#] Next page