Low Voltage

Forum to discuss amp circuits besides the 18 Watters and their ilk.

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Kcz5o
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Re: Low Voltage

Post by Kcz5o »

I have to change my response. I thought if the amp had sound in both positions ss and tube, that meant the diodes were good. I pulled the rectifier tube and now do not have sound in both positions. Will have to check and see how many diodes I ordered.
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TriodeLuvr
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Re: Low Voltage

Post by TriodeLuvr »

Right, the switch simply shunts the diodes across the 5AR4. If they're open, nothing happens when you switch to SS. The 5AR4 continues to supply B+. Easy to get fooled by that one!
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Kcz5o
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Re: Low Voltage

Post by Kcz5o »

Replaced the diodes and works without the tube. I've only put two kits together so far and I usually screw something up. I guess that how I learn more as long as its not fatal. I'm usually very careful. I drain the caps whenever I get close to the amp explaining how I forgot the drain resister.
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Kcz5o
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Re: Low Voltage

Post by Kcz5o »

One more quick question and hopefully I will be done. There is one more diode in the bias supply. If that also was damaged it either works or it doesn't correct? I am able to adjust the bias and it is stable so should be ok?
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TriodeLuvr
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Re: Low Voltage

Post by TriodeLuvr »

Kcz5o wrote:
Wed 12/16/20 10:53 am
One more quick question and hopefully I will be done. There is one more diode in the bias supply. If that also was damaged it either works or it doesn't correct? I am able to adjust the bias and it is stable so should be ok?
Based on your description of the problem, there's no reason to think the bias diode has been damaged. You know, I'm surprised the short across the caps didn't blow the HV fuse. The limiter must have been responsible for that. You might want to consider replacing those 1N4007s with something better at some point in the future. I use fast recovery 3A types in most builds at this voltage level. Glad you got it working!
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