Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plumcrazyfx on May 06, 2017, 07:49:48 am
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So I've been playing with my build a bit more and would like just a bit more firm bass response do I'm thinking of adding a choke and upgrading the tube to an EL34 (while moving to a Hammond 125GSE). I also have a ton of old RCA 6GB6Gs that I want to be able to use with an adaptor. I'm thinking if I add the choke between the first 2 caps (in place of the 500ohm resistor) I will be running the whole supply through the choke. What rating will I need for the choke? The EL34 datasheet I have says max signal current of 221ma. Am I reading that right?
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I's use a 4H to 10H choke rated for 100mA.
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> EL34 datasheet I have says max signal current of 221ma. Am I reading that right?
That sounds like a TWO tube MAX output condition.
The Fender 5C1 is one little 6V6 running ~~37mA, prolly 40-45mA counting G2 and small bottles.
If you have not changed from 5C1 OT and PT, any other power tube (6GB6, EL34) should be biased pretty-near where Fender set the 6V6. Say 40-43mA cathode, 50mA whole amplifier. (But do think about the higher heater consumption of the bigger bottles.)
The 100mA suggested is fine, *even* if you have up-sized OT/PT to "6L6 Champ" levels, (4K 10W OT, 100mA PT). If you really want to run the big bottles near 6V6 power level, you could use less.
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Yah, that was under the Class AB1 push pull when I looked at it again.
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I suspect you may want to increase the size of your OT. I have a rickenbacker M8e that won't allow me to play bass through it. (Yes, I know its not designed for bass, its designed for a Hawaiian guitar ). The OT is tiny, and an SE amp, but by design, it related to 5C1, (like humans and ringtailed monkeys, primates).
I hope you're not throwing good money after bad results. If you're experimenting to learn, then bad results are a reasonable choice of spending time and money.
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First of all, have you tried to increase the filter capacitors value ?
Franco
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I'm planning on moving to a larger power transformer, a 25w Hammond 125GSE output transformer, and a choke. I plan on moving the first cap to a 30uf, and the other 2 to a 20uf while also adding one to the preamp supply. Right now after some testing I'm leaning toward a KT66 and a 5AR4. My plan is to be able to use a wide variety of tubes with it.