Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jonyoungyi on November 27, 2017, 05:03:11 pm
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A while ago I built the Tweed Bluezmeister and it is such a killer amp! I really like the attack on each note from this amp and I really like the clean channel. I built it into a head and would like to build a stripped down version into a full cab.
I was curious if I could simply "snip" the entire overdrive section out of the amp and just build the Clean channel and Output section without changing anything else?
I've attached a copy of the schematic.
Any and all help is much appreciated!
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I was curious if I could simply "snip" the entire overdrive section out of the amp and just build the Clean channel and Output section without changing anything else?
Absolutely.
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For more reason behind that, the whole concept for the OD is that it is a switchable on/off. All you do is remove the switch and that OD and you've got the same amp minus the OD.
~Phil
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Thanks Sluckey and Phil!
I was a little worried/curious how that might affect my PT and such since I'm removing a tube, but I guess that just means "unused" current which translates to heat? (Nothing to be worried about, I'm sure).
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Thanks Sluckey and Phil!
I was a little worried/curious how that might affect my PT and such since I'm removing a tube, but I guess that just means "unused" current which translates to heat? (Nothing to be worried about, I'm sure).
No actually it's the opposite, the transformer wires generate less heat when less current runs through them. If you use less tubes than the transformer expects, it just runs cooler with less problems. You're thinking as if the transformer MUST run at a specific current. It doesn't. Current handling is how thick the gauge of wire is, and how much it handles before it overheats and melts. In a transformer that often ends up shorting wires, making the turns ratio go wrong etc. If you're running under current, it doesn't heat and gives a longer lasting transformer. In most cases you want to spec them to be close to the expected current rating so as to make the transformer cost less. This requires less copper when they can use smaller gauge wires. In your case, the overkill in current handling means you'll be perfectly fine, unless you want to try and re-scale the transformer for the new amp setup. Look at say the power transformer for an amp with 5 preamp tubes and 4 power tubes vs an amp with 2 preamp tubes and 2 power tubes. Much smaller, much less cost for the latter, as it needs smaller sized wires to provide the much smaller current.
~Phil
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> means "unused" current which translates to heat?
When I plug two dozen lights into my skinny extension cord, it gets hot.
If I plug a lot less lights, not hot.
Also: long skinny cord with lots of load, the 120V at this end comes out only 105V at the far end, dimmer. With less load it may only sag to 115V, near full bright.
So the practical result is a (marginally) cooler transformer (not as close to melt-down), and a slightly higher output voltage.
What are you threatening? One less 12AX7 on a two-6L6 amp? Bah, you could hardly find any difference.
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PRR,
You do a remarkably superb job consistently taking (sometimes very complex) concepts of electronics and explaining them in " everyday illustrations" (word pictures) that are understandable. Truly outstanding! I've not known very many people in the science/engineering field that
have the giftedness in teaching and illustrating like you do.
THANKS for your ongoing and gifted contributions to the forum! My respect and appreciation, Tubenit
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Ah! That makes sense! I kept thinking the Transformer would always run at X current, but I forget it all depends on the draw!
I didn't even think of the cables being the ones that would handle that heat. After reading this, I had a "duh" moment. The wires are carrying current that the tubes/circuit are demanding!!! DUH! haha
I agree with the practical and easy to understand illustration. It makes so much sense!
Thanks everyone! I'm happy to have learned something new from each of your posts! :D
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PRR,
You do a remarkably superb job consistently taking (sometimes very complex) concepts of electronics and explaining them in " everyday illustrations" (word pictures) that are understandable. Truly outstanding! I've not known very many people in the science/engineering field that
have the giftedness in teaching and illustrating like you do.
THANKS for your ongoing and gifted contributions to the forum! My respect and appreciation, Tubenit
PRR is a practical thinker with lots of experience and an edumacation :worthy1: