Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Platefire on September 30, 2010, 03:11:02 pm
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I was wondering will it cause any problems twisting the primary wires (Red=DC Power, blue=first PP pow tube plate and brown=2nd PP pow tube plate) together for about a 4" run before seperating them to go to their destinations or would it be better to provide complete seperation from the red/power and the plate wires. Before I do it, want to be sure I'm not creating a problem. Platefire
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Shouldn't be a problem. Once inside the bell, there's a whole lotta twisting going on. I've twisted OT leads before.
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I'm also very interested in this.
Although I've done that before in several amps without any noticeable inconvenience, would it be better not to twist these wires?
Could maybe DC ripple induce noise in the power tube's plates?
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I think I've done it before without any problems. I guess I'm questioning things I've done previously that I have doubt about or wasn't sure about and never ask about.
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IIRC, twisting wires increases CMRR (common mode rejection ratio) which is a good thing. This is why it's suggested to twist AC filament wires. I don't see how twisting an AC pair with a DC line can cause any problem unless the DC is very dirty in which case there's a bigger issue to resolve.
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I asked this question some time ago, and no one thought it was a problem, so if they are long enough (and I don't like cutting them short) I twist them just to keep wiring neater.
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If the load impedance is much higher than 10K, and the wires are more than a few feet long, you might be able to measure a difference.
For the usual 8K-4K loading and 1-foot leads, it won't hurt, and may HELP reduce squeal from primary lead radiation getting back into earlier stages.
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Good enough! Thanks and case closed. Platefire :smiley: