Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: BobL on December 27, 2020, 11:06:58 pm
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I'm about to start building a 6G3 project, and I'm going to put it into a custom chassis into a tweed twin cab, so I should have a fair amount of space for the board if I want to use it.
I had a couple questions:
The last build I did was sluckey's single channel AB763, and I just put the cap board caps on the left end of the main board since I had more room in the tweed chassis, and that seemed to work just fine.
Is there any reason not to do that in this case if I can fit them? I'll be doing both channels, and I wasn't sure if I'd want them away from the trem circuit or something of that nature? I have a pan if that's just a better way to go... but it just seems like that creates longer wire runs.
Same question on the bias circuit - is that board separated from everything else because of noise, or space? With the AB763, I kept that on the main board as well, per sluckey's layout.
Last question: I ordered a custom chassis for this to get the right PT knockout, and I'll be putting the rest of the holes in myself. The chassis I have coming is aluminum, and I'm wondering if I can use the chassis as ground to lugs, or if it's not conductive enough, and I need to use an alternate grounding scheme?
Thanks for any input!
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Well, aluminum is quite conductive, so that's not a problem. The problem is where you make your ground lug connections, you can get a loss of conductivity because of the way aluminum reacts with other metals. You may have a loss of conductivity at the connection over time. You definitely want to ground the chassis to the ground lug on your power cord, but for circuit grounds, you might want to provide a ground line, and then ground that somewhere on the chassis, such as at the input jack.
Just my thoughts on it....
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There is no Aluminum in our world. It's all Aluminum Oxide. Which is one of the better insulators.
They say there is Al under the oxide surface, but as fast as we scratch it off, it grows back.
Soldering is dubious too. Don't use chassis to carry power or signal currents. You must bond metal to wall-outlet 3rd pin. Use a sharp toothy washer/lug and a dedicated screw and nut.