Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dbishopbliss on October 03, 2013, 08:00:57 am
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I measured the chassis of my Bandmaster and the location of the holes for the tube sockets and transformer to see how the board I am designing will fit. I plan on having the filter caps inside the chassis instead of in a doghouse below. The grey rectangles represent the first two capacitors mounted to a terminal strip as Doug recommends.
The first diagram represents a single board (I color coded the different versions of the circuit for easy reference but its still a single board). I have a few concerns about this layout but I'm not sure if they should be concerns:
- The board is a little crowded with the first two filter caps
- The rectifier diodes are close to the rest of the circuit which means there will be AC near the signal that could cause noise.
- The vibrato, phase inverter and power sections of the circuit aren't really next to their tubes.
The second diagram represents a main board, a bias board and a rectifier terminal strip. Even though the I separated the first five sections, they are intended to be one big board. Here is what I like about the layout:
- The AC is kept away from the rest of the circuit.
- The circuit sections are closer to their respective tubes
- Because there is more room I could re-arrange some of the components to be less crowded.
What do you think? Is there really any advantage to layout 2 or am I over analyzing this?
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#1 is fine.
The diodes next to the bias circuit are not a problem
All my boards have been built that way without any issues
The wire lengths to the tubes should not be an issue
As long as you keep the heaters as a twisted pair and away from the real low level signals you will be fine
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Yes, #1 is fine. Generally speaking some things to consider in component layout are: ease/cost of production (real estate even in an amp has a cost $$$) , performance, ease of troubleshooting, and thermal issues. Electrolytic caps (and caps in general) have a better life expectancy in cooler environments; maybe one reason Fender used the daughter board below the main chassis (or the multi-section vertical mount can). I do like your modular approach in #2