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Alan Hope 24th September 2012 12:22 AM

Does it matter if the tubes touch?
Loving my TSE, swapped out Sylvania 45s for TJ Meshplate 45s, and after a horrible and very depressing muddy 8 hours or so they opened out big-time and sound fantastic, extended bass and treble. Very very happy.

However, they are much larger than the Sylvanias and, when seated fully in the sockets, touch.

I can't really think why that should be a problem, and may even damp them slightly. If it is a problem, then I'm not sure what to do about it.


Richard Ellis 24th September 2012 12:31 AM

The "rule of thumb" is one and a half envelope widths between tubes, of that which is two different sizes, 1 1/2 times diameter of the smallest. Touching the two?.......Heat transfer one to the other, uneven heating, hot spots, EM fields..... the list goes on why this is not a good idea at all.

__________________________________________________ _______Rick.......

Alan Hope 24th September 2012 12:46 AM

Thanks Richard. However in order to separate the tubes I will have to move them off the board. I read a thread somewhere here which suggested that that can cause problems.

Looks like I have no option though ...

Richard Ellis 24th September 2012 12:53 AM

Talk to George about relocating the sockets........When one builds a chassis, make it bigger than you think it should be.....then make it bigger still.

__________________________________________________ _Rick.....

Alan Hope 24th September 2012 06:34 AM

My chassis is big ... I learned from my last amp (Decware kit) that plenty of space inside is good. I haven't yet drilled the aluminium top-plate so no physical problem relocating the tubes, just that I had mounted the pcb just below the top-plate so the tubes on the pcb would poke through the holes.

I'm happy to mount the tubes actually on the top-plate, that's physically better in some ways, just they can no longer be on the pcb so this will introduce short lengths of wire which may either pick up hum, or alter the electronics in some way - not sure how critical that part of the circuit is.

The amp hums very slightly on switch-on, but becomes pretty much silent when B+ kicks in and I would like it to stay that way.

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