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EL84 amp concept

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El Sid:
I initially bought the non-functioning EL84 amp (below) from sergiochinelli to play around with different valve circuits. But the longer I've been looking at it in my workshop the more I've felt that that beautiful (dare I say it) vintage Engel and Partridge iron deserves pride of place.

So I will use the chassis as it is now for the testbed, getting the amp to sound as good as it can. But I really want a new chassis once that's done. I want to have something different from the standard flat, valves-in-front, transformers-at-the-back chassis. I've seen some pics of big old amps (usually cinema/broadcast etc) that are vertically arranged, and that got me thinking. This is where I ended up:

I have looked around, and it seems that most valves are happy to be on their sides (although some need a specific orientation). I think cooling won't be a problem as the flow of air won't be impeded. One negative is that the signal wires will make quite long runs to the selector, volume and then pre stage, but I'm sure that can be managed with careful screening and layout. Also it won't be the cheapest easiest chassis to make.  But I think it will look quite cool! I'd please like any comments criticism etc on this concept.

(Discussion here on the electrical aspects of this amp)

The more vertical shape is really interesting.
Imho it would be great project.
(Though I'm not an engineer, so can't comment on technical matters.)

There's an Octave design that's really beautiful, though the valves are still mounted in the traditional upright way.

Aesthetically speaking, there's certainly something to be said for mounting the valves in a non-traditional orientation.

Love that V6 version above! Why don't you consider a V4 option? Think it would be easier to build as well and signal  & filament wires will be shorter.

Remember to twist the filament wires and keep them in the corners of the chassis as far as reasonably possible.


El Sid,

Regarding the 'rather long' signal leads in your new design; as long as you use screened wire and keep them to the sides, i.e. following the chassis bends/folds, you should certainly have no problem. One can use quite longer cables in more difficult equipment without picking up stray fields, unless something else is seriously wrong.

And well-done free-hand sketches! (part of your daily routine?)

I like the way this layout keeps the heat of the valves away from the transformers . Good thinking methinks .


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