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Old 21st Mar 2012, 10:10 pm   #23
Neil Purling
Nonode
 
Join Date: Jul 2005
Location: Hull, East Yorkshire, UK.
Posts: 2,083
Default Re: Mullard 3-3 information required

The circuit referred to in post #1 is the Mullard prototype.
Interesting that the Sterns kit has two inputs, with filtering of some kind on the input.
I guess it's purpose is to cut surface noise experienced with shellac 78's,more 'hiss' than a snake pit. I don't play 78's very often, so I won't be bothering with the filtration.
Very, interesting that the cutting template for the prototype denotes the completed chassis was 8x6x2 (inches). How wonderfully compact.
I am restricted by the space I have available on a shelf (see post #8). Every input, output and control MUST be on the front of the chassis. I have kept any AC mains conductor well away from any signal stage, and that will continue to be so.
I am going to have to remember to make the tag board up as a mirror-image of that illustrated in these constructional guides and mount the 'pots' in the different order too.

Has anyone done the circuit with Octal base valves, like EF37a and EL33 output?
As this is about Components choice a simple 'Yes' or 'No' will do to express if it is possible without expanding any further. Just in case anyone else wants to have a go at making a 3-3 of what is to hand.

Sideband: I'd love to see your effort on the scrap chassis.
I guess it makes you want get a better o/p transformer or start from 'scratch'.
You said it was "deafeningly loud'" in the workshop, so that'd be enough for there, but not fit to venture into 'respectable' areas of the house.
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