help with power supply

[unrealdave]

Hi - I bought this power supply in its current state but no circuit with it and wondered if anyone has seen a kit like it?

It looks good quality, and it seems well built.

There is a place for a valve rectifier but I don't know which one.
any ideas?

[Terry]

There is a place for a valve rectifier but I don't know which one.
any ideas?

Being B9A and assuming a 6.3V heater winding is provided will narrow it down to an EZ80 or EZ81, dependent on maximum current.

It looks a bit unusual, to say the least! It looks as if you have 4 silicon diodes, rear left, for a bridge rectifier for the low voltage supply which is obviously fed to a stabilizer of some kind - probably two - based around the devices on the heat sinks.

The Bulgin male beside the transformer will be Mains in - if you can find the matching female! - and there are two unmarked terminals on the front edge.

However, there doesn't seem to be any other output connection potential unless there are other connectors we can't see.

I think you are going to have to trace this out in order to find out exactly what is going on unless someone can recognise it from somewhere ...

... and just as I was about to preview this the site froze up on me!

Fortunately I had the wit to do a CTRL+A, CTRL+c to copy it to the clipboard because otherwise I would have lost it!

[unrealdave]

I’ve got a matching female connector so no worries there

The unmarked terminals are the outputs see the new pic



It’s a Sowter transformer and these are expensive, and the kit with it probably cost a penny or two, and it is a kit I think.  I thought it might be a china special but the transformer and other bits don’t seem to point that way.


My best guess is that it is the power supply for two valve HiFi mono block amps.

[Terry]

It doesn't seem to have been completed - there are three connections from the mains transformer, by the look of it, to a terminal block that goes nowhere!

Particularly worrying is that all the wiring passing through the chassis are in small holes with sharp edges and no trace of a grommet anywhere ...

Presumably those output terminals are some sort of miniature multi-pin plug and socket. They won't have much of a current carrying capacity, surely, and the breakdown voltage is unlikely to be very high.

I still think you will have to trace out the circuit to really find out what is going on or what is supposed to happen, then post it here for additional comment.

Then strip the thing down to its component parts, ream out and insulate the holes in the chassis, fit more suitable connectors and re-build it!

[pwdrive]

Is that a connector I can see on the right hand side of the PCB?

I agree about a rectifier valve unless by some remote possibility it's a series pass valve.

Lawrence.

[ppppenguin]

Could it be a valve rectifier to give the magic "valve sound" but in series with silicon to make sure nothing can go wrong. Or perhaps a bridge with half and half valve/silicon? there's no knowing what kind of audiophoolery is going on.

[unrealdave]

It doesn't seem to have been completed - there are three connections from the mains transformer, by the look of it, to a terminal block that goes nowhere!

Agreed.  I might just strip it down but will see if I can get the circuit first.  I am going to look in the shed I got it from.

[unrealdave]

Is that a connector I can see on the right hand side of the PCB?

There are two connectors - the do not look meaty though.

[unrealdave]

there's no knowing what kind of audiophoolery is going on.

Exactly, also was it wired up correctly?  Who knows? 

[ppppenguin]

We can take a look at it tomorrow when I'm over at your place. I reckon you'll need to trace out the circuit to make sense of it.