Bulgin Mains Socket - Fix or Replace?

ESchap

I've just got a '74 Hiwatt that is in really good original condition, except for where someone has "bypassed" the Bulgin mains socket inside the chassis with a fixed cable.  A worse, unsafe mess you couldn't imagine, with taped off wires, connector bocks and all covered in electrical tape ... and it all sitting on the output valve sockets / wiring.

It can't be left as it is, so ........  

I could get a 3 pin Bulgin connector (plenty on eBay ... though £30 odd quid for NOS (Lol!)) and make a mains lead for it and re-instate the Bulgin socket (I've got a Bulgin Cable in my old Marshall and it seems perfectly safe to me!).

Or should I just have the Bulgin out and replace with a TAD Bulgin / IEC replacement socket?   Don't imagine it will hurt the value as it's a PA head.

ecc83

I am sure ICBM has said that if an amp has no intrinsic collector value, make it legal. So fit an IEC socket and you really should then have it PAT'ed.

BTW! Don't anyone pay 30 quid for a Bulgin I am sure I have at least one in a box somewhere plus the mating (and even more lethal!) cable plug. (I might even have one of the rocking horse---t rare bi-pin speaker connectors. They at least are safe)

Free but since it would only be going on an valuable "vintage" amp I would expect a bob or two sent to a charity.

Dave.

ICBM

Replace, always. Unless it's a true museum piece.

The Bulgin is not safe and never was - the cable retention in the plug is poor and it's easy to yank the wires out. Not so bad with the right-angle ones but they're still not great. It's not even a particularly reliable connector - having round pins means the contact is only ever really along a single line on each.

If you want unsafe, I've got an old Park 45 (early Marshall) head here, which is not only little better than home-made overall, the captive mains cable is terminated on two of the unused pins of the rectifier valve socket! OK, as long as nothing goes wrong it's not actually dangerous, but there really is so much that can potentially go wrong there… there is a reason why rectifier valves are designed with the high-voltage pins as far apart as possible!

jpfamps

There are some modern sockets like the TAD offering with IEC connectors that will fit in a old Bulgin socket hole with a small amount of filing.

This socket is cheaper than TAD.

http://uk.rs-online.com/web/p/iec-connectors/2378894/

After filing the hole out make sure you give the chassis a good clean to remove any filings.

jpfamps

ESchap said:

  A worse, unsafe mess you couldn't imagine, with taped off wires, connector bocks and all covered in electrical tape ... and it all sitting on the output valve sockets / wiring.

I don't need to imagine; I've seen worse!

EdGrip

I seem to remember there are IEC connectors that are made to fit where a Bulgin was without modification? 

If so, there's no reason not to do that. If you come to sell it later on and feel an original crap/dangerous Bulgin will add significantly more value than its cost, you can worry about it then. 

ESchap

Many thanks both and thanks for the offer of the Bulgin connector @ecc83. ;

However, think I'll go the TAD replacement route.   Only pain is that the Bulgin in the Hiwatt is riveted to the chassis (factory) so drilling required.

Did that Park 45 leave the factory like that @ICBM ?

ecc83

Anyhoos chaps! I do indeed have a mains plug and socket in my hot little.

Museum keepers please PM.

Dave.

ICBM

ESchap said:

Did that Park 45 leave the factory like that @ICBM ?

Yes, it looks like it. The wiring from the mains switch and fuseholder to the valve socket is beautifully cord-wrapped along with the transformer wiring, so it must be original. A bit of a shame, when I will need to undo it…

Although it's not destined for restoration any time soon I don't think. It was more of a "how bad is this?" investigation.

ESchap

It is a "museum piece" without the value unfortunately, it's a DR112 and both cosmetically and electrically it's in fantastic nick.  These amps really are a work of art, the wiring is so neat, bundles of wires all tidily "laced", soldering perfect.

As far as I can see, other than the messing with the Mains wiring, it is completely original. Everything, including the Plessey mains caps and RS preamp cathode caps.  Even has 6 x same date code Mullard ECC83's ... 1st week August 1973, sure they are original.  I tested them last night and they are all over 100% gm.   B+ voltages across the amp are good also.

It had a little bit of "idle" hum and I suspected the mains caps. It came with output valves 3 x RFT EL34's and one Chinese.  One RFT was very tired as was the Chinese, so one side of the output was biasing at under 20mA and the other over 40mA.   Have a few RFT's in the spares box and managed to put together a quad all sitting at 40mA. (no bias adjustment on this amp)   Amp sounds fantastic now the output section matches,  no hum etc. in spite of the ancient caps.

ICBM

I've got another of those in the "assessment" pile just now. In fact I should really go and do some work .