Is there a specialist in Australia who can rewind valve audio output transformers? I've started restoring my 1954 Pye Black Box BBH record-player, and it has the typical problem, an open circuit in the push-pull output transformer caused by leaky paper coupling capacitiors. The transformer is type F395, primary 15,000 ohms with centre tap, secondary 1.5 ohms.

On the other hand, if anyone has the guts of a Pye BBH with a good output transformer going spare, let me know.

I will try & follow up on that. I had a MIdwest come in with an electrodynamic speaker in it recently.

Both the bobbin & PP transformer had been rewound. So someone does do it.

Marc

Try Gil McPherson (02) 6238 0464

Might be an idea to post what the OP valves are. There is always the likelyhood that it was common to other things with those valves.

Pye was normally built by Astor.

Marc

Thanks, I'll try him.

It's an English-made player, but I think they were sold here. I've seen quite a few over the years. Output valves are two EL42. (Not sure if there's a 6xxx-number equivalent for that valve.) The transformer is horizontally mounted in a rectangular hole in the chassis, mounting bolts arranged 2" x 2.5". I'll post a picture shortly.

There is a mob in Newcastle, NSW that my late father used. I will ask my brother he lives there.

Steve Savell has done a couple for me with excellent results



savell.combigpond.com

Correct me if I'm wrong but I think the Pye Black Box uses an ultra-linear output transformer. Might be difficult to rewind. I have a circuit at home if you need one. I believe the EL42 to be a one off with no close relatives. (I'll have to check with my valve genealogy!)
EL42 specs: (cant find specs for P-P)
Class: A S/E. Va: 225. Vg2: 225. Vg1: -10.0. Ia: 26.0.
Ig2: 4.1. Ra: 90,000. S: 3.2. Rk: 360. Zout: 9,000.
Pout: 2.5. THD:10.

The ultra-linear version is the Mark2, mine's the Mark 1 with the simpler centre-tapped transformer. Here's a picture; the output transformer's on the left.

Image Link

I've found a power transformer from a Thorn amp using exactly the same size and type of former, which means I could try winding a replacement from scratch. The original uses extremely thin wire and tons of insulation, which is why they burn out. For a replacement I'd guess about 5000 turns of 0.2mm wire for the centre-tapped primary, and 50 of 1mm for the secondary. I'll try to get a quote first, though. It would take me days of work.

You might wish to check these out. The Hammond type 125B universal OP transformer could be a close match to the OP trans you require. It would save on the trouble & expense of a rewind.

http://www.hammondmfg.com/125a.htm.
http://www.hammondmfg.com/125.htm.

Thanks, the Hammond 125B looks just right electrically. I'd have to mount it on its side to clear the changer, that's all.

Airzone: There is a mob in Newcastle, NSW that my late father used. I will ask my brother he lives there.

If he's still in business, it would be good to know that winder's details for the record.

GTC Airzone,

If you discover the details and the gentleman doesn't mind I am happy to add him to the Services Directory.

^ Airzone mentioned this Newcastle "mob" in post #6 and was going to follow up.

(To the forum features wishlist, please add the ability to quote other posts.)

Ahhh yes. Please put my mistake down to the lateness of the hour.

I might be able to add quoting to the current website though it would most likely mean employing popup windows. Leave it with me.