I once owned an Airzone Radiostar with an AC/DC chassis. It had a full compliment of P-base valves and the barretter was the same. I understand that barretters also came with an ES base but I've never seen one that way.

I thought it might be a European built one that some one bought in BUT all the Caps etc, are Melbourne.

Definitely the oldest amp Ive got, looking forward to getting it running.


Josh

Might have to send you a picture, I have an AWA Radiola 613T which has a 302 ES Berritter.
One of the few radios I have kept to restore.

Josh

I understand that barretters also came with an ES base but I've never seen one that way.

What's an ES base?

I've seen baretters with a screw base (like an American light globe), and one with a 4-pin base. I might still have one somewhere.

What's an ES base?

Edison screw, as for light bulbs. Various sizes.

GES = Goliath Edison Screw
ES = Edison Screw
CES = Candelabra Edison Screw
SES = Small Edison Screw
MES = Miniature Edison Screw
LES = Lilliput Edison Screw

BC = Bayonet Cap
SBC = Small Bayonet Cap
MBC = Miniature Bayonet Cap

Ah, I see. Wasn't familiar with the initials.


Next week I'll see if it can find any baretters and take a photo.

Photo uploaded to Post 18.

Nice one Josh! Very unique mate!

Barretter: (Correct English spelling) is referred to as a Ballast tube in USA, where most will think Barretter is a gun (Beretta) not a hot wire regulator.

You cannot sub a light bulb for one of these as the wire & characteristics are not the same: Often an Iron filament & in an atmosphere of Hydrogen.

There are several examples, if you look up Ballast tubes. They did not only get used in Radio, I have seen one in a Lab pH meter.

https://frank.pocnet.net/sheets/141/b/B6.pdf

They did not only get used in Radio

Also used in telephony.

I found 3 baretters in my collection: a Philips 329, a STC 4121A, and an unmarked ES type. Perhaps someone can identify it.

Thanks Brad.

In answer to the question from Josh on the DC supply voltage, when I moved to Adelaide in the early 1980s my wife and I bought and renovated an old house which was built in 1925. This still had had the original switchboard and associated fuses but attached to the face panel was an ETSA brass label which stated that the switchboard had been converted from 230V DC to 240 AC. Later, because I made a point of checking, I saw similar labels on switchboards in other old houses in older parts of Adelaide. Also some of these houses had large three-pin power sockets similar to but not exactly the same as the current South African power sockets. Asking some of the old sparkies about this I learned that the power supply in Adelaide had originally been 220-230V DC and had been intended for lighting only. Starting In the 1930s there had been a gradual conversion to AC which was not completed until the mid 1950s.

As part of the renovation of my house, I replaced all the wiring, switchboard, switches and GPOs. I used a friend who was an A class electrician with myself as the labourer. In the ceiling I found that all the wiring for the lights was the original double cotton covered cables laid in wooden ducting; all of which was still in perfect condition. However the power wiring that had been added in the '40s was rubber insulated twin cables with a bare earth wire run in steel pipe ducts. This had deteriorated to the point that all the rubber insulation was just grey dust; how the lot had not caught fire was a miracle. The other interesting thing I found was that the original light switches were made with a china body and a brass face plate. The lever was also brass. However all the brass parts were in contact with the circuit but the switch was in the neutral side so that the plate and lever were effectively earthed. The light fitting remained 'live' even when the switch was off. This was complete the reverse of the wiring method used today and of course modern switches are fully insulated (or should be - some of the Chinese made gear makes me wonder).

So my guess would be that the amp when new was probably sold with the expectation that it might be used in a suburb that was still on a DC supply. Hence it would have to be an AC/DC design with possibility of a 'live' chassis.

Andrew

However all the brass parts were in contact with the circuit but the switch was in the neutral side so that the plate and lever were effectively earthed. The light fitting remained 'live' even when the switch was off.

Good grief !!!