Help identifying vintage amp

[NFXP]

tube layout: 5z3 6L6(x2) 6c5 6j7
Tone and Gain controls
1/4 input and screw on mic input
transformers are all hammond and yes they are chromed

Sorry i didnt have time to clean it up but its still drool worthy






any help identifying the age or manufacturer would be great thanks.

[Enzo]

It is some old Public Address amplifier. Are there any markings or numbers on the chassis?

DOubtful, but pull a tube or two and see if the sockets have a tube type number stamped into them. SOme old amp makers actually had sockets for each tube type. Octal sockets are octal sockets, but some would say 6L6 on them and some 6SL7 or whatever. I guess it was easier than stamping it on the chassis.

Age? Start looking for date codes on the parts. In particular, the volume controls. But also the other large things like transformers and caps.

[NFXP]

theres no makings anywhere on the chassis, not even tube locations, no parts with date codes, it has alot of canadian parts so im guessing this is going to be a obscure canadian off-brand. ill give it a cleaning tonight and see if i can find anything else.

[Enzo]

No date codes? Are there just no numbers at all on the pot bodies? It would be a very unusual piece of gear not to have date codes on the filter caps and transformers.

[NFXP]

One pot is marked a-10446 but who knows the date code format of C.C.M&Co. pots made in Canada. there is one Sprague Atom but no date code on that, the transformers have no numbers on them unless they are marked under the side covers. I thought for a second this might be a vintage home brew but the chassis is factory made. Hopefully someone recongizes the style and maybe find the brand that way. heres some clear pics.

[NFXP]

ive seen the same knob surround on a couple of other amps on the net but they were all unlabbled. Anyone know a good site with steel chassis P.A. amps and specs other then radiomuseum.org?

[trobbins]

There is numbering on the choke - anything else on that part. Parts typically need to be removed to see all the wording/marks on them. Sometimes there can be markings under the bell-ends of chokes and transformers.

What's the part underneath the input valve that the screened input goes to? It looks like a capacior or diode type small can - but I don't recognise it at all.

Are there any markings at all on the large, above chassis, electrolytic cans?

The wax covered foil/paper capacitors would have printed markings, and I've seen some manufacturers add faint overprinted date codes in a different colour.

The overall style and parts types (indicator bezels, phono jack on the LHS, caps, mains switch, potted OT) are similar to late 1940's, early 1950's, amplifiers in Australia.

Imho, the amp was definetely 'prefessionally' made. In Australia, very few of such amps had manufacturer markings. Sometimes photos of the amps can be seen in technical magazine adverts of that time, or even in newspaper adverts - either from the manufacturer adverts, or a major 'music equipment store' advert. They were typically used by business's, as few people at that time had home audio equipment, apart from a radio.

Ciao, Tim

[Enzo]

Mystery part. You mean that thing shaped like a chamber pot, upper right? SOmeone posted a photo of one of those not too long ago, and it turned out to be something odd like a little battery or something - made for biasing. Something they don;t do anymore. I forget now just what it was, but we saw one.

SUrprised the thread mount can caps have no markings.


As simple and as roomy as this amp is, it would not be hard at all to draw up a schematic from the unit.

[trobbins]

Ahh yes - I recall coming across battery biasing at one time on an early amp - that makes total sense now. Obviously not something one still expects to see in an amp - except where the amp was replaced and put away never to see the light of day for another 4-5 decades.

I have mostly restored something fairly close in style, age, and tube set (http://dalmura.com.au/projects/Austr...015W%20amp.pdf) - I had to buy in some 2501 microphone socket adaptors (5/8” Amphenol) - which meant putting it to one side, and it's now waiting in the 'queue'!

[NFXP]

SUrprised the thread mount can caps have no markings.

they are really faded, they are to different maufactures, one has a patent number the other might have had a code at some point but its not anywhere near ledgible.

[NFXP]

There is numbering on the choke - anything else on that part. Parts typically need to be removed to see all the wording/marks on them. Sometimes there can be markings under the bell-ends of chokes and transformers.

What's the part underneath the input valve that the screened input goes to? It looks like a capacior or diode type small can - but I don't recognise it at all.

Are there any markings at all on the large, above chassis, electrolytic cans?

The wax covered foil/paper capacitors would have printed markings, and I've seen some manufacturers add faint overprinted date codes in a different colour.

The overall style and parts types (indicator bezels, phono jack on the LHS, caps, mains switch, potted OT) are similar to late 1940's, early 1950's, amplifiers in Australia.

Imho, the amp was definetely 'prefessionally' made. In Australia, very few of such amps had manufacturer markings. Sometimes photos of the amps can be seen in technical magazine adverts of that time, or even in newspaper adverts - either from the manufacturer adverts, or a major 'music equipment store' advert. They were typically used by business's, as few people at that time had home audio equipment, apart from a radio.

Ciao, Tim

I havent taken anything apart but i might find something when i can examine every piece on its own.
What you said about austrailian amps makes sense for this amp, all the parts are made in canada and there are no markings, but what doesnt make sense to me is why chrome out the whole thing and not put a brand on it, it seems like it would be a premium amp since i dont think businesses cared about the finish. those chrome transformers and chassis are throwing me off otherwise i would have just accepted it as a no-name amp.
thanks for the info

[trobbins]

I agree - I was surprised at the chrome work done - but I suggest the metalwork wouldn't have been considered 'costly' in those days, in comparison to the transformers, and may have been considered beneficial for selling in a showroom environment. Hifi hadn't really been raised on a pedastal at that time, although the Williamson had instigated major rethinking in amp designs at the end of the 1940's.

[Enzo]

You still need screw-on connectors?

[trobbins]

Ahh, the OT is the chromed unit. The potted hammertone unit must be the choke.

It looks like the 6L6 screens are at B+.

[NFXP]

Ahh, the OT is the chromed unit. The potted hammertone unit must be the choke.

It looks like the 6L6 screens are at B+.

i think the choke is inside the chassis. and i dont know what the crinkle finished unit is