Is there anything useful here?

[Phil_S]

My friend repairs commercial ships. He says this was a Bogen PA that he replaced today and it was in working order; just old and not deemed reliable.
There are 4 chassis, only 3 shown, basically a pair of reasonably complete units. Pots date the equipment to 1972.

I see some parts to raid out and maybe the transformers can be sold on eBait? Chassis maybe be good as donors. These are very heavy units.

Your thoughts would be appreciated!

Phil

[DonMoose]

Being solid state, the chassis may be useful, but I'd be surprised if the iron does anything for a tube circuit.

That OT would be for a solid-state output to (most likely) a 70-volt distribution system.

The PT won't likely have a winding higher than 120V, and not likely a winding useful for heating more than a couple of preamp tubes.

... of course, I've been wrong on a regular basis.

Cool stuff, though. Need a whole-house audio rig?

[LeftyStrat]

Sorry, but I just had to chuckle. I just pictured some low-level deck swab commenting to his colleagues, "The captain's voice just doesn't sound as 'authoritative' through this new system as it did with the old PA. We need to find some NOS mustard caps."

[Phil_S]

If by any chance there are a pair of 80v or so secondaries, they can be put in series for 160-ish and through a doubler for close to 400v. I did that with a TV transformer through a FWB one time and got 300-ish B+ good for a champ-like build. Filament supply had to be supplemented. I'm guessing low to no demand for these units and weight makes them even less desirable.

I should have some fun taking them apart. There are useful parts including sandblock resistors, terminal strips, a few CC resistors with long leads, buss wire, even a couple of noval sockets that must have been used as plugs. The white Mallory caps are mostly low voltage rated ;-( There are some big honking e-caps with screw terminals and I'm going to bet they are not useful for guitar; I can't see the rating until I release them from the clamp. There are a few good can cap clamps. Mostly, this will be a lean harvest.

Chassis might be good donors for an amp. Size is on the large size but still within reason.

I wonder if the transistors have any value? Nope, quick search says they are $4 each if I got the right part.

I guess I'll start with the big transformers and see what I've got.

Lefty, good one about the Captain's voice! The ship had 90 rooms all wired to the PA, so it must have some significant power to is.

[skyboltone]

It's probably worth something as a working amp I would think. I know that I used a similar vintage amp as a modulator on a broadcast transmitter once. If you put a 600:600 isolation transformer between the output of the PA amp to the plates of the modulation tubes you have audio.

Other than that I can't think of a thing to use it for. You got a boat? You need an anchor?

[Phil_S]

It's probably worth something as a working amp I would think. I know that I used a similar vintage amp as a modulator on a broadcast transmitter once. If you put a 600:600 isolation transformer between the output of the PA amp to the plates of the modulation tubes you have audio.

Other than that I can't think of a thing to use it for. You got a boat? You need an anchor?

Nice idea....I'm having trouble finding the output tubes. Where should I look for those?

[Structo]

How about using them for a power amp or PA?

[skyboltone]

It's probably worth something as a working amp I would think. I know that I used a similar vintage amp as a modulator on a broadcast transmitter once. If you put a 600:600 isolation transformer between the output of the PA amp to the plates of the modulation tubes you have audio.

Other than that I can't think of a thing to use it for. You got a boat? You need an anchor?

Nice idea....I'm having trouble finding the output tubes. Where should I look for those?

They're in the caddy.

[Kagliostro]

The chassis seems usable and also the transformer may be, using a voltage multiplier

IMO

K

[Phil_S]

There is a power transformer, 24-0-24 with no load. I am reasonably sure the secondary leads are 16 AWG, maybe 14AWG. This and the size/weight leads me to believe the winding is rated for several hundred mA. I'm thinking a 2x doubler should give B+ in the 300's, but even the upper 200's would be useful. Surely there is enough there to power just about any EL84 or 6V6 type amp. I just need to add a filament transformer.

There are two other transformers, one large and one small. These must be output transformers of some sort. The large one has one center tapped winding and several others in pairs, with DCR in the 0.3-4.0 Ohms range. The smaller one has three separate windings, each about 1 Ohm. I am hoping the public library can find a Sam's Photofact for me. Otherwise, these appear to useless to me unless I want to break them down for an ill-fated self rewind attempt. The smaller one looks perfect for a 15-20W OT. The big one is HUGE!

Surprisingly, the power amp chassis is 17" x 6.75". The deck doesn't have too many holes and with a little bit of metal work I think it can be used for a tube amp! I've used much more challenging donor chassis. LOL, there is one noval socket, unknown use, but certainly not a tube I know and there is no obvious filament supply.

[Kagliostro]

The use of the noval socket may be was as connector for a cable

if you pull all the components you can put a thin sheet of alluminium on the surface of the chassis, fix it with rivets and use the chassis as a new one

K

[Andy Le Blanc]

I have heard of them being used for their distortion tone with a guitar as is.
Haven't tried it myself...