Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: strangedisc on January 16, 2013, 08:53:34 pm

Title: what kind of amps are these?
Post by: strangedisc on January 16, 2013, 08:53:34 pm
have had these for quite awhile.  just now got around to checking them out.  what exactly are they?    thanks
Title: Re: what kind of amps are these?
Post by: eleventeen on January 17, 2013, 10:28:20 am
Can't tell you *exactly* what they are. Sometimes this determination is better made looking at the ends (in this case) of the chassis which you pix do not show. Is there, for example, an octal plug, esp labelled "preamp" or "accessory"? Most hi-fi setups of that era used a separate preamp and power amp, and the tendency was to use an octal plug and interconnect cable to power up the preamp. Or, it could be more of an industrial item. Or, it could be an organ power amp. If it's an organ power amp, it would be a bit rare to see, for example, an impedance select switch or barrier strip...because there's (in most cases) only one speaker arrangement. If it was an organ amp, then maybe the volume control is not especially in a "user-friendly" spot, as it is pretty much set once and forgotten about. These kinds of clues can help identify.

They certainly look like that have entirely adequate iron for what would appear to be a dual 6L6 amp. What is that metal-tube rectifier, a 5Z3?

At first they sure look like great chassis to warp into a geetar amps, but at the same time you'll be seriously space limited trying to get any kind of preamp circuitry in there. Long, narrow chassis are good to a point---once they are narrow like these, it's hard to see how you could get a row of preamp tubes in there while placing a row of controls along one long side of the chassis. Working with this typically forces the builder to put stuff next other stuff that one would ordinarily like to avoid.

You realize there is essentially no circuitry at all in those...you don't even have a phase splitter tube!

Title: Re: what kind of amps are these?
Post by: Tom_Hull on January 17, 2013, 10:42:00 am
5z3 or what ever rectifiers link.since you mentioned that tube

it has a lot about rectifiers .if you like a nice download .

http://www.fourwater.com/files/fullrect.txt (http://www.fourwater.com/files/fullrect.txt)



tom
Title: Re: what kind of amps are these?
Post by: kagliostro on January 17, 2013, 01:34:43 pm
Hi Tom

Very useful file

Many thanks for sharing

K
Title: Re: what kind of amps are these?
Post by: DummyLoad on January 17, 2013, 10:04:15 pm
5T4 recto; sweetness. - it's_kind_of_like_a_5AR4_in_a_can. metalmania!! - probably designed for either 6L6 metal or 6L6G. the exposed resistors are dangerous. maybe military? do you have the pre-amps? looks like just the PS and output stage, no PI or pre.
hefty iron. revive them as is with a cap job. caps do seem fried is that rust or electrolyte on the cap cans?

--DL 
Title: Re: what kind of amps are these?
Post by: strangedisc on January 18, 2013, 07:43:07 pm
I don't see anything else that was in the box, except these.  that is somekind of build up on the one can.  I don't
really think I'm gonna mess around with these anyways.  And I don't have enough experience, to even know what
I'm doing!   :icon_biggrin:
Title: Re: what kind of amps are these?
Post by: DummyLoad on January 19, 2013, 09:02:06 am
I don't see anything else that was in the box, except these.  that is somekind of build up on the one can.  I don't
really think I'm gonna mess around with these anyways.  And I don't have enough experience, to even know what
I'm doing!   :icon_biggrin:

no manufacturer markings at all? on the transformers? chassis?

salvage those 6L6GC GE tubes in the one - the gettering looks nearly new on both tubes.

--DL

edit: ...they may be salvage from a theater.
Title: Re: what kind of amps are these?
Post by: eleventeen on January 19, 2013, 02:14:18 pm
Those will sell for decent money on fleabay as matched, industrial type dual-6L6 amps. Probably $80-$120 each.
Title: Re: what kind of amps are these?
Post by: strangedisc on January 20, 2013, 09:35:40 pm
hey,  ok,  thanks for all the info.        I'll go ahead and remove all the tubes, and ditch the chasis.                 
Title: Re: what kind of amps are these?
Post by: Ritchie200 on January 20, 2013, 11:17:49 pm
Maybe old juke box amps? :dontknow:

Jim
Title: Re: what kind of amps are these?
Post by: Jack1962 on January 30, 2013, 07:07:46 am
Yeah I'm with Ritchie the look like either old jukebox amps