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What are these???

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djn

djn

Member
Joined 2004
#1
I’m supposed to buy these in the morning but can figure out what they are. If you know them, what do you think?

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#6
I agree with your assesment that they are PP amplifiers. The topcap on only one of the preamp tubes also points in that direction.

I disagree with your statement that no commercial amp would have used 6L6's single ended. Attached are some examples of them:
 

Attachments

#8
The dial suggest an european amp, and the case is much like Philips, Siemens and Telefunken made their amps in the late 1940's and early 1950's. I guess it's an european theater amplifier OEM build by one of those brands. Hifi at that time were almost exclusive EL84 tubes in push pull configs in big radio consoles. Theater amps often used more powerfull pentodes at that time and were in metal cases like that.
 
#9
They look like vintage Vortexion or Grampian or maybe Geloso amplifiers, though I don't think they are. If they are PA amps they seem to have only one control, which is odd , waxx's comment about them being cinema amps might be nearer the mark. Either way they look like well made amps and worth getting,that said the OPT's might have a limited frequency range.
 
#10
Agree with max. To me I see a choke and an output transformer; an input tube with a top grid clip on one (the other can have a newer version of the tube) and two output tubes in PP, the second small tube being used for the two drivers. There is one cinch input. One banana for output.
One has a valve socket. so The other a solid state rectifier. . .
 
#11
Likely has a single plug/plugs for a microphone.

Looks like someone already drilled front panel on one of them to do a "guitar" conversion

both chassis labeled 6L6G
So assume would be around or after the 6L6G was available 57...58?
not sure when G tubes came out

Push/Pull
For portable PA 30 to 40 watts was pretty healthy wattage at the time
specially a portable package.

Power transformer is huge compared to most Public Address /Musical Instrument amps
Choke regulated power supply. Larger OT. Not a cheap unit.

I would actually assume likely American manufacture being Beam Tetrode.
 
#12
WhiteDragon said:
I would actually assume likely American manufacture being Beam Tetrode.
Click to expand...
Those pentode and beam tetrode tubes were also used down here. The 6L6 may be a US invention, but Europeans did copy those (and reverse also). And that kind of dial was not used in the US i thought, it was typical UK, but also used by European brands on the continent.

I helped remove an old theater setup 17 years ago from an old building in Ghent, Belgium, and there we found very similar amps with 6L6 tubes made by Siemens. That room was probally not used anymore since the theater went bankrupt in the 1965. The building was empty all the time untill it was demolished for a hotel in 2005. Friends of me lived there (in a "squat" style, so iligal), and were asked by the new owner to clean it out (to buy off prosecution and hard removel by the police, they could stay until the demolishing started). The amps we found were beyond repair altough and sold as "old iron" for the metals in it.
 
#13
waxx said:
The dial suggest an european amp,
Click to expand...
WhiteDragon said:
I would actually assume likely American manufacture being Beam Tetrode.
Click to expand...

Beam tetrodes existed on both sides of the pond, but all of the tube numbers on the chassis are distinctly American. I believe that these are old (pre-WWII) PA amps or theater amps. The 6J7 is a pentode often used as a mic amp, or a line amp. The 6SC7 is a dual triode used in gain stages and phase inverters. The 6L6G and 5U4G appeared in the 40's, and were common in PA and theater amps through the mid 50's. I used to find amps that looked like this as a kid in the early 60's. They made decent guitar amps at a time when your only measurement criteria was being loud. I still have an old Stromberg Carlson PA that matches the one I used for a guitar amp in the mid 60's. It's quite similar, but used 4 X 6L6G's for a bit more LOUD. It needs a good bit of fixing though.
 
#20
Agreed, lose the tank circuit and rewire V1 as an input. I am willing to bet the the drilled amp is already modded! All those waxie's are likely as leakey as an old boat and I am sure the can caps are as well. If done properly it will probably be a nice little amp!
 
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