What have I bought? (unknown tube amp)

[DWBH]

The OT looks like a Geloso Output Transformer

[img:529:356]http://www.qsl.net/i0jx/215.jpg[/img]

Usually those Geloso OT has a lot of output impedances

http://el34world.com/Forum/index.php?ac ... tach=21922

http://el34world.com/Forum/index.php?ac ... tach=21924

K

Thank you so much!
I found a code on the OT: 5406.
It's a Geloso 5406.

Just like this one:
http://www.ebay.it/itm/Geloso-Trasforma ... 4897.l4275

In page 71 of this PDF:
http://www.openfreedom.org/BTG/files/BT ... 9-Sett.pdf

5406
Output transformer for 6L6G pushpull class AB operating at 400V plate, 300V screen, -25vgrids. Built with two equal secondaries, balanced with respect to the primary, for combinations in series or parallel, as shown in the table, you get all the output impedances from 1.25 Ohm to 500 Ohm. Technical Data:
Primary Impedance: 6800 Ohm
Secondary Impedance: 1.25 / 2.5/5/7.5/10/14/18/30/75/100/125/300/350/400/450/500
Primary resistance 220 Ohm
Primary inductance 12 H
Maximum power: 35 W (+37.6 dB)
Efficiency: from 0.84 to 0.92 according to the outlet
Linear response (+-2dB) from 50 to 10000 Hz

So... maybe it once had 6L6s in there?

And, according to this (http://en.wikipedia.org/wiki/Geloso#Mounting_kits), Geloso once selled kits to be home-assembled. Hmm... the plot thickens.

[Cliff Schecht]

I'm guessing these transformers at one time powered a beautiful pair of Telefunken EL84's (if it was made in Germany, I'm inclined to agree because of the caps in there).

Don't think it had EL84s, since the 6550s use octal sockets... My eariler suggestion of EL156s aren't right either, since they require special socketes. May be just plain old EL34s? We need a German guitar amp/tube history buff to help us decipher this thing!

I was thinking both transformers are pulls, not original necessarily to what we see built in the OP pics. But who knows?!?

[Kagliostro]

it will be very interesting to reverse engineer the circuit

as to draw the schematic

May be this will say a bit more about the amp

for sure it will be useful on debug it

K

[DWBH]

PT's secondary:
5V for rectifier filament
3.15 0 3.15 for filaments
280 20 300 = 600 (kind of low, no?)