National Aztec, vintage tube amp I can't find any info on.

[Rustin]

Hello all. I've got this ancient looking tube amp I found at a thrift store. It works but I can't find a lick of information anywhere on the web about it. It has one logo that says National, which is on the front of the amp. Another logo that says aztec is found at the top of the amp near the controls. It has a single speaker by Jensen. The model number is 1240 T.It's kind of a light brownish tweed color. I'll post some pics when I get a chance, hopefully later tonight. Any help would be much appreciated. I was hoping to see how much the thing is worth. Thanks.

[tedmich]

http://www.valcopages.com/Schematics...240T_aztec.pdf
supposed to be identical to Gretsch Executive, see discussion here:
Schematic for Gretsch / Victoria amps?: Gretsch Amps: The Gretsch Pages

[EFK]

What's the tube lineup? Earlier versions used two 6V6 power tubes, then for I think one year they went to 6973 tubes. There's probably a 6sq7 in the preamp? Usually the tremolo oscillator. These were made when Valco was transitioning to 12AX7 tubes as preamp tubes. The aztec was something of the National-branded contemporary of the Supro 1690T, although the Supro used 6L6. Circuits share some similarities, though. FWIW, the aztec schematic above does not even remotely match one that I had here a few years back, and the Executive schematic is a completely new-made amp that doesn't have any real similarity with old Valco amps. Would love to see some pictures!

[tedmich]

Oh well, I tried...

well some things go extinct for a reason

if its not too complex (likely) you can just trace the schematic the old way...

[EFK]

Yep, what tedmich said - easiest thing to do with most of the oddball Valco-made amps is start at the inputs and just work your way right on through it.

[Rustin]

Whadda you think?

[EFK]

Oooooooh, yep, that looks exactly like the one I had. What's down in the power amp chassis - I can't tell if those are 6V6 or 6L6? Also - is yours marked for a 5V4 or a 5U4 rectifier? Just like the 1690T, I think they switched @ 1959/1960. Last one of these I saw on ebay went for somewhere around $600 dollars if I recall correctly, looked about the same condition. This was a while ago however - maybe a year, maybe more?

[Rustin]

You'll have to forgive me EFK, I don't know exactly where to locate the difference in numbers you are mentioning. I am in a tight financial situation and regrettably have to sell this amp. I appreciate your help so much.

[Rustin]

[QUOTE=Rustin;253604]You'll have to forgive me EFK, I don't know exactly where to locate the difference in numbers you are mentioning. I am in a tight financial situation and regrettably have to sell this amp. How much should I ask for this amp on Ebay? It would help me so much. I appreciate your help.

[Tremolux55]

These were all made by Valco and badged up as various companies. I have a circuit diagram for a Valco Aztec - the speaker set up may diffre but I suspect the circuit will be fairly similar. This is also very similar to the Supro Brentwood which i just restored last year - fabulous amp. Thanks to Mr Valco for the circuit diagram - hope he mdeosn't mind me sharing it.

[EFK]

Rustin I don;t know what to tell you about value because if you put it on the bay, I'll probably bid on it. Sooooo, one dollar!! hahahahahaha. Kind of a conflict of interest there. Tremolux55, thanks a LOT for that schematic. That's one I haven;t seen previously. I think mine must have been later, as the 5879 and 6SJ7 on the front end were replaced with 12AX7 (I mean stock).

[Rustin]

Well when I put it on Ebay I'll inform you. Trouble is, I probably won't take anything under $500. I was offered $300 dollars a while ago and declined it. I want it to go to a loving home where it will be played. Thanks.