NOAD - 1962 Grand Prix by Audio Guild

[DeathJag]

Yes I am still not working and yes I am not supposed to be buying anything. But I broke the rules for this. I have already forgiven myself. I'm sure I will work again someday.

$450 off CL and this one is BADASS! It is a closed back combo, which I absolutely love. Looks like an original 12 inch speaker in there, but it's hard to know. Somebody decided to use some a pair of yellowjackets so they could insert what looks like EL84s, where 7591s are supposed to to be. Which is a bummer because those tubes are expensive. I definitely would like to hear what they sound like so I guess I will have to spring for a vintage pair.

It sounds really fucking awesome, and I'm not kidding. I plugged the 2003 AVR I Jag into it and it sounded full and beefy, with plenty of clarity and no icepick highs.

It has both reverb and vibrato. Yes, VIBRATO! The fellow who designed this circuit apparently also designed the pitch-shifting Magnatone circuit. It sounds really fucking cool and not phasey. Really fucking cool. And to top it all off, there's a full-sized reverb pan in there! And get this, it fucking drips! I have never heard any on-amp reverb that dripped, but this does. It's also quite loud and clear. We plugged a base into it and it sounded crispy and thumpy.

Does anyone have any idea how to date this thing? I couldn't find anything about that.

[DeathJag]

Now that I am doing a little reading, it seems that these tubes are most likely 6GM5 tubes, which are supposedly electrically identical to 7591s. So with these yellow jacket adapters, this might be how the amp sounds with 7591s. Does anybody know what these tubes are?

The long string of characters looks like a 6N1411 – EB, then the number is 0584 below them. The N might be some Russian character, because it doesn't look like a N. Then there's a diamond with the letters 0TK, two, V, and eight for each in a corner.

[øøøøøøø]

6π14 is a Soviet EL84

What are the numbers on the power transformer end bell and the OT frame?

That will help affix a date to those parts

Amp looks cool as hell. I'd have bought it for 450 for sure. In fact, if you're ever selling...

[DeathJag]

6π14 is a Soviet EL84

What are the numbers on the power transformer end bell and the OT frame?

Oh snap! So I have not heard the 7591 tone through these el84s! Gonna rectify that.

Your tip about the transformer bell code is solid, both PT and OT made by Electrical Windings Transformer, both #682246. So that's the 46th week of '62! My favorite year for amps.

The Utah speaker frame code is 328243, which also puts it in 1962, 43rd week!

I found a schematic that looks pretty similar, for a model called Imperial. What a bummer that the Magnatone Audio Guild site is gone! That site would have audio guild schematics, but it is gone. I have not opened the chassis yet, but the transformers and tube lineup and input and outputs are identical, so I bet this amp is pretty close to this schematic.

Looks like there are two transistors, at the end of the reverb and tremolo circuits. Everything else looks pretty normal. Except that I see no triangles or lines for ground, but I see little circles that look like that would be where the grounds go. Weird. There are also several places that have weird symbols, like a vertical line with two circles on the top and bottom of one side. Here is a close-up of one of those, does anyone know what these are?



And here's the whole thing for posterity.

[JSett]

I'm with Brad on this one, 100% would have also bought this had it been available to me...£450 is a bargain. And actual vibrato is such a treat!

Little finds like this can end up being secret weapons. I'm gonna guess that it kicks out about 10-15w with those tubes so could be a fantastic studio amp.

Have you cranked it all the way yet?

[DeathJag]

I'm with Brad on this one, 100% would have also bought this had it been available to me...£450 is a bargain. And actual vibrato is such a treat!

Little finds like this can end up being secret weapons. I'm gonna guess that it kicks out about 10-15w with those tubes so could be a fantastic studio amp.

Have you cranked it all the way yet?

Totally! It was actually still pretty clean but it had some beautiful dirt. Plugged in a Hoffner bass copy and turned it all the way up and it was crisp and thumpy and awesome. I think it's 15 watts. It's much louder than other small combos I have tried, which could be because of the cool chambered and closed back design? I've always fantasized about a closed back combo amp but never had one. It is missing the double foot switch,Ii've seen a picture and that thing was super cool. Made out of wood with two little switches sticking out of it. Luckily both effects are locked in the on position with nothing plugged in. There's only one jack for the foot switch, so I imagine it's some sort of TRS thing.

The back panel had a short piece of wood glued to it that when the panel is on, it supports the speaker. It's weird but I've had it drying overnight before putting the back panel on.

This Utah speaker is pretty damn cool also! Never heard one before.

[JSett]

The block of wood is weird. I've seen them supporting between front baffle and rear panel but never against the speaker magnet itself!

A little crunch is perfect, that just means a boost should take it into pure deliciousness and hopefully not fart out.

Would love to hear it if you get a chance to do a little demo.

[DeathJag]

I'd love to record a demo, and perhaps this one time I will. I am super insecure about my playing and can never think of anything to play.

I have figured out that the thing I circled in that schematic above is simply a switch. Duh. One symbol I do not see anywhere is anything for ground. What is the story with that?

[øøøøøøø]

It’s intuitive to figure out where the grounds are, but it is strange that they don’t seem to be marked! Perhaps the amp grounds via sleeves of input/output jacks in practice so they decided that was good enough for the schematic?

Transistor for reverb recovery saved cost of a transformer, probably.

[thegreatbigsby]

Very cool amp! Very curious how it sounds!

Just a heads up, I've recently had to swap put JJ 7591s in my Ampeg Reverbojet and put new Tung-Sols in. Still not cheap, but cheaper than NOS, and they sound great! Better that the JJs.

[panoramic]

Nice one! I am currently trying to get an ELK amp I found on marketplace but I suspect it will fall through like most of my deals seem to do.