Mystery Guild Accordian Amp Model No. 50

josiahstumbomusic · Feb 24, 2013

Hello, this is my first post. I just picked this amp up at a pawn shop. I'm really not even that good at amp talk, but I'll try to explain it. It's got 5 tubes, 2 12ax7s and 3 50L6. It says nothing on the front, and the back simply says guild Model No. 50. Underneath it says 117 Volts 60 CY. A.C. It has 4 separate inputs. 1 says Accordion & Mike and the other says "for RECORDING" above the inputs and "for INSTRUMENTS" below the inputs. There is a volume control for the acccordion and mike and a separate one for INSTRUMENTS. The only other nob is the tone nob which also serves as the on/off switch. It has a serial number hand-scratched into metal plate. It has a 12" Jensen speaker.

It sounds AWESOME with my Tele and I'm very happy with it. I just can't find any info about it anywhere. I bartered down from 200 dollars to 160 at the pawn shop, and feel like I got myself a good deal.

I'll try to post pictures, but don't know if facebook links work?

https://www.facebook.com/media/set/?set ... 841&type=1

Thanks for your help identifying this!

Default · Feb 24, 2013

Be extraordinarily careful with that amp. There is NO transformer isolating you from the wall current and if you plug it into the wall the wrong way, the chassis has 120 volts on the chassis - do NOT play this on a concrete floor! Get an isolation transformer installed and a three prong grounded cord asap!

Default · Feb 24, 2013

I want one of these but I wouldnt plug one in until I had an isolation transformer and a grounded cord installed.
That being said, pics would be appreciated!

josiahstumbomusic · Feb 24, 2013

Thanks! I appreciate the word of caution. A few questions:

Do you know what era it's from? Would it just be called a "Model 50"? I couldn't find a single mention of it on the Web.

Is the transformer and cord replacement something I could learn to diy? If not is it worth to justify paying to put some work into it?

I appreciate your help!

AcornHouse · Feb 24, 2013

Welcome to the forum! An interesting first post.

Default · Feb 24, 2013

josiahstumbomusic said:
Thanks! I appreciate the word of caution. A few questions:

Do you know what era it's from? Would it just be called a "Model 50"? I couldn't find a single mention of it on the Web.

Is the transformer and cord replacement something I could learn to diy? If not is it worth to justify paying to put some work into it?

I appreciate your help!

This is an early to mid fifties amp. You model is very similar to the top-most amp in this thread. The tube heaters are wired in series, like Christmas tree lights, so if you pull one tube, the whole amp won't work. An isolation transformer isn't pricey and neither is a grounded cord, but if you don't know what you are doing, you can kill yourself. On the bright side, once you have that taken care of, 50L6 tubes are plentiful and cheap. You cannot sub any other tube for a 50L6, so don't put a 6V6 or 6L6 in there. It won't work.

Default · Feb 24, 2013

Default said:
Be extraordinarily careful with that amp. There is NO transformer isolating you from the wall current and if you plug it into the wall the wrong way, the chassis has 120 volts on the chassis - do NOT play this on a concrete floor! Get an isolation transformer installed and a three prong grounded cord asap!

josiahstumbomusic said:
Is the transformer and cord replacement something I could learn to diy? If not is it worth to justify paying to put some work into it?

Default said:
I want one of these but I wouldn't plug one in until I had an isolation transformer and a grounded cord installed.

From a safety angle, yes, you want to pay somebody to do this to make it safe. Otherwise, you are looking for a 3 cent, 60 year old capacitor to keep you from getting 120 volts passed through your body. Do a search on "death cap" on the forum and you'll see why it's important. :wink:

josiahstumbomusic · Feb 26, 2013

Default wrote:
Be extraordinarily careful with that amp. There is NO transformer isolating you from the wall current

If I got lucky and bought an amp that somebody else had already added a transformer to, how would I identify it? I ask because somebody notated in sharpie that they switched the tubes in 1974, and there is a piece in the midst of all of the electronics on the back that looks a lot newer than everything else.

I called a pro audio shop that does amp mods and they said adding a transformer and 3 prong cord would cost me 100 bucks, does that sound reasonable?

Thanks again! You guys are amazingly helpful!

Josiah

Default · Feb 26, 2013

Can you take the back off and take some detailed pics? If you get an account at imageshack, photobucket or Picassa, you can host them there and link to them on the forum.
That way, we can take a look and see if you have an isolation transformer already installed.
There's not a ton of data on early amps, so every little bit helps!

Default · Feb 26, 2013

Hundred bucks sounds right. Most of that is labor as every pic that i've seen with the back off has been a real rat's nest of wires.

josiahstumbomusic · Mar 28, 2013

It took me a long time, but I have taken a bunch of pictures and uploaded them here:

I'm assuming that the isolation transformer has not been installed, but it would be nice to have that confirmed before I take it to a shop.

Thanks, you guys have been incredibly helpful!

Default · Mar 28, 2013

Looks like you might hav one installed already. Wi check when I get home.

dapmdave · Mar 28, 2013

I can't tell anything about the guts, but that amp looks darn good from a cosmetic point of view.

Dave

josiahstumbomusic · Mar 28, 2013

Thanks! I agree! It was certainly a fun pawn shop find.

Default · Mar 28, 2013

I see no less than three transformers, although one might be a choke in the power supply. The output transformer is mounted on the speaker, there's one in the chassis and one hanging underneath. I think that would be the isolation transformer. Does the powercord connect to that transformer?
No grounded plug. I would still have it checked out. :?

josiahstumbomusic · Mar 29, 2013

The power cord is connected to the tone knob which is the on switch and to the fuse.

Default · Mar 29, 2013

josiahstumbomusic said:
The power cord is connected to the tone knob which is the on switch and to the fuse.

After the fuse, it goes to one of the tube sockets?

Default · Mar 29, 2013

The white wire up in the top right hand corner, with the electrical tape. Is that connected to one of the leads on the transformer?

Default said:
josiahstumbomusic said:

The power cord is connected to the tone knob which is the on switch and to the fuse.

Click to expand...

After the fuse, it goes to one of the tube sockets?

josiahstumbomusic · Mar 29, 2013

If the metal box-shaped piece in the top right of this picture is a transformer then yes, the fuse goes into this box, and that white wire with electrical tape goes from that transformer to the first tube.sorry for the newb vocabulary.

TonyT · Mar 29, 2013

Except for the getting dead part, that is one cool looking amp. I'd say worth the dough to make it safe.

Mystery Guild Accordian Amp Model No. 50

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