# Garnet Stencil Tube Amp Advise



## p_wats

Hey guys,

I recently picked up a Garnet stencil tube amp used (ie, one of the many tube amps made by Garnet, but sold under a different name by a department store). This one no longer has the name plate, but it looks very similar in features to a Vagabond I've seen and I'm told the model number was 10P-T. 

It's got 2 8" Marsland speakers, 2 12AX7 and 2 50EH5 tubes, 3 inputs and the controls are volume, treble, bass, tremolo (rate).

I bought it on prospect, as these old amps are supposed to be excellent, but this one just doesn't sound as good as I'd like (I think I got spoiled by my Pine 201 "Paul" amp). 

Right now it doesn't play too nicely with my other gear. I don't quite get a shock, but I can feel current buzzing through when it's plugged in to the same power strip as other amps that are on. I'm going to assume this is because of the lack of ground provided by the 2-prong chord (the guts seem to have 2 transformers, so that seems to be a good sign). Also, the treble adds a huge amount of buzz (but also far too much treble, so it sounds fine with the knob rolled back quite a bit). Basically, if I keep it I'd replace all the tubes and add a 3-prong chord. 

Anyway, I have the opportunity to trade this for a Pine 207 (another "Paul," but this time with 2 8" speakers and tremolo), so I'm trying to decide what to do! 




























































Any advise would be really appreciated!


----------



## Wild Bill

Like all techs, I hate looking at pictures! You can never see where the wires are going so it just makes your head hurt to try to trace the circuit. Give me a schematic any time! One look and things are plain as day.

Still, from what I can see you can't just add a 3-wire cord. This amp may have two transformers but there is still NO power transformer to provide isolation!

What you have is two output transformers, exactly the same. The 50C5's are output tubes and their output trannies are likely paralleled to provide the total power. This is a rather poor way to do things as far as efficiency goes but for a smart guy like Gar Gilles it made sense. You see, the 50C5 tube was used in millions of table model radios, along with a suitable output transformer. What is produced in such high volumes is sold much cheaper as a replacement part for repairs. This was a way for Gar to keep the cost down.

I suggest you get a real tech to make sure the "death cap" is in good shape or else get a small line isolation transformer.


----------



## p_wats

Wild Bill said:


> Still, from what I can see you can't just add a 3-wire cord. This amp may have two transformers but there is still NO power transformer to provide isolation!
> 
> What you have is two output transformers, exactly the same. The 50C5's are output tubes and their output trannies are likely paralleled to provide the total power. This is a rather poor way to do things as far as efficiency goes but for a smart guy like Gar Gilles it made sense. You see, the 50C5 tube was used in millions of table model radios, along with a suitable output transformer. What is produced in such high volumes is sold much cheaper as a replacement part for repairs. This was a way for Gar to keep the cost down.
> 
> I suggest you get a real tech to make sure the "death cap" is in good shape or else get a small line isolation transformer.


Thanks for the info! I've barely been able to find any info on this amp online, so there's no schematic as of yet. I've got an external isolation transformer that I've been plugging it into, but it still seems to act slightly funny to me when other things are plugged in. In any case, I probably won't keep it if it needs work to be made safe, as it doesn't sound nearly as good as my Pine.


----------



## Lincoln

p_wats said:


> Thanks for the info! I've barely been able to find any info on this amp online, so there's no schematic as of yet. I've got an external isolation transformer that I've been plugging it into, but it still seems to act slightly funny to me when other things are plugged in. In any case, I probably won't keep it if it needs work to be made safe, as it doesn't sound nearly as good as my Pine.


I'm 99.8% sure I have a schematic for this amp at home. I'll post it up later on if I do.


----------



## p_wats

Lincoln said:


> I'm 99.8% sure I have a schematic for this amp at home. I'll post it up later on if I do.


Woah! That would be awesome. It's not a bad sounding amp by any means, but not quite as smooth and warm sounding as my Pine 201. I know a few amp techs that I'll have look at it if I've got the time.


----------



## madkatb

I think I have this same amp. Still has the T. Eaton & Co. sticker on the back. Garnet silkscreen labelled as a Vagabond ( I think that was the Eaton's brand). The pair of 50C5's are SRPP, only amp I've seen done that way, other than schematics. I have the isolation tranny for it but it's still on the "Projects to do" list. Only has one SS diode for rectification. I was wondering about putting a bridge rectifier in with the isolation tranny but will that drop the B+ too much?


----------



## p_wats

Hmm, I might have been wrong in my initial post. These could be 50eh5 tubes instead. Does that make sense to anyone?


----------



## p_wats

p_wats said:


> Hmm, I might have been wrong in my initial post. These could be 50eh5 tubes instead. Does that make sense to anyone?


Yep, just pulled them out. They are 50EH5s. I'll edit my original post to reflect this so people aren't mislead.


----------



## Lincoln

Here's the 10P-T









and here's a 10P just for fun


----------



## p_wats

Wow! Thanks. Does that mean then that mine isn't a 10p-t, as this one has 50EH5s instead of 50C5s?


----------



## zontar

Can someone point out where the tubes are in those pictures?
Am I missing something?

It looks a lot like one of my Garnet Stencils--especially on the outside, but I'll have to drag my amp over to h computer, take the back off and compare to be sure.


----------



## Wild Bill

p_wats said:


> Wow! Thanks. Does that mean then that mine isn't a 10p-t, as this one has 50EH5s instead of 50C5s?


The tubes aren't important. They have similar power specs. Gar probably just got a better deal on one or the other at the time. The important thing is the circuit!

The 10P clearly shows two output transformers in parallel, feeding two speakers in series. The 10P-T uses only one in the much more standard circuit.

Your amp has two output transformers. It must be the same or close to the 10P.

Incidently, the 10P circuit will have more distortion. That's probably why you don't like the tone as much. Power out will be in the neighbourhood of 3 watts.


----------



## Swampdonkeyamps

I just had a Granada amp in here for mods/repairs.... to reduce the chance of shock, I altered the primary AC by adding a 3 prong cord, and changing the hot line to first run through the fuse, then the power switch then into the lines that were initially hooked up after the fuse, which originally energized the chassis with 120 volts AC when the unit was OFF. Now there is no leakage current to ground. If anyone wants details, please let me know. It works great!


Chris Czech
Swampdonkey Amplifiers Home Page


----------



## ezcomes

sure...post some details!


----------



## JHarasym

Good source of info on Garnets is the Yahoo group:
garnet-amps : For fans/owners of Garnet guitar amps


----------



## Lincoln

Here's that 10P-T Schematic back again for Adam. 
View attachment 2568


----------



## zontar

Wow--that took a while.

Still cool to share.

And good to know if I ever decide to do anything with my Stencils (One has tubes (Not the one mentioned above.))


----------



## mok.eric

Swampdonkeyamps said:


> I just had a Granada amp in here for mods/repairs.... to reduce the chance of shock, I altered the primary AC by adding a 3 prong cord, and changing the hot line to first run through the fuse, then the power switch then into the lines that were initially hooked up after the fuse, which originally energized the chassis with 120 volts AC when the unit was OFF. Now there is no leakage current to ground. If anyone wants details, please let me know. It works great!
> 
> 
> Chris Czech
> Swampdonkey Amplifiers Home Page


About how much does this cost? And how much do you guys think one of these is worth? I've got a United 10PT that I'm thinking of selling, but I'm still kind of on the fence.


----------



## MrChris

Does any one have the scmatics for a garnett pt 10 amp with the 2 8 inch marshland speakers. Thanks


----------



## Lincoln

MrChris said:


> Does any one have the scmatics for a garnett pt 10 amp with the 2 8 inch marshland speakers. Thanks


Welcome MrChris, I'll have a look for that schematic when I get home tonight. I'll scan & post it up if I have one.


----------



## Lincoln

Here you go.


----------



## Lincoln

This one has two speakers and dual output transformers. it might be closer to what you have.


----------



## MrChris

Lincoln said:


> I'm 99.8% sure I have a schematic for this amp at home. I'll post it up later on if I do.


Hi do you have a scamadics for this garnet amp.my teck needs one before he will work on mine thank you. Has bad caps ect and wants to putnin a propernground plug


----------



## MrChris

Lincoln said:


> I'm 99.8% sure I have a schematic for this amp at home. I'll post it up later on if I do.


----------



## Lincoln

MrChris said:


> Hi do you have a scamadics for this garnet amp.my teck needs one before he will work on mine thank you. Has bad caps ect and wants to putnin a propernground plug


The two Garnet schematics I have are posted up there MrChris. That's all there is. Give of those to your tech, and I'm sure he can figure it out.


----------



## alwaysflat

Back to the OP, I'd make a trade for the 207 if the speakers were decent ( straight up trade ? woo-hoo). I love 6V6 and no muss no fuss safety and easy to tweak. Looks to me that the 2nd schematic might be a Mod that sets up for the replacement of the broken tone section when the common is joined with the chassis ground. A p-p 50C5 sounds like fun though. (2c ... I have no sentiment for some of the old Marslands. )


----------



## filmdiary

I know this thread is as old as the hills but thought to add to it in case there's anyone like me is out there ...

I bought a 'Capri' branded amp a few years ago that had the 10PT label next to the light. I found this thread 2 weeks ago after being at home going a bit nutso like everyone else. I had not played through the amp in years because of a serious hum that showed up some time after I bought it. It sat in a corner looking sad... isolated... ... I decided after reading about isolation transformers to see if I might be able to bring it back to life. I watched uncle Doug videos for a week... looked at circuit diagrams for the 10P and 10 PT and started tracing out the Capri chassis... The Capri fwiw has 2 speakers and 2 OT's as well as a tremolo circuit. I finally figured It's the evil child of both those designs and I had a hell of a time (being a novice electrician) wrapping my head around what had happened to this thing. A pair of filter caps were hot glued into the chassis... I finally pried one loose to try to find it's value and lo and behold the pair of 40 UF 150 V filter caps on the schematic had been replaced by a couple of 100 UF 150's...

As mentioned the amp when powered had a big hum that got a lot worse when the treble pot was turned up. From what I read it was likely either a grounding problem or a bad cap. I took heed from everyone that said to be really careful with amps lacking a power transformer... short of throwing it in the garbage. Instead I ordered a N68X and followed Wild Bills advice. To keep the O.G. switch I disconnected it and now have it running between the hot from the mains to the primary of the iso tranny. I connected one leg of the secondary to each end of where the AC used to be.

I built a current limiter set-up to make sure I hadn't made some drastic error, plugged the amp into it, connected the secondaries to my multimeter, took a chop stick and threw the switch. No explosion... not nearly as much hum any more either... reading 125 Volts from the secondaries of the iso transformer... The Les Paul growls pretty fiercely though it and I have to back the treble way down or it becomes quite tinny. It took 2 weeks of learning the circuit but kind of like an acid trip after a while it began to make sense ... and now I have a nice little living room amp. Thank you to all the people who were generous enough to post videos about these dangerous beasts...

My question for this forum now is about those filter caps. I'm thinking of ordering a pair of electrolytics that Gar originally spec'd out for these amps. Can anyone tell me what effect they might have?

Thanks in advance!

John.


----------



## jb welder

See other thread here: Effect of capacitor values on a transformerless Garnet...


----------

