Vintage *FAKE* Fender Amp

[vigilante397]

I have a friend in town that runs a recording studio and I brought the amp by tonight to show it off as he's a huge gear head (that's pretty much the basis of our friendship ) and he fell in love. He says it sounds a lot like he would imagine a Fender Supro would sound like if it was EL84 powered. He just played with it through a strat for a bit and loved it, but I assured him it really sings with humbuckers. So I'm letting him hold onto it for a couple days so he can try it with his Custom Shop ES-335 (trying to talk him into trading me that one ). But he's already assured me that "If you sell this thing, I will buy it."

I'm still having a musical identity crisis deciding if I'm a drummer that also plays guitar or a guitarist that also plays drums, but if I decide I'm a drummer that also plays guitar (most likely, as I'm nowhere near as comfortable on guitar; I can jump into any jam session on drums, but guitar you need to tell me the key, all the changes, and give me two weeks to practice) then I will do a recording so I can show you all how it sounds, trace the schematic for future reference, then let go of it for a profit

[mth5044]

I can see your boutique amp business coming in to fruition.

[Hatredman]

Yes, and you can even base your logo on the fake Fender onde

[vigilante397]

Yes, and you can even base your logo on the fake Fender onde

Would I get sued if I call it a "Femder"?

[Dito]

Would I get sued if I call it a "Femder"?

Ignorance is bliss. Stick with the old G.I. Joe story and tell people the original logo fell off during transport on a military helicopter.

My motto: if the real story is boring, make up a better one.

[vigilante397]

Remember that time a million years ago I said I would trace the schematic? Well I did it. While I was tracing it, however, I was checking out the EQ and it looked so close to a Baxandall that I'm pretty sure I actually just hooked it back up wrong when I re-housed it, so I fixed it to be a true Baxandall and I LOVE what it did to the tone. Actually takes dirt pedals pretty well now. And sorry if the schematic looks a little weird, I'm trying to force myself to use Altium more Oh, and I forgot to mark on there: V1 and V2 are 12AX7, V3 is an EL84.

Too small image taken from a screenshot:



And a PDF so you can actually see things https://www.dropbox.com/s/jiayumqqnjntyho/Schematic%20Prints.pdf?dl=0

As is I estimate it to be about 5W, and through a 12" speaker it sounds incredible. I'm thinking about using this to start my new boutique amp company I'll still keep this exact configuration, but I also want to try adding another EL84 in push-pull to get closer to 15W or so for a more practical gigging amp. More on that later in the summer when my life has calmed down a little more

[duck_arse]

nathan - did we ask, or did you tell us - is the "tremolo" a rate pot or a depth pot? I was going to say "yr circuit looks to be missing a pot in series w/ R24", but now I'm not going to.

[vigilante397]

nathan - did we ask, or did you tell us - is the "tremolo" a rate pot or a depth pot? I was going to say "yr circuit looks to be missing a pot in series w/ R24", but now I'm not going to.

It's a depth pot. Really good sounding tremolo BTW.

[tubelectron]

Less important question, is there anyone out there that is comfortable working tolex and/or grill cloth that could help me out if I can get this to you?

I could help you if you were located near my home... In France... 

















Let me tell you that it is not so difficult to achieve by yourself, if you are used to build, paint and etch stompboxes !

For sure, you can find many tutorials on the web to explain you how to proceed. It is somewhat similar to wallpaper putting, in a more accurate way and less surface  .

First, you need to practice a bit on dummy material in order to understand the basics : how to realize joints, seams, angles, rounded junctions, how and where to cut the tolex to obtain the right size without wasting it, etc...

A real key point is the glue. You need to choose the appropriate glue, not the all-aroung neoprene, universal or so. Without that, you job will be not be neat, nor presentable and durable, if you arrive at end...

The glue that I used on the pictured amps above is : http://www.tube-town.net/ttstore/Tolex-entoilage/Tolex/Tolex-Glue-SG5-500-ml::4756.html. It is very friendly to use, allowing you to position / reposition the Tolex for a moment when putting it.

But I am in Europe, nonetheless you can surely find the equivalent glue at MojoTone or any amp parts dealer in the USA, that by the way can sell you along some Tolex leftover sheets of different colors for practice.

A+!

[Giglawyer]

Less important question, is there anyone out there that is comfortable working tolex and/or grill cloth that could help me out if I can get this to you?

I could help you if you were located near my home... In France... 

You, sir, have MAD skills.  Wow...nice looking amps.

[vigilante397]

I could help you if you were located near my home... In France... 

One of these days I hope to get out to that part of the world, but alas it will not be any time soon Thanks for the tips though, I'll definitely look into it. Also I've seen your amps in a few different places and I'm a huge fan

[tubelectron]

Thank you Guys !

I looked again to your little "Fender Fake" amplifier, vigilante397 :

- You shouldn't encounter much issues for retolexing the cab : it is straight and square angles. One strip for the cab, one cut for the back. I think that you can even preserve the grillcloth that appears to be still in good shape : a good cleaning, maybe a bit of gentle stretching with an hair-dryer (if it's plastic-made).

- You mention that it was probably made in Japan in the 50's, if I recall well. But personally, I am akeen to think that it could possibly be European-made, and probably Italian-made, from the 60's, looking to the components inside (with the exception of the orange drops caps).

A+!

[thermionix]

+1 on using the right tolex glue.  The 3M spray adhesive stuff will NOT yield good results.  Use a dropcloth if doing indoors, and wear clothes you don't care much about, tolex glue will not wash out.  It is water-based, but not water-soluable once dry.

I use a paint roller to apply to the back of the tolex and the cabinet.  Don't get the foam type, it will dissolve.  Do get extra rollers, the one you start with will be gummed up before you're done.  Spread the glue thin but completely.  Once it turns from milky to clear, the pieces are ready to apply.  Drying time can be sped up with a heat gun or hair dryer.

I tend to stick on slightly oversized pieces, then trim with a straightedge and exacto.  Pretty quick.  If you need to pre-cut a piece, remember that the tolex will stretch some, so slightly undersize it.  Don't worry about getting glue on the outside of the tolex, it will rub right off with your thumb even after it's dry.

After a few days, I like to tack down any loose edges with super glue.  Particularly where tolex overlaps.

Practice on scrap like Bruno says.  The corners are a bit tricky to make look neat.  Once you've done it a couple times, you'll have it down.

[tubelectron]

+1 on using the right tolex glue.  The 3M spray adhesive stuff will NOT yield good results.  Use a dropcloth if doing indoors, and wear clothes you don't care much about, tolex glue will not wash out.  It is water-based, but not water-soluable once dry.

I use a paint roller to apply to the back of the tolex and the cabinet.  Don't get the foam type, it will dissolve.  Do get extra rollers, the one you start with will be gummed up before you're done.  Spread the glue thin but completely.  Once it turns from milky to clear, the pieces are ready to apply.  Drying time can be sped up with a heat gun or hair dryer.

I tend to stick on slightly oversized pieces, then trim with a straightedge and exacto.  Pretty quick.  If you need to pre-cut a piece, remember that the tolex will stretch some, so slightly undersize it.  Don't worry about getting glue on the outside of the tolex, it will rub right off with your thumb even after it's dry.

After a few days, I like to tack down any loose edges with super glue.  Particularly where tolex overlaps.

Practice on scrap like Bruno says.  The corners are a bit tricky to make look neat.  Once you've done it a couple times, you'll have it down.

Exact complementary description to what I wrote before 

Good tip, thermionix : I didn't thought of using a paint roller, solely a flat brush  ... But I will come to it for larger surfaces I think !

A+!

[vigilante397]

- You mention that it was probably made in Japan in the 50's, if I recall well. But personally, I am akeen to think that it could possibly be European-made, and probably Italian-made, from the 60's, looking to the components inside (with the exception of the orange drops caps).

A+!

I don't think it was made in the 50s anymore, but I believed it was Japanese made because all the caps (excepting orange drops of course) are Japanese and the tubes and speaker it had when I got it were Japanese made. Out of curiosity, what about the components makes you think it's Italian made?

[thermionix]

I don't think it was made in the 50s anymore, but I believed it was Japanese made because all the caps (excepting orange drops of course) are Japanese and the tubes and speaker it had when I got it were Japanese made. Out of curiosity, what about the components makes you think it's Italian made?

Those greenish caps are Mullard/Philips "mustard" caps, made in England and Europe.  Serious Mojo parts!  Old Marshall, Vox, and Traynor amps were made with them, along with some classic recording gear, and a few pedals.  Jap tubes and speaker may not be original to the amp.

Can't quite make it out in the pics, but that multi-section can cap looks like maybe a US-made Mallory.  Wouldn't be a bad idea to replace that, btw.  Decades-old electros might fly in a low-voltage pedal, but when they fail or leak current in a tube amp, they can take out power transformers.

[davent]

Hi Nathan, Are you sure about R2 being 1k? Usually see 100k/1k5 plate/cathode combo, like the first triode.

dave

[thermionix]

Hi Nathan, Are you sure about R2 being 1k? Usually see 100k/1k5 plate/cathode combo, like the first triode.

dave

You are definitely correct, you can see the two 100K plate resistors in the photos.  Also, the schematic is incomplete at the HV secondary of the PT.  Surely it's supposed to be a full-wave rectifier.

[vigilante397]

Hi Nathan, Are you sure about R2 being 1k? Usually see 100k/1k5 plate/cathode combo, like the first triode.

dave

You are definitely correct, you can see the two 100K plate resistors in the photos.  Also, the schematic is incomplete at the HV secondary of the PT.  Surely it's supposed to be a full-wave rectifier.

Good catch, it definitely is a 100k on the plate. Altium defaults every resistor to 1k until you change it and I apparently missed that one.

It seems weird, but I promise the schematic shows exactly how the power supply is. One of the HV secondaries is attached to nothing and the other is set up as a half-wave rectifier with the center tap.

I haven't tested any of the caps for leaking (mostly because it sounds really good as is), but I'll do it when I get home Sunday. I'll also double-check labels on all the caps for where they were made.

[wavley]

You'd know if the coupling caps were leaking because it sounds like a scratchy pot (Crackle Okay on an SHO).

I'd do any electrolytic caps for sure, and any coupling caps that cause a scratchy pot, otherwise I'd leave orange drops and mustards alone.  Maybe replace the ceramic discs.

I'm messing around with my Harmony 525, maybe going to use the unused half of the input 12AX7 in parallel with the input stage because I love the sound of parallel input triodes and I noticed yesterday that the schematic has .005uF input cap with what I consider to be pretty low grid to ground of 270k and you pretty much have the same thing going on.  Except you don't have any grid stoppers.  I have three channels: 47k and two 470k, thinking about switching one of the 470k's to 68k for a more normal value and just bypassing the input cap.  When I parallel the input triodes I might have to play around with that 270k to ground, we'll see.

Push-Pull requires a different output transformer right?  And your driver tube will have to be rewired as a paraphrase phase inverter if you want to be push-pull.  If your current transformer can handle it maybe you could try just a second EL84 in parallel single ended for a bit more.  Or, I build an amp recently and used the quite reasonably priced 25 watt single ended output transformer from Weber with a single KT66 (well any octal actually, but I like the 66 best)  It's huge, but I think the amp is really fantastic sounding, all the rawness of a no feedback single ended amp, but with a more open sound than the 15 watt transformer that a lot folks would use in the same situation.