tube amp mods.

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MatchBookNotes

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Hey, what kind of mods can you get done to old point to point circuitry tube amps?
 
Tube amp mods

this question is a bit like asking how long is a piece of string.
Any particular amp you have in mind?
what sort of mod do you envisage?
I`ve built clones of old PtP amps and been very happy with the results, but most of mine are in the Fender vein and not designed to do mental distortion, etc.
Give us a bit more info.
 
I'm starting to ask that same question, too, ever since I learned how to drain filter capacitors (which gets me past that ever present "you may die" disclaimer). There are some bbs's devoted to the topic -- sewatt.com for single ended (single power tube) amps and ppwatt.com for pushpull (two or more power tubes? probably more to it than that) ones - although they appear to be closely affiliated (along with several others) you have to sign up on each one, which is strange. You can find stuff on this board too, no doubt. So far, it seems to me that you first need to fully understand the circuit of the amp, which shouldn't be that hard for most of them, and then you can apply standard principles to decide what to do. I'm not there yet :)

I'm kind of considering taking or auditing a basic electronics class somewhere.
 
cool on the remake. I have an old guitar mate 2. it has 2 el84 or 34(they're thin and long and i know there's a difference, i wont' be doing the modding myself for a long time) and 2 12ax7a and one 12ax7u. I don't really like the tremolo that's on it, maybe add a reverb or what is there? I don't want to complicate the circuit too much but the boost/trebble switch seems pretty useless in my opinion too. the boost just makes it really muddy not really a boost of anything.
 
MatchBookNotes said:
cool on the remake. I have an old guitar mate 2. it has 2 el84 or 34(they're thin and long and i know there's a difference, i wont' be doing the modding myself for a long time) and 2 12ax7a and one 12ax7u. I don't really like the tremolo that's on it, maybe add a reverb or what is there? I don't want to complicate the circuit too much but the boost/trebble switch seems pretty useless in my opinion too. the boost just makes it really muddy not really a boost of anything.
Click to expand...



Long and thin would be EL84s.


As to what can be done, just about anything. As to what YOU can do, it depends on how much time you want to spend learning about this stuff. It all depends on what you are after - you'll have to describe what you want a bit better. I've not been that happy with my amp's tremolo recently, so I've been working on redesigning it with a solid state oscillator (which should improve it quite a bit). Adding a reverb is more problematic. The tremolo probably only uses one half of a 12AX7, and a reverb needs two halves IF you want to keep a 100% tube audio path. You could do it by using solid state for either the driver or the make-up stage, but then you need to put in some other power supply for the transistors.

To a large degree, once you understand the basic topology you can look at other schematics and take the sections you want for your amp. It's less than ideal to be adding tubes, but most other things can be accomplished if you think hard enough.

As a first step, you might try recapping the amp. If it hasn't been used a lot, the electrolytic caps are likely to be dried out and in need of replacement.


Light

"Cowards can never be moral."
M.K. Gandhi
 
  1. The Guitar Mate should have Reverb.
  2. After that.........

    th_can_o_worms.jpg

If the amplifier is not what you want, I am sure someone will take it off of your hands, and you can buy something more to your liking ;).
 
Light said:
Long and thin would be EL84s.


As to what can be done, just about anything. As to what YOU can do, it depends on how much time you want to spend learning about this stuff. It all depends on what you are after - you'll have to describe what you want a bit better. I've not been that happy with my amp's tremolo recently, so I've been working on redesigning it with a solid state oscillator (which should improve it quite a bit). Adding a reverb is more problematic. The tremolo probably only uses one half of a 12AX7, and a reverb needs two halves IF you want to keep a 100% tube audio path. You could do it by using solid state for either the driver or the make-up stage, but then you need to put in some other power supply for the transistors.

To a large degree, once you understand the basic topology you can look at other schematics and take the sections you want for your amp. It's less than ideal to be adding tubes, but most other things can be accomplished if you think hard enough.

As a first step, you might try recapping the amp. If it hasn't been used a lot, the electrolytic caps are likely to be dried out and in need of replacement.


Light

"Cowards can never be moral."
M.K. Gandhi
Click to expand...


How much would the solid state parts cost? There's a good tech whom my amp is currently in the possession of replacing something that wore out in it because the tubes still worked it just made a loud monotonous buzzing sound. would that be the caps? as it was sitting in a closet for a number of years. uh yeah, labours not that exspensive so what do parts cost?
 
MatchBookNotes said:
Hey, what kind of mods can you get done to old point to point circuitry tube amps?
Click to expand...
By the time you get thru paying for mods you could just buy an amp that does what you want already.Why pay $600.00 to $800.00 to have Bray mod
a JCM800 when you can buy a Splawn Quickrod for less than you paid for the amp and mod?
 
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