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Guitar amp conversion ?

turbo_wagon

turbo_wagon

Member
I see that people like to convert Hi-Fi amps and consoles for Gutar amplification. What is usually involved in this for say, an integrated console with phono, tape and tuner inputs. I imagine that one of the tuner or tape inputs would be suitable a guitar.

I have this nifty looking little Philco console record player with a preamp that has mono-phono, stereo-phono, stereo tape and stereo tuner settings. I was thinking that it would be cool to use as an amp for an acoustic guitar.
 
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conversion

I converted an Eico HF-12 for guitar use. It likewise had a 4 channel switch, which I bypassed completely by running the input jack hot line into the first tube's triode via a resistor. I can't say that I've been happy with the sound yet. I'm still experimenting with caps and resistors. I think, though, that the PI is not right for electric guitar. It might be good for acoustic, though, since it gives tons of headroom, clarity and boom.

Be warned, though, many members take offense to this profane of the sacred.
 
Some consider the best tube units for guitar conversions are.....organ amps and PA amps.
Many a Leslie and Hammond organ amp has found a "second life", as a guitar amp.
PA amps are also very desirable for guitar amp conversion.
PA amps were build to be VERY rugged, have multiple gain stages......and have mutable front panel controls.....which can be replaced with one or two 1/4" jacks, volume & tone controls. an ON-OFF switch, a stand-by switch, and a jeweled light.
My 12 watt, 6V6 PP, 60's Webster PA amp sounds awesome when played into an open-backed 1 x 12 speaker cabinet (re-coned 1960 Jensen P12R speaker).

Steve
 
The speaker plays an enormous role in shaping the sound of a guitar amp. Electric guitars don't sound good through hi-fi speakers. An acoustic guitar might sound good through hi-fi speakers, but a lot probably depends on how the pickup is voiced. There are special combo amps designed for amplified acoustic guitars, I imagine they have wider frequency response speakers than regular guitar amps, but I don't know if they are approaching hi-fi linearity. Try it and see. I think you'd be best off using the tuner input or the tape input (if it is for a tape amp and not a tape head). The phono inputs will have some kind of equalization and may have too much gain it they are for low-level magnetic cartridges.
 
interested thread..im using to new all valve guitar amps for my hi fi sytem along with the guitar speakers to match sorta..good thing my guitar amps have a clean channel and a dirty one with the distortion and so forth.i would probably agree with the comment about the speakers..i used to have a quitar years ago i played through a pioneer amp into some jbl speakers you just got
a basically loud sounding quitar without alot of change
 
What I'm thinking is that I'd use it as a sort of practice amp with an acoustic guitar with one of those clip-in pickups. I'm not going to do any serious modifications other than maybe a plug socket and I'm not going to be travelling with it either.
 
Personally I find using Hi-Fi for guitar a waste, not a profanity. Don't really need Hi-Fi frequency response for guitar use. I would tend to agree with the organ and PA point of view. They are cheaper and readily available.
 
turbo_wagon said:
What I'm thinking is that I'd use it as a sort of practice amp with an acoustic guitar with one of those clip-in pickups. I'm not going to do any serious modifications other than maybe a plug socket and I'm not going to be travelling with it either.
Click to expand...

For acoustic pickups better amps are a real factor. My Ovation is light years different thru audio gear compared to the guitar gear and the Martins even more so. Not that big a diffence for the Les Paul or the Strat.
 
I like paraphase splitters best for guitar in PP amps, as they have a nice harmonic texture when overdriven. These are usually found in lower end amps, not really hi-fi amps.

No hi-fi amp is going to sound very great, sometimes will sound horrid even, without modification for guitar. Tube Guitar amps are MADE to have harmonic distortion, hifi amps are made to NOT have distortion.

I don't believe it is profane to do a conversion on a lost or junk amp, but on a rare, expensive, or otherwise excellent sounding hi-fi amp, then yeah. Its sort of like the difference between cutting up a deusenberg or a rusted out VW to make a rat rod.
 
-- how can I convert a Leslie 147 organ amplifier to a guitar amplifier?
-- do I need a pre-amplifier to do this?
 
Thanks everyone for your responses

thank you for all your information.
So if I'm going to use the Leslie 147 amplifier, do I need to use a pre-amp with volume, treble and bass control? I tried hooking a microphone up to the input and could only get very very low volume.
 
I'd offer my help, but I do not know anything about the amp in question. PA amps work because (partially) they have at least a volume control and preamp. The Leslie amp must have had some form of preamp ahead of it. Can you obtain it? It may have been in the organ.
 
leslie amp 2 6550 output tubes 1 12au7a and rec.tube oc3 and a d1 d2 d3 d4 rec

JonL said:
I'd offer my help, but I do not know anything about the amp in question. PA amps work because (partially) they have at least a volume control and preamp. The Leslie amp must have had some form of preamp ahead of it. Can you obtain it? It may have been in the organ.
Click to expand...

tubes 2 6550 1 12au7a 1 rec oc3 bridge rec.
 
Sounds like it will need a lot of rework to make it guitar amp, but still may be worthwhile. The 6550s are good for lots of clean power. Most guitar amps would use a 12AT7 or 12AX7 as the driver stage in place of the 12AU7 to get more gain. That part is easy. The OC3 is a voltage regulator, I'm not expert enough to know how/why they are applied in an amp like this (although I'm recapping an Epiphone that has an OC3 also). I think that you will need to add another gain stage. It could be a 12AX7 or an octal preamp tube (6SN7, I think). You'll need to add at least a volume control and probably a "tone" control if not a complete tone stack with treble, bass, and mid (if desired). This is all doable, but much more complicated than simply sticking a jack in the thing and wiring it up to a speaker cabinet.

Disclaimer: I'm really not expert enough to give you much advice, but no one else is jumping in here. I think what I've told you is accurate, and it is about as much as I could tell you.
 
It would work fine clean if you ran something like a Tech 21 Sansamp or one of their character series pedals into it. These are made for direct recording and give a line level signal out to a PA. All the sound modifications come from the box, all that's needed is a good clean amp and speakers. Running into a tube amp should add some warmth to the sound, which is already great coming out of the Tech 21's.
 
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