So a resumè:

Yes you can convert a HIFI amp to a guitar amp.

- My idea is to build a separate preamp with everything inside to:
- Increase the input sensitivity if necessary. Give the guitar input a high impedance.
(Take measures against RF disturbance. This is an issue with sensitive, high impedant inputs.)
- Make the output of the preamp deliver a signal that is suitable to drive the AUX, CD, Radio or whatever input of the HIFI amp you wish.
- If you want to overdrive the amp, do it in the preamp and not in the HIFI amp. This way the HIFI amp will live longer and you can manipulate the character of the overdrive to sound the way you want. Also you can use the overdriven signal at lower volume levels.
- Build the finished preamp and the entire HIFI amp in one cabinet for easy connection, transport and for protection against the rough life on stage. Realise that HIFI amps are mechanically not designed to be dragged about. It also makes it easier to swap the HIFI amp if you decide to use another one.
GG

Hi folks,

Even worse, I need two pair of glasses for this kind of work. My colleague nicknamed me "Mister Six-Eyes".

A long time ago I took the trouble to design and make PCB's. I quit that because all my designs are one-off product. Breadboards are ideal for this purpose. Reliable, rugged and easy to modify. As said I use the thing as a kind of testbed for my designs. In this case changing a component mostly means changing a module. The cabinet by the way was made of an old cassette-deck I had lying around.

But to come back to the root of this topic: I am sort of kidnapping it. The idea was to give Vitrolin an idea how to solve the issue of converting a HI FI amp to a guitar amplifier.

GG

And the picture........

Hi guys

Phil, you're speaking right from my heart. When I was younger I spent a lot of effort to make things look good. I quit with that nonsens.

Here is another picture of the interior of my preamp. I built a modular system to be able to use it as a kind of testbed.
From left to right you see the high impedance input amp, the second stage with gain control, a 5 band equalizer, the (optical) compressor and the last amplifier stage with soft clipping.
The DIN plugs are used for interconnection of the stages and power supply connections. This way I can easily replace one of the stages by something else. Apart from the equalizer I developed each stage myself.

UsuallyI use the amp with two of these cabinets.

Friendly greetings from the Netherlands
Geurt

Hi
The idea I meant was not using a PA amp but to build a separate preamp in such a way that it can be combined easily with A power amp to make a nice matched couple. I will attach pictures of my amp to show what I mean.
GG

Hi

May be a useful tip. I did it this way for my bass guitar amp.
I took a stereo PA amp, which you might consider a 'HIFI' amp. I built a preamplifier with the same width as the PA amp. I built both components in a wooden housing the same way as in a 19" flight case. The box forms a very good protection an can be made as nice as you wish. All cabling between the Pre- and Poweramp can be hidden in the back of the cabinet. It also makes it possible to experiment with different preamps, install effects and so on.
I am very content about this solution.
GG

Well I did repair the pots. :tu: They were broken due to stupid :duh manufacturing. Plastic parts inside broke. I glued them together with rapid glue <3). It works excellent again.

Bassbuddy

Hi
For a friend I have to repair a Squier SQ15 guitar amp. Three of the pots are broken. One is linear, one is logarithmic and the third is anti-log. I would like to see the schematic to see how I can repair it if I can't get hold of the original parts, (especially the anti-log pot). I even considered to repair the pots to keep it as original as possible.

Bassbuddy