Hi there,
I am new to this forum, but I have to say I am glad to find an SS forum, so I don't have to worry about narrowminded people, that keep telling you how stupid you are for playing a SS- Amp..You NEED TUBES!!! Enough wining for now..
I just bought a superb looking and sounding Trace Elliot Supertramp. Built approx. 1995, 80 watts, 2 channels, 2 drive modes, boost, presence, mastervolume, spring reverb, Celestion G12T-60..
(http://www.mijnalbum.nl/Foto-LMOFASM8.jpg)
My question..would it be possible to make the drive mode footswitchable? Now there is just a tiny switch and I would like to have the option to switch it by foot..Does anyone here tried something similar like this? Something I need to consider?
Cheers,
Dutch
Quite a lot is possible but I have a feeling that a modification like that would be quite difficult to implement and therefore it's maybe not worth it. If you take a look at the schematic (see my recent post at the "schematics" section if you don't have one yet), you see that the "mode" switch SW1 is a SPDT switch that selects between two signal sources, one of them passing through few more gain stages. Since the switch seems to be at a high gain signal path you likely can't just take it to a remote location (e.g. foot pedal) without introducing noises, oscillation or some kind of misbehaviour. However, you could replace that switch by a relay, JFET, LDR - or any suitable switching element - and then build a switching logic circuit that is controlled by a separate footswitch. (Sort of like what they did with the other switches.) Naturally you would have to design this circuit, likely build a circuit board for it, figure out the way to mount it, drill a hole for a footswitch jack etc. Technically – and in theory, the modification, by itself, is quite simple if you know what to do but it will require quite a lot of work. In practice there also may be many reasons that make implementing the mod extremely difficult. For example, there is a very good chance that the switch is mounted to a PC board with a very small clearance to chassis and you will not really have room to install the mod – at least not neatly. But yes: circuit wise it certainly can be done.
Dear Teemuk,
Thanks a lot for all this information. I thought this mod would be relativley easy...Good thing to check this forum first, because I tend to think I have some knowledge on electronics, but there is really still a lot to learn..Thanks, I will think this over and open the Supertramp up, and check what's inside..
Keep up the good work here..
Cheers,
Dutch
It looks fairly simple to me from the scematic I have , I don't see a SPDT on my diagram it shows a SPST, looks real simple take out the switch run some sheilded cable to a footswitch, looks simple to me. Which diagram are you going by Teemuk I'm looking at the Supertramp& Twin Tramp diagram ?
I use the same diagram and I see a SPDT switch. What comes to shielded wire run ...well, it could work - and if it does, good – but I have my doubts: With all the high gain and the high load impedances involved I think a few meter wire run to a foot pedal is not such a good idea - even if shielded, which would be mandatory anyway. As I mentioned, that configuration could easily add more unwanted noises - or at worst burst into oscillation. If I would try to implement something like that I would at least buffer that wire run.
Quote from: teemuk on July 03, 2008, 03:07:25 PM
I use the same diagram and I see a SPDT switch. What comes to shielded wire run
well, it could work - and if it does, good but I have my doubts: With all the high gain and the high load impedances involved I think a few meter wire run to a foot pedal is not such a good idea - even if shielded, which would be mandatory anyway. As I mentioned, that configuration could easily add more unwanted noises - or at worst burst into oscillation. If I would try to implement something like that I would at least buffer that wire run.
I yes I see the what your saying , loads of gain, after looking at it further, I don't know , it is possible , you would have to build a buffered relayu circuit ( to prevent RF oscillation and pop when switching) as Teemuk stated, hoever all this can be done by the a DIY'er if the person really wanted to, myself I would just plug my TS9DX in more than enough gain from it or most any good OD or Distortion pedal. With the same footprint(stuff on the floor).
Rock On