Amp Reverb Mod

[JMeliski]

Hello Guys,

I have taken just bout every screw out of my Hot Rod Deluxe and I am going to modify it in a few days (or try to at least!). I want to remove the reverb knob and add a 1/4 inch socket in its place. I will then hook up a cable (mono or stereo - whichever is needed) to that and another receptor at the other end. This receptor will be connected to a potentiometer on a pedal (just like a voume pedal). I have no idea what I am doing but I am going to try anyways. I have biased my own amp as well as rewired and modded my Strat. Besides the usual, be careful and don't electrocute yourself, does anyone have any advice on this for me? If anyone knows how to do this, detailed explanation would be much appreciated! Like I said, I am doing this in a few days with or without a response. I think I can figure it out but would like some help, if possible.

Thanks!

John

[Phostenix]

Are you trying to "remote" the Reverb level control with a volume pedal?

[JMeliski]

yeah...kinda. Not with a volume pedal though. I'm going to make a little "expession" pedal with a pot. Might even use the one from the amp, i'm not sure yet. and some string and a stick. Maybe a piece of wood to hold it all together. the 1/4 inch is just for convenience. I could use speaker wire but I want a more solid connection (without having to leave the pedal connected to the amp all the time, ya know? instead of twisting speaker wire together from my pedal to the amp after transport).

[Enzo]

You MUST use shielded cable for this. You will not like the results if you use speaker wire. it will be hum city.


SO on and off isn;t enough for reverb while playing?

[Robert M. Martinelli]

A better ( cleaner ? ) solution ( IMHO ) would be to use two LDRs, installing the first inside the amp and controlling it by varying its control voltage from outside the amp ( pedal ) using the second LDR for this purpose. This way the chances for the mod to introduce hum/noise would be eliminated.

JM2CW

Hope this helps

Best regards

Bob

[JMeliski]

On and off probably would be fine, assuming that I could set the level but I figure, if I'm going through the trouble to make it into a functional pedal, then why not? I will certainly look into the LDRs and b ure to use sheilded cable (I didn't think about the hum - thanks!).

[JMeliski]

So, I have completely amazed myself in my first successful attempt at modifying my amp. There is a great site called The Unofficial Fender Hot Rod site which is, unfortunately, unmaintained and that site was a huge help! Here are my results in 'field study' format in case anyone wanted to do this as well.

I will assume that anyone doing this knows what they are doing and knows that it is EXTREMELY DANGEROUS!!!! Don't go poking through your amp as you read this, rookie. After taking it all apart I decided that my first step was to remove the reverb pot so I did that with a soldering iron and a pair of pliers, meanwhile keeping my hands away from the capacitors. Then I did some more research and learned what a resistor is so I went to Radioshack and got the biggest one I could find. I tested that it worked and I was using it properly (which I could have figured due to the spark) with a multi-meter. Then, I went back to Radioshack and bought a project box for lke 2 or 4 dollars to use as a pedal. I drilled a hole in my November of 2001 Fender amp which is no longer under warranty - using a 5/8" drill in order to house a 1/4" stereo jack (my friend drilled it actually). Then I soldered 3 very thin, unshielded wires to the circuit board where the pot came from and hooked them up to the jack. I guessed that the left-most pin of the pot was the ground due to my multi-meter resistance testing (I think 20K was the setting?). Oh, I think this is important...I soldered a piece of wire from one pot on each side of the reverb spot (Presence and ?Treble?...I don't know) anyway, I think that verifies that they are grounded. Next move was to make a stereo cable which I did with an old mic cord. I used my project box from Radioshack to host the reverb knob which came directly from the amp's circuit board (recycle!), a stomp-switch and a jack. If you get this far then you know what you are doing and can set that up easily on your own and add an LED light. The knob on my pedal works and I didn't install an LED light but the switch doesn't work. I'm pretty confident that I can make one soon with an expression pedal, and on/off and an LED but I will need to do a bt more research. In essence, all I have done so far is move the reverb knob about 10 feet away from where it was. Its pretty cool tho. I definitely suggest a swinging door on the back of the amp. This would mke it easier to line up the spot for the jack before you drill but also (and I did this!) once you get the jack mounted onto the back of your amp and its all one big piece, and you put it in place only to find out you messed upon the location of the jack by about an 1/8 of an inch; you may pull the back off to set it down and forget that its hooked to your circuit board which, if you are lucky, will only tear out those 3 wires you just put in. I also fried a part of the circuit board cause I didn't have the board bolted down when I turned on the amp but I just resoldered a connection and its fine.

You will need:
Simple Electronic Knowledge
Safety Equipment
Soldering Equipment
Drill
Saw, Hinge and latch (optional)
Wire
Wire Cutters
Screwdrivers
Pliers
Stereo Cable
2 Stereo Jacks
Pedal Casing
2-4 Hours