Stage Center Reverb

[thom]

Hi,

My name is Thomas, first-time poster, long-time lurker.

Looking at and getting inpiration from the great projects on the forum, I've built the Stage Center Reverb (with charge pump wiring) from the GGG website.
It works great, and I'm now thinking about a stand-alone enclosure.
I'm using a 3PDT handswitch (instead of footswitch), and was wondering if it would be possible to add a 1/4 jack socket to the enclosure to occasionally plug in an external (stand-alone) footswitch.

I'm pretty novice when it comes to electronics, so you've been warned !

Thanks in advance.

Thomas

[psychedelicfish]

Is it true bypass? If it were electrically switched, as described here, it would be fairly simple using a switched jack to disconnect your hand switch when the footswitch is connected. However, it is not so easy with true bypass, because you have multiple poles, so you would need many signals leaving the box, and shielding, as your signal would be leaving the enclosure. So, in short, unless it has electrical switching (which I doubt, because you're using a 3PDT switch), it's not really plausible.

[thom]

Yes, it is true bypass AFAIK (http://www.generalguitargadgets.com/pdf/ggg_sc_reverb_lo3.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a).

Oh well, it did sound a bit of a long shot anyway. Thanks for trying to help, though.

[mth5044]

Anything is possible! Check out the fender schematics and how they would do the bypass of the reverb. If you are really into it, check out the remote switching in GEOFEX, relay switching or the Tone Gods wicked switches. I'd imagine if you got a stage center reverb up and working, you should be able to get a hang of these switching ideas without a problem.

[Mark Hammer]

Believe it or not, MANY great classic guitar amps that include reverb "bypass" the reverb with the remote SPST footswitch, simply by grounding out the reverb pan output.  That's it.  Nothing more complicated, except that the cable going to the remote footswitch should be shielded to prevent it acting like an antenna and combining AM radio reception with reverb signal.

In the case of the SCR, that would involve taking point E in the schematc, and connecting it to ground.

Pretty simple, huh? 

[thom]

Anything is possible! Check out the fender schematics and how they would do the bypass of the reverb. If you are really into it, check out the remote switching in GEOFEX, relay switching or the Tone Gods wicked switches. I'd imagine if you got a stage center reverb up and working, you should be able to get a hang of these switching ideas without a problem.

Thanks for the heads up, but although I'm ok at following instructions, I'm not so good at working them out !
I'm still at a crawling stage when it comes to reading a schematic, so I'm a bit lost without a layout.

[thom]

Believe it or not, MANY great classic guitar amps that include reverb "bypass" the reverb with the remote SPST footswitch, simply by grounding out the reverb pan output.  That's it.  Nothing more complicated, except that the cable going to the remote footswitch should be shielded to prevent it acting like an antenna and combining AM radio reception with reverb signal.

In the case of the SCR, that would involve taking point E in the schematc, and connecting it to ground.

Pretty simple, huh? 

Thanks for your answer, I'm sure it really is simple, but I'm a bit out of my depth here.
So, shouldn't the stereo jack socket be connected to the SCR's 3PDT switch at all?

Point E in the schematic: should it be wired to the PCB's ground ot the jack's ground?

Sorry for all the questions, but I usually do get it in the end 

[mth5044]

Consider the 3PDT toggle you have on the unit itself to be the overall on/off switch and the remote switch to be the new bypass when it's plugged in. They will act somewhat independently, although the remote bypass will only turn the reverb on and off if the toggle switch is on. If the toggle is off, the remote bypass switch won't do anything.

As far as hooking it up, I've drawn up a little diagram for you based off of what Mark was talking about and how Fender, etc, does it with the reverb and vibrato switches.



The output of the reverb is happily going to point E until you throw the switch, connecting it to ground. The output of the reverb pan will be muted by your signal will still make it through to the other side. I believe that's the way to do it, someone may correct me if it's wrong!

[Mark Hammer]

I can't see your drawing, but if your description accurately depicts the drawing, yes that is exactly how its done.  Since the SCR includes a splitter and mixer, there is no need to bypass the entire circuit, unless you don't like something the splitter/mixer do to your tone.

Incidentally, if one has concerns about what the use of a long shielded cable for the footswitch might do to tone, I suppose it is always possible to ground out the reverb return signal with a FET, Boss-style, and simply actuate the FET remotely with the footswitch.  That way the footswitch cable would not carry audio.

[thom]

Thanks Matthew, that's clearly explained and makes total sense. That's exactly what I was hoping for.

Just to make I sure I understand everything:

1. I wire point E of PCB to positive of RCA output of reverb tank

2. I then wire RCA output to the tip of 1/4 jack socket

3. Then sleeve of jack socket to ground of PCB

4. I assume "remote footswitch" in your diagram is the 1/4 jack plug?

Sorry for banging on about a 1/4 jack, but it would be great to be able plug the footswitch in and out.

Thanks again.

[mth5044]

Yep, point E should connect to both the RCA that connects the output of the reverb pan to the PCB as well as the tip of the 'remote footswitch' jack. When there is nothing in that jack, it will operate normally, the signal will act (basically) like the wire from the RCA to the remote footswitch jack isn't even there.

The remote footswitch jack and switch at the bottom of my diagram are external to the enclosure that you have your reverb in, probably on the ground or wherever you like to step on things. You would connect the remote footswitch jack (on the remote footswitch!) to the 'to footswitch' jack on the main enclosure with a normal TS cable/guitar cable. All of the sleeves of the jacks are connected to ground - the two in the main enclosure with the pan via PCB or wherever you have a ground point, and the sleeve of the remote footswitch via the cable. The switch, when activated, takes the output of the reverb tank to ground. Easy peasy!

[thom]

Yep, point E should connect to both the RCA that connects the output of the reverb pan to the PCB as well as the tip of the 'remote footswitch' jack. When there is nothing in that jack, it will operate normally, the signal will act (basically) like the wire from the RCA to the remote footswitch jack isn't even there.

The remote footswitch jack and switch at the bottom of my diagram are external to the enclosure that you have your reverb in, probably on the ground or wherever you like to step on things. You would connect the remote footswitch jack (on the remote footswitch!) to the 'to footswitch' jack on the main enclosure with a normal TS cable/guitar cable. All of the sleeves of the jacks are connected to ground - the two in the main enclosure with the pan via PCB or wherever you have a ground point, and the sleeve of the remote footswitch via the cable. The switch, when activated, takes the output of the reverb tank to ground. Easy peasy!

Thanks a lot, that was very helpful.
I'm really looking forward to putting that into practice (sounds quite easy after putting together the SCR from a development board!)

[thom]

Hi all,

Thanks again for your help and clear explanations.

I've finally got round to finishing the reverb, here are some pictures.

It's only my first project but I think I've been bitten by the bug.
Expect more questions in the future

[bluebunny]

I've finally got round to finishing the reverb, here are some pictures.

Very nice.  Clever name.  The wooden footswitch is the cutest thing ever. 

It's only my first project but I think I've been bitten by the bug.
Expect more questions in the future

What, like "how do I stop"?  Not a chance...   

[ch1naski]

Welcome, thom.

That wooden remote switch box is a beauty. All of the project is. Great work.

[Kipper4]

Welcome, thom.

That wooden remote switch box is a beauty. All of the project is. Great work.

True this
Welcome

[thom]

Thanks guys!

I'm going to start work on a big muff ram's head next, and I might even have a go at etching if I can dig up a laser printer from somewhere 

[mth5044]

Awesome! Nice wooden box. I never found an enclosure for the pan so mine never got boxed up.