DC5a Foot Switch and the GEQ Selector

[lockbody]

My DC5a has this little problem where if you don't plug a FS into the front and you set the GEQ switch on the back for "Lead" it works as you expect - no GEQ on the rhythm channel, and GEQ on the Lead, but plug in one of the two foot switches I have, either a one button Rectifier, or two button DC(b) FS, and the GEQ is turned on for both channels. You can also set the selector for "Rhythm", and the same thing happens - GEQ on both channels.

Weird huh?

Well, looking at the schematic for the DC5a, it shows a 3300ohm resistor inline with the + inside the FS itself. Something the Rectifier and the DC(b) footswitches don't have. The DC-5b schematic doesn't show it either, only the 5a.

Is this my problem? I was just using the search function a little while ago searching for "LDRs" and came upon one post regarding switching problems in a 50 Caliber, and one person mentioned "And I bet you're just using any ol' foot switch without a resistor in it.".

Was there any reason for Mesa to do this other than the obvious one of forcing people to buy their proprietary foot switch? I do know I'm going to be making a trip to Radio Shack tomorrow to see if adding the resistor fixes my problem.

 

[Monsta-Tone]

It's a current limitting resistor, and yes, you need it.
Years ago, before Mesa had the DC drawings available on their tech site, I had the same problem. George Mueller actually started ranting and raving because he couldn't find his drawings. Poor guy, he has a dumb *** on the phone asking stupid questions about his amp and someone stole his drawings. :lol:

I never looked inside my 5b (spare that I bought off of ebay), or my 10's footswitch, but I'm pretty sure they are there. I just might have to pop it open and see!


It has nothing do do with propriety, believe it or not. It is simply that the switching circuit is fairly complex and I think that they basically ran into the proverbial wall and needed to start shipping them out.

 

[lockbody]

I never looked inside my 5b (spare that I bought off of ebay), or my 10's footswitch, but I'm pretty sure they are there. I just might have to pop it open and see!

Nope, it's not. I've got a "b" foot switch and it's not in there. Not on the "b" schematic either.

 

[Monsta-Tone]

Hmmm!

I have one with and one without?!?!?! The one with the resistors must be a very early 2 button model. Or, maybe it came that way because I got it on ebay? :lol:

 

[eschoendorff]

It's a current limitting resistor, and yes, you need it.
Years ago, before Mesa had the DC drawings available on their tech site, I had the same problem. George Mueller actually started ranting and raving because he couldn't find his drawings. Poor guy, he has a dumb *** on the phone asking stupid questions about his amp and someone stole his drawings. :lol:

I never looked inside my 5b (spare that I bought off of ebay), or my 10's footswitch, but I'm pretty sure they are there. I just might have to pop it open and see!


It has nothing do do with propriety, believe it or not. It is simply that the switching circuit is fairly complex and I think that they basically ran into the proverbial wall and needed to start shipping them out.

I hat eto hijack a thread here, but who is George Mueller?

 

[lockbody]

I hate to hijack a thread here, but who is George Mueller?

He's a Mesa tech, and apparently the only one who care one wit about the DC's.

 

[lockbody]

It's a current limitting resistor, and yes, you need it.
...
It has nothing do do with propriety, believe it or not. It is simply that the switching circuit is fairly complex and I think that they basically ran into the proverbial wall and needed to start shipping them out.

So do you need the resistor for the rear Rev/EQ footswitch, too?

 

[Monsta-Tone]

I hate to hijack a thread here, but who is George Mueller?

He's a Mesa tech, and apparently the only one who care one wit about the DC's.

I'm not sure exactly how much of the design he did, but I know he did some of it. He did sound very fond of them when I talked to him.



I don't know about the EQ/REV footswitch, but I would think so. I have modified several of the "A" versions to have the Channel/EQ footswitch jack up front and they have all needed it. Basically, I leave the jack in the back intact and run a shielded wire to a new jack in the front. So, the circuitry is the same as it was before the mod.

 

[lockbody]

Where does the resistor go? I tried it with my Rectifier FS between the tip and switch, and it wouldn't even switch channels at all.

Got a pic of that B with the resistors?

 

[lockbody]

Does anybody have a pic of the inside of their "A" footswitch, or can make a quick drawing? Thanks.

 

[Kage]

I would love to see this too. I have a 2-button footswitch for the B version (came with my A version amp) and it would be nice to turn it into the A version. It'll change the channel in the front jack but won't do squat in the back.

 

[igfraso]

Kage:
would you like to sell your B version 2-button footswitch?
If yes, please send me a PM.
Thank you

 

[lockbody]

Kage:
would you like to sell your B version 2-button footswitch?
If yes, please send me a PM.
Thank you

PM sent

 

[Kage]

Kage:
would you like to sell your B version 2-button footswitch?
If yes, please send me a PM.
Thank you

Sorry, I just saw this, I actually traded the amp with the footswitch for an F-100.

 

[igfraso]

Thank you anyway, Kage.
Enjoy your F-100.
Daniel

 

[thurston]

Bump...Does anyone have a picture or schematic for the DC-5a foot-switch(es)?

 

[lockbody]

Bump...Does anyone have a picture or schematic for the DC-5a foot-switch(es)?

http://www.forum.grailtone.com/viewtopic.php?f=28&t=38292

See my post at the bottom. You want your foot switch to look like the one on the right. Schematicheaven.com has DC-5a schematics.

 

[Dondante]

I have a generic dual switch made by Live Wire Solutions that I use on a DC-5. Can I add LED to it? Will the lead from amp to footswitch power the LED? Thanks