EQ footswitching problem with new DC-5

[blacklight_uk]

Hi guys my new DC-5 combo arrived today and i immediately found a clean sound that i am really happy with! I haven't quite found my sound out of the dirty channel yet but i'm getting close.

I do have a problem though. It seems that even though i have set the rotary switch on the back for the EQ/Reverb to "footswitch", the footswitch only turns on the reverb. The EQ stays on all the time no matter what i do and i know this because moving the sliders i can hear it altering the tone. I really really want my EQ to be switchable but i don't know what to do.

The amp came with two footswitches that are not Mesa. One is a Carlsbro one, the other a cheap nameless one. I'm wondering if the footswitches are the problem. I had a crazy idea that i might need a footswitch with a stereo cable? But that's just a guess...

Any help would be great cos i'm stumped :?

Thanks in advance,
Josh

 

[edward]

You can check to see if the footswitch works or if the channel switching is at fault with a guitar cable. Plug any old cable into the appropriate footswitch jack. Ground play the guitar and see whether the EQ (or reveb) is on. Now take the tip of the cable that's plugged into the footswitch jack and ground it to the sleeve. That effect should now "switch" ...to off or on, whatever is opposite. Open the circuit back up and it should switch back.

I can't recall, however, if the EQ is tip-to-sleeve, or if it's ring-to-sleeve (as there are 2 different DC5s out there). This may be your issue. If it's ring-to-sleeve, then all you need a stereo cable where you ground the ring (the middle part) of the stereo plug, and that circuit switches your EQ. Simple, really, to rewire the footswitch if this is, indeed your case. Or just pick up a proper Mesa EQ/Rev switch from ebay as they are constantly popping up (assuming your amp IS working as it should, of course).

Edward

 

[Alivefor5]

You have the early version DC-5 (so do I).

Use the footswitch with one button and a standard guitar cord in the front footswitch jack for rhythm and lead channel selection.

Use the two button footswitch with a stereo shielded cable in the EQ/reverb footswitch jack in the back. Set the rotary knob for footswitch.
You're good to go for all functions.

After a while you'll probably end up like the rest us and not use the EQ/reverb footswitch. When you pull the cord out the reverb is always on so you'll probably set the rotary knob to lead so the EQ comes on in lead and the reverb will go off if you turn the knob down in the front.

Lately I've been using the EQ only on the rhythm channel for a stunningly full sound. Then switching to lead without EQ and reverb knob off and getting the singing snarl I want with just the channel knobs.

Lots of versatility there, I'm sure you'll find lots you like.

 

[Monsta-Tone]

It is fairly easy, if you have worked on amps before, to mod the amp so that the front footswitch is able to turn the EQ on & off, and switch channels.


Here is what I do to all of my Version A DC amps:
Unplug the amp

Discharge caps by turning the Power switch off and then taking the Standby switch off of Standby (put it in the position that it would be in to play the amp)

Open the chassis up

Take a digital picture of the input and footswitch jack, making sure that you get all wire connections in the picture

Unscrew the nut on the Input jack and move it out of the way

Unsolder the wires (maybe take another picture of the jack before doing this) to the Footswitch jack

Remove the footswitch jack

Replace the jack with a Stereo jack, I usually use a plastic one so that it is isolated from the chassis
I use Part # S-H601B from Antique Electronic Supply, www.tubesandmore.com
It only comes with 1 ferrule (plastic washer) and you need 2 for it to fit snugly in the chassis

You will most likely have to drill the hole for the jack out 1 size bigger before putting the new jack in. I tried to use a Switchcraft Stereo jack and there was an issue with the grounding on the Footswitch circuit that caused it to not work right.

Re-solder the channel switching wires to the new jack, using the TIP for channel switching

Get a long piece of SHIELDED WIRE and solder one end of it to the solder lug for the EQ that is on the original jack at the back of the amp

Also, solder the shield for the wire to the ground on the existing jack

Solder the other end to the MIDDLE solder tab on the new footswitch jack

Do not ground both ends of the shield on the wire. Simply cut the shield off on the end that goes to the front of the amp. I usually use a bit of heat shrink to cover the shield so that it won't short out anywhere.

Make sure that the new wire is not touching any of the tubes, it will melt and smell horrible


You should now be able to use a 2 button footswitch in the front of the amp.

Look around to make sure everything is done in the amp

Install the Input jack, close the amp up and try it out



A couple of notes:
Make sure you use shielded wire, otherwise, the amp will hum like crazy
Make sure that you measure the voltage on the filter caps in the power supply before reaching into the amp to insure that the caps are not holding a charge
Make sure that you tie-wrap the new wire so that it will not vibrate or touch any of the tubes

Make absolutely sure that you are comfortable with working on amps before trying to do so, otherwise take it to a good tech.

 

[Monsta-Tone]

I forgot to mention that you must make sure to solder the wires to the side of the jack that will make contact with the footswitch jack. Otherwise, neither button will work.



Also, there are a few versions of the footswitch for a DC. The extremely early ones used a strange circuit inside the footswitch.



P-H471 also from Antique Electronic Supply should work.

I am sure that there are several places in the UK that you can get these items also.

Cliff's jacks also work very well for the new footswitch jack
Part # S-H505
Same part that is used on the backs of most Mesas, most Marshall jacks and countless others.


Hope this helps.