mesa midi quad/formula footswitch ?

[psihiatros]

Hi.
I have a midi equipted Quad preamp and i have the footswitch of the Formula pre which is kind of a midi footswitch i think ?
Can i connect them,in order to change channels (lead1/lead2) on the quad with the formula footswitch?
thanx,
Chris.

 

[RectoStudioGuy]

Not too many of those midi Quads around. Are both footswitch and Quad 5 pin? if so, try it. Unlikely that you'd cause harm by connecting to the switch port.

 

[Tripoutski]

The Formula foot switch is not a MIDI switch, although the jack does resemble it. There is no MIDI in the Formula Pre at all.

 

[psihiatros]

The Formula foot switch is not a MIDI switch, although the jack does resemble it. There is no MIDI in the Formula Pre at all.

oh..
So, if it's not midi then i shouldn't do it, should I?
I don't want to do anything stupid and cost a damage, nor to the quad neither to the formula footswitch,right?

 

[RectoStudioGuy]

It will not hurt it but will not do anything if it is not midi.

 

[psihiatros]

Allrighty then.
Thanx RectoStudioGuy :wink:

 

[Tripoutski]

It will not hurt it but will not do anything if it is not midi.

WAIT! That is not exactly true. For example; the center pin on the Formula Pre powers the footswitch and sends out 5 volts DC, which is pin 2 of the MIDI standard and is the ground. MIDI pin 4 is -5 volts @ 220 ohms in the MIDI standard and is wired for the EQ switch. This would put out about 10 mA. If the voltage is higher (and it does vary with some manufacturers because MIDI is not voltage concentric) the mA's can get 2-3 times that.

All of the contacts in the Pre's footswitch jack go through a LM3914 semiconducter before going to the relays, so this little semiconducter (designed for controlling LEDs) is the first thing that will see anything odd being plugged in.

In a nutshell, the Pre's semiconducter may not like what it is getting at all (although you may not see or hear any ill-effects) and I am sure that whatever MIDI device that is plugged into it would not appreciate the 5 volts coming down the ground wire.

I am just sayin'! :wink:

For what it is worth, I have a G-Major which does switch the Pre via MIDI. I am one of the few Formula Pre lovers around and the G-Major MIDI relays make it very usable.