Please help me understand this schematic (Marshall 9001 footswitch)

[bensoniski]

Ok...in the top left is the bit for the footswitch. Pin 6 is 15V, Pin 5 is ground. According to the schematic, the LED will always be on, right? But that can't be right!

Could anyone help me with the wiring for this, please?

I have this suggestion: am I right?


Any help appreciated! Thanks!

[frankclarke]

No, not if it is short-circuited by the switch.

[bensoniski]

Aha...I think I get it now.

So I want to wire it like this?

[CGDARK]

No, it should be like this:



CG

[bensoniski]

Many thanks, frankclarke and CG.

CG, I bow to your superior drawing skills! 

As the current takes the path of least resistance and skips the LED to go through the switch, I assume that I would not be able to have a red/green LED, using red for on and green for off?

(Final question on this, I promise!!) 

[CGDARK]

Many thanks, frankclarke and CG.

CG, I bow to your superior drawing skills! 

As the current takes the path of least resistance and skips the LED to go through the switch, I assume that I would not be able to have a red/green LED, using red for on and green for off?

(Final question on this, I promise!!) 

Well, thanks for the compliment.

About your question, with this configuration you can't, but if you use a DPDT switch as in my schematic you can use the second pole to whatever leds you want without interfering with the amp switching. I can help you with that, if you want.

CG

[bensoniski]

Thanks, CG. I think I have it.

Another lead from Pin 6 to the DPDT, using the other set of poles, so that the LED switches on when the other one is off. I don't know why I didn't think of that before!

Thanks again for the help. I'll probably make it this weekend of next week some time. I'll try and post pics and, should there be any problems, come back and ask questions!

[bensoniski]

Well...

Thanks for the help. The pedal works, or so it seems. When I apply a bit of current to pin 6 and the ground to pin 5, I can turn the LEDs on and off with the switches.

But now it seems that the preamp needs a bit of work. There is no current coming from pin 6 on the preamp. An old cable which I had used before no longer works, which really makes me think something has come loose inside. I'll crack it open over the weekend (if I find time) and have a look. Something tells me that it will be spending some time with a tech, though...

[MetalGod]

Well...

Thanks for the help. The pedal works, or so it seems. When I apply a bit of current to pin 6 and the ground to pin 5, I can turn the LEDs on and off with the switches.

But now it seems that the preamp needs a bit of work. There is no current coming from pin 6 on the preamp. An old cable which I had used before no longer works, which really makes me think something has come loose inside. I'll crack it open over the weekend (if I find time) and have a look. Something tells me that it will be spending some time with a tech, though...

Thats a great sounding preamp btw, I'm always on the lookout for one on the cheap.  They were apparently modelled after the JCM800 Jubilee preamp stage.  I remember when I played one in the early 90s it sounded great.

[Paul Marossy]

Hey, you want a Marshall 9005 power amp to go with your 9001? I have one for sale... If you're interested, PM me.

Anyhow, so does this preamp use a cord with a multi-pin connector? I had a Peavey amp in the 80s that had that type of cable and a couple of the pins got messed up somehow and the footswitch didn't work on the amp anymore because of the cable...

[bensoniski]

MetalGod (if that is your real name...!) - yes, these preamps rock one like a hurricane. I am truly in love with mine. It has, over the year or so I've had it, managed to make me consider getting rid of my other amps.

Paul - thanks, I already pair it with a 9005. That's a great power amp - you should hang on to it and try and get a 9001!

The 9001 uses a multi-pin jack, but I can't remember how it is wired up. I opened it up a few weeks back, but that was to see how I was going to repair some damaged jacks. I didn't really look at the footswitch bit.

[Paul Marossy]

I thought you might already have one. I don't really ever use mine, but like you say, it does sound good. 

[bensoniski]

Ah, the sweet taste of victory...soured by a slight feeling of foolishness.

I opened up the preamp. I had opened it up a few weeks back to look at the jacks, and I had taken out the pcb the jacks were on. To do that, I disconnected a connector...the one which was attached to the footswitch out. I had forgotten to reconnect it.   

So...hurrah! The footswitch works! First time!

Thanks again to CGDARK for your wiring diagram. I followed it to the T. I forgot to take photos - sorry. If, somewhere down the line, someone else makes one and wants pics, I can crack open the footswitch and take some. I also saved CG's diagram, so if it no longer is showing, I can send that. And, while I'm talking to Future Person, good luck!

[CGDARK]

Ah, the sweet taste of victory...soured by a slight feeling of foolishness.

I opened up the preamp. I had opened it up a few weeks back to look at the jacks, and I had taken out the pcb the jacks were on. To do that, I disconnected a connector...the one which was attached to the footswitch out. I had forgotten to reconnect it.   

So...hurrah! The footswitch works! First time!

Thanks again to CGDARK for your wiring diagram. I followed it to the T. I forgot to take photos - sorry. If, somewhere down the line, someone else makes one and wants pics, I can crack open the footswitch and take some. I also saved CG's diagram, so if it no longer is showing, I can send that. And, while I'm talking to Future Person, good luck!

Glad to know it worked. Congratulations!

CG

[Paul Marossy]

So...hurrah! The footswitch works! First time!

Yayyyy!