Session 400 Question?

George King · Post by **George King** » 22 Sep 2003 8:45 pm

I have an early '75 peavey session 400.My question ,to anyone who can answer,is do they make a reverb control that will plug into the back of the amp,so that you can control the amount of reverb from your guitar?I think all the ones I've seen are just a button on and off switch.My session 500 has one with a knob to control reverb and effects and so does my Webb amp.The later session 500 has a different multi wire plug that wont plug into the session 400.Is there any way to do this?Thanks

Bob Metzger · Post by **Bob Metzger** » 23 Sep 2003 12:02 am

It's easy to do and I do it with every steel amp I own.

First, find out the value of the reverb pot in the amp and get one just like it. Next, get a stereo switched jack with normally closed switches on the ring and tip. You'll have to un-mount the reverb pot if it's hardwired to a printed circuitboard. Re-connect the outside pot lug going to ground to the PC board with a short wire. Wire up the other side lug and the wiper lug of the internal reverb pot to the switches of the jack. Wire the corresponding circuitboard points to the ring and tip of the stereo jack.You must use shielded cable for this, either 2x 2-conductor or a shielded
multi-conductor cable with 4 wires. When nothing is plugged into this jack, the jack switches will connect to the ring and tip (normally closed), making the internal reverb pot work normally. When an external pot is plugged into the jack, it connects to the ring and tip, disconnecting the switches (and the internal pot) and your remote reverb pot is functional.

Put it on a long, shielded 2 conductor cable (you'll, of course, need a stereo ring-tip-sleeve plug on one end) and mount it in a little housing that can be designed to clip to a steel guitar leg. I usually mount the stereo jack in place of the reverb on/off jack on the back panel of my amp(s) as this is a more usable feature. The amp can't tell which pot is controlling the reverb!

This should take under an hour to hook up.

Think about it for awhile; it's a little tricky but not complicated. I call one pot lug the 'send' and the other the 'return' and this helps me organize everything.

Bob M.[This message was edited by Bob Metzger on 23 September 2003 at 01:08 AM.][This message was edited by Bob Metzger on 23 September 2003 at 04:04 PM.][This message was edited by Bob Metzger on 23 September 2003 at 04:10 PM.][This message was edited by Bob Metzger on 25 September 2003 at 02:26 PM.]

Bill Crook · Post by **Bill Crook** » 23 Sep 2003 3:09 am

What would be wrong with just putting a "pot on a cable and plugeing it into the reverb jack ?? Instead of haveing a on or off mode via the switch,you could control how much on or off you have.

Works fine,last a long time.

Bill

Bob Metzger · Post by **Bob Metzger** » 23 Sep 2003 10:39 am

Another good solution!

George King · Post by **George King** » 23 Sep 2003 8:12 pm

Hey Guys, I tried pluging the reverb control from my webb amp into the peavey and it seemed like it was very sensitive.Either on or off with out anything in the middle.Is it because the reverb pot from the webb is of a different value or what?