Line Switch Newbie Question

[Richman]

If I connect my MP-1 output to my Alessis Midiverb3 and then to JCM 800 2203X return input...Should my line switch on top of my MP-1 be toward the rear or front of unit...I'm guessing toward the back position for line level into power amp input on marshall half stack????

I picked this all original MP-1 up for 100 U.S. dollars.... The only thing that has been done to it is tube replacement. Everthing seems to work great but sometimes I have to turn it on a couple times to get it to start up...I'm hoping someone on this forum will explain the fix for that problem...

Thanks for any info,
Richman

[Zettx]

Yow Richman, maybe 'MarshallJMP' can help to solve this problem, you never know my friend !
- maybe there is a problem with the power supply....

[Richman]

Thanks dude...I hope my question about the switch on top was'nt too stupid....Got no answers yet on that....My MP-1 sounds killer bone stock but I would like to hear the difference between stock and the 3'rd tube mod... 8)

[MarshallJMP]

Hey Richman

This is usually a power problem.It can happen if the wall voltage is too low,can you measure the wall voltage and let me know?

[MarshallJMP]

Yes leave the topswitch in line position.

[Richman]

Thanks Bro....I will check my AC reading and let you know...If it's 110-120V could the switch itself be going bad? Also I checked out your mods...Very cool stuff...

Thanks,
Richman :metal:

[Richman]

MarshallJMP....wall current is good 117V AC...I gigged last week with it and it did the same thing.  ??????

[MarshallJMP]

Ok,other things that can cause this.

-Something wrong in the reset circuit

-Bad cap in the power supply

-One of tube heaters draws too much current at startup (try starting without tubes)

-Transformer

[Chucky]

My old stock 1.37 MP-1 does the same, and I have been told it is the rocker switch that is getting old...
I don't mind it, I just have to switch it a few times and it goes on eventually.
Seems really to be just like a bad contact.
After it powers up it never fails.     :banana-upsidedown:

[MarshallJMP]

You can easy test if it's the switch. if you let it on and plug it in a plug with a switch,and use that to switch it on.If it still does it it's not the switch.Wow that's alot of switches  :lol:

[rnolan]

Thanks dude...I hope my question about the switch on top was'nt too stupid....Got no answers yet on that....My MP-1 sounds killer bone stock but I would like to hear the difference between stock and the 3'rd tube mod... 8)

Just noticed this question, in case you haven't worked it out yet/so far, the switch on top (only available in the earlier models) switches the MP1 outputs between instrument level and line level so if you wanted to plug the MP1 out put(s) into a guitar amp(s) input(s) you won't overload the guitar amp input(s).  For MP1 outs to power amp you switch it to line level.
Maybe someone who has both the stock MP1 and a 3TM can do some short sound clips for you to hear the difference (Like RandallRG (Steve) before he sells his stock MP1 or maybe MJMP if he has time).