A pair of MP-1 Preamps with issues needing assistance.

[rnolan]

Hey Kevin, hey good news re V2 unit  . 

You could do the rear jack mod on the V1 unit, MJMP sells this with all the bits ready to go.  It will change the rear jack input to inst instead of line level and while I understand keeping the rear input line level just in case you ever have a need, I struggle to think of a use case (I have thought of 1 or 2 e.g. use the MP-1 as an insert on a mixer channel) that needs it.  The mod also changes the front input to a normal jack style (albeit IIRC with slightly longer shank to mount through the front plate) rather than the PCB mounted sockets. (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm) 

@MJMP, don't you have the headphone jacks in stock again? Your web site says "in stock again".

[kissfan113]

rnolan, I think I have located some jacks that match and meet original spec, they're shipping from denmark so it'll be a hot minute before I have them in hand, hopefully they work for me. If they fail I'll likely do the rear input mod and find the proper jack for the headphones, if I can keep both units stock sans battery mod for ease of upkeep I hope to, but that's a bridge I'll have to cross when it comes time. I appreciate everyone's help and I'll keep updating this post until both units are 100% tip top shape.
Kevin

[rnolan]

Hey Kevin, no worries,  :thumb-up:

[MarshallJMP]

Yes I have them in stock, it was the return jack that was out of stock for a while.

[kissfan113]

Got the new jacks in the mail and got them installed today, the V1 unit is a working great now, have to track down one case screw and the nut and screw for one side of the transformer and it is 100% good as new. Don't know how I managed to overlook the missing transformer mounting hardware before but it became very apparent to me today, the case screw I don't remember losing as I laid all my screws in one spot on the work table but it has certainly disappeared so I'll have to find a replacement.

[rnolan]

Cool, great news  :thumb-up: , yes those little screws can be elusive  :dunno: .  All my 2nd hand MP-2s are missing a few, but they came like that.  You can buy the screws, MJMP posted the specs ages ago, not sure what thread (no pun intended) it was in.  You can also get very slightly larger thread for if/when the case screw holes get to loose.

[MarshallJMP]

The screws that holds the lids are 4-40 x 1/4

[kissfan113]

Marshall would you happen to know the specs on the transformer screws and nuts for a V1 unit, it has one screw and a nylon nut I wasn't sure if that was the factory or someone else's doings

[MarshallJMP]

Do you mean a complete nylon nut or a locknut? Now I never seen either in a MP-1.

For what I can can see these are 6-32 x 1/4 and the nuts have a external tooth washer on them.

[kissfan113]

It's a full nylon nut which I thought was an odd choice for the application, I'll aim to find the proper hardware

[MarshallJMP]

That's not original for sure.