Kansas City amplifier repair?

[spauldingrules]

I got a Mesa amp that needs work.  Any recommendations?  It's not a warranty repair.

 

[mayfly]

what's wrong with it?  Maybe we can walk you through it.

 

[spauldingrules]

I just want to make sure it's safe.  I don't want to step up to the mic and get zapped.  It has a big round yellow three prong plug on the end of the power cord - it doesn't look original - it looks more like a dryer plug or something.  But it fits a normal jack and works fine.  The reverb also didn't work, but I pulled it out and sprayed de-oxit on everything, and it works now.  The spray cleaned up ALL of the crackling, so I think I am all good.  That stuff is worth $20 a can!!  Any idea about the plug?  It's a 1984 Mesa Son of Boogie (Mark I reissue) and it sounds great.  I also wanted an opinion on whether the speaker is worn out - it sounds good, but SO different than when I run it through a variety of 1x12 cabs that I have.  It's a 150 watt Black Shadow speaker that weighs a ton.  I just don't want it to blow at a gig.  Thanks for any input!!

 

[Cagey]

It's unlikely you'll blow that speaker. Those are actually Eminence Delta Pro 12s private-labelled for Mesa. They're essentially a clone of an EVM-12L. Very heavy-duty speaker. Some guys like them better than Celestions or some of the other typical guitar speakers in wide use, but they do have a somewhat flat response curve to them so they take some getting used to. If you've got a higher-end amp like a Mesa, it's a good way to go. Plus, they're more efficient than most so you get a LOT more loudness out of the things.

 

[spauldingrules]

Thanks Cagey - it's amazing what a difference a speaker makes.  I have 3 1x12 avatar cabs that I mix and match, and I can get almost any tone I need.  The speaker is brutally loud!  And I really like it with single coils (which I guess are naturally more "scooped" so it works) much more so than my humbucker guitars.

Any idea about the yellow plug?

 

[spauldingrules]

Oh, and it's obvious this amp was made to play with a band!  Hits all the right frequencies to be heard.

 

[Cagey]

Any idea about the yellow plug?

It's probably just a replacement plug that happens to be much heavier duty than what normally comes on amp cordsets. Some of them can be pretty beefy...

 

[mayfly]

Any idea about the yellow plug?

It's probably just a replacement plug that happens to be much heavier duty than what normally comes on amp cordsets. Some of them can be pretty beefy...

+1 the plug is probably fine - as long as the ground pin really is attached to the chassis ground you'll be OK.

Mesas never had the 'death cap', so you shouldn't need to worry.

 

[spauldingrules]

Oh, and something else I just discovered last night.  There are 4 mounting screws on the top of the amp that hold the chassis up on the top of the cab.  The screw heads are on the top of the amp, and screw down into the chassis.  I was tightening them up, and two were stripped, so I went to the hardware store and got some replacements.  As I removed and replaced, two had ground connection terminals attached to them.  The wire looked like the ground on a vintage humbucker (that meshy cover type).  Anyway, one wire was still attached internally, but on the other screw the terminal and a bit of wire just came out as I removed the screw, disconnected from wherever it was connected to.  Is this any major issue? The amp is still dead silent when unplayed, no matter how loud it is turned up.  Any ideas?

 

[mayfly]

gonna need some photos for that one.

 

[spauldingrules]

Here is a photo of the plug.  Is it safe having that metal exposed?  I'll get pics of the wires later.

 

[Cagey]

Yeah, that's just a strain relief so you don't pull the cord out of the plug. It's not electrically connected to anything internally.

 

[spauldingrules]

Ok - so I pulled out the chassis and took a look.  It looks like the wire is just shielding the cab?  I'm not really sure what these wires do!  I emailed Mesa, and they got back very quickly.  However, the guy I got a message from wasn't super familiar with the "sob" model.  He told me to take a look and see if I could repair or replace the wire, because it was there for a reason if it was there at all.  He said it's not rocket science and I should be able to handle it - a nice change of pace from most modern companies who would never advise someone to try to fix something himself.

Anyway, here are some pics - i just soldered some new wire to the old and ran it out the hole to the mounting screw, like the old wire was.  Works fine - amp is still dead silent, even at high volume.  This amp is sweet!  Sounds great with the band.  Here are some pics of the wire, and my replacement.

 

[spauldingrules]

more pix