MK III Needs to see a tech, Recommendations?

[jnapo]

I have a Mark III that I purchased back in the late 80s. I have replaced all the tubes and I am still experiencing some trouble with the sound. It is hard to describe but on a clean setting when you strike certain notes something in the amp resonates with the sound and seems to put a fuzzy distortion on the note.

So I am looking for a good amp tech in the Maryland area. Recommendations?

 

[tommyhawk13]

Before you take it anywhere, look for anything obvious. Are the tubes secure, and not touching any metal? Loose wires? Kangaroo rat building a nest on your circuit board?

To be on the safe side, I'd pack up the chassis & send it to Petaluma.
They went through mine & replaced all sorts of stuff a few years ago, and the costs were not that high. Other than shipping, it was about the same thing I would expect to pay someone local, but I knew it would be done right!

 

[Restless Rocks]

I'm not sure who to recommend in your area but if you do get it serviced locally be sure and request the "Boogiebabies 20 point maintenance" schedule. This should include a good cleaning of your pots, tube sockets, input, and especially the effects loop jacks. Also we highly recommend a full filter cap replacement for all amps prior to 1995. You will be amazed at what simply cleaning your pots may do for this problem. There is a very competent tech in the NY area whom you may be able to send your amp to: He'll weigh in on this I'd say 8)

 

[jnapo]

I replaced all the tubes last year. The buzz rattle from what I can tell is not related to a tube. The idea of sending it back to Boogie may be the solution. I was hoping to get it service here in Maryland because I have a show that I need to do in June that will last three consecutive weekends.

Thanks for the information. If anyone else has recommmendations please let me know.

 

[Restless Rocks]

You didn't tell us if you tried a different speaker to eliminate the possibility of a bad speaker. Sending the amp to Mesa is always the best option for an overhaul and tune-up.

 

[Boogiebabies]

The saddest thing is that most amps sent back to Mesa are tube related issues. I'd start with the preamp. There is a very high chance that someone will make it into a cap job which may turn out to be a very valid point.

Possibilities:

Preamp Tubes- Had a brand new 12AX7 sound like a Fuzz Face.
Power Tubes
Dirty Sockets
Bad Pots/Dirty Pots
Dirty Jacks including the loop, input etc..
Reduced Value in plate load resistor forcing the tube to go into cutoff
Cap Replacement
malfunctioning cathode cap
malfunctioning coupling cap
The Speaker or cable
It's just dirty from having a fan blow dust into in for over a decade
It's never been maintenanced
Reverbs wigging out

I would start with the tubes.

Don't Panic and always bring your towel.

 

[jnapo]

I did not give the speaker a thought. I have a thiele enclosure so I can disconnect the one in the cabinet and check the amp with both independently. Let you know the results tomorrow.

If I send back to Boogie for tune up do you think they will complain about the J.J. tubes that I am using?

 

[Buddy]

If I were sending my III to Petaluma , I would pull the chassis from the cabinet, remove the tubes , and just ship the chassis .
Uber-pad it , put that in a box , pad the box and rebox the resulting boxed and padded chassisbox .
They probably got some tubes laying around for testing and such .

 

[jnapo]

So I disconnected all the effects and moved everything away from the amp. I unplugged the thiele extension and just used the speaker in the combo. Sure enough the buzz was there when certain notes are played. Switched to the thiele and the buzz followed to the thiele.

Should a consider disconnecting the reverb and testing this way?

Before shipping back to Boogie I imagine I will need to contact them and make arrangements for them to expect the amp. Has anyone had their amp back to boogie for the filter cap replacement recently? How long did it take for them to turn the amp around and what kind of fee did they charge? I understand that each amp is different but this will kind of establish a ball park price.

 

[AR]

Not meaning to sound like a tool, just offering some advice -- you've checked for fret buzz or something loose on your guitar, right?

You never know, could save you some shipping costs.

 

[Boogiebabies]

I would still try the preamp tubes before getting an RA. Buzzing or minor ghost notes is not an exact diagnosis for a cap job. I've had a preamp tube ghost note on me. It was like an octave pedal. If you have very undefined tone with new tubes, Ghost notes, buzzing and a flabby bottom end you can be assured it will most likely need a cap job. I am sure everyone would agree that it's good to have them replaced after 10 years, but that's your call. It seems like there is a filter cap paranoia here lately.

 

[jnapo]

Want to thank everyone for the suggestions.

I checked the guitar, no fret buzz. Just to make sure pulled out another guitar and it exhibited the same issue. I also played the two guitars unplugged to make sure there were no issues with them. Both play clean.

I can check the preamp tubes. I have the old tubes that I took out and will go through each one in the amp to see if replacing with another tube resolves the problem.

I checked the Boogie web site for authorized service centers in my area. The list one that is realitively close. I may call them and get an idea of the number of Boogies that they fix on a monthly basis plus what other amps they are authorized to service. I missed my opportunity to call Boogie they are closed on Friday but that will give me the weekend to swap some tubes to be sure.

Again thanks for the help.