MusicMan HD-130 410... need some help!

Hello fellow TDPRIers!

Tbp, this time it's not me who needs help, but a good friend who happens to be our other guitarist.

He got himself an old MusicMan HD-130 (pictured below), after falling in love with this amp and getting a good price on it. It appears to be one of the earlier MM amps, because it's still got a 12AX7 in it.

My buddy plans to put some additional money into the amp to be able to get the best out of it. The amp sounds great as is and especially the tremolo is to die for. However, it's going to the amp tech next week to have it thoroughly checked and there are some issues with it:

First thing, the reverb is dead. Can this be fixed? If not, could somebody recommend a good replacement tank?

Second thing (and this is probably hard to believe), it could seriously use some more clean headroom - things get dirty pretty quick, which is to say at practice room levels.
At practice yesterday we set it like I usually go about setting my SF Twin Reverb (MV version) - MV cranked all the way up and adjusting the overall volume with the channel volume knob.

While the TR was absolutely clean at practice volume (who'd have guessed it :lol: ), the MM was much dirtier at the same volume. It did behave like this on all inputs and in both channels. The amp wasn't boosted in any way and I double-checked with my Tele, which has low output PUs.

Is this normal for such an amp? If the answer is yes, how would you go about increasing the clean headroom? Replacement speakers? Different tubes? For the music we make, we both need really loud, pristine cleans and I always thought MMs could hold up to a TR in that regard. Don't get me wrong, it's loud as hell but it gets dirty really quick at the same time. Btw, it was freshly retubed with EL 34s so I don't think it's about the tubes.

IF this turns out to be normal, my buddy would be glad for some pointers on which tubes / replacement speakers / whatever else he should look for.

Thanks in advance,
Stephan

PS: I've added a pic of one of the speakers in case they turn out to be the problem...

For whatever reason I tend to like musicman amps with the master volume on about 6-7 and not up on 10.............not sure if this will help at all.

Yeah, we tried that as well but iirc that resulted in still more dirt... I think the MV / Channel Volume knobs act in a similar way to the according knobs on Silverface amps with MV.

If it turns out there is really a problem with the amp I'll keep this in mind for when it's back in shape.

Probably needs To be recapped. I used to have the 210 version and it was as clean as any twin I've played and loud as hell. Those speakers are sweet and I wouldn't replace those . I'm not sure about the speakers in the 410 but the one's in the 210 are rated at 65w each.

Thanks for your reply! Good to hear that those amps are usually clean and loud, my buddy and I had started to wonder after yesterday's experience.

If it's really just the caps, the visit to the amp doctor should sort that out. I'm sure our guitarist will be glad to hear that :wink:.

Oh yeah- sorry I forgot to mention that amp should be loud and clean without a doubt......I would take it to the shop and they should be able to very easily and pretty cheapily fix the reverb as well. For pure clean tone MM rivals my silverface twin but it falls down when I try to overdrive it- it is as if it were made for clean to my ears.

That amp should indeed be painfully loud before breaking up. I would bet its the electrolytics and few other odd caps and she'll peel paint.

As for the reverb, it could be a number of things. The tech should be able to determine what's going on there in short order as well. Could ba a simple as a tube, could be cabling, could be tank or elements thereof. If its the tank, Accutronics should be able to provide an excellent replacement for not much money.

That amp should indeed be painfully loud before breaking up+1. Had a MM HD130-212 and L-O-U-D. Don't know that I ever played it loud enough to break up. My old MM RD112-50 is also very loud & clean right to the max. One clean machine.

He should be fine after some simple trouble-shooting.

I'm with ASC67.MM HDs should be clean all the way up to F16-on-afterburner SPL .Whatever the tech finds should be interesting.

I have a question, I know the rd's =Reverb/distortion? what does H/D stand for?

Thanks a lot for your replies, much appreciated!

Both my buddy and me don't know much about the technical side of amps, so it's comforting to hear that the issues this amp has are likely to be solved by replacing the caps and replacing the reverb tank in the worst case scenario. Once more, TDPRI saves the day! :wink: In any case, the speakers are all working and even in this condition, the amp sounds fabulous unless you're playing it (really) loud.

If the reverb tank turns out to be dead, thanks for the hint to Accutronics... I just checked prices and those are really affordable.

Good to hear that it's really supposed to be a clean machine even at crazy volumes, as that is exactly what we need as a foundation for our guitar sounds. The clean sound this amp delivers is really something, it's different from my TR's cleans, but beautiful nonetheless. I really hope the amp tech will be able to get it back in shape.

Some observations on the MM so far: The attack is absolutely immediate, the notes seem to flow from the speakers before you even hit the strings. It's super-transparent, brutally honest and has got a certain shimmer or chime to it. Guess that's because of the EL 34s. We both can't stop raving about how great the tremolo is on this amp. It's really different from the tremolo my TR and Bandmaster Reverb have, somehow more intense and pronounced (I guess it's using a different, somewhat steeper waveform than the average Fender tremolo), but very pleasing to the ear at the same time. I love the Fender tremolo on my amps for its subtleness but now I'm starting to GAS for an additional tremolo pedal to give me that sound as well.

@Billy B.: I don't know what it stands for, but the layout (controls and effects) is almost the same as with your run-of-the-mill Fender reverb amp.

It's got a "normal" channel and a "vibrato" channel with two inputs for each channel. The normal channel has only got channel volume, treble and bass controls. The vibrato channel has got channel volume, treble, middle, bass, reverb, speed and intensity controls for the tremolo as well as a bright switch and a "deep" switch (you don't usually see that on a Fender amp) and finally a Master Volume.
Effects are reverb and tremolo.

Regards,
Stephan

what does H/D stand for? I think "Heavy Duty" and if that's correct, it is sure accurate.

Thanks Guys, no one has ever had an answer for Me on that. I used to play with another Guitar player who had the rd and it was a great rock & roll amp and oh so loud

Just had a thought...I recall that many older Fender amps' reverb will not function without a footswitch or suitable 'jumper' to put the reverb in the circuit--is it possible that the footswitch (which seems present in the photo) isn't working properly, and that's why the reverb doesn't work?

And I thought it was the early ones that used SS phase inverters, and later Leo swapped back to 12AX7 tubes for the PI...though I could be (am frequently am) wrong.

MM reverb works without the footswitch, at least mine did.

When I read the title of this thread, I thought you just needed help lifting and moving it.

I've serviced quite a few MMs, and will not speculate on your lack of headroom or anything else until the report comes in from that tech who's got it on the bench. They should be relatively clean, clear and loud.

Many did not have a squeaky-clean clean. They had a bit of smoke in the clean sound rather than say the SF Princeton sort of clean. They also tend to be a bit deceptive, as smooth as they are the sound doesn't tell you it's loud until you notice that your ears feel full of cotton when you stop playing.

I'd wait for the report from the bench before worrying about it. In the world of hybrid SS and tube amps the SS part usually fails first, except for MusicMan. That preamp PCB is robust.

The footswitch shorts out the reverb. Reverb will work without it.

About the reverb and the footswitch: It seems to be the original switch and the connections / cables (at least the ones which can be seen from the outside) look good. The tremolo side of the switch works without a problem. Good call though, I had a similar problem with my TR where the reverb would randomly cease to work due to a bad connection of the footswitch.

However, my buddy informed me today that the previous owner told him he had to have the reverb fixed at some point. At that time, the tank itself was still working but there was a loose connection in the circuit somewhere. After hearing that, I now think it's likely that this problem wasn't fixed properly and just reappeared. Our local amp tech should be able to figure this out, I guess.

About the solid state / tube phase inverter, I think they switched from tube to solid state on the later models. I've found a history of the MM amps here (http://pacair.com/mmamps/Misc__Info/History/history.html) right after starting this thread where this is mentioned.

When I read the title of this thread, I thought you just needed help lifting and moving it.

Good one :lol:! If you want to volunteer helping us lug our old monsters around, you're cordially invited to do so :wink:.
It's indeed about as heavy as my Twin, I didn't notice a big difference in weight when I tried lifting both. On the plus side, the Twin is a bit smaller and mine came with casters.

We'll gladly lift those though. Those dinosaurs deliver great sounds in spades and with the current trend moving toward smaller and weaker amps, the deals to be found on big, powerful (and yes, heavy and unwieldy) amps are just too good to pass up on.

Concerning casters... does anybody know if those MMs originally came with casters? We noticed four holes on the bottom side of the amp. Just curious if it had casters when it came from the factory or if somebody retrofitted it with casters at some point...

@Ronsonic: Just saw your reply when typing the above. Thanks for your post, very interesting information.

Thanks to anyone who took their time and posted in this thread, much appreciated! I'll keep this thread up to date when more info (from the amp tech) comes in.
In the future maybe this could be a helpful thread for somebody looking into these amps.

Regards,
Stephan

The HD-130 came stock with casters.

Get HD amps to sing. Caution! Be sure all high voltage capacitors are discharged before attempting any work or take to a competent repair person.

Check, clean boards and replace any bad capacitors be sure to use "plenty of silicon adhesive" to all keep these from vibrating loose.
1. Check all transformer voltages.
2.Replace power tubes with premium "Matched Sets" the best you can afford but replace the whole set.
Check all tube sockets and replace any chipped or burned & make sure tubes are inserted correct & lock in tightly.
3. Set the Bias Voltage to .7 volts... The factory shows this at 1 volt but this causes premature tube wear & replacement, all you you loose is then 3dB of headroom. This really cleans it up as well as allow it to sing when overdriven.
Hope this helps