Music Man help?

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RickW

RickW

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Does anyone know of a parts or manual supplier for vintage Music Man amps? There's a repair guy in my area but he's outrageously priced...like $200 an hour! I want to fix some cosmetic issues (corners, handle, etc...mainly pitted, rusty chrome). I'm also looking to replace the tubes (I believe the originals were still in there). I don't really know squat from tubes, but the ones I'm replacing are Sylvania 6CA7 EL34 (4 of them) and i'm not sure if these are still available or if there are replacements. The amp is a 1976 (?) Music man HD130 head. It actually sat (since new) on a friends houseboat until I got it maybe 4 years ago. I let it sit until about 2 months ago when I wanted to use it as a rehearsal amp. It worked fine for a couple of weeks but then it started to cut out. I had to shut it off and turn it on again, only to have it cut out again a few minutes later. It did this a few times before I turned it around to discover that 2 of the tubes were incredibly lit up...like the whole tube was a bulb...and I haven't turned it on since. I took the tubes out with the intent of replacing them to see if that fixed the problem, but I'm thinking that something had to cause just those particular tubes to react that way and not the others. So, I need to find some info on these and there doesn't seem to be much available. Any info would be greatly appreciated. Thanks.
 
Those tubes are old and were failing. Google or eBay for comparable replacements. No Music Man parts likely available as these are old amps. Anything cosmetic you want done will be custom and probably as you suspect, expensive. Replace the tubes and give it a good workout to ensure it's going to hold up before you invest in anything cosmetic.
 
RickW said:
Does anyone know of a parts or manual supplier for vintage Music Man amps? There's a repair guy in my area but he's outrageously priced...like $200 an hour! I want to fix some cosmetic issues (corners, handle, etc...mainly pitted, rusty chrome). I'm also looking to replace the tubes (I believe the originals were still in there). I don't really know squat from tubes, but the ones I'm replacing are Sylvania 6CA7 EL34 (4 of them) and i'm not sure if these are still available or if there are replacements. The amp is a 1976 (?) Music man HD130 head. It actually sat (since new) on a friends houseboat until I got it maybe 4 years ago. I let it sit until about 2 months ago when I wanted to use it as a rehearsal amp. It worked fine for a couple of weeks but then it started to cut out. I had to shut it off and turn it on again, only to have it cut out again a few minutes later. It did this a few times before I turned it around to discover that 2 of the tubes were incredibly lit up...like the whole tube was a bulb...and I haven't turned it on since. I took the tubes out with the intent of replacing them to see if that fixed the problem, but I'm thinking that something had to cause just those particular tubes to react that way and not the others. So, I need to find some info on these and there doesn't seem to be much available. Any info would be greatly appreciated. Thanks.
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It might be the tubes themselves or it might be something else in the circuitry causing them to light up. Of course, the tubes might be toast now, too, even if that is the case, but changing them without checking out the rest of the amp might be a waste of money and tubes.
 
A matched set of Groove Tubes el34s will run you about $80. If you use the amp a lot you will be replacing those about once a year - sooner if you push the power section which is where the good crunch is. I had the combo version of that amp years ago. Great sounding thing but extremely loud. The pre-amp is SS so to get good tube distortion it was all up to the power tubes and you had to run damn near full out - at least 8+. YMMV.

My only concern with your amp would be that it sat on a boat that long. Damp environment (salt water too?) would not be a good thing for all manner of components. Start with the tubes - you're gonna need 'em anyway. If it still has issues after that take it to a tech. You might want to anyway at least to check the bias with the new tubes.


lou
 
Check this out: http://www.pacair.com/cgi-bin/discus/discus.cgi?pg=topics

I found Music Man amp schematics at the Ernie Ball site, but just took a look and think they may be gone. Do a google search and you might find something.

My HD-130 Reverb is now gone, replaced by something I can actually carry around (44 lb head, 100 lb speaker cab!).
 
ggunn said:
It might be the tubes themselves or it might be something else in the circuitry causing them to light up. Of course, the tubes might be toast now, too, even if that is the case, but changing them without checking out the rest of the amp might be a waste of money and tubes.
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That is exactly what I'm afraid of. I don't really want to replace the tubes without checking what's causing the problem. But, it's possible it's the tubes themselves that are the problem. Connundrum.:rolleyes:
 
Sky Blue Lou said:
A matched set of Groove Tubes el34s will run you about $80. If you use the amp a lot you will be replacing those about once a year - sooner if you push the power section which is where the good crunch is. I had the combo version of that amp years ago. Great sounding thing but extremely loud. The pre-amp is SS so to get good tube distortion it was all up to the power tubes and you had to run damn near full out - at least 8+. YMMV.

My only concern with your amp would be that it sat on a boat that long. Damp environment (salt water too?) would not be a good thing for all manner of components. Start with the tubes - you're gonna need 'em anyway. If it still has issues after that take it to a tech. You might want to anyway at least to check the bias with the new tubes.


lou
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Thanks! I actually haven't used the amp much at all, and it will probably see minimal use when working properly as I only use it in a specific band that doesn't work much. I'm not worried about "crunch" either as I use it for bass. It's been plenty loud at rehearsal before it went wacky.

So, are you saying it may be OK to try it with new tubes to see if that solves the problem? I do realize they have to be biased once they're in and that's something I'll probably leave for a professional. Thanks for the advice!
 
RickW said:
So, are you saying it may be OK to try it with new tubes to see if that solves the problem?
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I'm no expert so I'm not saying that. It is what I would do but I'm a bit reckless (optimistic?)


lou
 
RickW said:
That is exactly what I'm afraid of. I don't really want to replace the tubes without checking what's causing the problem. But, it's possible it's the tubes themselves that are the problem. Connundrum.:rolleyes:
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Is it two of the power tubes that are lit up? You know, you can run some (maybe all) 4 power tube amps with just two of them in place if it's an opposing pair that you remove. It will just have less power.
 
I have the 65 watt 2x12 combo version of that MusicMan and it has a half power switch, I believe it's on the transformer voltage, and half power was always enough for clubs.

Besides the malfunctioning tubes, I would be concerned about the power supply caps, the amps are close to 40 years old now and electrolytic caps will dry out and cause a lot of problems, they keep the steady voltage available to those power tubes.
 
Anfontan said:
I have the 65 watt 2x12 combo version of that MusicMan and it has a half power switch, I believe it's on the transformer voltage, and half power was always enough for clubs.

Besides the malfunctioning tubes, I would be concerned about the power supply caps, the amps are close to 40 years old now and electrolytic caps will dry out and cause a lot of problems, they keep the steady voltage available to those power tubes.
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The half power switch on an amp with four power tubes usually takes one pair of tubes off line; it doesn't do anything with the power supply transformer. The power supply filter caps may indeed need changing, but I don't see how these caps could be causing the problem he is describing. If one of them shorts it will take out the high voltage supply and blow the mains fuse, and if it goes open it will cause the amp to hum like a banshee.
 
ggunn said:
The half power switch on an amp with four power tubes usually takes one pair of tubes off line; it doesn't do anything with the power supply transformer. The power supply filter caps may indeed need changing, but I don't see how these caps could be causing the problem he is describing. If one of them shorts it will take out the high voltage supply and blow the mains fuse, and if it goes open it will cause the amp to hum like a banshee.
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The amp DID hum very loud - in turn the volume disappeared. I should have mentioned that but you actually just reminded me of that problem. The 2 tubes lit up like on fire, the hum was very loud and I could hear myself playing but the hum was much louder than my volume. 'm thinking I should have a pro look at this since it sounds like it's way out of my league. I did find some Sylvania "Fat Bottle" tubes (which is what I removed) online for $190 a pair and there's no way I can afford that. Electro Harmonix and Groove Tubes make some more affordable. I'm assuming these are fairly good brands.
 
RickW said:
The amp DID hum very loud - in turn the volume disappeared. I should have mentioned that but you actually just reminded me of that problem. The 2 tubes lit up like on fire, the hum was very loud and I could hear myself playing but the hum was much louder than my volume. 'm thinking I should have a pro look at this since it sounds like it's way out of my league. I did find some Sylvania "Fat Bottle" tubes (which is what I removed) online for $190 a pair and there's no way I can afford that. Electro Harmonix and Groove Tubes make some more affordable. I'm assuming these are fairly good brands.
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You should definitely have the amp looked at by a competent tech before you spend big bux on new tubes.
 
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