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'62 6g6-b bassman problem

Niblos

Member
Messages
434
I have a quick question concerning my '62 6g6-b. I have noticed a slight rattle or what could resemble a blown speaker sound when I hit the lower A and G strings on the guitar. I have replaced all the tubes (3x), updated to celestion vintage 30s, checked all the electronics for leakage, measured all correct voltages, and even changed the power transformer (Heyboer 125P7A) hoping to resolve this. However today I actually found my friend's silverface bassman also has this problem through a different cabinet (solid state). It only happens when I turn the amp up to 5 or higher.

My friend borrowed my AA165 blackface but I am getting it back over the weekend to see if this also affects it. It may just be a bassman thing?

Today we found the reading did much better when I turned up the amp to 5 or so and backed off on the guitar volume. I had been running the guitar's volume at full blast and that may have overloaded the signal. Does that make any sense?

I am using a Ibanez custom agent that has the Super 70's (They look identical to Gibson PAF type humbuckers), tvjones in the SSU 6120 Gretsch, and filtertrons in the '04 White Falcon. I wouldn't think any of these were too hot but who knows?
 
Last edited:

chaz

Member
Messages
1,556
Experience has shown me that vibration noises can come from almost anywhere. A friend had a Matchless where the output transformer would buzz sympathetically on some notes. You've tried changing amps, try changing locations. I've had rooms that did this making me think it was something in the amp. Having a friend on hand to play the note(s) while you search, poke, and prod is necessary. Good luck!
 

Rosewood

Member
Messages
1,864
Experience has shown me that vibration noises can come from almost anywhere. A friend had a Matchless where the output transformer would buzz sympathetically on some notes. You've tried changing amps, try changing locations. I've had rooms that did this making me think it was something in the amp. Having a friend on hand to play the note(s) while you search, poke, and prod is necessary. Good luck!
That's right, I play my amps in a repair shop full of tools and it sounds like speaker scrub, rattle, buzz, twang city.
 

meterman

Member
Messages
7,890
I was getting a similar sound with a dirty input jack at higher volumes the connection was compromised and it 'farted out' sounding somewhat like a blown speaker, try some Deoxit on the input jacks maybe? Worth a shot, can't hurt anything....I've got an old Ibanez LP with Super 70s in it and they are hot but that should not be a problem...
 

RussB

low rent hobbyist
Messages
11,171
Did you really swap out the PT?

That's like saying "my car stall out when I turn left, so I changed all 4 tires"


Might be the cab/speakers
 

Niblos

Member
Messages
434
Did you really swap out the PT?

That's like saying "my car stall out when I turn left, so I changed all 4 tires"


Might be the cab/speakers
No -the power transformer was replaced due to the original being fried when I got it. I just upgraded it to a Heyboer recently.


Since the silverface also has the same problem through a different cabinet I have ruled this one out.
 

RussB

low rent hobbyist
Messages
11,171
..and even changed the power transformer (Heyboer 125P7A) hoping to resolve this. ?
sorry for misunderstanding your comments.


You say you've tested the electrolytics in the 6G6. Have you ever replaced them?

By the way, this not an inherent issue in Fenber Bassman heads
 

SatelliteAmps

Member
Messages
6,186
Try to replace anything that is used in both setups. Meaning, try a different guitar cable (and different guitars), make sure there are no effects or anything extra in the setup. Try a different speaker cable. Try a different room, with a different electrical supply. With everything else you've said you've done, one of the three things should track down the issue.
 

Niblos

Member
Messages
434
sorry for misunderstanding your comments.

Not a problem at all; I thank you for your input. When I purchased the amp it was outback in an old shed with a burnt transformer (painted black). My tech just looked at the (infamous) inside label that read "6G6-A" and ordered a hand-wound equivalent around 470 plate voltage. Luckily it turned out to be a 6G6-B (what I really was after) and that called specifically for a 125P7A that reads around 430-435. You live and learn!

My first thought was a blown speaker so I upgraded one side to a celestion vintage 30. I run an original Jenson on the other side but after I hooked the head up to my buddy's solid state yamaha I knew it wasn't the cabinet.

So today I finally was able to try my AA165 bassman out and guess what? It did exactly the same thing with the gretsch or ibanez's volume wide open. So it doesn't seem to be a problem at all I guess; I just learned the valuable lesson of rolling back one's volume on the guitar. I guess I am going to get a volume mod after all.

Thank you so much for everyone's imput. You guys are amazing!
 

Niblos

Member
Messages
434
Crank her up today boys! She is purring like a kitten. Again thanks so much for your help.
 




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