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Vintage threads from the first ten years

Re: HELP! - Fender Tonemaster knackered (?)......

5/21/2000 5:40 PM
Carlo	Re: HELP! - Fender Tonemaster knackered (?)...... Hi Ian - it happens at rehearsal, but not on the bench. So what are the differences between the two setups? At rehearsal do you place the head on top of the speaker cabinet? You also mentioned playing at a loud volume at rehearsal. When your testing it at the repair shop do you hook it up to a speaker cab and play through it the way you do at rehearsal? If you could set things up at the shop the way you do at rehearsal you'll have a better chance of getting the problem to occur while the amp is at the shop. Or conversely, if you could take the chassis out of the head at rehearsal and carefully set it up as close to your usual way as possible. This way when the problem occurs, you can try tapping everything (especially the ground connections) to see if you can find the culprit. You'll wanna turn the volume down to the point you can still hear the hum, but low enough so you don't ruin your speakers. By the way, did you check the filter caps and solder connections under the cap cover too? As always be very careful while poking aroud inside a live amp. Carlo

5/21/2000 5:40 PM

Carlo

Re: HELP! - Fender Tonemaster knackered (?)......

Hi Ian - it happens at rehearsal, but not on the bench. So what are the differences between the two setups? At rehearsal do you place the head on top of the speaker cabinet? You also mentioned playing at a loud volume at rehearsal.
When your testing it at the repair shop do you hook it up to a speaker cab and play through it the way you do at rehearsal?
If you could set things up at the shop the way you do at rehearsal you'll have a better chance of getting the problem to occur while the amp is at the shop.
Or conversely, if you could take the chassis out of the head at rehearsal and carefully set it up as close to your usual way as possible. This way when the problem occurs, you can try tapping everything (especially the ground connections) to see if you can find the culprit. You'll wanna turn the volume down to the point you can still hear the hum, but low enough so you don't ruin your speakers.
By the way, did you check the filter caps and solder connections under the cap cover too?

As always be very careful while poking aroud inside a live amp.

Carlo

5/21/2000 5:59 PM
Gus	on my laney vc30 one of the tube sockets connection became intermitant when playing,chinese tube in the socket no problem,a sovtec problem,it turns out the chinese tubes have larger diameter pins so with heat and vibration it caused a problem the amp is class AB so it does heat up more with playing loud. A new quailty socket fixed my problem.

5/22/2000 2:34 PM
Ian Anderson	Actually, that last post about the tube socket diameters might be quite close to home. The sockets are a bit loose and do not hold the tubes very tightly so I installed some tube retainers in there to hold them in place better. I told the tech this when we had it benched and he said it was not a problem. We had it hooked up to a load resitor and thru a osciloscope running at full power switching channels every now and again. I suggested played through my speaker cab, but he said it would not make a difference. I might just replace the tube sockets on the output section and see if that helps coz they could do with it anyway. Any advice on which ones to put in there? Looks like the nearest (reputable) tech to me (I'm in Newcastle) turns out be the guys in Huddersfield who build the Matamp stuff - looks like a long drive is ahead of me. ... Ian

5/22/2000 2:34 PM

Ian Anderson

Actually, that last post about the tube socket diameters might be quite close to home. The sockets are a bit loose and do not hold the tubes very tightly so I installed some tube retainers in there to hold them in place better. I told the tech this when we had it benched and he said it was not a problem.

We had it hooked up to a load resitor and thru a osciloscope running at full power switching channels every now and again. I suggested played through my speaker cab, but he said it would not make a difference.

I might just replace the tube sockets on the output section and see if that helps coz they could do with it anyway.

Any advice on which ones to put in there?

Looks like the nearest (reputable) tech to me (I'm in Newcastle) turns out be the guys in Huddersfield who build the Matamp stuff - looks like a long drive is ahead of me.

... Ian

5/22/2000 8:54 PM
Doc	The sockets may not actually need replacing. You can "re-tension" the pin connectors on octal sockets easily, if the tube socket connectors are cylindrical. Some sockets have split blade type connectors that make a line contact along either side of a tube pin, and if they get too loose, they can't be effectively retensioned and the sockets will need replacing. When I retension sockets, I use a common wooden throwing dart as a probe. It has a tapered metal point, which seems to be the ideal tool. The idea is to carefully fit the pointed probe between the plastic insulation and the outside of the tubular connector sleeve (be very careful if the socket is ceramic, as you may crack it and ruin it). Try to fold the open ends in at the split, and try to reshape the cylinder into one of a diameter slightly smaller than that of the tube's pins. After you're done each socket, carefully refit the tube. Rock the tube around and make sure all pins are started into their corresponding connectors before pushing the tube all the way home. Doc

5/22/2000 8:54 PM

Doc

The sockets may not actually need replacing. You can "re-tension" the pin connectors on octal sockets easily, if the tube socket connectors are cylindrical. Some sockets have split blade type connectors that make a line contact along either side of a tube pin, and if they get too loose, they can't be effectively retensioned and the sockets will need replacing.

When I retension sockets, I use a common wooden throwing dart as a probe. It has a tapered metal point, which seems to be the ideal tool. The idea is to carefully fit the pointed probe between the plastic insulation and the outside of the tubular connector sleeve (be very careful if the socket is ceramic, as you may crack it and ruin it). Try to fold the open ends in at the split, and try to reshape the cylinder into one of a diameter slightly smaller than that of the tube's pins. After you're done each socket, carefully refit the tube. Rock the tube around and make sure all pins are started into their corresponding connectors before pushing the tube all the way home.

Doc

5/23/2000 2:46 AM

Eric H

quote:
"I use a common wooden throwing dart"

You must be from the Eastern U.S., Doc, I don't know how many on the left coast have even seen one of these :>)

-Eric

5/23/2000 6:51 AM

Rick Erickson

quote:
"When I retension sockets, I use a common wooden throwing dart as a probe. It has a tapered metal point, which seems to be the ideal tool. "

I cut the (sharp) end off a safety pin and put it in an exacto blade handle. Same basic tool and it works great as you stated for tube socket tensioning. Have to be careful though - the handle is aluminum.
RE

5/23/2000 6:57 AM
Rick Erickson	Another trick - take some old tubes, pre and power and bust them up to get at the pins. Now attach them to toothpicks, small dowels, a WD-40 hose or whatever works for you. What you end up with is a tube pin on a handle that you can use to check the tension on each socket contact, only tweaking the contacts that are actually loose. They also work great for checking the grip after re-tensioning and for recovering from an over tensioned & collapsed contact - Not that I've ever done that... RE

5/23/2000 6:57 AM

Rick Erickson

Another trick - take some old tubes, pre and power and bust them up to get at the pins. Now attach them to toothpicks, small dowels, a WD-40 hose or whatever works for you. What you end up with is a tube pin on a handle that you can use to check the tension on each socket contact, only tweaking the contacts that are actually loose. They also work great for checking the grip after re-tensioning and for recovering from an over tensioned & collapsed contact - Not that I've ever done that...
RE

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