HT Club 40 Volume Drop when warmed up

hi hope maybe someone else has had this problem and could recomend a fix,,
my amp works fine when first turned on but after 15-20 my volume drops to the point that full cranked is the same as about 3 when first put on, not enough volume to play with drummer for sure, took it back to where i bought it and they had it for a week and said they couldn't get it to do it, that its fine and wont help me, just dont seem to want to help, changed all tubes no change, any ideas?

did you check your cables / guitar for wiring problems ?

yes

stevesmith5000 wrote:hi hope maybe someone else has had this problem and could recomend a fix,,
my amp works fine when first turned on but after 15-20 my volume drops to the point that full cranked is the same as about 3 when first put on, not enough volume to play with drummer for sure, took it back to where i bought it and they had it for a week and said they couldn't get it to do it, that its fine and wont help me, just dont seem to want to help, changed all tubes no change, any ideas?

I recently had a similar problem with the same amp. Only my drop was drastic, to a whisper if you will. I had it back to a factory authorized repair facility here in NJ. they had it on four different occasions. They could not make what I was describing happen when they had it! Finally on that fourth occasion it was happenning when I brought it in and I showed them. They had it for a week, and could not make it happen again . finally out of frustration the tech began just tapping around on the board , and found this little square ( Im not sure what he called it (diode, resistor, etc) it was something. it was the size of a button on a small cell phone and was gray i beleive in color.I mean this tiny thing was the whole problem. amp has been fine since. very tough thing to find when it is intermittent.Hope this helps

I had a very similar problem recently with the HT-60 Soloist. When you first turned the amp on it was fine. About 10-15 minutes later it the volume was so low I had to crank things way up just to hear something!

Without a schematic to go by, I was running a little blind. I too started tapping components and when that didn't work, I started FLEXING components until I found a film capacitor in the tone control circuit (I think, but it could have been a 0.01µF coupling cap as well) that reacted to forward pressure by restoring the signal to normal and this promptly disappeared when the pressure was removed!

I just happened to have an EXACT replacement in one of my capacitor drawers so I had to remove the entire main board, carefully replace the cap and then put it all back together before I could even try it. Well, the problem never came back and I have gigged a few times with the amp since with no issues at all.

I noticed a construction technique used on these amps that was most likely responsible for the cap failure. All of the thru-hole components (such as these caps) are inserted into the board then the leads are bent to keep the parts from falling out so the board can be handled. Apparently these boards are hand-stuffed and processed and they are not using machine insertion and other automation.

Film capacitors are especially sensitive to being mechanically abused in this manner and it wouldn't surprise me a bit to see this issue being repeated across many amps!


Steve

I am looking into a very similar problem on an HT Studio 20h. So far replacing tubes has not helped. I will be volt testing the sockets and looking at the board next. One difference seems to be that just the clean channel is out, drive seems unaffected, if that makes sense. (This is my guitarist's amp, I don't use it.)
I find the info about the flexing of the film cap very helpful

Brad