Jadis Amp right channel issue

[DaveF]

Gentleman, having an issue with my Jadis amp where there seems to be no sound coming out of the right channel. Yesterday the system was fine but today when I powered up I noticed no sound at all coming from the right speaker. This is the case for both CD and vinyl playback so its not a source of interconnect problem.
At first I suspected the speaker itself so I swapped around the speaker connections after I powered down. To my surprise, the right speaker this time was fine while the left had no sound. This seems to point at the Jadis amp.

All the power tubes (8 in total) appear to be lit and you can the little orange glow in all of them. Obviously the next step is to swap the 4 tubes from one side to the other but I'm a little reluctant to do this for fear that there is a bigger problem inside. Probably no choice anyway, its next logical step. Also there are number of smaller signal tubes 3x12AU7 and 2x12AU7.
There was no unusual crackling, smoke or smell at all. It was simply a case of not getting any sound from the right channel after powering on this evening.

Anyway, thought I'd post it here as I'm sure some of you might have come across this before so I'd be grateful if you could share your thoughts.

[fergus]

As the valves themselves are lighting up Dave this would not seem to be where the problem lies. If it were me I would take the relevant valves out and give the pins a clean just to ensure that it was not a connection issue.

I had a similiar problem last year with my Shine amp and when I took it down to Cloney's it transpired to be a simple resistor issue. Hopefully your problem will transpire to be something equally as simple.

Best of luck!

[tony]

Sorry see Fergus got in just before me but we seem to concur

Hopefully only a dodgy valve but strange there is no sound at all from one channel. Never happened thank god here. The Prima luna gave a problem with one channel but it was well announced. Smoke not disasterous but noticeably crackling then gone. Turned out to be a resistor that had given up the ghost.

Maybe one of the signal valves have blown or a fuse or resistor has packed in.

I know the feeling you are afraid tests might cause more problems. No expert but would suggest swapping power valves to the good side first. If working ok which I suspect they will would progress to the signal valves.

After that manual online if you don't have it to see if there are any inline fuses that might have blown but would have thought they would stop the amp powering up.

If there is a positive looks like you have saved a lot of money on Quad Panel replacement!!

[Diapason]

Ask Steve about this one. I seem to recall he went through a stage of blowing fuses on his amps. Hopefully that's all it is.

[Steve]

Have indeed blown a few fuses. Mainly due to batch of JJ-T KT88's which seemed to expire, at times dramatically, way before their time. But you indicate that all output valves are still fine and no fireworks? So may well be one of the small signal tubes. One of the 12AU7's on my mono's expired gracefully number of years back and channel went correspondingly dead.. There's also a single main fuse on the power transformer on each of the amps which can kill the show too. With the build quality on the Jadis kit, would be very hopeful, Dave, that the problem is of this nature.

(should also add that just a week ago, left channel on my setup went awol. After brief panic, realised that, for whatever reason, speaker cable connection on the amp end had become loose. Stereo was resumed after clamping the spades back in position...)

[DaveF]

so it looks like that one of the output valves on the amp is blown and it took a bunch of resistors along with it. So nothing too serious. Resistors are coming in later in the week. I really have to decide now on whether to stay with kt88s or take the plunge and go for kt120s from Tung Sol. 8 of them will set me back ~400 Euro from Hot Rox in the UK. Not too bad considering some dopes spend that on a power chord.

[tony]

Read the Capvs4 thread you were already there. I am asking Jadis about KT120's for my amp out of curiosity.
I think you will like them Dave. They really tighten up the bass albeit listening through those Sonus Fabers is a pleasure probably regardless of what valves are in the amp. Steve has a thread on wigwam about the KT120's and explains what they brought to the table. Much tighter all round compared to KT88's. Glad btw little damage was done. Your other alternative is the KT88 Gold Lion reissues if you prefer a warmer sound

[fergus]

Delighted to see that it was nothing more serious Dave. You should be back up and running pretty quickly and enjoying things again.