Trouble with valve gear

Jackie3horn

Hello,
I have a bunch of valve amplifiers that give me all kinds of trouble..

mainly i am writing this to ask whether anyone had comparable problems with same style amps or even similar. I am new here and after reading the charter it really gets difficult to write a post having to remember all the questions that you can't ask here and be banned by the forum peoples.

Anyway i will start,
I Have two 30 watt valve combos one is a 70's period Vox AC30. It has no circuit boards but the old style point to point soldering. It worked fine for a while. When i got it some of the valves were gone so i replaced them alongside with a capacitor that has seen some serious heat and started melting.

Secondly i have a Laney VC30,
i got it from an amp fixer in limerick who is meant to be this valve amp Guru but has not been able to fix or even do as little as identify the problem. However from more previous investigations it became apparent that there is more than just one problem with it. I was told to replace valves which i did but problems persisted.

now to the manifestations themselves weirdly enough the Vox and Laney do the exact same thing. They heat up fine and play nicely for a while until everything starts to go wrong. at the beginning of each session all the valves in both amps glow nice and evenly then the amps start to drop in volume and sound more and more distorted plus going progressively quieter. similar to what it sounds like when you power the amp off and keep playing.
At this stage two of the output valves(el84) will be dark and the other two glow heavily red hot. in both amps the same.

the laney develops another plethora of squeaky noises at this stage and a life on its own.

I heard somewhere that the Vc C30 is based on the AC30 design i wonder how similar they really are, and could it be the same problem with both amps, soon as it looks the same really.


My third problem child is an Ibanez Valbee. A little 5 watt valve powered practice combo. Which just stopped working one day completely without warning. the lights will still light up and all so its not just a fuse or something. A friend had a look for me and said the transformer is gone in it.

First of all had anyone ever experience with any ibanez amps or even this one as i cant seem to find parts or customer service contacts anywhere, as i think ibanez never really built those themselves, and really only build guitars.

Then the more general question, i am always really careful with my gear its sitting in a nice warm house and i warm it up properly before playing and never drive it tooo hard. Well... loud yes, but never hourlong ''controls to the max'' orgies. I have lived in several different houses, but could it be faulty mains or something, but if thats the case why doesn't everything else electrical in the house break too?

am i cursed when it comes to valve gear??

If anyone can shed a bit more light on this i would be very grateful..
thanks for reading

hope i stayed within the realm of legal conduct in this forum and wont be punished heavily he he..

TroutMask

The VC30 and the AC30 have similar output stages, however, the Laney has a few ICs tucked away in there where you can't see them. So it's a valve/solid state hybrid. The AC30 needs a rebuild, the electrolytic (can) caps need to be replaced and it sounds like the plate resistors on the output valves are going open, this would explain the the glowing valves - the symptom is a deep ruby-red glow on the grey plates inside the valves. You don't want to run it like this as you can damage the amp by leaving it in this state. Time for a complete rebuild, Owen in Some Neck guitars knows a good tech.

godfrey

www.audiotronix.ie for all repairs, and especially for valve gear...

g

Jackie3horn

Thanks lads..

@trout mask:Yes the glow is deep red on the shields, also the valves have developed scorchmarks on the inside.

I will better get the amps seen as i dont really know what i am doing there anyway, and am no totally keen on electrocuting myself or burning down my gear.. As soon as the faults appear i usually switch the amps off and i havent used them for playing since they went faulty..

thanks for the replies. However if anyone can help me with my part supply problem for the little ibanez amp mentioned in my post i would be most appreciative