Peavey Classic 30 Issues

nick · 2010-03-16T19:28:59+00:00

I took my amp to Graemestock where it got a bit of a workout by Cannons band and whoever else jammed. Then took it to the Farm Blues jam, brought it home and...

Peavey Classic 30 Issues

peters

Jack Flash Jr wrote:
peters wrote: Seeing that it was my son's Vox I was using, the master volume did not go beyond six.
You did indeed look after your son's gear very well... but little do you know what we were doing with it while you were eating your boerie roll ?

I can see that I am going to have to buy my own amp, if future boerie rolls are involved ..... if he reads this topic I am so dead !!!

nick

A temporary fix till I can order a set of 4 matched JJ's 8)

nick

Amp runs fine for a while, switch it off leave it to cool down. Come back about an hour later turn it on and it starts humming and then two valves glow twice as bright as the others..

kayDUB

hmm, i know pretty much jack about this, but might be a bias issue? since you only replaced one tube?

nick

kayDUB wrote: hmm, i know pretty much jack about this, but might be a bias issue? since you only replaced one tube?

Its a fixed bias amp, plus the tube I replaced was exactly the same make etc as the one I removed. It seems to be behaving now though..

oh and I burnt my finger properly on one of the EL84s ☹

nick

Spoke too soon, just blew another tube ☹

MikeM

That sucks man ☹

Sean

Great photo though... :-[ ...sorry, too soon to joke about it?

nick

Sean wrote: Great photo though... :-[ ...sorry, too soon to joke about it?

nah, I want to take a few more pictures, tubes have this lovely blue glow (when working properly ? )

nick

Seems it blew a fuse, not sure what its for, says 250v 1a on it, where can I source another one?

AlanRatcliffe

Just about any electrical store will have. Many hardware stores have as well. Get a few.

To be honest, I'd speak to Matt or Karel first though (just to be on the safe side) and replace all the power valves before replacing the fuse. Admittedly, I'm paranoid of this high voltage electronics stuff...

MikeM

Yea Nick.. Messing up 2 tubes and a fuse doesn't sound right..

nick

F2 is the heater fuse so must be a bad set of power valves (I hope). New fuse, new valves and try again ☹

TomCat

nick wrote:

Amp runs fine for a while, switch it off leave it to cool down. Come back about an hour later turn it on and it starts humming and then two valves glow twice as bright as the others..

Looks to me like the biasing on one side is up the spout, possibly a biasing resistor that has gone US or a bad solder joint seeing that it happened after the amp was transported.

Time for a tech to look at it and find out what is wrong there.

nick

TomCat wrote:
nick wrote:

Amp runs fine for a while, switch it off leave it to cool down. Come back about an hour later turn it on and it starts humming and then two valves glow twice as bright as the others..

Looks to me like the biasing on one side is up the spout, possibly a biasing resistor that has gone US or a bad solder joint seeing that it happened after the amp was transported.

Time for a tech to look at it and find out what is wrong there.

After this picture I switched the valves around and then only a single valve was glowing bright and it was then second from the left.. Then the tube started going nuts and the fuse blew

Karel-Mars

Where is Matt and Karel? Probably rolling some tubes and smoking some amps in the workshop 8)

That blue glow does look unsettling. Note: the fuses used in tube amps are special. SLOWBLOW fuses are what you need. Get them from electronic shops. They cost a bit more than the fast blow types which are more common. Like someone said; get ten.

Tubes are not necessarily your problem though. The vibrations/heat in combos causes cracks to appear in the solder joints that are on the pcb. A good tech should be able to scan the pcb and resolder the bad joints.

Tubes are vulnarable to damage when some of their connecting points are not connected, especially the input grid (through which the fixed bias voltage appears). Rather switch off till you get it fixed ?

nick

Karel Mars wrote: Where is Matt and Karel? Probably rolling some tubes and smoking some amps in the workshop 8)

That blue glow does look unsettling. Note: the fuses used in tube amps are special. SLOWBLOW fuses are what you need. Get them from electronic shops. They cost a bit more than the fast blow types which are more common. Like someone said; get ten.

Tubes are not necessarily your problem though. The vibrations/heat in combos causes cracks to appear in the solder joints that are on the pcb. A good tech should be able to scan the pcb and resolder the bad joints.

Tubes are vulnarable to damage when some of their connecting points are not connected, especially the input grid (through which the fixed bias voltage appears). Rather switch off till you get it fixed ?

I bought 5 250v 1a slowblow fuses from Mantech during lunch, a whole R4. Im going to put in a new fuse and try out the 2 new tubes I have and if I cant find a combination or it pops the fuse again can you have a look? ☹

nick

New fuse in, pre-amp valves in, power valves in, one arc's hectically inside the tube, swop that one out with the spare other 3 and its always that tube. Need a single EL84 thats working to confirm this, still dont see how 3 tubes could randomly die without something upstream causing it ☹

FenderBender

+1 Karel

3 tubes behaving the same way is indicative of something else being wrong, more than likely bad joints, as you mentioned.
I had a Peavey in a little while back with loads of dry joints and a few hairline cracks between the tracks and the solder pads due to hot and heavy components shaking loose during transport.

[deleted]

In other words, the blues jam killed your amp, Nick. Which is...more fodder for the next blues jam!