ratttling Blues master

[norburybrook]

Hi Guys,

Annoying little issue with my Bluesmaster; it rattles when on top of it's matching EV cab.

I've tightened everything I can think of, so ; Do the valves internals rattle?

I can't think of anything else it can be. What can I do as the amp sounds beautiful otherwise?



Marcus

[ayan]

Hi Guys,

Annoying little issue with my Bluesmaster; it rattles when on top of it's matching EV cab.

I've tightened everything I can think of, so ; Do the valves internals rattle?

I can't think of anything else it can be. What can I do as the amp sounds beautiful otherwise?



Marcus

Absolutely yes. Historically, this has been the number one reason I've sent tubes back. It may take about 20 minutes for the tubes to get nice and warm and loose to where they start to rattle.

Gil

[norburybrook]

Hmmm....a matched set of quad 6L6's aren't cheap on this side of the pond!!!

I suppose it's too late to send them back now after 6 months.



Marcus

[xtian]

My last rattle hunt was a bitch. Turned out to be two flying signal wires running from the turret board to the volume controls. I had the wires routed flat against the face plate, and when I moved the wires away, so they weren't touching the chassis, it solved the rattle. Wasn't a physical rattle, though, it was some weird magnetic coupling!

Tools that helped me find the issue: iPhone based sine wave generator and chopstick.

[norburybrook]

This is definitely a metallic , frequency dependent mechanical rattle.

M

[glasman]

You could try tube dampers (o-rings) to quiet the tubes. I have used them in the past and normally work well.

Check fleabay (ebay).

[norburybrook]

I've e already tried that, all 4 output valves have them.

I've never really understood the use though as surely a silicone ring round the outside of the glass cannot stop the internals rattling.

Actually , it might not be the output valves, I suppose it could be one of the 12 AX7's......how would you test?....... valve swapping session?


M

[ayan]

I've e already tried that, all 4 output valves have them.

I've never really understood the use though as surely a silicone ring round the outside of the glass cannot stop the internals rattling.

Actually , it might not be the output valves, I suppose it could be one of the 12 AX7's......how would you test?....... valve swapping session?


M

It could be the preamp tubes too. In that case, you can put an oven mitten on and grab the little bugger physically and see if that helps with the rattle. I also had to eat it once with a quartet of 6L6s because I didn't test them right after getting them. By the time I decided to use them, about one year later, I found out one would rattle after a warm up period. You can still save the most closely matched two. No need to have a perfectly matched quartet in an amp, you can make do with two matched pairs provided they are not on opposite sides of the spectrum bias-wise.

G.

[norburybrook]

Well I have a 50/100w switch so I could swap out my known good pair from my #102 and see if I can find the culprits.


Can I remove the unused pair completely if I use the 50w switch?



M

[ayan]

Well I have a 50/100w switch so I could swap out my known good pair from my #102 and see if I can find the culprits.

Can I remove the unused pair completely if I use the 50w switch?


M

Even if you don't flip the switch to the 50W position, you can pull out one tube from each side of the OT and play. Now, if you don't plug your "X-ohm" speaker into the "X/2 ohm" speaker jack, you will wear the tubes out faster. For what it's worth, I always play my 8 ohm cabinet into the 4 ohm OT tap using all 4 tubes. So, a deliberate mismatch since I prefer the feel of the amp that way -- noticeably spongier.

G.

[Structo]

I have a 4x EL84 combo amp that would rattle a bit when turned up.

I bought some of those high heat O-rings to dampen the tubes.

It did help a lot, but just remember that combo amps are much
more susceptible to filament rattle than a separate head and spkr cab.
Combo amps are a torture chamber for tubes with more heat and sonic problems from loud sound waves hitting the tubes.

Many modern tubes have a spiral filament to counter rattle or ringing.
I think that may be only preamp tubes though.

A lot of vintage tubes had this problem since amplifiers back in the day weren't turned up too loud in most cases.

Good luck!