recto tube rattle?

ayoldguy1 · Post by **ayoldguy1** » Sun Feb 09, 2003 2:29 am

Hey all- I just bought an AD15-12 and at high volume/bass, I hear a rattle- i think the rectifier, since when I tap it w/o it being switched on I hear a slight rattle- from the back of the cab where the tubes are. What can I do about this- I'm kinda new to tube amps. Thanks!

-Alan

VintageJon · Post by **VintageJon** » Sun Feb 09, 2003 3:27 am

Seen this many times. It sounds like what is commonly known in the industry as filament rattle. (The filaments in the tube are rattling).

Suggest you replace the rectifier tube. If it's a GZ34/5AR4 there is very good news. JJ is about to release a new GZ34 that appears to be a
modern production Mullard. Both "beta test" release examples I've been
beta-testing are excellent with no rattle and the best high-voltage/
lowest internal resistance I've seen in a GZ34. Available thru Antique
Electronics next week sometime- according to my sources.

-Jon

ayoldguy1 · Post by **ayoldguy1** » Sun Feb 09, 2003 4:45 am

Thanks. Now that you mention it it seems that it sounds like a filament, like in a light bulb. I'll look into that JJ tube. Thanks again.

-Alan

deforest · Post by **deforest** » Fri Feb 14, 2003 6:42 am

What was not stated is if the rattle is coming from the speaker or is it a mechanical noise from the amps vibration. Many tubes will rattle if tapped and be fine. If it is a mechanical vibration then yes the recto tube is probably it. If it is a sonic noise from the speaker then: Warm up the amp and leave it on with the volume up not too loud. Many times the problem is a preamp tube but it could be a power tube. Tap each tube gently with a pencil and see which one makes a rattle from the speaker when tapped.
-DeForest

recto tube rattle?

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