Greetings - I recently bought an old Rickenbacker lap steel with a little matching amp - Model M-8. It worked before it was shipped to me.
Then it arrived, I noticed that one of the four tubes had come loose in shipping and had presumably bounced around some. The loose tube was a 6V6 GTA. The tube was not broken and there was no obvious damage to anything else in the cabinet.
Well, the amp does not work. It powers up and the 3 visible tubes (one is shielded)all light up - although the tube that came loose is slower to light up and is less bright. I do get a hum from the speaker (the normal sound I would expect), and the hum gets louder and softer by adjusting the volume pot. But I get no response plugging into my guitar.
I cleaned off the electrical connections and checked for any loose wiring. Any advice on diagnosing this would be appreciated. Are tubes fragile enought that I need to replace the loose one ?
If you need any more info (other tube ID, etc) let me know. Thanks in advance for your help!
Need Help Diagnosing Ricky Tube Amp Problem
Moderator: Shoshanah Marohn
-
Loren Larson
- Posts: 26
- Joined: 31 Mar 2003 1:01 am
- Location: Plymouth, Minnesota, USA
-
Ole Dantoft
- Posts: 413
- Joined: 31 May 2001 12:01 am
- Location: Copenhagen, Denmark
- Contact:
Loren,
To answer your last question first : Yes, tubes ARE indeed fragile enough to be damaged if bounced around !
However, it doesn't seem to me like that's your problem in this case. The 6V6 is a power amp tube and your power amp must be working - at least to some degree - if you can get a hum that follows the volume control - that indicates a fault in the preamp. Have you checked all the other tubes, even those in shields, that they havent come loose ?
Even if there's no immidiate physical damage or loose tubes, take it to a repair guy, because when a relatively small and light tube like a 6V6 is actually forced out of it's socket, chances are that the amp has gotten a pretty good beating and anything inside could have come loose. This could even be hazardous for you, so have it checked !
Ole
P.S. : "The amp worked before being shipped to me" - is that fact or salesmans-talk ? Just curious !
To answer your last question first : Yes, tubes ARE indeed fragile enough to be damaged if bounced around !
However, it doesn't seem to me like that's your problem in this case. The 6V6 is a power amp tube and your power amp must be working - at least to some degree - if you can get a hum that follows the volume control - that indicates a fault in the preamp. Have you checked all the other tubes, even those in shields, that they havent come loose ?
Even if there's no immidiate physical damage or loose tubes, take it to a repair guy, because when a relatively small and light tube like a 6V6 is actually forced out of it's socket, chances are that the amp has gotten a pretty good beating and anything inside could have come loose. This could even be hazardous for you, so have it checked !
Ole
P.S. : "The amp worked before being shipped to me" - is that fact or salesmans-talk ? Just curious !
-
Jim Florence
- Posts: 794
- Joined: 4 Aug 1998 11:00 pm
- Location: wilburton, Ok. US * R.I.P.
Depends on whether you have 2 6V6s [Push- pull}. If you do have two of them and one is bad , that can hum, as the two 6V6s cancel each other out on the hum thing. But since the hum does follow the volume control, like he said that is indicative that the preamp is at least working some. A small vintage
amp is easy to fix. Put new tubes in it, and it will probably work fine.Oh yeah, if it is push-pull, the amp will still work with only one of them, just sound like crap.
amp is easy to fix. Put new tubes in it, and it will probably work fine.Oh yeah, if it is push-pull, the amp will still work with only one of them, just sound like crap.