I had a power tube go out on me Saturday and I replaced the quartet with an older set (with low hours). As I was playing for a while I started to notice a weird harmony. The amp was generating some sort of lower frequency sub-harmonic ghost note (not sure what the technical term for this phenomenon is called).
Does anyone know why this would occur and how to fix it?
Planning on it as soon as new ones arrive but was unsure if power tubes could produce that sort of phenomenon. So the questions becomes can power tubes cause that problem or is it likely something else is causing it?
Post by headshrinker (Marc) on Oct 23, 2012 8:17:49 GMT -7
Tubes can cause that sort of problem. Especially if they are getting vibrated. If you have a head and cab try separating the head from the cab and see if it goes away. You might also try swapping the position of the tubes. What vibrates in one position doesn't always in another. If you had the amp up loud you might have a speaker thing going on. Try another speaker if you have one. Also try the old tapping on the tubes with a pencil eraser and see if you can reproduce it. Don't forget the preamp tubes.
Any reliable tech can replace a cap. If you send it to the Doctor they will also check all the voltages throughout the amp. They will know what the design voltages should be and, from past experience, what else to look for.
If I lived as close as you do I would take it up there myself. I always like doing business face to face.
Jaguarguy (Mike): Hey Gary - Joe Walsh used a G12 65 in his Galaxie and it sounds great!
Mar 25, 2019 23:05:29 GMT -7
GuitarZ: So, I cranked up the privacy protection on my browsers, facebook, etc. I have to say I miss the music ads and such. I really don't need ads for watches and other random stuff. Maybe the internet knowing me isn't such a bad thing.
Mar 26, 2019 14:01:24 GMT -7
hayesgary307: hanks alot (Mike) I have been going through a Vintage 30 in a open back pine cabinet and through a Marshall 1936 C/B 2-12 I'll check and see what kind of speakers are in the 1936. I've had for a long time and I have forgot whats in it . Thanks for you help
Mar 27, 2019 12:06:54 GMT -7
Joey Beverages: hayesgary307 try a Z 210 or Z 410 with Galaxie ... also, yes the G1265 is most tasty and excellent
Mar 28, 2019 6:03:29 GMT -7
The Bad Poodle: This may be a truism... when you work in a corporate structure, the worst decisions always come from the top.
Mar 29, 2019 16:26:10 GMT -7
Lefty: The fish rots from the head down.
Apr 1, 2019 13:26:26 GMT -7
TeeDawg: Bad Poodle..........truer words have never been said. Imagine what it's like working for NASA. This ain't the nasa that went to the moon fo sho.
Apr 26, 2019 5:59:08 GMT -7
brayks: I have been absent for waaay to long. hope all are doing well!
May 1, 2019 10:19:39 GMT -7
GuitarZ: I'm okay with the AARP letters. You're still living and breathing? What the heck am I to think when a funeral home sends me a free consultation offer? Ouch!
Jun 21, 2019 15:41:26 GMT -7
The Bad Poodle: I bought airline tickets online... now every few days i get emails that read "Your trip is almost here but aren't you forgetting something?? You don't have trip insurance!" and i'm thinking..."is there something i should know about your plane maintenance?"
Jun 21, 2019 16:02:32 GMT -7
GuitarZ: Reminds me of buying my Honda. When they tried to sell me the maintenance package, I said "Is your car not reliable?" Long story short my wife teamed up with the sales lady to buy the maint package. Never again!
Jun 21, 2019 16:16:53 GMT -7