[decesaro]

Aren't all tubes supposed to lit up ? I have a few tubes that can with my mg head and as I was going thru the stock I ran across one that didn't lit up , when I went to plug in my head phones , sound came thru the 580's ,does this just mean that the tubes on its way out or is it right for some not to lit up . I didnt here any distortion thru the phones ,
Also how do I go about ordering tubes for the mg head , is it as easy as ordering tubes with the same pin sizes or is it more involved
Thanks


Id also like to add that this amp has changed the way I listen to music ,Ive never heard an amp sound so full and warm ,I cant seem to stop listem to this set up ,I can tell you this that Im going to definently look into some tube amps for my magnapans ,I real think thats whats been missing with those speakers some much needed warmth

 

[gdahl]

decesaro,

All tubes of the type you are using are supposed to light up, but sometimes it doesn't show up very well.

When a tube is made, the filament is folded over itself several times and slid into the cathode sleeve. Usually a bit of the filament peeks out the end of the filament sleeve. When you see the tube light up, the brightest part is that little bit that peeks out.

Sometimes the way things line up in a particular tube, there isn't any filament protruding from either end of the cathode sleeve, so the tube won't appear to light up. The cathode sleeve itself usually glows faintly, though, and if you operate the tube in darkness you should be able to see it somewhere unless the flashing (mirrored surface) is completely concealing it.

Normally, some tubes will appear to not light as obviously as their neighbors. It doesn't hurt to check the filament voltage if in doubt, or test the tube with a tube tester.

 

[Hirsch]

Quote:

Originally posted by decesaro Also how do I go about ordering tubes for the mg head , is it as easy as ordering tubes with the same pin sizes or is it more involved

Hoo boy. There's a bit more involved. You need to determine which type of tube the amp uses (there are MANY tubes at each pin size). Then, you need to figure out if there are any possible substitutions for each of the types, in that amp. Then, you need to figure out which brand of each type sounds best with your amp. Ultimately, that may come down to your personal taste. Not all brands sound alike. Then, you've got to figure out your budget, because the well-regarded older tubes often don't come cheap. Once you've gotten all that sorted out to the best of your abilities, you've got to figure out where to buy them. Take a chance on ebay, or buy from an established dealer?

There's a lot of information on tubes for the MG Head here, if you do a search. Nick Dangerous has an MG Head tube rolling page, IIRC. Those might be places to start...

 

[decesaro]

Quote:

Originally posted by gdahl decesaro, All tubes of the type you are using are supposed to light up, but sometimes it doesn't show up very well. When a tube is made, the filament is folded over itself several times and slid into the cathode sleeve. Usually a bit of the filament peeks out the end of the filament sleeve. When you see the tube light up, the brightest part is that little bit that peeks out. Sometimes the way things line up in a particular tube, there isn't any filament protruding from either end of the cathode sleeve, so the tube won't appear to light up. The cathode sleeve itself usually glows faintly, though, and if you operate the tube in darkness you should be able to see it somewhere unless the flashing (mirrored surface) is completely concealing it. Normally, some tubes will appear to not light as obviously as their neighbors. It doesn't hurt to check the filament voltage if in doubt, or test the tube with a tube tester.

Thanks I didnt know that the filament was inserted into a sleeve its very small and its had to see whats going on in there ,
I went ahead and looked at it again and yes it does lit up very faintly ,Thanks for explaining that .

 

[decesaro]

Quote:

Originally posted by Hirsch Hoo boy. There's a bit more involved. You need to determine which type of tube the amp uses (there are MANY tubes at each pin size). Then, you need to figure out if there are any possible substitutions for each of the types, in that amp. Then, you need to figure out which brand of each type sounds best with your amp. Ultimately, that may come down to your personal taste. Not all brands sound alike. Then, you've got to figure out your budget, because the well-regarded older tubes often don't come cheap. Once you've gotten all that sorted out to the best of your abilities, you've got to figure out where to buy them. Take a chance on ebay, or buy from an established dealer? There's a lot of information on tubes for the MG Head here, if you do a search. Nick Dangerous has an MG Head tube rolling page, IIRC. Those might be places to start...

O my this sounds like it could cost some money if I do this on my own ,I think Ill do a search for some tube rolling to start with , Ill also look up Nick Dangerous
Thanks

 

[gdahl]

The MG Head uses two 6BQ5's and one 12AX7. Here are some possible sources for tubes:

Triode Electronics is my favorite place to get tubes. Reasonable prices and no-nonsense good service. Owner Ned Carlson has some useful guidelines for tube selection on his site.

Antique Electronic Supply is where you can fine an especially wide selection, usually including rare types. Antique's prices reflect (and even are a factor in establishing) collector pricing, which you will probably notice when you see the prices for some of the brands!

IMHO, the high-priced collectible tubes don't necessarily produce sonic improvements proportional to their cost. Some of the inexpensive tubes sound excellent, but then, not all do. Good luck!