I just was on eBay and saw someone say that their guitar amplifier had better fidelity because they had replaced ("upgraded") the metal tubes with glass ones. I had to laugh at the fool. Just because they look pretty doesn't mean that they work better. The metal tubes are actually the better ones because they don't allow in any interferance. With wide open amplifiers with speakers of very wide range, I have never heard an increase in fidelity by switching from metal to glass tubes.

T.D.

Hi Thomas

Those are the same guys who say one brand of tube sounds better than another. My ears can't tell the difference.

There are a few differences between glass and metal, capacity & temperature. Capacity in PF shouldn't effect audio. Metal tubes, especially 6F6, operate much hotter than glass due to size. Don't see how this makes a difference either?

Norm

:I just was on eBay and saw someone say that their guitar amplifier had better fidelity because they had replaced ("upgraded") the metal tubes with glass ones. I had to laugh at the fool. Just because they look pretty doesn't mean that they work better. The metal tubes are actually the better ones because they don't allow in any interferance. With wide open amplifiers with speakers of very wide range, I have never heard an increase in fidelity by switching from metal to glass tubes.
:
:T.D.

Well, as for brands....sometimes there is a difference. You have to listen very closely. This is not something to go by, though, because it depends on when the tube was made and all. Looking at various 6V6G tubes made by RCA, the plate shape, etc. changes over the years, which will change how the tube operates slightly. That said, one cannot swear by a brand. Still, different tube construction does change the audio ever so slightly. If you have a musical ear (I have a very musical ear--cursed almost) and some fairly good speakers, you can detect the difference on occasion, but if you do not, you will be able to enjoy all the tubes. For instance, my Super Silvertone 6V6G which goes in my Silvertone phonograph Radio Recorder has a slightly harsh sound to it--in the middle register. Put in a 6V6GT made by Sylvania in the 1960s, and the sound is more even and the highs tend to come out more clearly. Same if you put in a Zenith 6V6G from the 1940s or 1930s. The Zenith tends to have a brighter sound than the Silvertone. This repeats itself when other Silvertone 6V6 tubes of the 1940 vintage are used. They tend to be ever so slightly harsh and accentuate the trumpets really well. The Zeniths and the Sylvania tend to accentuate the hiss of a flute.

There are also differences between tube types...a 6V6 tends to bring out more of the highs above 10 KC, where-as a 6F6 or 6K6 tends to be slightly muffled in that register. If the circuit is designed around the tube at hand, though, usually you can make it do what you want it to. Tube emission also has something to do with how the audio sounds.

Anyway, these are subtle differences not to be worried with unless you are playing symphonies through your best speakers. With an AM radio you do not notice these differences much.

T.D.

:Hi Thomas
:
: Those are the same guys who say one brand of tube sounds better than another. My ears can't tell the difference.
:
: There are a few differences between glass and metal, capacity & temperature. Capacity in PF shouldn't effect audio. Metal tubes, especially 6F6, operate much hotter than glass due to size. Don't see how this makes a difference either?
:
:Norm
:
:
::I just was on eBay and saw someone say that their guitar amplifier had better fidelity because they had replaced ("upgraded") the metal tubes with glass ones. I had to laugh at the fool. Just because they look pretty doesn't mean that they work better. The metal tubes are actually the better ones because they don't allow in any interferance. With wide open amplifiers with speakers of very wide range, I have never heard an increase in fidelity by switching from metal to glass tubes.
::
::T.D.