Amp Tubes.

[64Firebird]

Can anyone tell about the different tones of different tubes or give me a link to some info? I'm playing Blues through a 64 Blond Fender Bassman 50 watt amp and 2X12 cab.

[mixmkr]

I think the russian tubes give you more of a J-station sound, while the chineese tubes sound more POD-ish.... I think if the tubes are mismatched...they'll tend to make things sound more like the zoom products.

[M.Brane]

Get yourself a copy of Aspen Pittman's "The Tube Amp Book". He explains the different types of tubes and their signature sound very well. I also helps that it's from a guitarist's point of view and not that of an "audiophile".

As a general rule 6L6's tend to have a round clean tone which gets more mids as it's pushed into distortion. Think old time rock & roll.

EL34's have more of a flat, hi-fi clean tone but tend to distort sooner and smoother than 6L6's. They also pick up an upper-midrange bite a-la classic Marshall crunch.

6550's are very clean and tend to stay that way until really pushed when they clip harder like an FET. Think metal tone.

How the tubes are used in the circuit has a lot to do with the sound as well. A class-A curcuit will yeild more distortion with less output but it's a sweeter distortion than A/B.

The differences in preamp tubes is more from gain standpoint, the 12AU7 & 12AY7 being lower gain than the classic 12AX7. I run a 12AY7 in the normal channel of my Super for bass and electric/acoustic.

Of course within these basics you have tubes of the same type that sound different from one another due to slight differences in construction

Hope this helps.

[64Firebird]

Yes, that does help and I'll look for that book.

[bongolation]

Are you asking about the specifics of various makes of tubes that you are using in this amp, like "what's a good 12AX7?"

[fenix]

Originally posted by 64Firebird
Can anyone tell about the different tones of different tubes or give me a link to some info? I'm playing Blues through a 64 Blond Fender Bassman 50 watt amp and 2X12 cab.

Make sure when you switch to different kinds of tubes that you have your amp re-biased!

[bongolation]

Originally posted by fenix
Make sure when you switch to different kinds of tubes that you have your amp re-biased!

You should mention that this applies only to power tubes.

Also, many amps are not readily biasable (is that a word?), being cathode-biased and soforth, so-called "self-biasing" amps - which is something of a misnomer.

[LocusLarsen]

I was thinking about re-tubing my Blues Junior....I wan't it to get as clean as possible so when driven it shimmers more so than distorting into distortion. Okay, that made no sense, so, when the amp breaks up I want it to be smooooooooth as silk.

On a side note, isn't the BJ reverb a 3 spring and not a 6 spring like the Delux and Deville? Is that replaceable?

[LocusLarsen]

I am mostly using a Tele but do have a Les Paul. The Tele sound pretty good right now and the LP breaks up a bit uglier than I would like it too.

[bongolation]

Originally posted by LocusLarsen
I was thinking about re-tubing my Blues Junior....I wan't it to get as clean as possible so when driven it shimmers more so than distorting into distortion. Okay, that made no sense, so, when the amp breaks up I want it to be smooooooooth as silk.

On a side note, isn't the BJ reverb a 3 spring and not a 6 spring like the Delux and Deville? Is that replaceable?

You might want to try JJ EL84s and experiment with some different 12AX7s. Basically, there's not a lot you can do with a Blues Junior. They are what they are.

I believe the reverb pan is a two-spring, but I haven't looked. It's that same unit as on a bunch of cheaper Fender amps.

The Blues Junior reverb circuit was its weak link until the final US revision D that was in production for only a few months before amp manufacturing was moved to Baja. It's a solid-state circuit that operates on a TL072 JFET OpAmp and is usually somewhat noisy and weak. I hate it. In 2001, they changed the OpAmp to a 4560 and moved the reverb circuit to a different spot in the signal path after a few jillion complaints from users.

I don't think that changing the pan will matter much, as the existing circuit doesn't have the grunt to run the original one.

[64Firebird]

Originally posted by bongolation
Are you asking about the specifics of various makes of tubes that you are using in this amp, like "what's a good 12AX7?"

More like what's difference between a 6L6 and an EL34 or whatever tonally.

[Tom Hicks]

Check this tube article out...
tube article

[Sonixx]

Try your questions on one of these:

Fender and Marshall Discussion Boards

Fender Discussion Page - Amp Mods and Repairs

Guitar Discussion Forum

[64Firebird]

Thanks guys. Great artical Tom, just what I had in mind.