6L6GC vs EL34 vs KT77 Tubes... Educate me please

  • Thread starter Thread starter MetalThrasher
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I just got a matched set of JJ EL34's. Can I just take out the 6L6's and put in the EL34's without any bias adjustments?
 
Beyond Black said:
Absolutely not. Must bias the amp.
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That's what I thought. What should the bias reading be for each EL34? Sorry for the dumb question but I just want to be cautious before I attempt anything.
 
MetalThrasher said:
That's what I thought. What should the bias reading be for each EL34? Sorry for the dumb question but I just want to be cautious before I attempt anything.
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You should really calculate that based upon the plate voltage of the amp. Though for most EL34 tubes you can use about 32 MA. On your KSR though it looks like there is a meter on the front where you can just turn the bias pot until the green light is lit.
 
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Ok thanks everyone! I sent an email to Kyle about this. I'm not touching anything until I hear from him.
 
TheGreatGreen said:
Here's a small article by Cliff Chase of Fractal Audio, whose job is to analyze and understand tube amps as much as possible because he has to emulate them accurately enough so that people buy his modeler:



So to sum it up, mostly, any differences in tone between tubes will manifest as being slightly more or slightly less mid scooped due to whatever differences in impedance and therefore damping there will be between the tube types. You're not going to get vastly different, or more / less distortion or anything cast like that.
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Exactly right, changing your tubes won’t have a drastic difference!
 
My experience is that 6L6s are the tightest by far with the most headroom. They have deeper bass and extended highs that give a sharp pick attack.
EL34s are percieved to be tighter, but I think its deceptive because of the comparable lack of deep bass with a pronounced upper midrange. You are just working with a narrower range of response but the sound itself is loose and breaking up with distortion.
EL34 players may think 6L6s are stale because they lack the upper mid breakup that EL34s are known for which is a different feel on the strings when playing.
KT77s are somewhat of a mix but the Tube is overall more compressed with less perceived headroom.
It's cool to try different things, but I end up reverting back to what the amp was designed for after the honeymoon is over..
 
To my knowledge 6l6 amp is not going to work out to well with el34`s without changing some stuff.
 
panhead said:
To my knowledge 6l6 amp is not going to work out to well with el34`s without changing some stuff.
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Will be fine just need to bias
However, it’s a delusion to think switching power tubes changes tone to a degree it’s really noticeable. The dude from fractal Audio is an expert and he’s right. To all of you who disagree, not to be a dick, but you’re experiencing a placebo effect, plain and simple
 
I have EL34's in my PA50. I don't think personally you are going to see much of a difference switching tubes.
 
TheGreatGreen said:
Here's a small article by Cliff Chase of Fractal Audio, whose job is to analyze and understand tube amps as much as possible because he has to emulate them accurately enough so that people buy his modeler:



So to sum it up, mostly, any differences in tone between tubes will manifest as being slightly more or slightly less mid scooped due to whatever differences in impedance and therefore damping there will be between the tube types. You're not going to get vastly different, or more / less distortion or anything cast like that.
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Haha. I don't care how or why he comes to the conclusions here, the bottom line for pretty much anyone who plays through a tube amp is that yes different power tubes DO sound AND feel different when you switch them in an amp. Maybe not enough for some to really care; but for others that 5-10% difference (or more) is HUGE and an important factor in almost everyone's tone quest. EL34s have their 'breakup' or 'distortion' that adds to the playing experience; while a 6L6 amp that same point takes away from the experience a bit(most don't care for a 6L6 tone when it gets to the point of power tube distortion). So he can throw out all the knowledge he wants to justify his conclusions but if you think about it, maybe this is why his products fall short when it really comes down to true Tube amp feel...he doesn't seem to put much emphasis on the 'different tubes give different results' fact that we all know to be true.
Different power tubes will manifest OBVIOUS tonal differences in the same amp.
Fact.
 
Br8krofChainz said:
Will be fine just need to bias
However, it’s a delusion to think switching power tubes changes tone to a degree it’s really noticeable. The dude from fractal Audio is an expert and he’s right. To all of you who disagree, not to be a dick, but you’re experiencing a placebo effect, plain and simple
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Wrong. Get your ears checked. They are obviously shot. Oh, and where did Cliff go to "tube school" to become an expert? He's a software programmer correct? Last I knew that's a little different than becoming an 'expert' in tube amp circuits/design.
Again, see my previous post. This is exactly why his products fall far short when truly emulating a tube amp. He thinks all power tubes sound the same. :ROFLMAO:
 
Br8krofChainz said:
Will be fine just need to bias
However, it’s a delusion to think switching power tubes changes tone to a degree it’s really noticeable. The dude from fractal Audio is an expert and he’s right. To all of you who disagree, not to be a dick, but you’re experiencing a placebo effect, plain and simple
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This is a timely thread that I needed to chime in on. I have a shit load (100+) of NOS tubes that I'm just starting to test before I sell them.
This quote is so wrong!!!! At least you acknowledge you are being a dick, that's admirable.

I gave my friend quad of tubes, NOS GE 6CA7's, just yesterday and he called twice to tell me about what a difference they made. Night and day he said, and he had new tubes in his amp already, a self biasing amp.

Did you ever swap out old tubes for new? No fucking difference, right? Wrong. Sooooo wrong.
 
Br8krofChainz said:
Will be fine just need to bias
However, it’s a delusion to think switching power tubes changes tone to a degree it’s really noticeable. The dude from fractal Audio is an expert and he’s right. To all of you who disagree, not to be a dick, but you’re experiencing a placebo effect, plain and simple
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:hys::hys::hys:
Your post would make sense on April Fool’s Day. Dude, Helen Keller would notice the difference between 6L6’s and EL34’s. Not to be a dick. :thumbsup:
 
Br8krofChainz said:
Will be fine just need to bias
However, it’s a delusion to think switching power tubes changes tone to a degree it’s really noticeable. The dude from fractal Audio is an expert and he’s right. To all of you who disagree, not to be a dick, but you’re experiencing a placebo effect, plain and simple
Click to expand...
The El34`s most likely will not bias up correctly as in low/ been there.
 
panhead said:
To my knowledge 6l6 amp is not going to work out to well with el34`s without changing some stuff.
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Exactly. Better make sure with the manufacturer first; or change at your own risk.
 
KSR amps can generally take any octal tube. I'd be surprised if the PA-50 was any different. Plus you can order with either el34 or 6l6 stock. My guess is he's not making 2 different versions
 
I'm confused how the Fractal dude initially states it makes no difference, (which he states as an objective 'fact' not just his opinion:)

"Well, the fact is that power tubes do NOT sound different. They do not have any intrinsic tone."

then goes on to explain how using different types of tubes results in a different resulting tone:

"It is the impedance of the speaker that affects the tone of the amp and different types of power tubes react differently with that impedance."
"Essentially the EL34 has a higher damping factor than a 6L6. This higher damping factor reduces the mid-scoop due to the speaker impedance. This makes the tone have more midrange."

So using different tubes in the same amp and speaker set up will, or won't change the end result tone?
Power tubes do not sound different but having more or less midrange as a result of swapping tube types as the only variable somehow doesn't sound different coming out of the same amp and speakers?
 
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