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

Uh…different pinouts on the EL34 and 6L6. If the amp isn’t specifically designed to take both (as in a single-ended design) then it won’t work.
 
Geo said:
People don't realize that they are mostly hearing the preamp.
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Then why do I hear a noticeable difference in my rectifier when I swap in EL34s in place of 6L6s? Same preamp no?

Power tube changes make a noticeable difference in tone, to my ears anyway. Maybe I hear things you don't.
 
ZEN Amps said:
He's right on both counts. The tubes themselves do not have an intrinsic frequency response. However they generally perform differently in amps. Why? Well Cliff explained this in part but it may not be easy to follow. It may be semantics but it's the way a tube interacts with the circuit, output transformer and speaker system as a whole that determines 'tone'.

Here's a terrible analogy I'll probably get mocked for, and is not meant to be condescending but here goes. Pretend a tube is a completely colourless/tasteless food additive. Additive 1 is coincidentally called EL34, and 2 is called 6L6. Taste now = tone.

- Add EL34 to your Ma's pasta sauce. It reacts with all the other ingredients and the sauce is now very salty.
- Add 6L6 and it turns out sweet.

Fact 1 - EL34 and 6L6 have no taste.
Fact 2 - In this specific case, the two sauces taste different.
Incorrect assumption 1 - EL34 is salty, 6L6 is sweet
Incorrect assumption 2 - adding EL34 will always make the sauce saltier, 6L6 will always sweeten.

To complicate things further - adding EL34 to your wife's pasta sauce makes it bitter, and 6L6 makes it salty.

So why does this happen? Impossible to explain without all the technical talk - understanding tube circuits and the complexities of the entire ecosystem is not for the faint hearted, it's a deep deep subject. Cliff attempted to summarise the basics and was been misquoted on various forums more times than I can count.

To sum up - a tube does nothing in isolation, and it's 'tone' is entirely dependent on the specific situation (the sum of all the ingredients). Hell even different speakers will make your amp react differently. Nothing happens in isolation.

End bad analogy. Flame away if you wish - but if you do, please include a good sauce recipe at least.

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Again, see my Rectifier analogy...same amp, same transformers, same preamp tubes/circuit. Why then do I and many many others hear a noticeable difference when swapping out different power tubes? EL34, 6L6, KT77, KT88....they all sound different from each other in Rectifiers.
 
You hear a difference because there is a net result difference. No argument here my friend, we've had similar results in an amp we're designing, and in many others too. Typically pretty subtle, but measurable by instruments and discernible to attuned ears.

The point I think that is often missed, and then leads to confusion and argument is the why. Maybe I'm not explaining it all that well, but as a general trend amps produce more lows and an attenuated midrange when using 6L6's, whereas an EL34 may result in the amp producing less low end resonance and a flatter midrange. However the tube itself doesn't have this sound intrinsically embedded in it. I think it's assumed there is an EQ curve associated with different tube types - not the case at all.

So in a Recto say, the amp/speaker combination will produce more low end when 6L6's are used due to the particulars of the circuit, the output transformer etc. This is not the same as saying 6L6's have more bottom end. For some this may seem pedantic but I don't see it that way, it's about definitions and understanding the bigger picture.

I hope this doesn't come across as preachy, or that I think I'm a know-it-all...but man there's a shit tonne of argument online about this. So here's my take on it after decades of playing around with these fun but dangerous boxes we call guitar amps:

- The guys that say swapping output tubes changes the tone are correct.
- Those that say output tubes make no difference are incorrect - but the changes may be insignificantly small.
- Argument about 'how much' difference there is entirely subjective and can be grossly exaggerated or downplayed depending on the individual (and their situation, hearing or agenda).
- Putting in 6L6's may or may not give you more bottom end, less mids etc. It's entirely dependent on the amp and cab in question.
- Practicing for an extra 10mins a day will have more affect on your tone than most of this stuff.

Now where are those sauce recipes?
 
All good. Cliff's burst just came across as a bit contradictory and heavy handed without explaining exactly why as eloquently as you have. Your last paragraph is perfect for me.

I'd share my sauce recipe... but it's a secret even from my wife. Gotta keep some mystery :)
 
ZEN Amps said:
You hear a difference because there is a net result difference. No argument here my friend, we've had similar results in an amp we're designing, and in many others too. Typically pretty subtle, but measurable by instruments and discernible to attuned ears.

The point I think that is often missed, and then leads to confusion and argument is the why. Maybe I'm not explaining it all that well, but as a general trend amps produce more lows and an attenuated midrange when using 6L6's, whereas an EL34 may result in the amp producing less low end resonance and a flatter midrange. However the tube itself doesn't have this sound intrinsically embedded in it. I think it's assumed there is an EQ curve associated with different tube types - not the case at all.

So in a Recto say, the amp/speaker combination will produce more low end when 6L6's are used due to the particulars of the circuit, the output transformer etc. This is not the same as saying 6L6's have more bottom end. For some this may seem pedantic but I don't see it that way, it's about definitions and understanding the bigger picture.

I hope this doesn't come across as preachy, or that I think I'm a know-it-all...but man there's a shit tonne of argument online about this. So here's my take on it after decades of playing around with these fun but dangerous boxes we call guitar amps:

- The guys that say swapping output tubes changes the tone are correct.
- Those that say output tubes make no difference are incorrect - but the changes may be insignificantly small.
- Argument about 'how much' difference there is entirely subjective and can be grossly exaggerated or downplayed depending on the individual (and their situation, hearing or agenda).
- Putting in 6L6's may or may not give you more bottom end, less mids etc. It's entirely dependent on the amp and cab in question.
- Practicing for an extra 10mins a day will have more affect on your tone than most of this stuff.

Now where are those sauce recipes?
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When I think about it, there is a subtle yet noticeable change in the tone, mainly the compression/low end response when I switch to a lower impedance on my amp through the same cab i.e. switching to the 4 ohm out from the 16 ohm, while playing a 16 ohm cab.
 
ZEN Amps said:
You hear a difference because there is a net result difference. No argument here my friend, we've had similar results in an amp we're designing, and in many others too. Typically pretty subtle, but measurable by instruments and discernible to attuned ears.

The point I think that is often missed, and then leads to confusion and argument is the why. Maybe I'm not explaining it all that well, but as a general trend amps produce more lows and an attenuated midrange when using 6L6's, whereas an EL34 may result in the amp producing less low end resonance and a flatter midrange. However the tube itself doesn't have this sound intrinsically embedded in it. I think it's assumed there is an EQ curve associated with different tube types - not the case at all.

So in a Recto say, the amp/speaker combination will produce more low end when 6L6's are used due to the particulars of the circuit, the output transformer etc. This is not the same as saying 6L6's have more bottom end. For some this may seem pedantic but I don't see it that way, it's about definitions and understanding the bigger picture.

I hope this doesn't come across as preachy, or that I think I'm a know-it-all...but man there's a shit tonne of argument online about this. So here's my take on it after decades of playing around with these fun but dangerous boxes we call guitar amps:

- The guys that say swapping output tubes changes the tone are correct.
- Those that say output tubes make no difference are incorrect - but the changes may be insignificantly small.
- Argument about 'how much' difference there is entirely subjective and can be grossly exaggerated or downplayed depending on the individual (and their situation, hearing or agenda).
- Putting in 6L6's may or may not give you more bottom end, less mids etc. It's entirely dependent on the amp and cab in question.
- Practicing for an extra 10mins a day will have more affect on your tone than most of this stuff.

Now where are those sauce recipes?
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Excellent explanation, and much better than Cliff’s....Basically it’s a “sum of all parts” thing.
 
Beyond Black said:
Excellent explanation, and much better than Cliff’s....Basically it’s a “sum of all parts” thing.
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But that’s not what’s being touted on this forum. Folks are saying there’s a “major difference” in tone. There just isn’t, it’s subtle. Most is placebo to my previous point
 
Even different brands of the same tube type can sound and feel different, even if the differences are sometimes very subtle. Differences in tube characteristics also come into play with how they interact with other components in the circuit. Some of it will depend on just how hard you are pushing them. There's some trial and error along with letting your ears decide, keeping in mind that your expectations can influence what you think you're hearing.
 
Racerxrated said:
When I think about it, there is a subtle yet noticeable change in the tone, mainly the compression/low end response when I switch to a lower impedance on my amp through the same cab i.e. switching to the 4 ohm out from the 16 ohm, while playing a 16 ohm cab.
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Yes changing the output tranny / speaker impedance relationship will absolutely have an affect.

Beyond Black said:
Excellent explanation, and much better than Cliff’s....Basically it’s a “sum of all parts” thing.
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Yep totally. I would add it's a sum, plus some weird multiplication and division thrown in for fun.

Br8krofChainz said:
But that’s not what’s being touted on this forum. Folks are saying there’s a “major difference” in tone. There just isn’t, it’s subtle. Most is placebo to my previous point
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'Major difference' is a totally subjective term. For some guys, in their particular situation, to their ears, maybe they feel it is. Maybe you would if you played their rig, maybe not. Placebo effect is also a very real thing, no denying that. Humans are more complex than tube amps, that's for sure. One thing is absolutely guaranteed to happen in any online tone, music or gear discussion - there's no god damn way in hell there will ever been any widespread agreement on virtually anything.

blacknoizemachine said:
Even different brands of the same tube type can sound and feel different, even if the differences are sometimes very subtle. Differences in tube characteristics also come into play with how they interact with other components in the circuit. Some of it will depend on just how hard you are pushing them. There's some trial and error along with letting your ears decide, keeping in mind that your expectations can influence what you think you're hearing.
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Yep often very subtle but the differences are usually measurable, and can vary batch to batch.

Philhouse said:
All good. Cliff's burst just came across as a bit contradictory and heavy handed without explaining exactly why as eloquently as you have. Your last paragraph is perfect for me.

I'd share my sauce recipe... but it's a secret even from my wife. Gotta keep some mystery :)
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Damn you, people that don't want to share recipes usually have really good ones.
 
Br8krofChainz said:
But that’s not what’s being touted on this forum. Folks are saying there’s a “major difference” in tone. There just isn’t, it’s subtle. Most is placebo to my previous point
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Your ears are different than mine, others...so while you detect a 'subtle' difference, others detect a major difference. I hear major differences in my vintage Marshalls when I switch brands of EL34s, let alone a completely different tube type altogether.
That's what I hear. I don't think you can speak for anyone in a general sense, on what THEY hear.
Saying that 'there just isn't a major difference' and speaking for everyone, is not the answer.
That's simply your opinion. Many of us will disagree with you. That's our opinion.
See how that works? Simple stuff really.
 
Racerxrated said:
Your ears are different than mine, others...so while you detect a 'subtle' difference, others detect a major difference. I hear major differences in my vintage Marshalls when I switch brands of EL34s, let alone a completely different tube type altogether.
That's what I hear. I don't think you can speak for anyone in a general sense, on what THEY hear.
Saying that 'there just isn't a major difference' and speaking for everyone, is not the answer.
That's simply your opinion. Many of us will disagree with you. That's our opinion.
See how that works? Simple stuff really.
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Yep, this. It's an impossible argument really. In order to have even vague agreement we'd all have to define what a small, moderate, and big difference actually is. Good luck with that. Threads often descend into chaos because one man's life changing tonal discovery may be barely noticeable to others.

Whilst the topic is hot, what are you guys preferring for current production EL34's and 6L6's these days?
 
ZEN Amps said:
Brands you're digging?
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KT77 Gold Lion/Genalex
For Rev.2 Überschalls with mega high pV, the EHX 6550 have slayed
I love the PreferredSeries EL34 and 12AX7 - they're GREAT glass.
Svetlana 12AX7 for smoothness
EiYugo for Phase Inverter
Sovtek LPS as always for PI as well

But www.thetubestore.com are amazingly fast shippers, they're glass always biases true within a couple 0.0X mA for matched sets, customer service is amazing, and they're super knowledgeable too - present them with a situation, and they'll be like "amp, guitar, what kinda music, what environment, what SPLs, what's the problem, what needs tweaking, what have you tried, have you tried this, made sure this is working on your rig..." and once that's all said and done, Jon and Co. will offer great recommendations.

Caveat, I've never been a big fan of 6L6 based heads - I'm all about EL34/KT77 (=C= EL34, I mean, NEXT level!!!!, GoldLion KT77) and KT88/6550 (GoldLion / =C= respectively). Preferred Series when feeling adventurous for powertubes; Preferred Series for high gain low noise preamps, just a great business to work with - done.
 
Super helpful, thanks mate. No such option here in Australia so good to know of other sellers.
 
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Gold Lion KT77's also for me. Had Ruby BHT 34's and MSTR (I think) and tried some JJ KT77's all in my VH4 and stopped looking after the GL's. I'd love to try the 6550s but Aus is a long way from Germany and I wouldn't know who to send my baby to if I broke it. Peter would :gethim:
6L6's.. I can't think off the top of my head.

Didn't know you were in Aus, maybe I could share my Spag bol sauce... :scared:
 
mhenson42 said:
I have a huge stash of KT88s, 6L6s, el34s/e34Ls, 6550s and KT77s and all sorts of pre-amp tubes. None of them will change the tone/feel of an amp as much as simply swapping the speakers and/or cab.
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Yup, or using a different pickup in your guitar. The differences are there, but they're more subtle than you'd think. Take a Dual Rectifier for instance... switching from 6l6's to el34's in a recto doesn't make a huge difference, there will be a little less low end, and a little more midrange content with the el34's, but that's about it.
 
anomaly said:
Take a Dual Rectifier for instance... switching from 6l6's to el34's in a recto doesn't make a huge difference, there will be a little less low end, and a little more midrange content with the el34's, but that's about it.
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For some players, less low end and more midrange is a huge difference... so for them tubes matter. You don't seem to be one of them - that's cool. Be a pretty boring forum if we all shared the same exact opinions!
 
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