6CA7s vs JJ E34Ls

Re: 6CA7s vs JJ E34Ls

No argument there. But I would be willing to bet that in a properly biases amp, with everything else being equal, especially when pushed hard, that the KT-88 will have more head room and a tighter bottom than the EL 34. The EL 34 will have crunchier mids.

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Re: 6CA7s vs JJ E34Ls

Demanic said:
No argument there. But I would be willing to bet that in a properly biases amp, with everything else being equal, especially when pushed hard, that the KT-88 will have more head room and a tighter bottom than the EL 34. The EL 34 will have crunchier mids.

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That was my experience running both EL-34s and KT-88s in my Marshall Jubilee and in a '78 JMP 2203. In the Jubilee I liked the EL-34s better; I didn't think KT-88s really added anything to that amp. In the JMP I liked both types for different reasons and would choose based on what tones I wanted.
 
Re: 6CA7s vs JJ E34Ls

Demanic said:
No argument there. But I would be willing to bet that in a properly biases amp, with everything else being equal, especially when pushed hard, that the KT-88 will have more head room and a tighter bottom than the EL 34. The EL 34 will have crunchier mids.

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This the problem though... all else being equal... They cant be. More to it than just proper bias. To get a KT88 where its really running good is way out of the reach of an amp that runs EL34's. Its going to have massively different transformers and smoothing caps.
You can design a hi fi amp that will run EL34's glassy clean without a whisper hint of distortion at any volume. You can also design a low headroom saggy bottom KT88 amp.

Its much easier to say in X amp Y tube sounds like Z.

Which is effectively the comparison you are trying to make. Taking a 100 watt amp and using tubes capable of more than 200 watts will increase the amount of current the tubes can handle before they start to clip. IF the amp can even dish that much out.

In fact ENGL savages that are 120 watt amps from a PAIR of KT88's are actually pretty damn crunchy.
 
Re: 6CA7s vs JJ E34Ls

dystrust said:
That was my experience running both EL-34s and KT-88s in my Marshall Jubilee and in a '78 JMP 2203. In the Jubilee I liked the EL-34s better; I didn't think KT-88s really added anything to that amp. In the JMP I liked both types for different reasons and would choose based on what tones I wanted.
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Yeah but we still run into the issue that you arent pushing the KT88's really that hard in this example. If you follow the 70% plate dissipation rule that you use for EL34's you cannot get a JMP transformer to run 70% of what a KT88 will take. Even the 6550's in my JMP i think are at only 63% iirc. They function fine but it doesnt hit the mark of Demanics "properly biased" If there really is such a thing. This is why putting KT88's into a 100 watt EL34 amp dont turn it into a 200 watt amp.
 
Re: 6CA7s vs JJ E34Ls

OK, you win. I don't know enough on the subject, am not capable of speaking specifically enough to make any sort of valid point and will refrain from any further comments on the matter.

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Re: 6CA7s vs JJ E34Ls

Edgecrusher said:
Yeah but we still run into the issue that you arent pushing the KT88's really that hard in this example. If you follow the 70% plate dissipation rule that you use for EL34's you cannot get a JMP transformer to run 70% of what a KT88 will take. Even the 6550's in my JMP i think are at only 63% iirc. They function fine but it doesnt hit the mark of Demanics "properly biased" If there really is such a thing. This is why putting KT88's into a 100 watt EL34 amp dont turn it into a 200 watt amp.
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It isn't that simple as tubes have different bias points as a function of plate voltage. I don't remember what plate voltage on the JMP was, but it biased EL-34s at 35-37mA and KT-88s at 42-44mA (after a resistor swap). You're right that KT-88s won't produce 200W at 400-450V on the plates (probably closer to 120W), but saying that they're not properly biased isn't true.
 
Re: 6CA7s vs JJ E34Ls

dystrust said:
but saying that they're not properly biased isn't true.
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hence my comment "properly biased if there is such a thing" What is properly biased. If you take it that is 70% of plate disapation then no they couldnt possibly be. If you take it that they are in the amp and functioning correctly then sure they were. But bias is a range and runs pretty wide in some amp.
 
Re: 6CA7s vs JJ E34Ls

Demanic said:
OK, you win. I don't know enough on the subject, am not capable of speaking specifically enough to make any sort of valid point and will refrain from any further comments on the matter.

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Sorry dude I think we just like speak different languages or something. I'm really not trying to beat you up or make you feel bad. If you do I apologize and I really dont want to dissuade you from further discussion.

My intent was to inform and give you some information that maybe you didnt know. Maybe i come off wrong but i'm always up for it if someone can give me a tid bit of info that maybe i didnt understand or didnt know and was trying to do the same.
 
Re: 6CA7s vs JJ E34Ls

K, now I'm going to go back on my word and make one more comments. Which is to say that I appreciate learning all that I can, and offer my own opinions when I have them that are based on my own admittedly not exhaustive experience.
I find I am more irritable today than usual. I'll blame it on the moon.

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Re: 6CA7s vs JJ E34Ls

You are probably right on that. I meant that the earth's moon is nearing it's "full" phase.

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Re: 6CA7s vs JJ E34Ls

Demanic said:
You are probably right on that. I meant that the earth's moon is nearing it's "full" phase.

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I think I found our problem... Our sense's of humour run perpendicular to each other. I knew you meant moon like the astral body... but decided to make a stupid joke out of it... Swing and a miss
 
Re: 6CA7s vs JJ E34Ls

Like I said, I blame it on the moon. I knew what you meant and intentionally chose to be even dryer with my humorous response. This too shall pass.

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Re: 6CA7s vs JJ E34Ls

I have thoughts on the whole 6CA7 thing, but I don't have a moment to articulate them right now. I will get back to you guys on that. :p
 
Re: 6CA7s vs JJ E34Ls

What I meant by articulation - is more of a responsiveness i guess .... E34Ls, are very responsive, in fact, fullshred -> E34Ls is so responsive that it is a pain in the a$$ sometimes, as this signal chain responds to every little nick on an almost telepathic level. E34Ls are really precise on alternate, palm muted picking of E (low) A, G strings fore example. Will l lose some of this with 6CA7s vs El's? Thank you.
 
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Re: 6CA7s vs JJ E34Ls

My experience is probably not too relevant, but I've got EHX 6CA7 in my Tweaker, and their breakup is HARSH, but tight.
I have to make sure not to push them too hard otherwise they sound too clinical. Not a problem if you make good use of your volume/tone pots, I guess. But by that point the volume's pretty high so not a common test scenario for me.
 
Re: 6CA7s vs JJ E34Ls

Edgecrusher said:
Depends a bit on what 6CA7 we are talking about. The EH version on the market right now is actually a 6L6 in that its a beam tetrode but they use an EL34 pin out so it runs without mods on EL34 amps. The JJ version I havent seen up close but looks to be the closest electronically to what a 6CA7 was originally. I have no idea what the Shuguang 6CA7 is suppose to be its a completely different plate and getter structure, its acutally kind of a strange tube.

Sound wise the EH's basically sound like a 6l6 but have a bigger bottom with higher headroom. The JJ's sound more like a EL34 but with more headroom and different mid texture. The shuguangs are interesting, glassy but seem to lack the big bottom of the others.

As for chewier... 6CA7's are a move in the wrong direction.
Click to expand...
You are correct that the EH version is a beam tetrode like a 6L6GC, but that's basically because it is a tweaked 6L6GC, and it really sounds like it.

The original Sylvania 6CA7 is also a beam tetrode, supposedly based on their 6550.

The JJ version seems to be reviewed most favorably to the original Sylvania. A lot of people say it's close, but a tad warmer in the mids. I've been pretty happy with my JJs. They do what they say. They have the bottom end of a 6L6GC with the mids and top of an EL34. Cranked in a Marshall 1959-type circuit they definitely have an EVH vibe with chewy mids and a nice solid bottom end. Match them up with the right speakers and you'd nail that.

As far as what the OP wants, the EH version might actually be better for him. I'm not sure what Lynch's amps came with, but some US-import Marshalls did come stock with 6550s from the distributor, so it depends on what amp Lynch had and when he got it.
 
Re: 6CA7s vs JJ E34Ls

EL34s can get "constipated" for lack of a better term. The 6CA7 retains clarity.

I highly recommend for new manufacture - EHX 6CA7s

I run mine biased 40ma @ 100v.
 
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