6CA7s vs EL34s. What do you think?

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Rick Lee
Rick Lee
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I've been running EL34s in my Marshalls forever. I decided to try a pair of EH 6CA7s in my 1987xl. They sound way bigger, like my 100 watters sound with EL34s. I like it, but kind of miss the pissed off distortion and compression of my otherwise stock 1987xl. I'm tinkering with resistors on the bias circuit to see how hot or cold I can go. And I'm testing stuff on a 4x12, whereas I usually run this head through a 2x12. What do you think?
 
KT77’s. They have the big round tone of the 6CA7’s with the aggression of an EL34, but not quite as aggressive as an EH EL34. They are the most aggressive sounding tube in the family IMO next to E34L and then KT77’s, particularly Gold Lions.
 
I like them in my Mesa Stiletto Ace. Gives it a bit bigger bottom and bit sweeter top end
 
I have some Sylvanias here and while they do add a 3D thing they are short on that great 34 mid compression we all love. Bigger bottom though.
 
I kinda cringe when there is talk of EL34's and 6CA7's Today they are basically the same tube (manufactures simply consolidated production) and years back they started using EL34/6CA7 interchangeably likely because people didn't understand and manufacturers wanted to sell their product.... a "real" 6CA7 is NOT an EL34 and is a beam forming tetrode like the 6L6. The reason for the bigger bottle is because the plates are bigger and shaped like a wing. They sound very different from EL34's as well... like an EL34, 6L6 and 6550 had a child. I added the 6550 in there since the 6CA7 has more bottom end than an EL34. The real KT77 was closer to the Sylvania 6CA7 than the EL34.

All of that said doesn't mean the new "6CA7" doesn't sound good. The EH 6CA7 is very nice.
 
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psychodave said:
I kinda cringe when there is talk of EL34's and 6CA7's Today they are basically the same tube (manufactures simply consolidated production) and years back they started using EL34/6CA7 interchangeably likely because people didn't understand and manufacturers wanted to sell their product.... a "real" 6CA7 is NOT an EL34 and is a beam forming tetrode like the 6L6. The reason for the bigger bottle is because the plates are bigger and shaped like a wing. They sound very different from EL34's as well... like an EL34, 6L6 and 6550 had a child. I added the 6550 in there since the 6CA7 has more bottom end than an EL34. The real KT77 was closer to the Sylvania 6CA7 than the EL34.

All of that said doesn't mean the new "6CA7" doesn't sound good. The EH 6CA7 is very nice.
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I am fairly certain the EH6CA7 is a beam forming element/tertrode like a 6L6. It is as close to an original 6CA7 in new production as you can get.

I liked them more than the JJ6ca7 because my JJ's blew up right out of the box when I installed them so I never got to really hear them.

The JJ6CA7 is a power pentode just like an EL34.
 
harddriver said:
I am fairly certain the EH6CA7 is a beam forming element/tertrode like a 6L6. It is as close to an original 6CA7 in new production as you can get.

I liked them more than the JJ6ca7 because my JJ's blew up right out of the box when I installed them so I never got to really hear them.

The JJ6CA7 is a power pentode just like an EL34.
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Yep. 100%
 
harddriver said:
I am fairly certain the EH6CA7 is a beam forming element/tertrode like a 6L6. It is as close to an original 6CA7 in new production as you can get.

I liked them more than the JJ6ca7 because my JJ's blew up right out of the box when I installed them so I never got to really hear them.

The JJ6CA7 is a power pentode just like an EL34.
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Now I have to look into the EH’s. 😂

I just looked them up. So far they say they are tetrode… I’m still skeptical. 🤣
 
harddriver said:
I am fairly certain the EH6CA7 is a beam forming element/tertrode like a 6L6. It is as close to an original 6CA7 in new production as you can get.

I liked them more than the JJ6ca7 because my JJ's blew up right out of the box when I installed them so I never got to really hear them.

The JJ6CA7 is a power pentode just like an EL34.
Click to expand...

Been wanting to try 6CA7s in my MCII and was gonna go JJ as I like most all their PTs, but I may opt to give the EH a shot instead. I do love the JJE34L in the Wizard more than the JJKT77 and =C=s I tried, but am still curious about the 6Ca7. Tube swaps are like splitting hairs to my ears when it comes to tone change, but I'd be up for trying the EH for the hell of it. Been really considering trying a quad of original Tesla black base EL34 in the Wizard but fuck they're pricey.
 
So how would somebody need to prep their EL34 amp to use KT77 tubes with it?
 
Any amp set up for EL34's can run KT77, 6CA7, 6L6, 6550 or KT88's usually but you may have to swap a couple of bias resistor in the bias circuit to add or subtract bias voltage so the tube can be biased correctly. Some amps have a pretty wide bias range it just depends on how hold or cold biaswise you lilke running you amps that will dictate who you set up your bias circuit.

Now conversely an amp designed strictly around only 6L6's may not be able to take EL34 type variants because of how the power tube pinout is wired on the tube socket so be careful there and double check how the socket is wired. The pinouts are different from EL34's to 6L6's/6CA7's.
 
I really thought the JJ6CA7 is a gorgeously built tube, the glass envelope is extremely thick and the internals looked great. I really wanted to hear them but alas they had issues right out of the gate, so I am reluctant to buy them again.

I installed those EH6CA7's just to see if the JJ's were having and issues and sure enough they were. Now do I think they are as robust with longevity as Sylvania 6CA7's..... No I don't... but I don't with any newer production tubes made these days. YMMV....
 
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I've got two quads of Sylvanias in my stash. I have a quad of the EH's.... I need to start tinkering. lol
 
I love my JJ 6CA7 tubes. The EH 6CA7s didn't do it for me.
All my amps have had the 6CA7s in the last three years.
My other amps kill wirh the 6CA7. They have been my go to tube for about 3 years now. To me they sound like the lows of a 6L6, with thick kids and warm highs. No bright, crisp highs of a 6L6.
I like to change it up and switch it up, so I recently went back to 6L6 in my Mark V, but man the JJ 6CA7s make the Crunch and more British modes of my V, sound glorious! Awesome tube.
In my experience, KT77s seemed too harsh for my tastes but I don't think they were biased correctly. I want to try some again in my Mark V. I want somethingbfor my V that has the thick mids of my 6CA7s, but brighter, but retains the lows.
 
Rdodson said:
I have a clip of my old BE100 with a quad of EH6CA7s. Sounds great (to me) but I'm not a chugga guy. :)

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Mr dodson you make that BE100 sound glorious, I hear hints of EVH in the tone you're getting in that vid even though it's a single coil guitfiddle....NICE.................... I'm going to say the tone is coming from those EH6CA7's.:yes::2thumbsup:
 
I don't know that I'm so curious as to buy another pair but this time JJs. However, I have a Marshall Origin 50C being delivered any minute now. I will tinker with it and may throw these EH6CA7s in there and put EL34s back into my 1987xl.
 
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