EL34 & 6CA7 difference?

0 Members and 1 Guest are viewing this topic. Read 21461 times.

bacobits1

EL34 & 6CA7 difference?
« on: 15 Dec 2008, 08:38 pm »
Boris, what is the difference between these 2? EL34 and 6CA7
You specifically state only use EL34,  E34L in the i34.
You know me I always have to futz with something.

Den

Audiovista

Re: EL34 & 6CA7 difference?
« Reply #1 on: 19 Dec 2008, 01:50 am »
Hi Den,

Good question... I'm not sure, there are minor differences in their characteristics, but nothing  that would indicate anything major, other than EL being EU design and the other one US (or one is a copy of the other one...). I did not hear 6CA7 in i34, so I may be missing something.

For i34 I recommend JJ E34L (those come with the amp). And specifically cannot recommend EH EL34. Everything in between may be hit or miss.... as is always the case with tube rolling....

Even though i34 runs the tubes very conservatively, you still need them in good condition to get maximum performance. Using weaker tubes negates benefits of component derating.


tybee

Re: EL34 & 6CA7 difference?
« Reply #2 on: 19 Dec 2008, 12:45 pm »
Den,

I have used several El34s, 6CA7s, and JJ KT77 and Genalex KT77 in my custom SE integrated.  The 6CA7s sound much closer to neutral (some might say sterile sounding) when compared to many EL34s.  6CA7s seem to emphasize bass in a nice way.  I found the JJ KT77s much like the 6CA7s but alittle better balanced.  Genalex KT77s are my tube of choice now which seems to be bettered balanced overall.

My amp seems to show the differences in power tubes much better than others, so changing power tubes may not give you as much change in your rig.

Tybee

bacobits1

Re: EL34 & 6CA7 difference?
« Reply #3 on: 19 Dec 2008, 06:35 pm »
Hi Tybee,
Thanks for the comments. I should leave well enough alone the amp sounds just great as it is.
The reason this came up is I have seen tubes labeled one or the other and some NOS Mullard I think
that had both numbers on them. Boris specifies EL34 only so I asked. I would like to try the Winged'C" EL34
later on but I have a set of Cryoed JJ's as a back up.

D

richidoo

Re: EL34 & 6CA7 difference?
« Reply #4 on: 19 Dec 2008, 07:28 pm »
6CA7 is military spec (ruggedized) EL34. Functionally identical and swappable.

ltr317

Re: EL34 & 6CA7 difference?
« Reply #5 on: 19 Dec 2008, 08:20 pm »

There is no difference between the two except the USA uses 6CA7 as the type code, and Europe uses EL34.  Several manufacturers use both codes on their tube, as well as for their 6BQ5/EL84 output tube code.   

Audiovista

Re: EL34 & 6CA7 difference?
« Reply #6 on: 19 Dec 2008, 10:21 pm »
I remember reading somewhere comprehensive listening comparison between 6CA7 and EL34 but, as Tybee said, it is likely to be amplifier dependent.

Looking at the specs, small difference in transconductance should not be sonically significant in a closed loop system (such as i34).

Den, if you replace E34L with EL34, make sure to readjust bias.

bacobits1

Re: EL34 & 6CA7 difference?
« Reply #7 on: 20 Dec 2008, 12:14 am »
Thanks Boris. Yes any power tube replacement is followed by a bias adjustment.
I'm refusing to mess with anything for awhile.  :icon_lol:

D

Audiovista

Re: EL34 & 6CA7 difference?
« Reply #8 on: 20 Dec 2008, 01:04 am »

I'm refusing to mess with anything for awhile.  :icon_lol:
D

And I'm very ok with that.  :thumb: :D

toobluvr

Re: EL34 & 6CA7 difference?
« Reply #9 on: 9 Jul 2009, 07:41 pm »
Hi Den,

Good question... I'm not sure, there are minor differences in their characteristics, but nothing  that would indicate anything major, other than EL being EU design and the other one US (or one is a copy of the other one...). I did not hear 6CA7 in i34, so I may be missing something.

For i34 I recommend JJ E34L (those come with the amp). And specifically cannot recommend EH EL34. Everything in between may be hit or miss.... as is always the case with tube rolling....

Even though i34 runs the tubes very conservatively, you still need them in good condition to get maximum performance. Using weaker tubes negates benefits of component derating.

Hi Boris....

Any particular reason you recommend against EH el34's?

I am using them in the i-34 and prefer them to the stock JJ's.

John

ltr317

Re: EL34 & 6CA7 difference?
« Reply #10 on: 9 Jul 2009, 07:56 pm »
Hi Den,

Good question... I'm not sure, there are minor differences in their characteristics, but nothing  that would indicate anything major, other than EL being EU design and the other one US (or one is a copy of the other one...). I did not hear 6CA7 in i34, so I may be missing something.

For i34 I recommend JJ E34L (those come with the amp). And specifically cannot recommend EH EL34. Everything in between may be hit or miss.... as is always the case with tube rolling....

Even though i34 runs the tubes very conservatively, you still need them in good condition to get maximum performance. Using weaker tubes negates benefits of component derating.

Hi Boris....

Any particular reason you recommend against EH el34's?

I am using them in the i-34 and prefer them to the stock JJ's.

John

Don't know what Boris' experience has been with EH EL34s, but from my and 2 other peoples experience, the EH EL34 have had bad quality control.  On 3 separate occasions, at least 1 tube went nuclear on my amp.  After replacing with a fresh tube, another one would go nuclear a few days later.  All the EH tubes either had low hours or were new.  Same problem with the 2 other guys.  I swiched back to the chinese tubes that came with the amp and have never had any problems with them.

toobluvr

Re: EL34 & 6CA7 difference?
« Reply #11 on: 9 Jul 2009, 08:12 pm »
Interesting experience, ltr317.

I do agree that the JJ's are very rugged and seem to hold up well to abuse.  They were also included in my Dodd 120 monos, which I sense pushes tubes hard.

I have also used the EH in my Dodds.  I have had no EH failures in either amp.

In both amps, I find the JJ's a bit flat, dry, clinical and uninvolving.  I prefer EH and Svet "winged C's"  in both amps for the greater bloom, fluidity and tone that they bring to the party.
« Last Edit: 9 Jul 2009, 10:54 pm by toobluvr »

BobM

Re: EL34 & 6CA7 difference?
« Reply #12 on: 9 Jul 2009, 08:27 pm »
I found that JJ EL34's in general required a boosting of the bias. The Electro Harmonix 6CA7's were hotter and needed the bias turned down.

In general the 6CA7's sounded a bit more extended on top and the bass was better controlled (in ultralinear mode). The EL34's sounded better in triode mode in the mids, but didn't control the woofers on my speakers very well that way.

This on an Audio Prism Debut II amp.

Audiovista

Re: EL34 & 6CA7 difference?
« Reply #13 on: 10 Jul 2009, 01:39 am »
I stopped being fan of EH when 20% of the tubes in the first batch either did not work or had very low gain. That was EL34, and 40% of 12AX7 (smaller batch) had very low gain in one of the two internal triodes. Maybe I got bad batches, don't know, just did not want to take chances.

JJ's E34L (not EL34) are quite a bit more robust and so far I have less than 2% failure rate in burn-in. As for the sound, I thought E34L sounds leaner and more linear with more articulation in the bass. EH tubes may sound more euphonic and this is a territory where tastes rule.

My goal was maximum linearity and lowest THD with as little feedback as I can get by. E34L got me there. Luckilly there are many different versions of EL34 and I can see that some will sound better, depending on the other links in the audio chain.

Rasta

  • Jr. Member
  • Posts: 121
Re: EL34 & 6CA7 difference?
« Reply #14 on: 10 Jul 2009, 02:04 am »
Boris, what is the difference between these 2? EL34 and 6CA7
You specifically state only use EL34,  E34L in the i34.
You know me I always have to futz with something.

Den

I've been wondering the same thing.  I really want to throw some nos tubes in here but I'm not sure what would work well.

As a side note, I just swapped out my new MiniWatt for the i34 - I can breathe again.  The i34 is so much more satisfying.  I was considering using the MiniWatt for a bedroom system and selling the i34, but that is not going to happen.  The MiniWatt is very lit up and fatiguing.  I would say it is priced accurately and a good value and fun, but not in the same league as the i34.

bacobits1

Re: EL34 & 6CA7 difference?
« Reply #15 on: 24 Jul 2009, 02:06 pm »
I have not tried anything else in the i34 since asking this.
I don't have the $$ right now to go NOS or just different say wingned 'C" everybody raves about.
Sometimes I change things for the sake of changing things. Duh! Not always for the better.

I do have a set of JJ E34L cryoed, I had thenm in but did to put any hours on them a la "break in" that is.

If you change to something else let us know here what you think of any changes.

D
« Last Edit: 24 Jul 2009, 09:05 pm by bacobits1 »

neobop

  • Full Member
  • Posts: 3448
  • BIRD LIVES
Re: EL34 & 6CA7 difference?
« Reply #16 on: 9 Mar 2013, 03:47 am »
The KT77 is a drop in replacement for the EL34/6CA7.  I think Tybee has it nailed, but it depends on your amp.  Here's a site with reviews using guitar amps.  I think you might find it interesting:
http://www.thetubestore.com/EL34-Tube-Review

neo

Audiovista

Re: EL34 & 6CA7 difference?
« Reply #17 on: 9 Mar 2013, 03:52 am »
I was thinking of trying KT77, but never got around to doing it. i34 is using E34L.