EL34 versus KT88 tubes

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swb

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EL34 versus KT88 tubes
« on: 19 Nov 2007, 11:22 pm »
What type of tube amplifier would you people recommend to drive a small pair of British bookshelf speakers (88db)?  An EL34/6CA7 based amp or a 6550C/KT88 based amp, and how many watts?

Right now, I am playing around with a small, bedroom system.  It is probably about a 10' X 12' room with QUAD 12L2 speakers.  I may eventually want to use the new amp to drive the top half of my Von Schweikert VR-3.5 speakers (with VR-S/3 self-powered subwoofer)which are in a room about twice that size.

I would like to achieve smooth, liquid, transparent, and 3 dimensional midrange and highs with a huge soundstage, precise imaging, and dynamic bloom; along with deep and tight bass (that's all!!!).  (Or as close as I can realistically get to that with the aforementioned limitations ;-)

twitch54

Re: EL34 versus KT88 tubes
« Reply #1 on: 20 Nov 2007, 12:40 am »
I loved your last paragraph, I think you need to see Santa Claus !!

Anyway I too power a small second system in my house with a Jolida 302-B (EL-34's) driving a pair of Totem Arro's (similar effeciency as your speakers)and it has volume to spare ! Granted there are far better amps out there but it has been flawless for over two years and only cost me $750 new, so I'm happy with the EL-34 sound.


mjosef

Re: EL34 versus KT88 tubes
« Reply #2 on: 20 Nov 2007, 12:51 am »
If you do get an EL34 based amp...try the JJ KT77's, you may never go back to EL34 again.
40Watts should be more than enough for 75-90dB with those speakers in that size room.

swb

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Re: EL34 versus KT88 tubes
« Reply #3 on: 20 Nov 2007, 01:23 pm »
Thanks guys!  I figured that I might as well be honest about my desires...right!?  Right now I am using a hybrid integrated amp (Jolida 1501A).  I am very happy with the lows (surprisingly deep and tight) and highs (very nice silky smooth extension) but was hoping that the midrange would be a bit warmer and more open.  Some of the problem may be the small room too though???  I am using an NAD C542 HDCD CD player and WireWorld Atlantis cables in this bedroom system.  I suspect the silver in the wiring may be contributing to the nice extension.  If I could just warm/open up the mids a bit, I would be very satisfied with this little rig  aa
« Last Edit: 20 Nov 2007, 03:12 pm by swb »

MarkR7

Re: EL34 versus KT88 tubes
« Reply #4 on: 20 Nov 2007, 02:58 pm »
Not to over-generalize here, because ultimately it's dependent on the amps and how they implement the various tubes, and the quality of their transformers, but in my experiences.....

KT-88 / 6550 tubes will be less tubey and will give you sharper imaging, better frequency extremes and tighter, deeper bass whereas EL34s (especially SED Winged Cs, which I prefered to JJ E34Ls and KT-77s) will give you the smoothness, liquidity, warmer midrange, better, more holographic soundstage bloom.

And yes, I have generalized quite a bit here....

swb

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Re: EL34 versus KT88 tubes
« Reply #5 on: 20 Nov 2007, 09:39 pm »
What about the Cayin A70T?  Supposedly, you can switch tube flavours.  Anybody ever try that?  Thanks!

Freo-1

Re: EL34 versus KT88 tubes
« Reply #6 on: 20 Nov 2007, 11:39 pm »
Well, it really depends on a lot of issues (speaker choice, driver tube setup, bias configuration, transformer quality, etc).

In my experience, sometimes, the EL 34 setup sounds sweeter. I used to own Dyna MK IV's and MK III's, and I always preferred the sound of the MK IV, as the sound of the MK IV's seemed more natural.

Then, I had an amp with a EL 34 based output in triode using a Curcio 6DJ8 front end, which was really sweet sounding. However, I recently acquired a Harmon Kardon Citation II, and restored it to employ 5687 front end setup, as well as power supply and bias upgrades. The  resultant sound is remarkable. Using the Re-Issued Gold Lion KT-88 output valves, the sound has incredible realism, dynamics, and totally natural sound not achieved by any EL 34 based setup I have heard. Using GE 6550A valves provides a different and pleasant sonic signature (more midrange presence, but not necessarily more accurate). (Your actual mileage may vary).

In summary, KT-88, IMHO, for the speaker type mentioned, provides the best overall potential performance.   
« Last Edit: 20 Nov 2007, 11:53 pm by Freo-1 »

linkweewee

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Re: EL34 versus KT88 tubes
« Reply #7 on: 21 Nov 2007, 12:36 am »
I went from the highly regarded EL 34 Audiomat Arpege to an Antique Sound Lab AQ 1001-DT KT 88 integrated and I prefer the ASL amp as it's got more grunt and sounds just as good with the right mix of tubes. Tube rolling will really affect the sound of either an EL 34 or KT 88 amp in my experience.

charlez

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Re: EL34 versus KT88 tubes
« Reply #8 on: 21 Nov 2007, 12:52 am »
I too have been using a Jolida 1501RC hybrid and, while generally happy with it, decided I wanted an all-tube amp for all the typical reasons. Here were the finalists I narrowed my choices to: a Jolida 801A, a Bella Extreme 3205 and a Tube Audio Design TAD-60. The Jolida is integrated, the Bella Extreme has both power and integrated models, and the TAD-60 is a power amp with a volume control. The Jolida uses 6550/KT88 power tubes, the Bella Extreme and the TAD-60 can use either 6550/KT88 or EL-34 power tubes. All were good choices IMHO.

Economics was a major factor in the final choice.. I was able to get a 2-year old stock Jolida in first-rate shape for about $700. There was a lightly used but fully modded Bella Extreme available for about $1100, and you can often get a refurbished TAD-60 with warranty for about $850.

So far I'm quite happy with the Jolida 801A, and have already improved the sound with a little tube rolling. I'm looking forward to replacing the 6550 tubes with new KT-88s from either Genalex or Shuguang. At some point, I would like to have the amp modded by Bill Baker at Response Audio to take it to another level.

When your final choices are close calls, it often doesn't make a lot of difference which you choose, or at least any differences are not likely to be determined until you've lived with the amp for a while.

EDS_

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Re: EL34 versus KT88 tubes
« Reply #9 on: 21 Nov 2007, 01:34 am »
Not to over-generalize here, because ultimately it's dependent on the amps and how they implement the various tubes, and the quality of their transformers, but in my experiences.....

KT-88 / 6550 tubes will be less tubey and will give you sharper imaging, better frequency extremes and tighter, deeper bass whereas EL34s (especially SED Winged Cs, which I prefer to JJ E34Ls and KT-77s) will give you the smoothness, liquidity, warmer midrange, better, more holographic soundstage bloom.

And yes, I have generalized quite a bit here....

I agree with your generalizations.

My Cary SLI-80 allows me to switch back and forth from KT-88s/6550s to EL-34s and I do.  If one's speakers have any tendency towards shrillness stay away from EL-34s. 

IMO the OP should strongly consider the Ram Labs EL-84 amps. 

Haoleb

Re: EL34 versus KT88 tubes
« Reply #10 on: 21 Nov 2007, 06:38 am »
I recently picked up a used Jolida JD302b and driving my 4 ohm Axiom M80's I was able to get some really decent volume. I did not see just how loud I could get it but I had it up to nearly where I listen with my Odyssey monoblocks. Right now I have the speakers biamped with the jolida and my odysseys and am listening just as loud as I ever do. Seems to have plenty of power :) Im not sure what clipping a tube amp would sound like But i dont think ive been there yet with this (not so) little amp  :thumb:

swb

  • Jr. Member
  • Posts: 6
Re: EL34 versus KT88 tubes
« Reply #11 on: 21 Nov 2007, 09:42 pm »
I too have been using a Jolida 1501RC hybrid and, while generally happy with it, decided I wanted an all-tube amp for all the typical reasons. Here were the finalists I narrowed my choices to: a Jolida 801A, a Bella Extreme 3205 and a Tube Audio Design TAD-60. The Jolida is integrated, the Bella Extreme has both power and integrated models, and the TAD-60 is a power amp with a volume control. The Jolida uses 6550/KT88 power tubes, the Bella Extreme and the TAD-60 can use either 6550/KT88 or EL-34 power tubes. All were good choices IMHO.

Economics was a major factor in the final choice.. I was able to get a 2-year old stock Jolida in first-rate shape for about $700. There was a lightly used but fully modded Bella Extreme available for about $1100, and you can often get a refurbished TAD-60 with warranty for about $850.

So far I'm quite happy with the Jolida 801A, and have already improved the sound with a little tube rolling. I'm looking forward to replacing the 6550 tubes with new KT-88s from either Genalex or Shuguang. At some point, I would like to have the amp modded by Bill Baker at Response Audio to take it to another level.

When your final choices are close calls, it often doesn't make a lot of difference which you choose, or at least any differences are not likely to be determined until you've lived with the amp for a while.

Thanks much for all of the great responses!  How (in general) does the 801A compare to the 1501RC?  Is it noticeably warmer, etc?  Is it noticeably less extended?