Which of these tubes is best?

Rodango · 1st May 2008, 05:59 PM

Opinions please...

I have a quad of each of the following tubes. I'm trying to select the best quad for the amp I just built. Which of these tubes is the most transparent? I have my own opinion but I'd be interested in other opinions too...

GE 6550
JJ KT88
SED KT88
EH KT90

Thanks!

Rodango · 1st May 2008, 08:20 PM

I just had my listening test... The "clear" winner (my amp, my ears)

The SEDs

They had the best clarity and lowest distortion.

On the other hand, the EH KT90s sounded like crap.

The JJs were almost as good as the SEDs but had a tiny amout of distortion

tubewade · 1st May 2008, 10:48 PM

Thanks for that info. I would've guessed GE, SED, EH then JJ. The results may be different in a different amp??? Thanks for sharing.

Wade

cerrem · 2nd May 2008, 12:53 AM

Keep in mind that for a fair comparison you need to make sure all the brands are of equivalent transconductance and DC quiescent currents..... Also plate resistance will have variance...

Chris

Rodango · 2nd May 2008, 05:15 AM

Quote:

Originally posted by cerrem
Keep in mind that for a fair comparison you need to make sure all the brands are of equivalent transconductance and DC quiescent currents..... Also plate resistance will have variance...

Chris

Yeah, they are...

I just tried the GE6550s and was surprised! I knew that was the most indestructible 6550 ever made (only power tube approved for the tube destroying Fender 400PS) but I didn't know they had such good balance and clarity! They might be #1 and if not, they're a close #2. I'll need to do some more listening...

tubewade · 2nd May 2008, 11:41 AM

Regarding the GE valves...

Many people seem to overlook GE 6L6GCs, for some reason, but I find them excellent, in the same class as RCA black plates. GE have made some really fine valves over the years. I also believe that their 6005 5-star is as good as any available 6AQ5.

Wade

Rodango · 3rd May 2008, 04:58 AM

OK, I have the order selected. This is for my ears with my amp. YMMV.

Consolation prize - KT90EH
Third Prize - JJ KT88
Second prize - GE6550A

And the Clear Winner - SED KT88 - Yes we have a First Place winner!

Now if anyone wants to send me a quad of Genalex's, let me know! ha ha ha ..

3rd May 2008, 04:58 AM	#7
Rodango diyAudio Member Join Date: Jul 2007 Location: Salem, OR	Final Results OK, I have the order selected. This is for my ears with my amp. YMMV. Consolation prize - KT90EH Third Prize - JJ KT88 Second prize - GE6550A And the Clear Winner - SED KT88 - Yes we have a First Place winner! Now if anyone wants to send me a quad of Genalex's, let me know! ha ha ha ..

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1st May 2008, 05:59 PM	#1
Rodango diyAudio Member Join Date: Jul 2007 Location: Salem, OR	Which of these tubes is best? Opinions please... I have a quad of each of the following tubes. I'm trying to select the best quad for the amp I just built. Which of these tubes is the most transparent? I have my own opinion but I'd be interested in other opinions too... GE 6550 JJ KT88 SED KT88 EH KT90 Thanks!

1st May 2008, 08:20 PM	#2
Rodango diyAudio Member Join Date: Jul 2007 Location: Salem, OR	The envelope please... I just had my listening test... The "clear" winner (my amp, my ears) The SEDs They had the best clarity and lowest distortion. On the other hand, the EH KT90s sounded like crap. The JJs were almost as good as the SEDs but had a tiny amout of distortion

1st May 2008, 10:48 PM	#3
tubewade diyAudio Member Join Date: Jun 2007	Thanks for that info. I would've guessed GE, SED, EH then JJ. The results may be different in a different amp??? Thanks for sharing. Wade

2nd May 2008, 12:53 AM	#4
cerrem diyAudio Member Join Date: Jun 2005 Location: San Diego, CA	Keep in mind that for a fair comparison you need to make sure all the brands are of equivalent transconductance and DC quiescent currents..... Also plate resistance will have variance... Chris

2nd May 2008, 11:41 AM	#6
tubewade diyAudio Member Join Date: Jun 2007	Regarding the GE valves... Many people seem to overlook GE 6L6GCs, for some reason, but I find them excellent, in the same class as RCA black plates. GE have made some really fine valves over the years. I also believe that their 6005 5-star is as good as any available 6AQ5. Wade