[R_burke]

does anyone know what my options are:
KT88 and 6550, but can I do EL-34 or anything else

Also, what are the differences in sound - I understand the KT88/6550 differences, but not familiar with any other comparisons

[Niteshade]

Hello-
 
Your amp can possibly use EL34's if pins 1 and 8 are shorted together. You will have to rebias for smaller tubes. I don't know what the plate & screen voltages are for that model- but try and find out and post it before trying smaller tubes.

[EDS_]

I have used an SLI-80 for several years...........

EL-34s will work great just plug/bias/play.  If you use the Cary phonojack bias device EL-34s need to be set to 75 mA

Here's a list of what I've tried and bias settings - settings supplied by Cary.
6550
KT-88
KT-90
EL-34 all of these biased to 75 mA

KT-77 biased to 70 mA
________________________________


Here are some that I have not tried
6L6
KT-66
6881 these three should be biased to 50 mA

FWiiW EL-34s sound great in the SLI-80.

If you need biasing info. regarding the SLI-80 I would be happy to share the info from my manual.


ETA - I use EL-34s roughly 85% of the time. 

[R_burke]

I have used an SLI-80 for several years...........

EL-34s will work great just plug/bias/play.  If you use the Cary phonojack bias device EL-34s need to be set to 75 mA

Here's a list of what I've tried and bias settings - settings supplied by Cary.
6550
KT-88
KT-90
EL-34 all of these biased to 75 mA

KT-77 biased to 70 mA
________________________________


Here are some that I have not tried
6L6
KT-66
6881 these three should be biased to 50 mA

FWiiW EL-34s sound great in the SLI-80.

If you need biasing info. regarding the SLI-80 I would be happy to share the info from my manual.


ETA - I use EL-34s roughly 85% of the time.

Excellent, thanks.  How about a little on the sound and what type of music is best with the different types of tubes

Richard

[EDS_]

I have used an SLI-80 for several years...........

EL-34s will work great just plug/bias/play.  If you use the Cary phonojack bias device EL-34s need to be set to 75 mA

Here's a list of what I've tried and bias settings - settings supplied by Cary.
6550
KT-88
KT-90
EL-34 all of these biased to 75 mA

KT-77 biased to 70 mA
________________________________


Here are some that I have not tried
6L6
KT-66
6881 these three should be biased to 50 mA

FWiiW EL-34s sound great in the SLI-80.

If you need biasing info. regarding the SLI-80 I would be happy to share the info from my manual.


ETA - I use EL-34s roughly 85% of the time.

Excellent, thanks.  How about a little on the sound and what type of music is best with the different types of tubes

Richard

Hi Richard,
I use Spendor S5e speakers. Low sensitivity @~84dbw with an a fairly begin impedance demand.

Generally, 6550/KT-88s sound a little more dry and have a little more bass but only a little more bass.  EL-34s have a more vibrant top end they seem to handle strings, wind instruments and vocals a bit more to my liking. 

Assuming you haven't already; you might consider upgrading the 6922 set to a JJ e88cc or another 6922 equivalent set that bests the stock 6922s.  Same with the 6sn7 tubes - the Chicom stock pieces blow.  You might try the new issues electro-harmonix 6sn7 tubes. They are fairly cheap and crush the Chicom tubes.

Regarding EL-34 tubes, I like the Tesla - E34L.  Again they're fairly cheap and they sound GREAT.

I used the stock rectifiers.

My listening runs from Bach, The Butthole Surfers, Pantera, Cecilia Bartoli, Miles Davis - Charlie Parker - Mingus to Ted Nugent and Tool.  The EL-34s just sound better to me.

[R_burke]

EDS_

Thanks again - appreciate the input and I will try rolling the other tubes as well as the power tubes.

BTW my speakers are GR-Research OB-5s with 91dbw. so my need for the KT88/6550 is even less

[EDS_]

EDS_

Thanks again - appreciate the input and I will try rolling the other tubes as well as the power tubes.

BTW my speakers are GR-Research OB-5s with 91dbw. so my need for the KT88/6550 is even less

Oh man, the SLI-80 and the OB-5s have got to be great match.  Be sure to try EL-34s in triode and let us know what you think.  Actually, I'm curious how the 6550s sound in triode through the OB-5s.

Good times.