tube question for ARC Ref 3 users

Are you using a standard 6550 C tube in power stage or have you found other solutions? I'm using 6L6GC at the moment. My humble opinion is that sound is better with 6L6GC (better resolution with same musicality). Any other ideas?
Mkilpi. I've been wondering the same thing. Hopefully you'll get some response. Also would like to know if the NOS 6H30's make a difference.

Why not use 6C33Bs for outputs?
If the 6l6GC is the stock tube that ARC used to ship with all REF3's, than I prefer the sound of the 6550C.
ARC initially shipped Ref 3 with 6L6G in power supply. They soon switched to 6550C. They apparently found it to be more extended/resolving and to controll bass better.
Trying to outdo the pros at ARC are we?
PBB, actually I had heard that the pros at ARC switched to 6550C because of non-pro customer findings.
I will try tung-sol 6550 in power supply tomorrow.
Mkilpi, what do you think of the Tung-Sol 6550? Is it a Tung-Sol original (50-60's version) or a recent version?
I've heard some say that a original Tung-Sol 6550 from the 60's is the way to go, though I haven't experimented yet on my own.

I agree with Guido

Stick with the 6550C
Interesting subject. Any thought on Frank's question on the 6H30 tube regarding the audible sonic differences of manufacturer/dating of the tubes? Also applicable to the 6550C?

I need to replace tubes later this year. Would be very interesting to know if a potential audible improvement on the already great (glorious) performance of the ref3 is possible!
I replaced the stock 6550C tube with a NOS Tung-Sol
black plate (1950's) with wonderful results. Have not
replaced stock 6H30 tubes. NOS tube did take alittle
break-in to sound it's best. Nice improvement to an
already great line stage.
VMK, I'm glad you had wonderful result. . . could you please elaborate with some comparative findings? Thanks, Guido
I compared the stock ARC 6550C, the Tung-Sol
6550C (current production), and NOS Tung-Sol black
plate 6550C in my ARC Ref 3. I was always happy with the
stock 6550C tube. Ultimately I found the NOS tube added alittle more warmth that I really found captivating. All the fantastic resolution was there in spades but with alittle "CJ" warmth. I did not care for the current production Tung-Sol. I found it uninvolving and sterile