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Kt88 or 6550 tube for McIntosh MC275

Hi,  

I have a MC275 comes with original McIntosh KT88 tubes.  I am wondering if it is worthwhile to try other and what to try.  First question is, do I need a match quad?  Or I can get away with two matches pairs?  If I need matched quad, then it seems my only option is to get new production tubes as the NOS matched quads are very expensive.

For new production, I did some research.  It seems people prefer KT88 over 6550.  And the two brands for recommended are SED and Genalex Gold Lion reissue.  Are they better than the stock McIntosh tube?  Or should I save money and upgrade my other component such as my DAC or adding a preamp first?

thanks.
gte357s
gte357s OP
281 posts
 
It is a MC275 MK IV.  
@oldhvymec when you say matched, do you mean two matched pairs or a matched quad?  I read somewhere that since it is a push pull and auto bias, two matched pairs, one for each channel may be fine.  


annika
26 posts
 
I have a mkIV as well and found greater upgrade to sound by rolling in NOS for the small signal tubes. 

I did also replace power tubes with GL kt88s which made what I felt was a smaller improvement compared to the small signal tubes. 
oldhvymec
5,101 posts
 
A pair of pairs? LOL sounds funny. ME I'm picky.. I'd have to look at the way they auto bias. It's been a while. If I remember,  there was a reason I used quads in a 275, I think it was early break up. It's been 30 years ago.

I would still pick up quads for that 275. Match the signal valves too, pairs per rail. It uses like 12az7 right? match them in pairs and look at their position. preamp, signal, la-te-da. Put them in, that way.. L vs R (one pair)

I remember. To match the valves in my 60s if I wanted to use them and not have an issue, between the two. AND they will. I match left to right. I had a few problems with that. VERY sensitive, Klipsch La Scala, or Jensens speakers per say, show EVERY flaw, from higher floor noise, L/R, distortion, all kinds of crap, behind mismatched valves. Gotta be picky with the old stuff and the new for the BEST SQ.

Regards
mozartfan
2,143 posts
 
Genalex Gold Lion reissue

Yes the GL are very popular,, i tried them, returned them, 
Prefered the Svet's

I just posted a series of answers on this very topic last night.
6550=kt88
My prefered is the Svet 6550.
NOS- New Production, exact same tube.
KT88=6550
NOS 6550=New 6550

https://forum.audiogon.com/discussions/6550-vs-kt88-vs-kt90
oldhvymec
5,101 posts
 
I just posted a series of answers on this very topic last night.
6550=kt88

<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>.

One was designed in the US one was designed in the EU.

They physically look different, as does the KT 90 you reference also.

They are not the same, nor do they sound the same. ALL 3 differ in design, and vary from manufacture to boot.

6550 does not = KT88 and certainly not a KT90 valve, different all together again.

I read your findings, I had to wash my face with cool water and take a TUMS! Pure bla bla bla...

Please! You started a tube flipping business right... and paid 1500.00 for a pair of valves.

TUBE FLIPPING.  I admire you're stones... Mercy

VA, It's stands for Valves Anonymous. Might help. GA, Gamblers Any, AA, NA...

Regards
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