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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
jjss49's avatar
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jjss49
6,612 posts
 
mc275 is auto bias, correct? if so, then you don’t NEED matched tubes, though it may still be better to have them

another piece of advice... don’t chase old stock power tubes in the 6550 kt88 type, new tubes are excellent old tubes won’t outperform them, old stocks are giant waste of money from a sound quality perspective
three_easy_payments's avatar
three_easy_payments
2,097 posts
 
another piece of advice... don’t chase old stock power tubes

I tend to agree, unless they are 1950s NOS GEC KT66's.
gte357s OP
281 posts
 
Thanks for the reply.  Yes, it is auto bias.  


oldhvymec
5,101 posts
 
Is that an early MC275, or the later model? I notice a much greater difference in valves in the early model.

The preference to KT88 is because GREAT 6550s can break the bank.. 500-1000. a pair More than NOS KT88 GL

6550 GE TungSol, Old stock. That is a different sound than a KT88s

I like both, I have both Solvex and Golden Lyon (not my favorite). Good valves.

I have a few sets of 6550 GEs. I also found a Tube Tec valve that was pretty darn good.

I like the KT88, bottom to top, if the valve is going to be doing bass duty, too.

If it’s in a mid/highs, I use a 6550 GE. It’s just tough to beat that sound. It’s a little slim in the BASS department, but VERY smooth mids, and wonderful highs.
If you’re a vintage Klipsch, horn kind of guy.. They just do a great job with Macs, MC60s, and older 275s, sporting that valve, and Tellies/RCA for the signal valves.

Just so you know PSVANE makes a heck of a valve, over the last few years..Power and signal.. ShuGuang 6550s, are great valves also and without breaking the bank..

Very important to get matched valves with the old Macs, Yes it matters. Mac is different, not like anyone else... A Mac will show you every flaw in your system. Mismatch valves cause an early breakup, on the top especially. MATCH the valves...

Enjoy the sound..

Regards
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