KT88 for McIntosh MC275 mk.IV?


I've had Psvane black bottles for 11 years and liked them. At the time they were a clear improvement over stock tubes. I purchased 5 and rolled them quarterly, anticipating one will eventually fail, which happened. A second one has now failed so I need new tubes. These were probably used up already anyway.

The amp is currently used for midrange (300 to 1200Hz) amplification in an active system, so the frequency extremes aren't most important.

I'm looking at Genalex Gold Lion and Psvane. Any experiences that can help me decide?

I could buy 5 Gold Lions and spend $500, or buy 4 Psvanes for $500 and use the remainibg 2013 Psvanes as back up in case of failure.

Thank you!

lewinskih01

It does auto bias. However I don't know if it does it for each tube, pair or whole lot.

Maybe someone with MC275 mk.IV can tell. A quick search brought Ron-C (a McIntosh technical employee then) circa 2005 at Audiokharma McIntosh forum making comments about auto-bias, but no clarification about single/pair/whole lot.

I think that amp is auto bias? Does it auto bias each tube, a pair of tubes, or the whole lot? If it's the whole lot, they can go anywhere and you should have bought a matched quad. If it auto biases two tubes put the matched pairs in each paired bias location. Single bias a matched pair still go into the same amp channel. 

I went ahead and purchased 2 matched pairs of Gold Lion KT88.

Pair A has a tube rated 37 IP/4600 GM and another rated 38 IP/4700 GM.

Pair B has a tube rated 37 IP/4400 GM and another rated 36 IP/4500 GM.

 

Should I install A1 in V8, A2 in V9 and B1 in V10, B2 in V11, or a different order?

Thank you.

Thanks all for the input!

It's pretty unusual to get such a unified view on anything audio these days. I'll be getting Gold Lions. Will be interesting to compare the (used up) Psvanes to the new Gold Lions too.

Thanks again.

I use Gold Lions in everything. The Bob Carver VTA-180s I bought here on AG had all Gold Lion KT88s in it when I purchased it used. I actually replaced the vintage Mullard 12AX7s that were installed when I got it with Gold Lions as well. There is a chart that someone posted regarding relative gain by frequency range. Golds Lions were shown to be near equal across the range.

I've always considered Gold Lions as very reliable but of the four tubes I bought a year ago, two have already failed. In a friend's system, one failed - they were all purchased more or less at the same time. I hope that was just some unlucky batch and the next ones will be fine because I really like the sound. Anyone else have had problems with Gold Lions recently? 

Me too.  I have a quad of Gold Lion KT 88 and they have a lot of hours on them.  A lot ….  I took them out of service after about 4 years of hard use and kept them as a back up.  
 

I changed speakers and found that the JJ EL 34 sounded really good .  I had a tube that lost vacuum.  Put the GL back in.  
 

Fast forward to a few months ago,  I got a tube tester and put the KT 88 back in and they are still strong , close to the Apex matching sticker on the tubes. 
 

In an amp they are still tightly matched.  Pretty amazing considering how many hours I have listened to them.