Dennis Had Inspire Amps

[decooney]

@bombadil

Won't know until you try. There is a 2nd hand pair of 150s and 120s on USAM right now. One set from an inspire owner. A local audio outfit had two plus one spare of KT150s a while back, might still have them, I was gonna grab them but mine are lasting a long time

Tried both, and much prefer the KT150s in three different amps I've tried them in, and with the right input/signal tubes in front of them, it really helps. Tried 120s for a bit, and running the 150s now in my other monos, liking them a lot and more so once I got the right input/signal tubes in front of them. Definitely worth a final test at least.

[oldominion]

Hilarious as I am the seller of the KT150s on USAM! I absolutely loved them in my Dennis amp but now have too many tubes so am doing a clear out. I've actually just posted them in the AA Marketplace. Mods, please remove if there is a policy against promoting a sale in these boards. Naturally I'm not getting rich and any $ I make is going to go right back into tubes for my Dennis Had Inspire amp! LOL. But as a relative noob here I don't want to step on any toes...

FWIW the 150s were once my favorite tube in the Inspire and I said so on this board...best bass of any tube I tried, and this was super important to me as I am the owner of a pair of finicky Altec 604 8G's.

In my system however I began to realize that I was missing a more holographic presentation w the 150s/5ar4 that I had with the less powerful output tubes and Sophia 274B. Again, in my system, w the 150s I was hearing more of a PP style: powerful, big, juicy, maybe at the expense of the SET spookiness. And I began to miss the spookiness. (That said, the Genalex KT77 has what I'm hearing as the best balance between big, juicy PP sound and spooky SET sound).

As always YMMV. The 150s probably have 20-30 hours (approximation). I may also sell a matched pair of original Svetlana Winged C 6550's, which were also great in the Inspire...

[decooney]

@oldominion,
For what its worth, 20-30hrs on Tung Sol KT150s is very little time if they were not already pre-burned in 75hrs by the seller. Some tube sellers run and test them 75hrs before they send them out. The current quad set i'm running now changed at 75-100hrs and again around 200hrs. Bias stays put now and they do sound different compared to the first 20hrs. I went back to my local dealer with the same amps, and his were at 300hrs, and we both agreed they did sound quite different from brand new. Worth the wait, at least in our cases.

[Bombadil]

One of the oddities of Dennis' PSE amp is that he states that it produces more output power with KT88 tubes than with KT150. 23wpc with KT88 and 21wpc with KT150. I have never seen this in any other amp. He's running the KT150s way, way under what they can handle.

Of course he would need to use larger OPTs if he pushed the KT150s hard.