Been playing my new arrival for about 4 CD's and a half. Out of the box initial impression, amazing and it only gets better from there. In less than 15 minutes, it's already gone 3D and sounds as smooth as silk. My previous SET 13.5 KT88 put a little too much bite into the K55's and now it's liquid nirvana. Very happy with my purchase! Kevin, you're the best.

Yay. The second-to-last Prologue Four is on its way to me! I'm now officially a part of the Upscale Audio family...Thank you Mr. Deal for offering this tube noob a chance to experience the best there is in pure tube amp construction. Build quality really does matter. Sometime old bald guys need to stick together. Again, thank you Mr. Deal. I'm a solid customer for infinity..and beyond!

Finally settled in on all Gold Lions. The performance is perfect, the sound sublime. Driving some unmolested original Heresy Klipsch's and with the addition of a M&K sub, the system has a nice balance. Since these little amps are not longer available, I'm just very glad I snatched one when I could. Thanks to Kevin Deal and Upscale Audio for giving us low-dollar horn nuts a chance to experience sonic bliss.

Just bought a Four. Can't wait to hear it.

PrimaLuna amps are powerful! I've had to work an input attenuator into my system as this amp has so much boogie, it almost overwhelms my 104db sensitive La Scalas!. Now with a nice 4 band tone control and a bit of 'volume control', I can balance my system properly. I never expected this amp to be so bodacious. Kevin is right when he says this amp has balls.

This amp LOVES KT77 Gold Lions. The stock tubes are butter but the KT77 kicks it up a notch. I highly recommend getting a set from Kevin.

Mine is still impressing me. Decided to go back to the original EL34's and was surprised how nice they sounded. Once the driver tubes had settled in, the power tubes really sound buttery and smooth. The bass is nice and punchy, not too boomy like the KT88 can be at times. I just bought some Gold Lion KT77 as well as some Tung Sol KT120's to round out my tube rolling selection. Since this amp treats the tubes gently, I'm guessing i won't need more power tubes for a long time.

I can vouch for the Prologue Four, having bought it from Upscale Audio back in 2008, and served me well until mid 2015, when my power tubes for the left channel started to turn orange red-scary...it wasn't the tubes, as I switched with all my other variations of the el 34 tubes. No body I trust to fix here in Hawaii, and the cost to ship back for repairs I thought after 7 years that I'd change to another amp...anyway, I still have it... Yes, the build quality is exceptional, and back then many people were bashing chinese made amps...but man, the quality, the build, the shine...and I paid the going price at the time...!

If any owners get a chance, I recommend rolling in some 7581a Tung Sols. Hang on to your socks if you do.

Is still a good buy? My speakers are inefficient, sensitivity 85dB.

Whats the price? Can you ship to Bangladesh?

No remote?

love your prouducts I just bought from cjna yaqin mc10t tube amp 45 watts per channel and I have to say yaqin sound better mc 10t model 4 el34 2 12ax7 and 2 au7what do you have to say 800 Canadian dollars and sound better then your 3000 doller amp guys I bvought on amazon cany beat yaqin