Amp matching for Klipsch Forte III

@funthings

If you don’t go with a 300b, 2A3, 45 amp, check with members over on the Klipsch forum. Several over there successfully running Quicksilver Mid Mono amps. A buddy is running them with basic EL34 tubes in his QS Mid Monos, sounds great, lovely midrange.  I’m also a former Cary, Inspire, Parasound, QS amp owner saying this about the lower gain QS mid monos specifically for your speakers. Sweet with Forte III.

http://quicksilveraudio.com/products/midi-mono/

"Power is 40 watts at 50% triode operation with the standard EL34s or KT88s, 45 watts with KT120s and 50 watts with KT150s."

@funthings
...The XA-25 has good warmth, and I have a Primaluna EVO 300 preamp that I can use if I need some more.

A few friends did fairly extensive paring of the Pass XA-25 amp with various tube preamplifiers, and found the combo to work really well in many cases. Hey, your PL EVO preamp with select 12AU7 input tubes to fine tune with the Forte IIIs could work out nicely as an option to consider.  I’d try that first! :)

@funthings
Guess i/we should have not assumed you had not already tried others.  What tubes are you using in your current PL EVO 300 preamp now...

Are they the original stock ones or - ?

@funthings
08-29-2020 1:33pm
Thanks decooney, the tubes are stock.

@funthings
If you decide to pair your PL EVO 300 preamp with the Pass XA-25, doing some checking, the current model from uncle Kevy has six 12AU7 tube across the front. The center two are the input tubes, just start with those.  

There is some history with upscale replacing these two center inputs with CIFT 12AU7 for some customers on upgrade requests. They are just okay to me, not the best, all circuit dependent of course. You can just start with those two center ones first for the most impactful change. Depending on what changes you are looking for, brighter/detailed, softer/more laid back, etc.

Upscale has a fairly sporadic stock of U7s, running lower each year. Still some good stuff out there, depending on who you source good tubes from - any of the top5 dealers in the USA. Fwiw, I’ve tried over 20 different/brand variations of vintage U7s (on different amps/preamps) and most of the new issue stuff too. Lots of options for you to choose from and they all do sound different from one u7 to the next. Try that Evo 300 with the XA-25 for sure!

@funthings
Nice. Those Brimar u7s are pretty nice.
I’ve tried them and compared them in a few different amps and compared to some of my best early 60s Mullard Blackburn factory ones. If they are true NOS or have not been used in a while, need to give them at least 24-40hrs to burn off the coating and settle in some. It will change a few times until at least 40hrs, which should help settle some of the edge with bad recordings and make the XA-25 sound even more musical. My good friend ran the Pass XA-25 with a super nice 6SN7 tube preamp last year, felt it was as good as some of his upper end tube mono blocks excluding some layering and 3D soundstage kinda stuff. Some nice interconnects between the EVO 300 preamp and the XA-25 can help too.