tube amp for Apogee Tweeter mid-range

I recently upgraded the capacitors in the crossover of my Apogee Stage speakers. This was a good and bad thing at the same time. While it opened up the upper frequencies and let the subtle details shine through, it also exposed that "solid state" sound in my amplifiers. I'm using a Pass Labs x-150 to drive the Apogee bass panel and an old modified Sim Audio W3 amp to drive the tweeter midrange ribbon. While the Pass Labs may be a better amp, it was a horrible match when I had it driving the tweeter midrange ribbon. The sound was like turning the treble up to +11 on an old Radio Shack receiver!
Does anyone know of a musical Tube amp under 2K used, that would produce detailed and smooth (not dull) music to drive my Apogee Tweeter midrange ribbon. I'm currently using a Naim 202 preamp, Raysonic 128 CD player, Linn Sondeck with Koetsu Rosewood and Ayre phone pre-amp.
Ouch... I really like the sound of my (Nelson Pass designed) Threshold poweramp with my Apogees (Centaur Major). I'd suggest you take another approach and change the preamp for a tube amp. To my ears, Naim gear always sounds a tad bright.

Then again, it's all a matter of taste. For two K there are many poweramps available, especially secondhand. You can also 'tune' them a little bit by changing the tubes. Only problem of the Stages is the lowish impedance - not as bad as the Scintilla's, but 3 Ohm and a low sensitivity means a new poweramp has to be able to deliver some power. Make sure you test your new amp at home before buying.
I use all tubes with my Apogees....Amps, preamp, and DAC. I have Duetta Signatures, and MiniGrands...and I switch between them every few months.

I had been using Solid State (Krell) for a number of years, but switched to Rogue Audio tube mono's around three years ago...and I would never go back, unless I was forced to.

Biamping the Stage, Duetta Signatures, or any other two-way Apogee speaker is a waste of time and money, in my past experience....YMMV of course.

Around 100-200 good tube watts are all you need (my amps are 120 watt monos, and real toe tappers!). These amps drive both pair of Apogees as loud, and with enough control, to fill all my needs.

If you listen at above 90db very often (I don't)....150/200 watts may be in order for you.

Tube amps come in all flavor of coloration...or very little at all? In my search....I wanted Krell like bass, a better midrange (tube coloration?)....and very articulate highs....I chose the Rogue amps (Kt-88 tubes), and have been very happy.

My DAC is Monarchy M-24....NOS Amperex
My preamp is Audioprism Mantissa...NOS Amperex

Good luck in the hunt!

Hi Scott

How much breakin time is on the new caps that were installed? Is the crossover passive or electonic? Passive crossover caps and resistors can take up to 300hrs to burn in and open up. Your description of sound is what you can expect for the first 25 to 50 hours. After that things begin to mellow out and expand at the same time. What brand caps did you use?

Thank you for your responses,

You are probably right about the burn in time for the capacitors. I'm using Clarity Caps SA, and I remember when I built some speakers last year and had a similar problem. It took a good three months for the higher frequencies to settle down. Once they burned in, the sound was beautiful. After that time period I may try a Rogue amplifier since my local dealer carries Rogue.

Dave, When you said Biamping the Apogees is a waste of time, what effect did biamping have on the sound from your Apogees? When I first tried biamping with my Pass Labs x150 and Sim Audio W3, it really opened up the sound and allowed me to match the strength of each amplifier with either the bass panel or tweeter midrange ribbon. I have never tired using tube monoblocks to power the stages, only an Audio Research Vs110 amp. I though the sound frp, the Audio Research was a little to "soft and mellow" for my taste. Maybe I should try a few more tube amps.


I replaced the caps and resistors on a pair of Polk Sda srs speakers last year. I now have about 300+ hrs on them and just last month I noticed they opened up wide and deep.
Take your time with the upgrade to amps so you can hear each tweek as you go along. You can't go wrong with a Rogue amp or a single ended tube amp. The tweeter ribbon only needs a few watts to give you ear peircing SPL
I've listened to Pass Labs with a Dunlvy V setup and was very disappointed with the performance. Pass is very overpriced and over rated IMO
I listened to the same speakers with a pair of Lamm monblocks. I was left thinking something was wrong with the pass amps thats how dissapointing the sound was


Biamping...or at least passive biamping, didn't do anything for me. I came to the conclusion, that one single better quality amp, sounds better than two lessor quality amps. The ribbon doesn't really need gobs of power...and it shares midrange duty with the bass panel....all the two-ways do.

With the panel and ribbon, both reproducing some part of the midrange, using "unlike" amps is very hit and miss (worse case is trying to blend SS with tubes)...although I note, that it does work...and sound fine to you in your system....hit and miss (I guess you hit).

Biamping the larger three-way models works out a little better, because you have a dedicated midrange ribbon, and it crosses over to the bass panel at a much lower freq.

Maybe your dealer will let you take a pair of Rogue 150's home for a few days (have him put KT-88's in it, and use the 4 ohm speaker taps)....and a good tube preamp?

Ed brings up a good point about burn in, I'd give that some time also.


You can try Audio valve or Antique SOund Lab.

I agree with Dave that bi-amping is a waste of time.

B-amping (many many combinations) never worked for me because of lack of coherence. My current configuration is Apogee full range (modified) driven with one amp, the TRL GT-800. The negative effect of this excellent sound is total satisfaction which has made me lose all interest in trying out more amps and even posting on forums.