What Power Amplifier Should I Buy?

Sub, or better still subs in stereo are going to make a marked improvement in your system. That’s where the oomph is! Cheers 

I've had a Levinson preamp (326s) and it did not have the bottom end kick that others do.  It does other things well, but that's not a strong suit.  If the pre is holding back the low end it won't matter what amp you put behind it.

I’d look at the VTV Purifi amps.

before you get a new amp consider lowering your crossover frequency to around 70 Hz and if possible and high pass the input to your Bryson at 70 Hz. You can get some inexpensive FMODs from Lincoln Labs to try it out. 

It sounds like you don't use much more than 3-5 watts per channel now.  Why would an amplifier much more powerful than the 135 watt per channel amp improve on the matter?  It seems like the only metric people care about is power, so more must be better.  It simply is not the case.  There is much more to achieving good sound than can be measured, whether that measurement is power, harmonic distortion, intermodulation distortion, slewing induced distortion, signal to noise ratio, damping factor, etc.  If if were the case that we can determine quality by any set of measurements, there wouldn't be such a vast array of market choices, alternative designs and fundamentally different approaches to design; things would be narrowed to the objective "best" at each price level.

You should make an effort to hear for yourself an array of amplifiers.  You should not dismiss any type of amplifier based on limited experience with one particular amp; that would be like dismissing all American-made cars based on your experience with a Pinto.  I don't subscribe to the "tube sound" or "tube magic" idea because there is a VAST difference among tube amps (more variability than there is among good solid state amps) and there are many that, to me, anyway, sound more brittle, harsh, and unpleasant than most solid state amps (I particularly don't like most high-powered tube amps employing tubes like the KT88).

@hk_fan  ... thinking same thing!

Ever consider getting speakers of higher efficiency instead?

Perhaps a pair of Bryston 7B SST monoblocs?  If you like the Bryston sound (I do too) you can get a set of 7B SST (Super Steve Tanner) used with years of warranty left for 4-5K. I drive my woofers with these and the upgrade in sound quality and oomph was stunning. (Formerly I drove my 6 way towers with an Audio Research VT130 which is now the mid/tweeter amp.I find tubes to have flabby bass at loud levels) 

I had the s@me concern as you, and I recommend a look at the Odyssey power amps.  I replaced a 100 wpc tube amp with two mono Odyssey Stratos Extremes with several upgrades, almost making them equivalent to Kismet amps.  200 wpc, and the improvement was marked driving my Fyne Audio F-702s.

Coda #8 or S5.5 both with in the budget ,

Better than most and Second to none!

Outstanding resolution and extension and liquid midrange

Get the bryston 4b3. You already like the bryston sound and it will give you greater extension in all areas of your system. 

PS AUDIO BK250  Refurb for  $4300 is a steal.

All competently designed (low noise/distortion/output impedance) amps will be indistinguishable.

Well that’s just silly.  BTW, I agree adding a second sub is a good idea. 

Preamp may be holding you back...

@ditusa Thanks for showing me an alternate path. Could you explain how a second sub improves the imaging and sound stage?

Perhaps I used the wrong word. By "oomph" I meant more power for transients. I wasn't indicating that I needed more bass. I believe I have enough bass.

Oh, by the way, I use REW to calibrate and integrate the components. I aim for 1.5 dB/octave roll-off above 1KHz and 1.5dB rise from 200 Hz to 20Hz. I use a graphic equalizer to achieve an FR that's close to this.

OP,

One caution. Investing in a different amp at roughly the same investment level is likely to be trading one set of strengths and weaknesses for a different set. Unless you have made a big mistake on the overall sound ( like you bought a solid state and really would enjoy a warmer more natural sounding tube amp). In this case a sideways move can be of value.

My rule of thumb to avoid disappointment is to research thoroughly and invest no less than 2x. This will result in a serious improvement in all aspects of sound quality. Unless I can afford the jump, I just enjoy my system until I can.

All competently designed (low noise/distortion/output impedance) amps will be indistinguishable. If you still want to scratch that itch why not buy a pair of Fosi V3 Monos with a 48 volt supply for each amp. $399! 

@ditusa 

+1

@ditusa +1: Two subs for stereo is better than one in mono. The OP's Bryston amp has sufficient watts for the Revel speakers. Doubling or trippling the wattage is inconsequential.

@kevemaher,

In my opinion, I would buy a second 15'' subwoofer, you will get an improvement in imaging and sound stage and more ''oomph'' then you would from buying a bigger amp.

Mike

I’d think this SMcAudio DNA 1 would be worth a try and should be negotiable down to $2k at this point I’d think.  Plus, if you like what you hear you can send it back in for the more recent upgrades to get even more and still be well below your budget.  I recently had my upgraded DNA 0.5 in my friend’s system and it sounded beefier and more robust than his 3B SST2, which is why I thought this might give you what you’re looking for.  Best of luck. 

https://www.usaudiomart.com/details/650135552-mccormack-smc-audio-ultra-15-dna-1-power-amplifier-upgraded/