Bryston 4B3 or Ps Audio M700 monoblock?

I've had the 4BSST for 15 years.  Most of that time I used it with a Conrad Johnson tube preamp.  Then I bought a BP20 with the MPS1 and finally gave up on that tube noise. 

Recently I bought the 7BSST2 monoblocks with the BP26 and MPS2 for a total price of 6500 bucks to my door which I thought was damn good.  Soundwise, it's a huge improvement but in fairness to the 4BSST the preamp and power supply was a step up so it's a bit hard to know how much the monoblocks helped. 

My advice based on what's available is to negotiate for a pair of 7B3 because there are a lot of them now on Audiogon at pretty decent prices.  The warmth factor or whatever versus the 7BSST2 is hard to define but I trust Bryston and you are getting almost 20 years left on the warranty.
Seriously, PS Audio?  Cmon man.

I tested out a set of 7b3 monoblocks in my system.  I would say that the Cubed B3 series are not dry like the previous versions.  It's definitely a lot better sound, sweeter sound even.  Very high resolution amp.  However, I think it keeps the similar Bryston sonic signature which can be somewhat thin in the midrange and midbass/bass.  I generally recommend matching Bryston amps to a very warm/full preamp and use lots of pure copper gold-plated wiring.  A Marantz preamp would be great.

If you want to move and are looking for a fuller midrange, the Stellar Gain amps are very nice.  I have heard them and they are definitely more conventional sounding than the thin/fast Brystons.  The did not sound bad to me at all.

I suspect that the Bryston 4b3 will be a higher resolution with more "air", but may lack in midrange body and fullness that the PS Audio M700 amps would provide.  So in the end, it really depends what you want.

The Parasound A21 amps are very nice as well (I have owned A21/JC1s one and actually have an A21 for sale).  They are much fuller and natural sounding than the Bryston or PS Audio M700, but they are soft/rolled-off in the high frequencies.  The PS Audio M700 are probably the most neutral sounding of the three.  The Parasound would be just slightly on the warm side of neutral.  So, again, it depends on what type of sonic signature your looking for.

@benjosef1, if you get a chance to hear the 4B3 I will guess you will be very pleased with Bryston’s latest level of refinement.  I own a Pass 250.8 and after changing speakers was tempted to downgrade to a more environmentally friendly amplifier and purchased a used 4B3 to compare with my 250.8.   The Bryston was very smooth with no hints of harshness in my system.   I was very impressed with it and thought it competed well against my Pass amp; I also thought it has slightly more detail along with a tighter faster bass than my amp.   In the end I kept my 250.8 and sold the Bryston because the Pass offered better front to back soundstage and has a fuller more life like sound to my ears.   The 4B3 was very nice though and well worth its price relatively speaking; especially when you throw in the warranty and build quality...

For those who don't know a lot about the Stellar M700 monoblock, It was designed by a passionate young engineer named Darren Myers, who is also a committed audiophile. He worked for Classe and B&W before being hired by PS Audio. His excitement in designing gear that sounds really good is shown clearly in a YouTube video of an interview he did at AXPONA 2019 with Michael Fremer: https://www.youtube.com/watch?v=oFspgDyjEQo

I had already bought my M700s by the time I saw this video, but it was fun to find out a bit more about the main engineer behind the PS Audio Stellar gear.

benjosepf1,

     I'd suggest you audition the M700s in your room and system.  I think you'll find that the M700s are a very good match with your Rogue 99 tube preamp if you like the sonic qualities of this preamp.  
     The main characteristics you'll likely notice on the class D mono-blocks is that they have a very low noise floor, very low distortion levels and that they're very neutral.  They are like the audio ideal of a straight wire with gain meaning nothing is added or subtracted from the inputted signal.  This will result in the combination of the sonic qualities of your source components, the recordings and the Rogue 99 tubed preamp the main determinants of your system's overall sound, since the M700s will just be faithfully amplifying this combination's output without any added sound quality of its own.
     You should be aware that class D amps are very accurate and revealing which can sound very good if the quality of your recordings and other components in your system are of high quality.  However, if the quality of your recordings and other components in your system have deficiencies, class D amps will not sugar coat anything and you will be clearly aware of any deficiencies.  
     The downside of using class D amps is that the quality of some of your music , that sounded good to you through your previous amp, will not sound equally as good if it wasn't well recorded because the accuracy and transparency of a good class D amp will expose that deficiency. I use a pair of D-Sonic M3-600-M class D mono-blocks in my system and, fortunately, only my Coldplay albums were exposed as poorly recorded.
     The flipside of this, using class D amps with well recorded music, will be sound quality performance levels that are exceptionally good.  Music  emerges from a dead quiet background with live-music-like dynamics and a very detailed presentation that still sounds smooth, organic and natural.
    I suggest you give the M700s an audition and experience good class D performance and decide for yourself if you like the overall sound quality in your system.  I definitely advise doing so before buying anything else to ensure you make an informed decision.


Enjoy
 Tim