Bryston 4B3 or Ps Audio M700 monoblock?

I'd like to replace my 20 year old Bryston 4B SST with a new amplifier, solid state or hybrid. I have been considering the 4B3 and the PS Audio BHK 250. Both got great reviews but I am a bit concerned about the midrange withe the 4B3 and I do not like the amount of heat that the BHK 250 is  reported to produce. I am thinking now of the PS Audio M700. These are efficient class D and do not produce much heat. The M700 has also been reviewed favorably. It's a stereophyle class A.
I appreciate any thoughts on this, an din particular if you have experience with these amps.
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Former 4B3 owner and loved its sound and versatility. Got it for a great price and leveraged it, and other equipment, into my current ref system. Thought its sound very balanced and natural and would buy it again if needed. Have you considered the new Parasound A21+? Lots of power and proven Parasound sonics (doesn't have that sweet 20 year warranty but cost half as much full retail).
About 4 months ago, I replaced my classic Adcom 555-II amp with the PS Audio M700 mono blocks, and I have been very pleased with the upgrade in sound. The M700s are very clear, dynamic, and musical while running cool and not requiring a strong back to move them. Stereophile calls them "an outstanding bargain," and I enthusiastically agree. 

I am sure that the Bryston 4B3 is a strong performer, but it is also significantly more expensive than the M700 pair. I have not heard the Parasound A21+, but it would have been my second choice when I bought the M700s. The issues that drew me toward the M700s (in addition to the great reviews) were the fantastic discount available if you have any gear to trade in and the 30-day in-home trial from PS Audio. If you want to demo the M700s before you confirm your purchase, you can try them in your system and see if they create any magic with your gear. If they don't, just send them back. 

Good luck with your search for a new power amp!
Thank you for your comments.

By concerned I meant that although better than previous 4Bs, it still can be dry (i.e. less warm) compared to other top other class A or AB. In general I have been very happy with the 4B SST except for some dryness in the midrange and some harshness in the top midrange and treble. I mitigated this with a Rogue Magnum 99 tube preamp and the combination was great to my ears.

However, if I am getting a new amp, I'd like to get an amp that does not have those qualities, and although the 4B3 is supposedly better in this regard, I am not sure if it is better enough to my taste. Both PS Audio amplifiers are described as organic sounding and the M700 was even called tube-like. Was hoping someone who heard them and the 4B3 might comment on the differences.

I may very well try the M700 at home. I do not think I can do the same with the Bryston. 
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:

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.


     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.

Thanks to all for very helpful information. I think I'll give the M700 a try. Thanks again.

     Great, please post back on this thread with your impressions.

reflecting on your comments, I am curious as to why you think I should not consider PS Audio (gammonit-2000)
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To me Class D sounds just as good as the other classes, if done correctly, as with the other classes as well. Why would someone want a Class D?
1. More watts per dollar (usually)
2. If you keep it powered 24/7 then it's always warmed up. Even for a few minute listening session where you probably wouldn't turn on an A or A/B amp for just a few minutes.
3. No heat if your room gets hot.
"reflecting on your comments, I am curious as to why you think I should not consider PS Audio (gammonit-2000)"

Hello benjosef1,

     If you're directing your comment to me, I don't think I ever stated you should not consider the PS Audio Gammonit-2000.  I actually wasn't even aware of this amp, which I assume is a new product.  I went to and didn't find any mention of this amp.  I also googled it and only saw references to this thread.  I really can't comment on products I'm not even aware of. 
      If you could post a link to any info on this amp, I'd be glad to learn more about it and offer my opinion.  I'm fairly knowledgeable about class D amps in general but this one is new to me.


"Some responses... one would think they are the President of the company they have such a strong desire to 'sell' a product to others.   I would just add a lot of the selling going on is fan boy praise. Folks just love something and will say and do anything to get others to join the club. So IMO a little standing back and taking a deep breath. Realize some folks are very persuasive, and you may not get the same love' for whatever they are 'selling'/praising to the skies. Just sayin'"

Hello Elizabeth,
    Are you referring to me with your comments?  

Some responses... one would think they are the President of the company they have such a strong desire to 'sell' a product to others.I would just add a lot of the selling going on is fan boy praise. Folks just love something and will say and do anything to get others to join the club. So IMO a little standing back and taking a deep breath. Realize some folks are very persuasive, and you may not get the same love' for whatever they are 'selling'/praising to the skies.Just sayin'

Amen Elizabeth.  The level of fanboy-ism on here has really gotten out of hand.
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Tim, sorry for the confusion. I found your comments very helpful.

gammonit-2000 is a member here on the forum who was very skeptical about PS Audio and I was just wondering why.

I agree with Elizabeth and others who said you have to take recommendations with a grain of salt- a lot of this boils down to personal taste- and one has to judge for himself/herself.

Personally, I do find other hobbyists’ experience and perspectives helpful
both of these amps will sound identical with your loudspeaker assuming they arent wilsons with a sub 1ohm impedance dip. any differences in the midrange and bass will be placebo. amps do not sound different from one another assuming they are driving a well designed speaker with a smooth impedance modulus and phase.
Hello benjosef1,

     Hah!  Well, that explains why I couldn't find any info.  Duh.

    " I agree with Elizabeth and others who said you have to take recommendations with a grain of salt- a lot of this boils down to personal taste- and one has to judge for himself/herself."

     I completely agree, too. It's just such a broad brush statement that I don't know who she's directing it at.  Everybody, a few people, me?  I don't believe she was referring to me, but who knows?  I actually welcome constructive criticism but prefer it to be more directly delivered.
     Anyhow, It is good advice that I'm glad you're aware of.  I try to be as honest and helpful as I'm able to be.  Of course, I realize I may occasionally approach 'fan boy' status when discussing gear that I've personally had especially positive experiences owning or using such as class D amps and 4-sub distributed bass array systems.  But I believe this is really just the epitome of honest and helpful advice.
     My intent is typically to spread the word on equipment that I've personally used or owned, I've experienced very positive results with and I think is relevant and helpful.  If my enthusiasm is misconstrued by others as a strong desire to sell someone something, I'm not very concerned provided all my comments are completely truthful and I have no financial incentive. 
     I also like to advise others to try and buy products that have generous  return policies and free in-home trial periods. This significantly reduces the risks involved.  I believe PS offers a 30-day full refund policy and offers price discounts for equipment trade-ins.  
     Lastly, I strongly suggest you don't even consider that PS Audio Gammonit-2000 amp.

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Buy my amp.  It's new, it's Class G.

The M700 seems to have a lot of likes... and of course it is returnable. In addition I’d suggest you take a 45 minute drive up to Allentown and visit Digital Amplifier Company as they are getting a lot of great feedback for their class d which doesn’t use purchased class d chips but discrete components in circuits designed by Tommy O’Brien. 
Hello benjosef1,

I thought I should let you know that I’ve never personally auditioned the PS Audio M700 class D amps in my or any system. My suggestion you give them a try in your system was mainly based on professional reviews of their high quality performance, my knowledge and experiences of the high quality performance and sound quality levels attainable through good class D amps in general, the absence of any financial risks to you and the M700’s many other practical advantages over more traditional amps like the Bryston 4B3 and the PS BHK 250 such as size, weight, higher electrical efficiency, cooler operating temperature and affordability.
I believe snapsc’s suggestion of checking out the Digital Amplifier Company’s class D offerings is also very good advice. It emphasizes the points that you have many amp choices at your apparent budget, PS Audio doesn’t have a monopoly on very good class D sound performance and that learning about and listening to as many amps, of all types and technologies preferably in your own system, as possible is an excellent method of determining what you like and don’t like in an amp. You’ll not only be able to make a better informed amp choice for yourself but also be gaining valuable general amp knowledge and experience at the same time.
The last topic I wanted to caution you about is the surprisingly deep-seated ’amp type bias’ that I believe definitely exists, in varying degrees, among many members here on Audiogon and among audio/music enthusiasts in general. I first noticed this here on threads about 6 years ago when I initially began to become interested in class D amplification but it still currently persists. Elizabeth wisely cautioned about this amp type bias in an earlier post on this thread when she warned of class D "fanboys" and taking their advice with a grain of salt.

Good advice that I would suggest we all may want to expand to be wary of any advice giver’s amp type bias since identifying it can often be tricky. For example, Elizabeth wisely cautions of class D biased advice givers even while demonstrating her own bias favoring class AB amps in her first post on this thread when she stated she has zero interest in a PS Audio class D amp. Although her bias requires paying close attention and a modicum of memory, at least she identifies and admits to her own bias which many others completely fail to do when offering advice.
This is probably an opportune time for me to admit to my current bias toward class D amps and finally get to the point of this post. The truth is that virtually everyone with the sufficient meaningful knowledge of, and experience listening to, the various amp types to have developed an amp type bias just means they’ve discovered the amp type that has the qualities that they personally prefer in their own systems. In other words, they’ve developed an opinion based on an open minded and unbiased process of learning about and listening to the various amp types.
However, I suspect that many individuals continue attaining meaningful knowledge and listening experiences as well as keeping an open mind only to the point of selecting an amp to use in their own system. Once they purchase their amp of choice, human nature seems to dictate a shift in thinking and behavior more focused on defending and rationalizing their purchase decision rather than continuing an ongoing learning and experiencing process that explores the various existing and newer amp types in an open minded and fair manner.

My suggestion is to take all audio advice with a grain of salt, mine included, and instead seek to educate yourself via research and frequent auditioning of audio gear, preferably in your own system and room to keep any variables to a minimum. I believe trusting the objectivity of others advice on which amps to utilize in your own system is a poor substitute for learning, listening and deciding for one’s self.

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Hello Elizabeth,

     Thank you.   I believe we're all afflicted in varying degrees with biases that are not useful in life, choosing an audio amp or in giving advice on choosing an audio amp.  Of course, these biases are more detrimental and consequential regarding some issues than others but a little self awareness never hurts.

   I'm glad we agree and I appreciate your comments of agreement.  Maybe there's hope for us disagreeable and biased humans after all.

Can we at least agree that Bryston has a better warranty?
Hello gammonit_2000,

Agreed, as long as you buy a model that still carries a 20 year warranty.  I believe Bryston reduced the length on some of their models.

I know the digital stuff is 5 years but AFAIK the amps and preamps are still 20 years.  I could be wrong, it has happened before.

      Looks like you're correct except for  a few detals, below is from Bryston's website:

Warranty Details
 Bryston analog audio products and loud speakers are warranted to be free from manufacturing defects for twenty (20) years from the original date of manufacture. The warranty includes parts and labour. Speaker warranty is limited to the first time buyer and is non-transferable.

Bryston Digital products and cables are warranted for five (5) years from the original date of manufacture. The warranty includes parts and labour.

Bryston products having motorized moving parts, excluding motorized volume controls, are warranted for three years from the original date of manufacture. The warranty includes parts and labour.

Bryston will remedy the problem by repair or replacement, as we deem necessary, to restore the product to full performance. Bryston will pay return shipping costs for the full length of the specific product’s warranty.


It's interesting how this 7BSST2 combo with the BP26 and MPS-2 improved the sound over my old 4BSST with a BP20 and MPS-1. 

I suspect OP will fall in love with the PS Audio and live forever happily in Class D.  Or not.  Really seems a step back, all these rave reviews such as the glaringly bad KEF LS 50 get old.  I don't even trust the rave reviews on the Bryston BCD-3.  I am suspicious.  Really though their software apparently sucks on the digital side, like bad.  Mickey Mouse or was if Manic Mouse?  And a $375 remote?  I have one, and it's odd.  BR2

     Have you ever tried a good quality class D amp in your system or heard one in any system?

noble 100 I haven't, I need power and low impedance capability.  I went from 300 watts to 600 watts a channel.  These Infinity Kappa 8s need lots of juice down to literally under an ohm.  Am I missing something in the Class D department?
This is for gammonit_2000:

The BCD-3 is a very good, not great, player. I'm not a fan of its button ergonomics and they promised a plastic remote to replace the ridiculous $350 remote that is optional with the player and never delivered it to market, but, on the whole, it's solid. It doesn't read CDRs nearly as well as it should, and I've had issues with a few CDs that play perfectly in other players, but when you put a well-recorded and mastered CD in the deck, it will light you up with its quality. It sounds very, very good. It's "sound" is not dry and artificial like poor CD players, but rich, dynamic and reasonably rounded. Like Stereophile said, a B seems a fair rating, but, to me, a B isn't a knockout. I'm reasonably happy with the player but would be happy with better. At the price point, though, is there a competitor? I'm redbook all the way when it comes to digital.
beeswax, thanks for the comments.  It's a deal killer though to not read CDRs as that's what I already have a lot of and will be recording more of on the old Harmon Kardon CDR20. 

I'm actually falling deeply in love with the Rega Planet 2000 that I bought on here including a killer remote (the Solar) for all of 195 including shipping.  I think it sounds great to my ears.  I've never had CDs sound so "analog".  The top end is killer without that harshness, the soundstage is to eat off of, the bass is top notch, and zero listening fatigue. 
"noble 100 I haven’t, I need power and low impedance capability. I went from 300 watts to 600 watts a channel. These Infinity Kappa 8s need lots of juice down to literally under an ohm. Am I missing something in the Class D department?"

Hello gammonit,

     Are you missing something in the class D department? As a matter of fact, I believe there are a pair of mono-block class D amps that may perform extremely well with your notoriously difficult to drive Kappa 8s.
     They're the original D-Sonic M2-1500-M2 class D monos that were reviewed very favorably on this 6 Moons review back in 2012. In the review these amps were auditioned on the Apogee Duetta planar-magnetic speakers, which I believe also present speaker loads to the amps of down to literally under an ohm, with very good results. D-Sonic claims stability into below 2 ohm loads but apparently they're stiil stable even lower.
These amps are rated at 1,500 watts into an 8 ohm load, 2,400 into 4, deliver 160V and 30A and were priced new at $1,075 each at the time. Here’s a link to that review:

     Yes, this is from 7 years ago but I was thinking you could probably purchase a used pair currently for a reduced price if any owners are selling.
     Or, you could try out a new pair of their current version, the M3a-1500M that uses the latest Pascal class D power modules for $1,375 each, $2,750/pair. These have the same power output and the very low speaker impedance load capacity as the M2 series but now have a bit more neutral overall sound quality and several added internal monitoring safety features. Here’s a link to the new D-Sonic monoblock amps:

     I’m not sure which amp or amps you’re currently using on your Kappa 8s. However, I’d venture to guess they’re good quality but large, heavy, expensive, hot running requiring large heatsinks, inefficient class AB amps that currently perform and sound sufficiently good to you that you’re not actively searching for replacement amps right now.
     I’m fairly certain that, if you paid less than $50,000 for your current amp(s), either a used or new pair of the top of the line mono D-Sonic amps will outperform them by a significant margin in sound quality while also being much smaller, lighter, more affordable, cooler running and consuming a fraction of the electricity. I believe that’s what you’re missing in the class D department.

Running big inefficient Bryston 7BSST2.  Paid 4300 for two of them 10 years old.  Smaller and lighter doesn't do much until I need to move them.  Also just curious about shielding reqts for Class D?  Seems I was reading something about that aspect.  Obviously this is new to me on the Class D thing.  Anyway thanks for your comments and I will try to check out one of these units next time in the "big city"...
Hello gammonit_2000,

     I know your Brystons are nice amps but I know a good class D pair of monoblocks will also at a minimum match them on sound quality and pay for itself fairly quickly just on all the electricity you'd save, even if you left them on 24/7.
     Yes, rf interference can be an issue if the power modules aren't properly shielded internally.  But virtually all the good quality class D amps are properly shielded and you shouldn't have any issues. I have three, a Class D Audio SDA-440-CS and Emerald Physics EA-100.2SE stereo amps and a pair of D-Sonic M3-600-M mono-blocks, and I've never had any interference issues.  There's no special shielding requirements you need to take except buying a good quality amp from a good company.
     The problem is finding an audio shop to audition one.  Most class D amp companies sell internet direct to keep prices low.  But you can usually purchase the amp and get about 30 days to try it out at home in your system.  If you like it, you just keep it.  If you don't, you just send it back and get a full refund, no questions asked.
     Just an fyi, these amps are very neutral and revealing, like the audio ideal of 'a straight wire with gain'.  If upstream components and recordings are not high quality, it'll be easily noticed since there's no flavoring or coloring going on, nothing's added or subtracted from the inputted signals.  On the plus side you'll easily notice the effects of system changes, even power cord and cabling changes.
     I sincerely believe you'd be pleasantry surprised by the hi-end performance level of the numerous good class D amps currently available at relative bargain prices.

Thanks Tim,
I appreciate your input (so to speak).  I do like the "straight wire with gain" ala a CJ PV10B design for example.  I won't bash Class D again unless I actually hear one.
Hello Karl,

     I have no problem with individuals criticizing any amp or amp type if it's based on personal experience. I was hearing the same accolades and criticisms repeatedly of class D amps about 10 years ago on Audiogon forums and was curious about class D but didn't know who to believe. 
     Most of the accolades were coming from those that had dared to try a class D amp in their system   But I had a hunch that many of those repeating common criticisms of class D performance had never even heard a good class D amp in their systems or any system.  
     So, I just bought a Class D Audio SDS-440-CS amp with a 28-day free in-home trial period for about $600 and decided to find out for myself if class D was any good.  That was 10 yrs ago when I used all good quality class AB amps(Aragon, Adcom and McCormack) in my combo music and HT system.  
     The results of my personal experience comparing good class D amp performance with good class AB amps in my system and room are best summed up by the fact that I now utilize all class D amps, from three different companies (Class D Audio, Emerald Physics and D-Sonic) in my combo system.
     The main intent of my comments to you are not to bash you for bashing class D, although I believe you deserve some bashing for bashing class D without any personal listening experience with it, but to suggest you would probably enjoy their performance and other characteristics in your own system.
     But I do appreciate the reasonableness of your post and your intention to try to audition a good class D amp.  I think you'll be pleasantly surprised.

Thank you,
OP has been pretty quiet, I am now curious if he did order the PS M700 and if so what does he think vs. the Bryston 4BSST.  Since the 4BSST was my main amp for many years (and I still own one) this will be a somewhat reasonable comparison...
Hello Karl,

      Yes, no doubt the Bryston 4BSST is a very competent amp.  I've read very positive professional reviews of the class D M700s but have never personally heard them.  I'm also looking forward to hearing his impressions, hopefully he'll be posting again soon.

Sorry for not posting for a while. It's been hectic 
unfortunately i have to delay purchase until the beginning of the new year.

I will make sure to post impressions once I do.

Thanks again to all.

Well we had a nice chat and I learned a few things.
Thanks for the update and have a great rest of the year...