The PS Audio BHK Mono 600 Power Amplifier Review

Tom Martin review the PS Audio BHK 600 Power Amplifiers, details its brutish power power supply, its vacuum tube rectification stage, and relays some of the history behind the designer, the late Bascom H. King.
00:00-05:51 Specs
05:51-15:04 History, Design, Bascom H. King
15:04-18:11 First Thoughts on Sound
18:11-21:32 Reference Equipment and Tracks
21:32- Pros, Cons, and Further Thoughts
About Tom Martin:
Tom is a long-time audiophile. He began his reviewing career after acquiring the The Absolute Sound magazine in 1997 and then hi-fi+ magazine in 2002. He has worked closely with Harry Pearson and Robert Harley at TAS and with Roy Gregory and Alan Sircom at hi-fi+. Since Tom and his teams expanded the TAS and Plus platforms in the digital domain, he has served as Chief Content Officer.
What Is The Absolute Sound?
The Absolute Sound magazine has been a leading publication in high-end audio since 1972. Since the early 2000s, The Absolute Sound has expanded to include web, newsletter, digital magazine, social media, KZbin and Substack platforms. The Absolute Sound platforms have a global audience of over 500,000 audiophiles.
For more show reports, expert reviews, features, and commentary subscribe to our newsletter at: www.theabsolutesound.com
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[@davewin1792]

Tom without trying to sound like a broken record, this channel brings so much value to our hobby it's staggering. Guys keep in mind that even if you don't have the ability to own these amplifiers, their are what I would call ah-ha moments that can help us learn, and be better equipped in making purchasing decisions down the road.

[@hamidrezahabibi8111]

A great review from Tom on the Magnificent PS AUDIO BHK 600. 🎉😊

[@skipgordon5382]

Thanks for sharing. Excellent review. On my bucket list.

[@jeffreypicciolo7706]

Beautifully done review. I have the PS Audio S-300 amp in the strata line and can say that is a wonderful product as well although not in the same class as the BHK.

[@dougg1075]

Enjoying the reviews.

[@janetyer7147]

Tom Martin, thank you for another interesting video. It was a pleasure to watch. Very well done.

[@serloinoflamm1119]

Another great review. You have now reviewed several PS Audio products - have you ever considered reviewing a complete PS Audio system - from DS ii dac, pre, power and speakers? I think it would be fascinating to hear a review of a full single manufacturer system. I don’t think I have ever seen anyone carry out such a review.

[@thomasmartin2219]

I think it has been done with Linn and Quad back in the day, and there still aren’t that many options now. I think the other deterrent is that the reviewer is changing a lot of variables at once. But if folks want system reviews, they are possible. Single brand system reviews would be more rare, but still possible. Burmester, mbl, T+A, PS, Linn, Audio Group Denmark and I’m sure others.

[@serloinoflamm1119]

@@thomasmartin2219 Thanks. I have always wondered what it would be like to own all components from a single company. Never have and probably never will, but I do wonder sometimes…whether the technical synergies and in-house sound would outweigh personal choices (and a lifetime pursuing the perfect/absolute sound!)

[@jerry6789]

You have described my system. BHK Pre, BHK 250, DS2 Dac, PW transport,Stellar Phono, FR20 speakers, P15, Rega P8 TT. I cannot describe how amazing the system with all one system type playing well with each other. Pure bliss. ❤

[@adsph]

Well done video. Incredible mono block.

[@Nephilim-81]

I really quite like this review. Pretty genuine and informative.

[@cobar5342]

Thank you for a great review

[@EricRhodeslives]

Interesting review. Excellent!

[@jjgk228]

Excellent review...thanks!!!

[@garysmith8455]

Nicely reviewed Tom. You were recently at my local audio dealer and long time friends over at Safe and Sound! I think you were pleasantly surprised by such a fine store presentation in a small town. I am very much in the orchestral camp, and work for a pipe organ company (coming up on 35 years), and we are employed by the Boston Symphony Orchestra maintaining the 1940 Skinner organ at Tanglewood during the summer concert season.. In a few words, pipe organs and symphonic orchestras at full tilt have NO distortion since they are all acoustic. My only pet peeve with recordings of these instruments/ensembles is the wide spread use of multi channel/mono microphones all over the venue. Our friends over at PS Audio know me pretty well when it comes to this matter.😉(I have helped in 'coaching' Octave Records with their first ever, and recent recording of the pipe organ). Point is, VERY FEW and far between, that recording companies take the time and EXPENSE to record in TRUE STEREO where you can say 'stereo image', that being produced by ONLY 2 channels. Soundstage (as we know) is electronically placed signals by the engineer at a mixing desk. Thus turning a fine concert hall acoustic into a big studio. 😑 And no, the Decca tree is not true stereo, and it's common placement over the music director's head is NOT where perhaps you, or certainly I would want to hear a live orchestral performance. Composers of orchestral compositions arrange the musicians according to their dynamic range on stage, and are made to work these dynamics with a solo violin or piano at the front of a large ensemble. How many times have we heard recordings where a solo instrument is 'augmented' by loud respiratory noises from the performer?, which to me, can be a total distraction and usually due to a single solo hot spot mic close to that instrument. I believe that the audience perspective recording with only two channels would really make our music systems at home really shine, and certainly the BHK amps, would portray this wonderfully. Thanks your thoughts, and for reading my long 'side bar' comment.🙂

[@quadspeak]

Local audio dealer? What’s that. No such thing anymore sadly

[@markcuster6242]

I had BHK 300 monos with Magnepan 3.6 and later Rockport speakers. The BHKs were too soft for my taste and I sold them. But I kept the PS Audio Dirext Stream. Interesting to hear Tom comment on this BHK’s softness.

[@johnnycashlesscomedy8616]

I'm using the BHK300's and don't find any softness, but then again my tweeters are beryllium. I believe the review mentioned 1% softness in the very upper treble.

[@markcuster6242]

Always system dependent. My Rockports have beryllium tweeters as well. Room acoustics and hearing also plays into it. And personal taste. Sad to learn BHK has passed.

[@flavioc5389]

My dream amplifier.

[@danieljones8587]

Thanks for your review, I appreciate every one of them. A question out of curiosity has anyone compared these to the Mac 611s? I hear the 611s are very nice as well. BTW, PS Audio has the 300s on sale, right now for 50% off.

[@gtrguyinaz]

Very nice review…PS Audio has now moved into the upper crest of high end audio… I have very low output Dynaudio C5s speakers and already own a world class … big power amp developed by David Belles… 350 watts into 8 ohms etc… I point that was not addressed is damping factors…. Belles amp has very high damping factors and that does impact bass control and recovery… Congrats to PSAudio… Ido use their power plant and power cables ..

[@thomasmartin2219]

Here we have a specified damping factor >100, but in reality, of course, this depends on your speaker cables and speaker impedance.

[@gtrguyinaz]

@@thomasmartin2219 my Belles 350a reference has a factor of 2000 at 100 hz… so yes I want that for my sealed C5s speakers…

[@jamesbaxter2812]

Asking a second question. Have you looked at tap decks. I am looking at the Ballfinger. Thanks

[@ofir5000]

Please show more videos about speakers and complete systems Thanks (:

[@thomasmartin2219]

Coming. Anything in particular you’re interested in?

[@kingng3443]

Excellent review! From my experience, BHK 600 is a bargain. It's competitive with amps costing 2x to 5x more that I was considering.

[@rewingtaylor]

As a follow up how about a review of the BHK 300. It would be interesting to see what sacrificed sound wise at half the price.

[@FOH3663]

Hard to say, ... it would be the combination of compromises the "lesser" design utilizes.

[@davewin1792]

@@FOH3663 Very well said.

[@donpayne1040]

I think.. both output transistors types are push/push, but one side's phase is flipped, creating - and +.

[@antiWhiteism777]

​@TheTASmagazine --- Why are you using two amplifiers simultaneously? Is this something worth getting for movie/game center, or is it a waste if not using in a Hi-Fi music center?

[@antiWhiteism777]

​@TheTASmagazine --- Aren't soldering tubes directly to a PCB a sign of a low quality device?

[@michaelmyers7416]

I enjoyed the review, but not most of the comments. I like it when you say boys and girls but I know you’ve changed. Pressure from the gripers. Also, do not make apologies for people listening to classical music. I think most of the stuff that audio files listen to is dreck. But I don’t care what people listen to. I do want equipment that can handle the wide, dynamic range of a symphony, orchestra, and not get confused by the massive amount of details in symphonic compositions.

[@Expedition18]

You say it's dynamic, no errors and relaxed, does it color the sound or stream it faithfully?

[@thomasmartin2219]

I tried to categorize the primary error I hear as a slight treble softness. See 24:15ff. Sorry if I wasn’t clear enough that NO audio product is without errors (25:35). Finally, I am regularly impressed that better circuits yield better soundstaging and I have not had, say, the $100k+ amps in my system, so who knows? (See 23:25). I allude to but don’t really harp on the fact that if you had 82db efficient speakers, you might need even more power. Thanks for asking.

[@Alephkilo]

I remember reading sone reviews by Bascom King.. on sone of the early generation Classe amplifiers.

[@ChrisMag100]

I had a set of these in my system for a few weeks, driving a set of Focal Scala Utopias. It was an Interesting experience. Agree with your comments about imaging. That was my favorite aspect of the BHKs. I found that running NOS Russian mil-spec tubes, Reflector 6H23-EBs in the input stage brought better overall tonal balance in my system, compared to the supplied new-production tubes. I ended my time with the PS amps thinking “these would be great for Magnepans”.

[@user-oe1jk2ro4o]

Looks like an unfinished product And the back looks quite cheaply built

[@danieljones8587]

​@user-oe1jk2ro4o You're an unfinished product. 😅

[@charlesmanneschmidt7587]

A couple of nits: Although there have been newer versions of IR (now Vishay) MOSFETs, I would not call these output devices state-of-the-art. Audio designers like them because they work well for audio, but this type of MOSFET has been used for at least 30 years. Also, all analog engineers understand that p-channel devices, whether bipolar or FET, are inferior to their n-channel counterparts. This is not something new nor divined cleverly. This implementation to avoid p-channel MOSFETs in the output (aka quasi-complementary, also an old concept), however, may be new, novel, and clever. Seems to be a fine amp. I was a fan of Bascom King's work.

[@charlesmanneschmidt7587]

@@cengeb Not familiar with, but I can see that their TO3 devices went EOL last year. Who uses them?

[@skatter44]

Here's my dilemma, I'm torn between a pair of these BHK 600s or a pair of Bryston's 7B cubed. Anyone have any thoughts on which might be the better buy? I'm also in the midst of upgrading my speakers, I haven't decided on what speakers to get yet.

[@skatter44]

@@Dobbs65 Right. The price factor. Yeah, just looked up the price for the 600s on PS Audio's website. $32,500 for the pair. Ouch. Bryston it is then. Thanks!

[@akhtarizod5802]

I recommend neither, buy perreaux prisma 750 mono blocks, great sounding power amplifier.

[@skatter44]

@@akhtarizod5802 I've never heard of this company before. There are so many choices! Aaahhh! So, they are in New Zealand. Do they ship overseas? How could I demo one? I might just stick with a company that's located in the U.S. and more specifically, in the Eastern half. Thanks for the heads up on this company!

[@theaustralianconundrum]

PS Audio is an old school bunkum manufacturer of outrageously over priced equipment.@@skatter44

[@troybooker3534]

Do as Paul himself recommends. Get your speakers sorted 1st, then follow that up with your Amplification choice

[@oldschoolaudioenthusiast]

An interesting review. Regarding dynamic range - as I recall all things being equal at a given volume level you need a doubling of power to increase the perceived volume by 3db. So if 1 watt produces 85db, 2 watts should produce 88db, 4 watts 91db, 8 watts 94db and so on. Hence Tom's comments about needing about 1000 watts to reproduce 110db if you start out with 1 watt reproducing 80db. Hope this helps.

[@thomasmartin2219]

That’s the math. Thanks.

[@gtrguyinaz]

@@thomasmartin2219 yes… correct… So my 22 year old Confidence 5s have 83 db ….that why I have a big power amp… I listen in the 75 to 85 db range according to my simplistic test equipment….

[@thomasmartin2219]

@@gtrguyinaz makes sense. For the math interested, when you do these calcs, remember that SPL falls by about half, for each doubling of distance, so an 86db/1 watt efficient speaker would deliver 80db at 12 feet. Roughly. Less falloff for line arrays. Of course you may not need an amp that will reproduce the full possible dynamic range of a symphony orchestra! Finally, if you like these calcs, remember to check the units of your speaker sensitivity. They vary.

[@gtrguyinaz]

@@thomasmartin2219 yes and that is additionally helpful to all..

[@Toadcps]

Does anyone know what the music in the review is? I want it.

[@TheTASmagazine]

The Swindler by The Original Orchestra

[@Toadcps]

thank you

[@theaustralianconundrum]

You may be named the Absolute Sound however Absolutely no one needs to spend over US$10,000.00 for a perfectly acceptable audio result. The people that spend several times this amount are simply able to spend that kind of money. In the end it means nothing.@@TheTASmagazine

[@Relayer6a]

Tubes actually last a lot longer than people think if they are good quality and properly biased (This needs to be checked no less often than every 3 months or so at minimum.) There is no finite number, but a lot longer than 2 years. I think we as "tinkerers" just need something to "fix". 😀 Actually test your tubes before replacing them and you'll be surprised how often they are perfectly fine. It's probably more critical that you have a sonically good set of tubes and you want to make sure they are well matched. Don't buy tubes from bargain suppliers. BUT don't just buy them because they have an audiophile/designer name on them and are expensive. NONE of these audio companies actually make tubes. They just get their brand put on them. They might insist on certain tighter tolerances. But not always.

[@VideoArchiveGuy]

It depends upon your system. For example, my system is on playing something 24x7. For most tube amps that would mean replacing tubes every nine months or so.

[@Relayer6a]

@@VideoArchiveGuy Again, that's what people think. And even if you're right, yours is an extreme example. In typical use tubes last for many years. "Audiophiles" just need to tinker and change things and make up reasons to do it all of the time. You probably know this though.

[@VideoArchiveGuy]

@@Relayer6a I don't think it's as extreme as you think. Many audiophiles with solid state gear leave their system on all the time. For obvious reasons those with tube amps don't and it stops many from considering tube amps (or preamps). In my personal case, a tube phono stage makes sense as I don't play LPs all the time; the preamp and amp are always on so need to be solid state.

[@Relayer6a]

@@VideoArchiveGuy Lots of guys leave their solid state gear on all the time because that's what they are told to do to avoid warming it up. You're right though, you don't do that with tubes, but that's not what my original post was about. And there's a difference between leaving it on all the time because you want to and because you are listening to it 24/7.

[@razisn]

I doubt there are any recordings out there that reproduce the dynamic range of a full orchestra even if the technology allows it. All of them are compressed and limited to some degree to make them listenable in spaces with at least 40db of noise floor. I'm talking about good recordings not 'loudness wars' recordings of popular music.

[@DrBroncanuus]

I've read that hybrid amps are always flawed and will be inferior to solid state / all Tube designs....is this correct ?

[@glenncurry3041]

Strange ironic timing. You were talking about using two n channel output stages instead of fully complementary n/p stages as are typical. It rattled the cob webs and I was remembering how when I was doing travelling amp clinics at audio retail locations in the '70's I scoped Yamaha's using quasi-complemnetary output stages. Problem was they did not even reproduce both halfs of the sinewave very well. And then you mentioned Yamaha!

[@thomasmartin2219]

I should remind you that I have magical powers…But, seriously, at the (high) risk of overstepping my bounds, I believe Bascom’s stated intent in using N-channel devices for both halves of the wave was to avoid the distortion of using the “other sex” P-type device. What he borrowed from Yamaha I cannot say. I would bet the devices here and in 1992 and in 1975 were quite different.

[@glenncurry3041]

@@thomasmartin2219 I have just enough knowledge from an old degree to comprehend what he is doing. HOW is a whole other question! And yes that was just the cheap way out back then.

[@johnshaw359]

Bryston amps traditionally use quasi complementary outputs, they claim class A harmonic characteristics using this topology.

[@glenncurry3041]

@@johnshaw359 The problem with quasi complementary is each half of the wave is handled by different devices with different characteristics. Thus diffent output to each half even with a simple sine wave. Run a squarewave through and they typically look horrible.

[@johnshaw359]

@@glenncurry3041 That appears to be the opposite of the reason for using identical o/p devices. Bryston are -3db at 100khz.

[@soupistasty5]

THE ABSOLUTE SOUND youtube channel is the 'Chicago soft jazz club/bar' audio review channel. Your father 1st took you there years n' years ago; time & circumstance takes you away on occasion - BUT, given a free evening, whether alone or with friends, it's simply the best place to put some quality time in!

[@Standoffmuffin]

A set of these bad boys or a new truck 😏

[@RichTeer]

As a long time subscriber, I have one request: PLEASE bring back downloadable PDF digital issue. The ZINIO platform you recently started using just doesn’t cut it for me, and I’m seriously considering not renewing my (roughly 30 year) subscription. Having to use a dedicated app to read TAS just isn’t worth the inconvenience, and I like to keep my copies archived on my computer.

[@jamesbaxter2812]

Have looked at the other item that is sitin there. I have ask Paul. But did not get an answer. Can you also have a tape deck. Cd player

[@flargosa]

Does the amp case have to be so heavy and built like a tank?

[@thomasmartin2219]

Well, yes and no. If you are making big class a/b power, and you want to use a transformer-based power supply, then you are going to have a heavy amp. And as component weight goes up, so does the supporting structural weight because the amp has to survive shipping. But if you use class d, then the amp can be much lighter. See, for example, my Orchard Audio Starkrimson Ultra review. kzbin.info/www/bejne/jZvOd3-ihtJ1lc0&feature=sharea

[@melbguy1]

Bascom is dead, but his name is the gift that keeps on giving...

[@bigblueocean]

😂😂😂😂

[@Mark-lq3sb]

So is Jimmy Dean, but he keeps selling thousands and thousands of pounds of "Pure Pork Sausage."

[@melbguy1]

@@Mark-lq3sb Paul Mcgowan is a ruthless businessman and has a reputation for milking his friends for all they're worth, along with taking most of the credit for their work.

[@Mark-lq3sb]

@@melbguy1 ...and you get your facts from where?

[@melbguy1]

@@Mark-lq3sb I don't engage with trolls

[@user-od9iz9cv1w]

How does a pair of BHK 600 amps sound as compared to a pair of really good all tube amps like a VAC? I can imagine the dynamic slam of the BHK 600 being more powerful than the all triode amp. But does the triode further excel at low level information? I currently enjoy 110W triode monos driving alnico open baffles. I think Paul and Bascom describe the great match of a tube input stage and a solid state power stage as being optimal. I can imagine similar magic coming from triode input driving a SOTA class D power module.

[@thomasmartin2219]

My next amp review will try to cover this to a degree. I do find that generalizing from any single design element to SQ is hard.

[@user-od9iz9cv1w]

@@thomasmartin2219 I'd be fascinated to hear your thoughts on this.

[@chebrubin]

Their is no marketplace for a USA 2 channel Hi Fi Audio other than the ultra High End Audiophile ecosystem.

[@THEOMD57]

Big toys for rich boys ! I can not afford this amount of money , but if i could , i would go for something with large VUmeters, because i love cherries on my cakes( Greek proverb)

[@thomasmartin2219]

Interesting point. I think you’ll like our next amplifier review.

[@Habitual_Liar]

My friend has a PS Audio system. Crazy good dynamics but a bit dry and clinical for my taste.

[@mrpmj00]

Cool to learn from your video, but I'm no longer interested in amps heavier than 50 lbs. My new stereo amp NAD C298 is 25 lbs (1/4 the weight of BHK), and has better specs in mono mode (NAD is 620 watts, >800 damping factor, .005% THD, SNR >120), and runs cooler. Apple Music lossless and hires lossless

[@elderinmoi1571]

The way the tubes sit on the board looks false. I mean they are not soldered to it right 😂.

[@user-oe1jk2ro4o]

I think they rushed it a bit and it doesn't look like a finished product For example, I looked at the manual And in the opening of the tubes at the back you see transistors with cooling stickers and a pcb with all kinds of components. A customer should not see this. He should see only the sockets with the tubes. everything else, should be hidden. For a product of such price I expect more.

[@LuxAudio389]

They don't include a power cord🤦‍♂️😬

[@operafanatic971]

Each piece of equipment I bought from PS Audio comes with a power cord including BHK 600s.

[@Audfile]

For best class D: tiny, weightless, no heat. For best of class AB, bigger, heavier, is better. Need a 20 amp breaker and air conditioning for maximum comfort. Purchase price, equivalent.

[@chebrubin]

LOL this must be ChatGPT KZbin bot. Or OCD Mike.

[@n.lyndley.9889]

Yep, but no.

[@Audfile]

@@chebrubin ta-riggered!

[@philipw7058]

This guy put me to sleep 😴try a Classe CA-M 600 a much better amp when I compared them together in my system I went hands down with the Classe

[@nicoras8803]

I hate it when non-engineers talk absolute rubbish.

[@garth56]

So why can a 3-10 watt valve amplifier on a set of 102db sensitive speakers do better at holographic's than a 200 or even 300 watt solid state monster on a pair of 85db or less with 4-2 Ohm impedance. It's not about watts it's about power however pure power..Everyone has got this wrong

[@n.lyndley.9889]

pizza - pizzas watt - watts holographic - holographics

[@Pete.across.the.street]

I thought watts were a measure of power?

[@carljung9230]

guy doing the review is a hack grifter.

[@brodricj3023]

PS Audio is a solid high quality manufacturer? You can't be serious! Read the owner forums and you'll see how many problems all their products have, going back years and years. PS Audio even admit to selling stuff they know doesn't work properly!

[@johnnycashlesscomedy8616]

I've owned many of their products over the years and only had one issue once with one mono block running slightly warmer than the other, (the were a very early build). PS paid for round trip shipping of both amps just to check them out and perform any production run updates. PS sells a lot of units, so even if you could point to 10 people with problems with a particular component, that might mean 0.3 percent.

[@brodricj3023]

@@johnnycashlesscomedy8616 Lucky you. I've owned 12 PS Audio products. DAC's, power plants, disc players, etc. Some arrived DOA, eventually everything broke down. Nothing ever worked properly. I've been following the forums for 20+ years, there must be thousands of posts about PS stuff that doesn't work properly, or at all. And by their own admission, and Paul McGowan said this, they sell stuff that they know doesn't work properly.

[@TheBTG88]

Why would you buy a dozen of their products if they all had problem? Does not sound logical.

[@brodricj3023]

@@TheBTG88 The 12 includes products replaced under warranty several times over, which also broke down. PS Audio didn't get my money for 12 separate junk products.

[@TheBTG88]

@@brodricj3023 I see. One would have thought that after the second device failed, that you would have stopped there and moved on.

[@carljung9230]

ridiculous price of $32k. only a gullible person would go for this load of bunkum.

[@TheLevitatingChin]

Does PS stand for pure scam?

[@adv.rohitl.jbrasdesa2402]

Psaudio has severe quality issues and after service is non existent. Buyers beware😢

[@operafanatic971]

I have several pieces of ps audio equipment and service has been a pleasure if needed. turn around is fast and customer service is responsive.

[@jerry6789]

Sorry but I disagree. Their service is amazing as well as the quality of their products. My entire system is PS Audio. ❤❤

[@rsmood8362]

This review is shockingly bad. There is barely any comparisons or description of the sound quality.

[@n.lyndley.9889]

there IS a comparison there ARE comparisons

[@bolsesolheim7469]

Could not bother with products from Paul McGowan DrSolheim Norway

[@peanutbutterjellyjam2179]

Did he discover a specific design topology in a Yamaha product, or did he copy Yamaha's design?

[@silviosarunic3234]

Lamm M1.2 Reference

[@reestyfarts]

The audio equivalent of the cab forward oil burning steam locomotive in the Sacramento Railroad Museum. Powerful, huge, heavy, just in time for diesel electric power to kill it off.