PS Audio BHK 300 mono VS Modwright KWA 150SE mono VS D'agostino Classic stereo

mitch2, underrating the 8 Ohm output to let the lower impedances appear to double is not a new trick.

Thieliste,  not sure you want to hear this,  however,  each time I pull up Thiel 3.7 or 7.2 on YouTube,  nearly every video there was krell on these speaker's,  I mind you,  they sounded damn good to me,  I understand opinions are just that,  an opinion,  I believe you will have a smile for a long time after extensive break-in of the Dan D’Agostino classic stereo amplifier,  btw,  Dan himself helped me with my amplifier, I have the only modified krell 700cx out there,  this was completed December 2014, hugely better than a stock 700cx,  so yes,  I'm a Dan D’Agostino and Nelson pass fan, cheers. 

By the way i have decided that i will purchase a pair of Thiel CS 7.2 as soon as i find a pair for sale.
Therefore i have to take this into consideration for my amp selection.
Need an amp that will drive both 3.7s and 7.2s with ease and refinement.
The D'agostino classic amp would be a good starting point for some years until i can upgrade to the Momentum monoblocks.
If by any chance the Ypsilons can handle both of these speakers i would rather go the Ypsilon route.

Good observations mitch2, let us know when you can make an audition.
I wonder how the D'agostino classic would do against the Karan KAS 600.

I have no doubt the  D'agostino Classic Stereo Amp sounds excellent.  The Ken Kessler hi-fi news review compares the sound of the Classic Stereo favorably to (or, in the ballpark of) D'agostino's Momentum amp.

I observed the lab report in the hi-fi news review indicated the amp does not double power from 8 to 4 to 2 ohms.  There is plenty of power, no doubt, but it seems they may have played with the power specs a bit, i.e., underplaying the 8 ohm power to indicate a doubling into 4 ohms but, in fact, the results indicate the output is less than 600 wpc into 4 ohms, or about 150% of the output into 8 ohms.

The other thing I was curious about in looking at the pictures of the insides of the amp, was the absence of either big capacitors or lots of medium-sized capacitors.  There are four 6800uf storage caps mounted on each channel's board, and some smaller caps, but there appear to be like 16 output devices per channel so I am surprised there is not more capacitance provided.  It is possible there are other caps that I cannot see in the picture but it looks like there is a lot of empty space between the two boards and the associated heat sinks they are mounted to.

I guess I am used to the two huge (think 24oz Colt 45 tall-boy) capacitors in each of my Clayton monos (but that may not be a fair comparison since the Claytons are biased in Class A) or the 14 or so medium sized caps per side in my David Reich designed McCormack DNA-2 LAE.  Both of those amps are also rated at 300/600 wpc.

There is a dealer located near a city I travel to for work so if I get to hear the D'agostino Classic Stereo Amp I will report back.  If I were looking for similar power, it would be on my list to look at.

scar972 very good description of the D'agostino Classic amp thanks very much, it will serve everyone considering this amp.
So with this amp it is wise to consider a good tube preamp like VAC or VTL.

Scar972,  enjoyed reading your post,  very accurate. 

I've always considered Pass Lab to be one of the best solid state amp designer in the industry, having owned and listened to many of their XA and X models, I'd have to say the D'Agostino is on the same level. Never had extensive experience with any of the other amps mentioned beside listening at RMAF so I won't compare.
For a high powered amp it is very musical, it is on the warm side of neutral but not as warm as the Vac Phi 200 I previously owned and closer to the modified Audio Valve Challenger I still own using KT120.
Bass is tight and powerful when the music calls for it but with most material it is well textured and doesn't reveal itself as a high power amp. Never heard any hardening of the highs as the Absolute Sound review suggests, but how can they say an amp at this price is complete when there are so many much more expensive including other models from D'Agostino. Soundstage is noticeably deep, the width is consistent with other SS amp I've heard. Detail is excellent!
Overall, it is musical, refined, and and I'm a happy owner. This amp does require an extended warm up time similar to tubes especially if you don't listen often like I do.
For preamp, I would go VAC just because I'm currently using a tube pre and it's working for me.

I was being a smarty pants ;)

audiolabyrinth is the Tara Labs specialist.

Hi audiolabyrinth,

What cabling do your recommend? ;>)

Dave

Thieliste,  I highly recommend the Dan D’Agostino classic stereo amplifier for your setup, I also believe you get what you pay for,  thus the classic stereo amplifier is more expensive, cheers 

Thanks tom, i will investigate on the Audionet Max and it's matching preamp.

You are certainly taking the path of superb quality. 
Charles 

Well i will have the Nagra Jazz for the home audition of the Ypsilon Aelius ll.

French reviewer Joel Chevassus  I believe introduced the Totaldac to the public with his 6 Moons review a few years ago. He did an Audiophile-magazine. com review comparison of the Swiss Nagra Jazz and Canadian Coincident Statement Line Stages.  He was "highly" impressed with both.  It'd be interesting to know his thoughts of these two vs the VAC Signature preamplifier. 
Charles 

Yes Charles VAC makes some of the finest tube linestage out there.
The only brand that i can think of that could surpass the VACs is Robert Koda but out of reach for most of us.

With a source of the Totaldac d1Twelve’s quality, that’s an excellent start for the signal pathway. I can vouch for the VAC Signature preamplifier. A good friend owned it for 4 years and I heard it over hundreds of hours during that period. It is a true top tier component.  iit  "makes music " if you know what I mean.
Charles

scar972 i've been looking for you to have your opinion on the D'agostino Classic stereo as you're probably the only owner on this forum.
Can it compete with some much bigger boys quality wise ?
What kind of preamp should i consider with this kind of amp if i don't go the hybrid's route ?
I've been looking at the Dartzeel NBH-18NS with phono stage on the SS side or the VAC Signature MKlla with phono stage on the tube side.
Source wise there should be no problem as i'm heading towards the Totaldac d1-Twelve + server (4 box version).

Tomcy6,
Good point in regard to long term listening and living with a component. A short term home audition is useful and beats no opprotuhnity to audition. Thieliste can achieve some degree of valuable insight with the Aelius paired with his Thiels. 
Charles 

I think you’ve made your point Charles and we all agree. Listening is the best way to choose an amp but specs are not meaningless. The only remaining problem is that sometimes you need to listen for weeks or months to really get the sound of an amplifier and decide it’s the right one. I don’t think Thieliste’s dealer will be willing to hang out that long.

teeshot: "I completely agree that tubes should be in any system in which 3.7s are the loudspeaker. I got great results with a tube preamp mated to a high current solid state amp. With good source material such a setup performs at a level with systems costing more IMHO. With poor source material though 3.7s are an unforgiving mistress."

Exactly. Perhaps even more so with the 7.2s due to that 6k peak. Same goes for amps with a hot treble region or a lean overall balance.

Best to you teeshot,
Dave

I've been very happy with the D'Agostino Classic Stereo driving Magico.

I completely agree that tubes should be in any system in which 3.7s are the loudspeaker.  I got great results with a tube preamp mated to a high current solid state amp.  With good source material such a setup performs at a level with systems costing more IMHO. With poor source material though 3.7s are an unforgiving mistress.  

Tom did you trade in your CS 7.2s for the YG Annats ?
What amp would you recomment to a CS 3.7 - CS 7.2 owner ?
Audionet Max very good ?
Thanks,

Brice

Great summation Mitch though I must add that Fremer’s review of the BHK’s was done via unbalanced inputs. Honestly I don’t think the review was worth doing under those conditions. Like road testing a Lamborghini on low test gas or winter tires. Sure it gives you some sense but hides the real performance potential. The manufactures response said the same thing, that the balanced input sounds considerably better, and fixes and bass deficiencies Fremer (who I happen to really like) heard in his unbalanced system. Also the mosfets are N Chanel which is different than typically used and offers lower distortion and other advantages over traditional designs.

I spoke with a Stockholm Ypsilon dealer and he told me the Aelius sound extremely transparent.
I just hope there is a bit of warmth too for the Thiels.
My distributor will be dropping the Aelius ll and plug them to my system in the morning and we will do the auditions in the afternoon.

No problem Charles.
Let's keep this thread alive and informative.

Any Audionet Max users around ?
These monoblocks are seriously beefy and could probably drive CS 3.7 and 7.2s with ease and finesse.
Audionet are known to make top notch products, might have the opportunity to audition these in Munich this year.

Dlcockrum, as I hope my posts have clearly suggested: not from my perspective.:-)

charles1dad, the OP originally asked about 3 different amplifiers, later on it was revealed that he was planning on using these amps with the Thiel 3.7's and/or the Theil 7.2's. After that the OP added other amps for consideration. Teeshot reported experience with both the OP speakers and one of the amps the OP had questions about in combination with those very speakers.
Dlcockrum's posted about different speakers with different amplifiers.

Friends Charles and unsound,

I am missing the point of contention here. Sorry. I use and prefer a SS high-current amplifier than doubles down with the 5is (unsound) yet find that considerations outside the realm of measured/measurable specs are ultimately determinant of the level of my listening satisfaction (Charles). Are these things mutually exclusive or even remotely at odds with each other?

I mean absolutely no disrespect to either of you as I hope you know.

Best to you both as always,
Dave  

 charles1dad, interesting that you referenced dlcockrum yet were mute with regard to teeshot's more relative post.
 The extra power beyond the minimum recommended would only be needed to provide higher dB output for a given room size. In that sensitivity decreases (and increases)  proportionally with impedance in speakers such as the Thiels it's prudent to be mindful of actual power output in the given circumstances.
  In the case of a speaker with extended bass output such as the CS5's it might be fair to assume that that room size wouldn't be all that small to begin with.
  If everything is performing as it should be, and depending on the desired volume output in the given room size, other than increased dynamic range, decreased potential for distortion and clipping and with that, less likelihood of speaker driver damage;  there is no reason to expect the higher power amp to necessarily sound better, or visa versa .

Thiel recommended between 100-400 Watts for the CS5's. In my conversations with JIm Thiel he told me his all power recommendations were based upon quality ss amps that could double down, and that should one choose to use tubes, etc., they should increase the power  accordingly.

"dlcockrum i’m surprised you’re able to drive the most difficult Thiel ever with only 100 watts even if it’s doubling."

Quote from ’Blazing Saddles’: "It’s twue! It’s twue!" lol

Over 25 years with several different amplifiers driving the 5i’s (including one of the highest-wattage monsters of all time), I find that it is much more about current delivery and superior amplifier design (minimizing anomalies at the frequency extremes, the ability to reproduce correct timbre and deliver micro and macro dynamics optimally) than rated power (to a limit).

Enjoy this golden time in your audio journey, thieliste.

Dave

dlcockrum i'm surprised you're able to drive the most difficult Thiel ever with only 100 watts even if it's doubling.
I'm sure the D'agostino classic would be a perfect match for my CS 3.7 with let's say a VAC or VTL preamp.
But who knows perhaps the Ypsilon Aelius will have enough current and sound beautiful on the 3.7s.

I have never seen such excellent feedback/advice from so many on any one thread. thieliste, I think that your audition of the Ypsilon will tell you a lot.

I am totally delighted with a Classe' Audio DR-9 (100W/ch@8 ohms rated high current SS amp that doubles down to 2 ohms) with my "older" Thiel CS5is using a MW5400ES tubed player for the front end. The lower-rated-power DR-9 simply does more things right than my Krell FPB-600c at all but insane volume. May be the same with the Ypsilon vs the D'agostino or Krell in your system, dunno. Only your ears will know for sure.

Recent experience has taught me that tubes somewhere in the chain are magical with the Thiels. Makes them relax just the right amount to bring out the musicality vs analytical over-achievement without.  

As always, the synergy of the equipment chain makes the difference.
emailists' advice to leave a good amount of your budget for cables, cords, and a top power conditioner is prudent, IME.

Best to you thieliste,
Dave

I had Thiel 3.7s for a couple of years. From my firsthand experience, as I have posted here before, I would only recommend a high power high current amp for 3.7s.  I had the KW 150 and it simply ran out of steam and went into clipping even at medium volumes.  I would second the recommendation of BAT 600se and 655 Se as these amps really deliver a lot of current and give good dynamics.  I also had excellent results from Marantz MA9 monoblocks and a Krell Evo 402e. Jim Thiel used to demonstrate 3.7s with the 402e if that tells you anything. 

There is one other brand that i forgot in my list : Audionet

mitch2 thanks very much, you gave me some very good technical information here.
The problem is that i'm not going to be able to home audition all of the brands i'm considering, the list is very long :

D'agostino.
Ypsilon.
Aesthetix.
Karan Acoustics.
PS Audio.
BAT.
Modwright.

For the moment i will have the Ypsilon home demo in 2 weeks time.
The distributor is nice enough to organise a home demo for me and another client.

You have received lots of informative comments and interesting viewpoints to your question. Having recently gone through an amplifier search/trial I can attest to both the impact an amplifier can have on the sound of one’s system as well as the importance of personal listening preferences in choosing "just the right amp" for your system. Even between several very good and highly regarded amplifiers, minor sonic characteristics can easily affect your level of satisfaction in how your system sounds.

Regarding your three listed amplifiers, they all have their supporters and are all highly regarded amplifiers so the questions to answer are, first, are they all capable of delivering the level of dynamics you desire with the speakers you plan to use and, second, which of them sound best to you on the types of music you enjoy most.

The D’agostino and PS Audio amps should drive just about anything. As some have pointed out, the ability to double output when the impedance is halved is a desirable quality because it allows the amplifier to drive difficult loads with a minimum of frequency and output aberrations. Of the three, based on the posted measurements, the D’Agostino amp should drive about anything you would throw at it and should exhibit a tight fisted control of the bass.  I suspect the PS Audio amps will also work well with most speakers but I recommend reading JA's measurements section in the Stereophile review of the PS Audio amp because he concludes those amps may not work so well with speakers that have impedance dipping below 4 ohms.  I suspect the Modwright amp will not equal the other two in controlling a wide range of speakers because it has less power to begin with, and does not double power into even 4 ohms. For those reasons, unless I could confirm that it sounded excellent with a specific pair of speakers I was planning to keep, I would not consider the Modwright.

Some other differences to consider between the PS Audio amps and the D’Agostino, are,
1. The PS Audio BHK Sig. 300 amps are monoblocks, which I prefer both for separation of the power supplies and also because of the ability to use very short speaker cables,
2. The PS Audio amps have a tubed input stage, which means you may deal with minor tube noise and will have to replace tubes. This is not a big deal to me since you are only looking at two tubes per amp, but some may not like having that extra layer of maintenance and operational responsibility, particularly people who like to leave equipment powered up all the time,
3. The PS Audio amps use mosfet output transistors while the D’Agostino uses Sanken bi-polar output transistors (which I liked the sound of in a pair of Cary MB500 monos I once owned). In general, I like the sonic signature and control of bi-polar devices. In my personal amplifier evaluation, I was able to own and compare at the same time a pair of Lamm M1.2 Reference amps (that use an input tube and mosfets) against Clayton M300 amps that use Motorola bi-polar output transistors. I ended up selling the Lamms because I simply did not like the sound as well. Similar to a BAT amp I once owned that used mosfets, I found they made the Lamms sound comparably "soft" and particularly in the low frequencies (in fairness, the Lamms only output about a third of the power of the Claytons, which likely also had an effect). This possibly "softer" mosfet sound may be reflected in the Stereophile review of the BHK 300s where Michael Fremer says, "The BHK 300s’ bottom end is nimble, well textured, and rhythmically solid, though there’s still more weight, power, and physicality to be had in the very lowest octaves."

You should search out the reviews of these amps, however, I would caution you to take them with a grain of salt since the reviewer’s systems and listening preferences are not necessarily your own. As an example, although both writers wrote positive reviews of the D’Agostino Classic, Jacob Heilbrunn said, " If this amp has a weak spot, it’s the treble where it can harden slightly on very complex and dynamic passages," while Ken Kessler’s review did not find any problems with the treble and said, "The Classic eschews sibilance unless the recording is poor." Both reviews are very positive and, in particular, Kessler’s review speaks very highly of the Classic.

My strong suggestion is to listen to the amplifiers you are interested in before purchasing, and preferably listen to them in your own system. I ended up auditioning four different amplifiers and had to purchase all of them to do so but, in the end, I was able to distinguish clear differences and to choose the amplifiers I liked best. Good luck and let us know how you make out.

A member of the audiocircle forum Phil A is driving his CS 3.7s with a Modwright KWA 150SE and is very happy with the results.
He was using Bryston 14BSST before and found the Modwright much more musical.

Seemingly no love for the Modwright KWA-150SE amps in bridged mono mode. FWIW, i’ve heard the original KWA-150 & thought it had was very well engineered and finished. It had "plenty" of power as a single stereo amp to drive even a moderately difficult load in let’s say a medium size listening room. And the KWA-150SE has even more control. Run in bridged mono mode, the Modwright amps should be able to drive all but the most amp-crushing loads.

Sonically, I found the Modwright warm and tube-like. It has excellent resolution & inner detail, and as a result is one of the few amps i’ve heard at that price point which sounds musical at low listening levels. I think these amps are underrated, perhaps because they’ve been around for a while.

emailists i forgot to ask you what preamp are you using with the BHK 300's ?
Is it the BHK Signature preamp ? if so how good is it ?
Thanks.
tomcy6 thanks i did read the Stereophile reviews of the Ypsilon monos and preamp.