Recommendation for a highly resolving amp


I have Don Sachs 2 tube preamp driving Pass Labs X350.5 driving Sound Lab M545 ESL speakers. I like the sound very much, but when I went to hear my friend’s Spectral system (driving Quad2912 ESL) I realized my system can benefit from having a higher resolution amp. Spectral amps need all Spectral preamp/cabling, which would be quite expensive. What would you recommend?
128x128chungjh
I have an all Benchmark stack in my living room (with KEF LS50) and that is my favorite gear, DAC3B | LA4 | AHB2 x 2. I even owned the HPA4 before I sold it for a profit. So some poplar gear. However, I do not think the AHB2 would work as well with the OP's speakers. 

I have Thiel CS3,7s and while the Benchmark stack sounded very impressive with them there was some missing low end. The AHB2 stereo and mono do not play nice with 2 Ohm dips. It was easy to see this when I replaced the AHB2 with the KRELL K-300i, LSA Voyager 350 GAN, and the amp I settled on, the CODA #8. They all had better bass than the AHB2 on the Thiel CS3.7. On an easier to drive speaker the AHB2 would be what I would use in a heartbeat.
Definitely a good point about the OP's ESL speakers.  Specs for the Sound Lab M545 ESL speakers show 8 ohms (nominal) and 89dB, so *should* be okay???

I have found the Benchmark folks to be very responsive, so probably worth sending them a note to ask the question.

Full disclosure:  I do use an SVS SB-2000 powered sub alongside my JM Lab/Focal Mezzo Utopias.  Some of the music my wife likes benefits from the sub for ultrasonic playback ;)
The best recommendation I can think of is to stay the heck away from
your buddies home. Spectral gear with Quad 2912s? I can imagine nothing better. Sell your stuff and rent out a bedroom in his home. Maybe he needs a chauffeur?
What is his sub array?

Was it determined if the room and speakers are adjusted optimally
as suggested by Atma? Gotta start there. 


@chungjh, While not my cup of tea; I have to respect Spectral for being amongst the top of the heap for "resolution".
Benchmark told me that the AHB2 would work on my hard to drive speakers. they do work, officially in stereo mode (not officially on mono). However, working and being the very best is another matter. The AHB2 are not the best option on 2 Ohm speakers like mine.

That review of the Bryston 4B3 | Cambridge | and a single AHB2 is not an apples-to-apples comparison. A pair of AHB2 monos would have been the equivalent of the 4B3.

To me, the 4B3 does not sound as clean and fatigue free on top as the AHB2. I owned a lot of Bryston in the past, 3B-ST, 4B-SST, and  7B-SST but not the cubed line but have heard it and it has a bit of the old hardness than is not there on the AHB2.
I'm very certain the Benchmark AHB2 is the most resolving amp available... but you'll need to bridge mono them to get the same power you're getting from your Pass Labs.
Here is Dr. Mertens evaluation of the 4B3 from 2018. He is still using this pairing (which I copied) of the EAR and the 4B3 three years later in his reference system. Mainly for the resolution as a professional evaluator. I happen to agree with all his comments and using Magnepan, I can attest that fatigue is not an issue. I listen for 5 hours every night. To be fair, at the price point, the AHB2 is a fine choice. Not everyone wants to or can spend the kind of money the cubed series requires. However, if one is searching for transparency and resolution, then the Cubed amplifiers are top shelf. I’m not a fan boy, so have no interest in what the OP decides. Be happy. I know for a fact that I am....very.

https://www.fairaudio.de/test/bryston-bp17-und-bryston-4b-vor-endverstaerker-kombination/
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I am using the CODA #8 and CODA 07x preamp with my Thiel CS3.7. It is an very satisfying sound. IT has good detail, lots of power for my speakers, and non-fatiguing. I did hear some increased clarity and resolution when I recently heard the CODA 07x and CODA #16 amp. The plan is to trade in the #8 for the #16. But it is not a pressing concern and I will take my time to do so. The #8 is a very good amp and the #16 is a great amp.

I think the #8 was not as clear and detailed as the Benchmark AHB2. However, I do not feel many amps are of that caliber. When I heard the #16 I was thinking the #16 was like the AHB2 in clarity but way more powerful with a bit more warmth that the AHB2. If I did not own the AHB2 I would have thought the #8 had a lot of detail.

I also love my CODA #8 paired with my Benchmark LA4 preamp. The amps and preamps from these 2 companies (in any combination) really appeal to me.

BTW - I am currently listening to my Thiel CS3.7 in my small room with the AHB2 + Topping pre90 ($599 preamp). I think it sounds real good when I am not playing too loud (most of the time). However, that bottom end is really not there with the AHB2 and Thiel CS3.7. My CODA 07x is in for repairs so I am using this combo until the 07x gets back. The Topping pre90 does not work with the CODA #8.
@chungjh Is your friend familiar with your system, your room and your preferences, etc.? If yes, what is he advising?
My friend is a Spectral man, so he recommends a complete Spectral system. Along with all the MIT cables.
@chungjh  Thanks for answering my question. Your friend is going by his preferences and choices, not yours.

I recommend reaching out to others in your area to listen to your system and provide feedback, before making changes and purchases.

@lancelock has been very helpful in connecting me to the audiophile community in MD and DC. I suggest reaching out to him. He is in the Annapolis area.

The upcoming Capital Audio Fest may also allow you to connect to vendors and audiophiles in your vicinity.
Another vote for changing out your cables ~ w/o spending a fortune, you could go w/Synergistic Research Foundation cabling ~ I was a bit amazed when I installed them in my system...it would be a significant upgrade, and give you at least a good chunk of that detail that you're chasing.  And I agree w/everyone else who said that the PASS Labs amp is almost certainly not your problem.Don't be an unbeliever when it comes to cables, they really do make a difference; if you have bad/cheaper cables, and you dive into the deep [but not deepest, unless your main driver is a Ferrari, or your wife is OK w/a second mortgage] end of the pool, I'm guessing it will be your last upgrade. 
You sir have some very nice equipment, just sit back .Play some music and enjoy.Your on a money spending to make my system sound better trip.
^Hearing something different and appreciating what it does, is one thing; living with it long term is another.
@chungjh How are you streaming to your X1? Does Lumin provide a client? 

If you want to chase after more amps. I recently bought the LSA Voyager 350 GAN and had it modified ($500) by EVS and it was almost as clear and detailed as the AHB2 (maybe the same actually). In stock form it was not in the AHB2 class. However, the Voyager has a lot more power than the AHB2 and drove my Thiel CS3.7 easily. I sold it because I kept the CODA #8 which had a bit more bass but was not as detailed.

I still think your room is the issue and you can get the improvement you seek with the DSP approach. It is a much cheaper way to try instead of buying new gear.

BTW - @lancelock has the CODA #16 and just bought a CODA 07x which he may post his thoughts on.
@yyzsantabarbara,  X1 is directly connected to the ethernet/modem. X1 does not take wifi. Looking back, I don't think I was very clear with my intent. As many of you mentioned Pass/Don Sach are very high quality instruments and I agree. In fact it sounds VERY good-as good as my local dealer's set up with ARC Ref 6/ARC Ref 160S. But, I still feel I can better hear the "peach fuzz" and realism in music with my friend's system.
Let me get this straight. You’ve got a Pass amp and yet you don’t find it resolves enough? There’s nothing worse in this hobby than trying to throw money at an issue that can otherwise be fixed. Your buddies sound is unique to his room. First, what are you using for room treatments? Begin there. 
@chungjh I knew that was how you had connected the X1 but how are you streaming. What is the software client that you use to play music on the connected X1. Knowing this can open up some options.
The biggest difference is in the preamplifier. The tube sound is darker, and the transistor sound has a higher micro dynamic density. So Spectral sound is more vivid. You can refer to this article to analyze your equipment.
@chungjh
You have a nice system, but I agree that the quality of your cabling does not match the level of your components - they’re creating a sonic bottleneck. Initially, I was going to go your route and try to spend minimally on cables - I hated the idea of spending significant $ for them. But over time I VERY reluctantly realized that cables that don’t measure up to the quality of the audio chain will leave the sonics seriously short of of their potential performance.

A few vendors allow for free home trial. Also buying used can save you significant $ and if you don’t like them you can resell them.

The Cable Company has a cable library you can try for a fee also.  May be the best way to dial in the sound YOU like.
Due to a renovation type project at my house, I had to opportunity to have my system setup at a friends house for a while.  The acoustics of our two rooms are very different and my system sounded very different at his house.

I don't understand how listening to two different systems in different rooms could be sufficient to determine which component in one of the systems needs to be upgraded for that system to sound more like the other.
What you are saying is true. However, what I learned from his system is what it sounds like when there is higher resolution. I am not necessarily trying to recreate his sound; just better sound for my system.
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Getting back to the original question about a highly resolving amplifier my current Pass Labs XA25 is very resolving and transparent, some say the most transparent and resolving they have ever heard. 
It is much more so than the Parasound a21+ it replaced but not a night and day difference.  
The ultimate transparency and resolution you hear is a function of every component in the chain, the amplifier being one part.  
Still haven't determined what you mean by 'resolution'; it does seem that those in this discussion are talking about different things.
My friend is a Spectral man, so he recommends a complete Spectral system. Along with all the MIT cables.
Of course he would. But its not the best amp to use on Sound Labs IMO and IME. The best Sound Lab installations I've seen have used Purist Audio Design cables FWIW.
@atmasphere,

My friend uses his Spectrals to drive Quad ESLs and it sounds great. Would Soundlab ESL be that different than Quad?

@jdane, by resolution I mean clarity and realism. Like ultra high definition TV vs regular HD TV.
My friend uses his Spectrals to drive Quad ESLs and it sounds great. Would Soundlab ESL be that different than Quad?
Depending on the Quads, yes.
@jdane, by resolution I mean clarity and realism. Like ultra high definition TV vs regular HD TV.
Thanks.  Seems that a number of these terms are being used here simply as variations of "good."   I don't see any clear distinction among them.


Maybe, just maybe your excellent amp needs a tune up. The .8 series is 8 or 9 years old, the .5's obviously older. Nelson is as good as they get. I would still have my 250.5 if I had room.
I will be receiving Benchmark AHB2 amps in 1-2 weeks and do a comparison with X350.5. I have to say, the X350.5 sound is gorgeous and luscious.
You will hate the AHB2 if you love the luscious sound of the PASS. You will have more details for sure out of the silent AHB2 but not luscious,
@yyzsantabarbara 

Yes, I am aware that Pass and AHB2 at the opposite ends of the spectrum in sound. I do like luscious sound but I also like amps with high detail. I enjoyed listening to my friends Spectral amp, which I am assuming would sound more like AHB2. When I was listening to Louis Armstrong sing, it sound like he was in my listening room. What has your experience with AHB2 been like?
@chungjh I think the AHB2 is the best sounding amp I own or have owned. Now I am likely in a tiny select minority when I say this but I know what I like. No need for me to describe it since you will hear it for yourself soon.

I have my downstairs system as follows AHB2 mono| LA4 | DAC3B | KEF LS50s. The KEF LS50s get replaced by the Yamaha NS5000 once my 5 year old son becomes a bit bigger and I can clear up some of his toys.

The AHB2 system was not good enough for my hard to drive Thiel CS3.7 (2 Ohm dips) so I moved the Benchmark gear downstairs to the living room from my office. A single AHB2 in stereo is actually officially rated for 2 Ohm but the monos are not. They both can go down to that region but not with the power that I felt was needed for the CS3.7. So when Benchmark guys say that the AHB2 will work in 2 Ohm they are correct, but I am talking about he degree of goodness.

I have the CODA #8 and it is likely a less warm PASS, but more similar. It works great with my Thiel CS3.7. Recently I heard the CODA #16 with the same CODA 07x preamp I have at home. I was very impressed by the #16. It had the clarity of the AHB2 and also some warmth. So that amp maybe my next top amp. I will upgrade my #8 to the #16 when finances permit.
I was also thinking about Coda 16. It is hard to imagine 100W class A has the same detail as AHB2. It seems like Coda is not a well known company.
One strategy to get detail with sweetness may be to combine a tube pre with AHB2. Has anyone tried this?