Boulder 866 vs Gryphon Diablo 300

I’m looking for some input on an upgrade to my current system. First I’ll list below my current components:

Datasat LS10

Roon Nucleus Plus

ATI 3305 (330 watts x5)

ATI 3004 (300 watts x4)

Kef Reference 3’s with matching center. Kef R3 rears and Kef 8a Atmos speakers.

For those not familiar with the ATI 3300 amps, these are an incredible value. I used to have three PS Audio BHK 300 mono blocks from my front sound stage. I originally bought the ATI 3305 for my rear speakers. I did a pretty exhaustive A/B comparison between the ATI and the BHK and for 90% of the music they were indistinguishable from each other. The other 10% of the tracks the ATI would ever so slightly edge out the BHKs. So needless to say, I sold the BHKs.

To get back to my question. I’m perfectly happy with the HT side of things, but I would like better 2 channel performance. What I would like to add is either the Boulder 866 or the Gryphon Diablo 300. Both have HT bypass, The Gryphon has sub outs, the Boulder doesn’t. The Boulder is Roon Ready, the Gryphon isn’t. The Gryphon has more power and will match my ATI amps better when using everything for HT, but will I notice the difference in power when everything is level matched?

So outside of the obvious differences I’ve mentioned, what are the sound quality differences? For those of you that have auditioned both, what were your impressions on overall sound quality between the two?




Both are outstanding integrated amps, so you really can't go wrong with them. To me, the Gryphon Diablo 300 is quite magical in its ability to put you "there" without any details sticking out. Just one coherent picture right in front of you.


The Boulder is a bit cooler in its sound (not night and day differences though, it's shade of grey...), which may sound fantastic with some speakers, but with my Wilson Watt Puppy 8's, didn't sound as good as the Gryphon.


With all that said, I could live happily with either one.

Thanks Audiojan. I'm trying to audition both of these.   There are lot of positive reviews on the Diablo, but the Boulder came out during Covid and there are only a few reviews on it, all positive as well. 

I can’t compare them but I heard the Gryphon at Axpona and the sound was rich and detailed. As always, you have to try it in your system to hear the sound. Make sure there’s a decent return policy.

I had the Bolder on home loan and I really wanted it to be great sounding but sadly it was just OK.  Of course that might be system dependant, or relative to what one’s reference is.  At the time I was comparing to Luxman 595 which was better but still no cigar.  Not listened to Gryphon or BHK but I’d be surprised if the Bolder was better than the BHK monos.  Maybe a better pre amp is the way to go, I’ve a Levinson 523 which is expensive and probably why the integrated amps couldn’t compete. 

That is one thing that has been on my mind.  Is the Datasat holding me back so much that the amps themselves cannot really shine?  When I had the Mc207 and compared it to the BHK monos, there was a noticeable improvement in the bass.  With the BHK amps having better bottom end.   I was honestly shocked when the ATI 3305 was on par with the BHK!  

I auditioned the Boulder 866, McIntosh MA12000 and a Accuphase E-380 today.  The Boulder while very revealing, I found it very fatiguing!  I didn't like it at all.

Next I went tot he Accuphase.  I really liked this amp!  It was more laidback, I could listen to this amp all day.  As soon as I played the first song I relaxed and actually enjoyed the music. I was no longer analyzing it!   The only issue for me was no HT bypass, that is a must for me.  

The McIntosh was the last amp I listed too.  This is the new hybrid integrated.  Tube preamp with sold state 350 watt amp.  I really liked this amp as well.  Liquid vocals, tight bass slam and detailed highs but in no way fatiguing.  I may have walked out the door with this amp, but its on a 6 month +/- back order.  

I've trying to listen to the Gryphon, but the retailer that has it will never respond to messages, emails, texts or phone calls. No wonder his products are listed for years for sale. I may be writing that amp off. 

So so far I really like the McIntosh and that may be what I end up going with. 

You should check out the KRELL K-300i integrated amp. Stereophile compares it with the Boulder 866 on the Boulder review. My take away was that the reviewer considered it the best one. I think he also compared the MAC.




My old K-300i unit is being sold on USAAudiomart by the guy who bought from me. It is a killer sounding unit. Smooth, non-fatiguing, and powerful. I am all in on KRELL XD lineup these days. I sold the K-300i to fund the KRELL Duo 175XD and I was going to trade that in for the upcoming KRELL KSA i400 super amp.

However, I decided that I am not trading it in. I am keeping it to use as my headphone amp. I will have to work a bit longer to buy the KSA i400 for my future big system.

Listened to the Gryphon today. Compared it to a Luxman L-509X, Krell K-300i, and Esoteric F-03.

I used Magico A5 Speakers to test everything today and an Aurender A30 as the source.

The Diablo 300 really sounded great! Full, deep powerful bass, velvety vocals, excellent soundstage but the highs were just a bit too warm for me.

Luxman L-509X had the same everything the Diablo did but maybe a touch more bass and better highs. Beautiful craftsmanship and yes meters. I love meters on my equipment by the way. Don’t let the 120 watts X 2 fool you on this amp. It will 100% hang with the Diablo!

Krell K-300i- Very similar to the Luxman but I don’t feel had quite the bottom end of the Luxman and the Diablo. Excellent soundstage as well. A really great sounding integrated but just boring to look at.

The Esoteric had an insanely wide soundstage, there were times I swore there were speakers playing behind me. Overall the soundstage was horrible. You could hear the vocals coming out of the speakers. Not for me at all!

Last I listened to the Bel canto REF 600M. Yes they are class D, yes they are nothing to look at, but man do they sound good. It may have acutally sounded a touch better than the Luxman, maybe. If nothing else it sounded as good. I was really impressed with these little amps. But for this purchase I wanted a statement piece. So I passed on theses.

In the end I bought the Luxman. It was the lowest price of everything I’ve looked at. The McIntosh MA12000 was the sexiest amp, but it was to dull on the top. Accuphase is just to expensive for what it is, and was running out of power even though it was running smaller Dynaudio speakers yet the same watts as the Luxman.

The Luxman was lacking a DAC to play my Roon to so I bought the matching Luxman DO3X. Seeing that I didn’t need a streamer the shop I bought everything from (Chicago Precision Audio & Video Chicago) said this was the best bang for my buck and that it has a killer DAC! I have to agree. Everything is only at best a few hours old now, and it sounds great. It will only sound better and open up more as I get closer to that 200 hour mark.

I want to also thank Jay from Jays Audio Lab. I had a consultation with him earlier this week and he also really suggested I try the Luxman. The nice thing with living in Chicago is I can listen to just about anything. Either way, if you are in question about which way to go and want an unbiased opinion, Jay is worth every penny.


Great update to your demos. Congrats on your 509X a very nice sounding unit and rather pretty too. I have heard that one too and it was up there with the best sounding integrateds I have heard.

A word of advice do not listen to the Luxman M900u + C900u combo.


I better not listen to that combo yet.  If I do I'll want to buy it.  I did ask about the 900u when I was looking at the 509x, and was told that is a whole other animal but was just replaced by the 10X.  The 509x uses the 700u amp and the 700u preamp.  It's an amazing piece at an even better price.  The Krell is a pretty good value as well.  

The Luxman, Krell, and Gryphon were are all very holographic.  Each had a slightly different presentation. The Krell was slightly more forward than the Luxman and the Gryphon, depending on your taste you may like the Krell better.  It's really hard to say how "3D" the Accuphase, Boulder, and McIntosh group were compared to the other group as different showroom, sources, speakers.  All the amps were good in that regard except the Esoteric, I don't know what was going on with that. 

Almost sounds like the Esoteric was hooked up out of phase.  Congrats on the Luxman. 

Congrats! You can never go wrong with a Luxman. I had the 590AXII and still wish I hadn’t sold it. They sound as beautiful as they look. The extension, refinement, and richness of sound is a great combo. This is truly a statement piece.

Soix-  I agree on the Esoteric.  Something was not right!  I can't image they would make something that was that off. 

Congrats weelndeel. Nice combo. To me luxman d-03x (if you don’t care about scad) is one of the best sounding players/DACs within 10k range and is a bargain considering it’s price. 
I keep hearing how luxman separates m900 and c900 are much better than 509x or 590axll that I have. Please Anyone who listened both, can you describe what is actually better with separates?



The Boulder 866 is a neutral amp so if you heard it with magico speakers I can see how it may be fatiguing. It sounds superb with my Rockport Avior ii speakers though. The internal DAC is fantastic as well. Happy listening! 


The Boulder was played on Dynaudio Contour 20i speakers.  That combo was not good.  The shop also had Sonus Faber, I believe they are a warmer speaker and maybe that would be a better combo than the Dynaudio for the 866.  


I am glad i was able to help and steer you in the right direction. Knowledge is power and I'm glad you don't have to lose thousands of dollars trying stuff out. No need for that and I'm super thankful that you found my consultation service valuable. 

Cheers 🥂!