Robert Koda K160 Amps are on their way finally!

Agreed you could well be right since you have much more expericience then i have with Gryphon and R koda ,but the Antileon, Colosseum and Mephisto are not a class A monster like the New Apex .
Gryphon probably has applied new circuitry as well in the new design

The Gryphon did have me rethink the whole power issue again in a positive sense
I am no techie, but I do think there is something to be said for either very efficient speakers or very high powered amplification. I am aware that some audiophiles struggle with super high power as a general rule. But I do imagine (not heard any of them) that what D'Agostino Relentless, Boulder 3000 series and Gryphon Apex have done is pretty remarkable having heard the Mephisto and 2000 series Boulder.
 
I am no techie, but I do think there is something to be said for either very efficient speakers or very high powered amplification. I am aware that some audiophiles struggle with super high power as a general rule. But I do imagine (not heard any of them) that what D'Agostino Relentless, Boulder 3000 series and Gryphon Apex have done is pretty remarkable having heard the Mephisto and 2000 series Boulder.
High power does not overcome thermal compression issues in lower sensitivity speakers…this is why you cannot get the same dynamics no matter how much power you pour in.
 
High power does not overcome thermal compression issues in lower sensitivity speakers…this is why you cannot get the same dynamics no matter how much power you pour in.
Thank you! Where do you draw the line on efficiency to define a high efficiency speaker? 95db?
 
Thank you! Where do you draw the line on efficiency to define a high efficiency speaker? 95db?
Hard to say exactly. However that is high enough that for most listening you won’t use much power and so coils won’t get too hot.
 
Hard to say exactly. However that is high enough that for most listening you won’t use much power and so coils won’t get too hot.
Thanks!
 
...With the right speaker load, the Robert Kodas present a simple purity (deceptively simple) that is absolutely startling in a side by side comparison...and at least in comparison to the Mephisto, allow far more nuance, detail to float up into the room from the music. It was the first amp EVER after several months which recalibrated my ear and still had me wondering 'who was right' in the reproduction of music. In the end, I made my choice that the Robert Koda's level of nuance, subtlety of inflection and the ability not to 'balance' lots of complex orchestral work (because balance suggest the amp is actively doing something to the music)...but instead the amps' ability to somehow amplify all the complexity in such a way that all the individual music themes and strands come OUT of the amp exactly the way they came IN to the amp from the (also exceptional) Robert Koda K15EX preamp was what was compelling and decisive winning factor about the Robert Kodas.

As for all-out assault power, with 235 watts of pure Class A power (into 4ohms) on the Robert Kodas, I was not sure exactly what to expect on 'pure grunt capability' which was my only quandry when they first came in for audition. What surprised me was that on tracks like Dark Knight (soundtrack by Hans Zimmer), the Robert Kodas went very noticeably DEEPER than the Mephisto with GREATER power. Where the Gryphons battled back was in the upper and mid bass and lower mids they present a more deep, powerful and dense music flow which breathes life into music in a very special way. The question (for the first time ever for me) was whether relative to the all out purity of the Robert Koda I actually started to question whether that touch of life from the Gryphon was a stylistic design touch or not. I am not sure I know the answer, and if I still had the Gryphon...I am not sure I would care. It sounds great.

But in the end, the Robert Kodas are exceptional and pure in so many ways, I think Alan Sircom's recent sum up that it was the world's most powerful SET triode amp (without tubes) is probably the way I think about it. And that sounds pretty good to me.

Do let us know what you think about the Apex and Koda K160 when you hear them in Munich!

So it has been 2 months since I posted this observation in the context of a discussion about Gryphon and Robert Koda K160 (both pure Class A).

MY MAIN MESSAGE
I suppose my main message here in this post (which some like Marty, MikeL, Francisco and others definitely subscribe to) is keep honing your 'system' whatever equipment you choose.

THE OBSERVATION

- After making the above observation, I can restate that with Gryphon there is addictive 'breath of life' in music and instruments which seems to emanate from its enormous wellspring in the lower-mid/upper bass focus...I think because the body, foundation and depth of a lot of instruments lies here. And not many amps can deliver that. By contrast, the pure-as-water Robert Koda delivers an exceptional, but more serene/sublime musicality in this same space.

THE CHALLENGE
- So who is right? Well, it turns out in the last 60 days, I discovered it is not that simple.

THE APPROACH OF HONING (20 MONTHS)

- STEP 1: After going through the step-by-step effect of each change after installing the K160s, I realized how transparent the Robert Koda K160s really are:
- isolation and damping plates of the K160s
- placement of XLF speakers
- Entreq Pluton grounding of Robert Koda amplification
- change of i2s cable (really, that made a big difference?...it did!)
- addition of Waversa interface in between Transport and DAC...wow
- re-tubing the not-too-old but not-too-new PSU tubes in the Zanden DAC
The level of change, nuance was far greater to discern (not necessarily by overall sheer impact, but exactly what kind of impact each change was having, including the how's and why's

-
STEP 2: then started going step by step through the entire system from beginning to end...and went back to a piece of advice the legendary Brent Jessee of Brent Jessee Tubes once wrote to me: [paraphrasing] - "as much as you have loved the Amperex 7308 US PQ White Label (and it is a phenomenally good tube)"..."try the Mullard 7308" [different from the 6922 I am told...not just by higher voltage, but actually in its highs being far more articulate, disciplined and airy...and overall being a more disciplined tube while still being a1970s Mullard"

- STEP 3: So there I go...I get back to Brent after that advice from something like 3 years ago...and order one.

THE RESULT
- Shazam.

- This one tube, very very subtlely introduces just that infinitely deft push/prod into the lower mids/upper bass while matching and improving the Amperex 7308
(I retubed while waiting to get to know it, then ordering the Mullard and waiting for delivery)
- And voila, we have a pure-as-water set of all-out-assult amplification doing what it does best which the Gryphon could not match
- It does deeper bass with greater propulsion and far more detail
- And now suddenly with the 1 Mullard 7308, we have 'BREATH OF LIFE' and that extra heft in 'FOUNDATION' in our instrumentation, that delivers that 'instruments have now come to life in your room' sensation

THE CONCLUSION
So now there is NO area, where the system does not now fully and authoritatively surpass the system when it was under the great Gryphon spell. Therefore, my conclusion on amplification is now unequivocal. My winner between my earlier trophy Mephisto (admittedly Stereo) is the Robert Koda K160 Monos. It is pure-as-water, and it plays what comes through.


I love the 'Gryphon power' that comes through every system I have ever heard it in, no matter the source, the speakers...but it comes with its own demands on how you build a system around such a strong personality. I do not think you can 'undo' that powerful bass...(not that I would ever want to by the way...but it is an important observation for me.) And I have learned that lesson now that these very subtle shifts in system have eliminated any advantages of Gryphon's absolutely fantastic design. The Robert Koda wins (for me) not only for its overall superior technical and pure musical performance, but also because I see now it clearly gives me greater control over the entire system which ultimately is a personal goal I value.

BACK TO MY MAIN MESSAGE

AND...coming back to my main message...keep honing the system...I NEVER would have figured this out without the tremendous advice of people at Absolute Sounds/Hifi Trading Station, Airt Audio (Entreq, Stillpoints), HRS, Waversa, Z:Axis Audio and finally, Brent Jessee...and by going through the lengthy, semi-methodical process of honing the system piece at a time. But trust me, its worth it. So many of us here are blessed to have phenomenal equipment...but it STILL takes real effort to get the system really right...but its magic when it is. Onwards and upwards.
 
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Congratulations, Lloyd! Thank you very much for chronicling the evolving refinement and highest achievement of your system!
 
Lloyd, Brent transformed my fortunes getting me to move past the tubes in my preamp from the stock ones, Vostok ones off Ebay, Siemens ones from another specialist US dealer, to this current mix of Mazdas and Mullards.
Not only is noise well down, but musicality is right up, a somewhat harsh sound before (dynamic but gritty) replaced by something altogether more musical and smooth (tone colours and textural depth in spades).
So, your stress on "honing" is fully understood here, and Brent's amazingly good advice has been integral to me getting a result currently that was out of reach even a few years ago.
 
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Hi Spirit,

Yes, Brent is really very seasoned and very good. As great as his collection of tubes is, his advice is even better.
 
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LL21

Your descriptions are great and I can reconcile my preferences with them. The thread that works its way through your posts is that you miss the foundational midbass of the Gryphon. Once you have that, all other amplification seems to be lacking if just a bit. It is the hallmark of the live sound IMO and even a feature of vinyl vs digital to a degree. You moved up the volume control to try and find it, but tonal balance falters.

Very few amp designers nail that part of the spectrum and I believe many high quality amps, even the very best, can struggle briefly to actually provide the current when called upon, even at low volumes the circuit just will not give it to you.

The best designer I have heard that produces foundational articulate midbass similar to the Gryphon but also perhaps (cannot say for sure ) with a bit more purity of tone and bandwidth and silence you appreciate in the Koda, would be the top offerings from Vitus... I am surpirsed not once have they been mentioned.... My impression is they are the marriage of your Gryphon (that you still miss in one category) and and the more refined and resolute and fluid Koda.
 
LL21

Your descriptions are great and I can reconcile my preferences with them. The thread that works its way through your posts is that you miss the foundational midbass of the Gryphon. Once you have that, all other amplification seems to be lacking if just a bit. It is the hallmark of the live sound IMO and even a feature of vinyl vs digital to a degree. You moved up the volume control to try and find it, but tonal balance falters.

Very few amp designers nail that part of the spectrum and I believe many high quality amps, even the very best, can struggle briefly to actually provide the current when called upon, even at low volumes the circuit just will not give it to you.

The best designer I have heard that produces foundational articulate midbass similar to the Gryphon but also perhaps (cannot say for sure ) with a bit more purity of tone and bandwidth and silence you appreciate in the Koda, would be the top offerings from Vitus... I am surpirsed not once have they been mentioned.... My impression is they are the marriage of your Gryphon (that you still miss in one category) and and the more refined and resolute and fluid Koda.
Hi Knopf405,

Thanks for taking the time it all! Yes, midbass is becoming more and more clear to me as foundational and very very important to rooted-to-the-stage-floor-realism. Looking at mega speaker designs, the cone area dedicated to this in some of the newer and/or more advanced designed (Evolution Acoustics MM9, Magico M9, Genesis 1, Rockport Arrakis) is clearly an important element.

In amplification, the ability to deliver this at instantaneous speed, scale and effortlessness is also important. The key is HOW that gets delivered. In the case of the Gryphon, it is THERE. You dont have to do anything...in my limited experience, you can drop a Gryphon into almost any system and have it. It is wonderful, articulate and really re-sets many people's understanding of sound reproduction. It certainly did for me, and it has stuck with me.

That said, here is the interesting thing...over time, I have realized that perhaps Gryphon has done this exceptionally well on its own within its own design. But it also has meant that it instills that power/depth into the system. Let me be clear: I am an enormous fan of Gryphon. I owned the Antileon, Colosseum and Mephisto consecutively for ove 10 years. Is its wonderful and addictively satisfying midbass power a very very subtle touch of excess? Hard to say...not sure I ever really cared...until I got to the Robert Kodas.

And then 2 things happened.

1. I realized that the entire system had clearly been set up around the Gryphon going back over 10 years. And so when an amplifier comes in that does not have that extra element of midbass...there is an absence. The question is whether it is the new amps which are absent or that the Gryphon had a fullness around which the entire system had been effectivelyi voiced/setup?

After hundreds and hundreds of hours of listening very carefully...I realized over and over again that the depth and power of the Robert Koda was far deeper, more powerful, more propulsive in the lower bass than the mighty Gryphon Mephisto. So was I convinced that an amp that could best the mighty Gryphon in lower bass could suddenly then be 'light' in the midbass? The Robert Koda made me rethink what a completely even tonal and power spectrum meant in amplification.

2. So I set about reworking the system setup: speaker settings of the Wilson, re-looking at all the setup elements of the electronics. (And because the transparency of the Robert Kodas was extraordinary, I happened to also start thinking about cleaning up the digital signal with Waversa and enhancing the grounding using Entreq to keep the signal purer and purer.)

And so what I discovered about foundation through mid-bass power and articulation:

- after setup carefully, system midbass now is much more powerful and articulate with the Robert Koda than the Mephisto and delivers the initial, middle and end of key mid-bass impact...but you can now hear the beginning, middle and end of the entire impact...
- whereas before the Gryphon delivered the full weight of the impact without that articulation. Very fulsome, incredibly enriching and very articulate...standard setting...but nevertheless still not as powerful and articulate as the system now has with the Robert Koda which sets yet a new standard still

- Thus, after 10 years of setting the entire system up around absolutely phenomenal Gryphon sound with its own take on mid-bass fundamentals and foundation...it has taken some re-working to bring the system around to its own newly settled balance...but once done is performs at a level (even for a massive bass freak like me) which surpasses the Gryphon's drop it, set it and forget it beautiful sound.

You do have to be ready to work at it when bringing in superbly balanced and transparent equipment in a finely tuned system (tuned with other equipment), but boy is it worth it when you get it right.
 
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Thanks for that great information. Very disciplined of you to have teased out that last bit so that the Koda's sing and even exceed the Mephisto in this critical area.

I agree 100% there are very many highly regarded largely epic class A designs that have that signature "bottom up" sound profile where the strength of the presentation right off the bat is setting the entire landscape on solid midbass foundation which is always my preference. Very hard to tune that into a system if the amp lacks it, you can dial it down but not up. (I think of Pass, Gryphon, classic class A Krell).

It is also commonly a rather inarticulate impulse as in most of the Pass lineup sans the XA25 IMO. This is why so often these "thumpers" make such a necessary pairing with smaller two way monitors with a smallish midbass drivers, the speaker really needs that power and signature to sound anythng remotely in balance unless its cranked.

What is a fascinating topic however and one that is not recognized or discusssed much is what amplifier is a particular speaker designer using when he / she is voicing their design? They have to make a choice too. One of the more interesting interviews I stumbled across on this was with Hans Vitus when I was really new to them and loving their house sound:


The intersting section is when Hans discusses a common criticism of the Vitus sound being a bit excessive in the midbass. His response was intriguing suggesting that many speakers on the marked are voiced with amps that really cannot deliever the instantaneous current necessary and as such the speaker is voiced with built in bloat. My hunch is without saying it he is suggesting more US designs and not the likes of Raidho or Borrensen from his homeland. Also interesting is his disgust for toroidal transformer designs as being incapable of voltage stability and thus the real source of the deficiency.

I have two DAC's into my Vitus system I use at times, a Mola Tambaqui and a tweeked AMR DP777 tube DAC. Even the AMR (although softer on the leading edge) produces spectacular midbass slam and articulation but only into the Vitus gear (sl-102 , SM-011's).......

Also not a criticism as it does not matter, but there is no way the Koda is class A to 230w in that small of a chassis and with that power profile into decreasing loads...says nothing of its sound however which I am sure is as stunning as the amps look.
 
Thanks for that great information. Very disciplined of you to have teased out that last bit so that the Koda's sing and even exceed the Mephisto in this critical area.

I agree 100% there are very many highly regarded largely epic class A designs that have that signature "bottom up" sound profile where the strength of the presentation right off the bat is setting the entire landscape on solid midbass foundation which is always my preference. Very hard to tune that into a system if the amp lacks it, you can dial it down but not up. (I think of Pass, Gryphon, classic class A Krell).

It is also commonly a rather inarticulate impulse as in most of the Pass lineup sans the XA25 IMO. This is why so often these "thumpers" make such a necessary pairing with smaller two way monitors with a smallish midbass drivers, the speaker really needs that power and signature to sound anythng remotely in balance unless its cranked.

What is a fascinating topic however and one that is not recognized or discusssed much is what amplifier is a particular speaker designer using when he / she is voicing their design? They have to make a choice too. One of the more interesting interviews I stumbled across on this was with Hans Vitus when I was really new to them and loving their house sound:


The intersting section is when Hans discusses a common criticism of the Vitus sound being a bit excessive in the midbass. His response was intriguing suggesting that many speakers on the marked are voiced with amps that really cannot deliever the instantaneous current necessary and as such the speaker is voiced with built in bloat. My hunch is without saying it he is suggesting more US designs and not the likes of Raidho or Borrensen from his homeland. Also interesting is his disgust for toroidal transformer designs as being incapable of voltage stability and thus the real source of the deficiency.

I have two DAC's into my Vitus system I use at times, a Mola Tambaqui and a tweeked AMR DP777 tube DAC. Even the AMR (although softer on the leading edge) produces spectacular midbass slam and articulation but only into the Vitus gear (sl-102 , SM-011's).......

Also not a criticism as it does not matter, but there is no way the Koda is class A to 230w in that small of a chassis and with that power profile into decreasing loads...says nothing of its sound however which I am sure is as stunning as the amps look.
Great thread here! I remember an interview with Andy Payor who specifically said the ideal is to design the speaker and the amp together...and thus had some positive words to say about active bass, active crossover where you have that left of custom-designed control. But of course, speaker designers and amp designers rarely have that luxury unless they are doing it for their own company. So they make designs that aim to accommodate a variety of paired equipment...but as you say most likely 'voiced' using their own system or a series of their own systems.

Regarding Robert Koda, Robert is quite clear and categorical it is 230 watts Class A into 4ohms (I know nothing about tech but note it is drawing 1100 watts out of the wall at all times which is not inconsistent with pure Class A. An attachment of one of the files that came with the amp. Would love to understand more, though admit very limited technical background.
 

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  • Robert Koda K160 - Specs.pdf
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Also not a criticism as it does not matter, but there is no way the Koda is class A to 230w in that small of a chassis and with that power profile into decreasing loads...says nothing of its sound however which I am sure is as stunning as the amps look.

Back of the napkin calculations say that the amps biased at 8.6A and having 64v rails will easily meet the 8 and 4 ohm ratings. The 2ohm is more problematic but not by a huge margin.

As these are topologically 2 SE amps per channel, each has to produce only a quarter of the full power. It is hard to justify not calling this push pull operation as for all intents and purposes it is. Distortion spectrum will also be similar to a push pull amp.

I am a little more sceptical towards the remarkably low distortion at 50W and specifically towards the voltage gain section. Nearly 60v p-p is exceptionally hard to achieve without any form of negative feedback.
 
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Back of the napkin calculations say that the amps biased at 8.6A and having 64v rails will easily meet the 8 and 4 ohm ratings. The 2ohm is more problematic but not by a huge margin.

As these are topologically 2 SE amps per channel, each has to produce only a quarter of the full power. It is hard to justify not calling this push pull operation as for all intents and purposes it is. Distortion spectrum will also be similar to a push pull amp.

I am a little more sceptical towards the remarkably low distortion at 50W and specifically towards the voltage gain section. Nearly 60v p-p is exceptionally hard to achieve without any form of negative feedback.
Thank you for taking the time. Good to read and learn as I am no techie.

His preamp compares favorably with high end preamps which openly do use negative feedback, and yet Robert openly is against global negative feedback in his designs.
 

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Nice write up. Thanks.
 
Lloyd, Brent transformed my fortunes getting me to move past the tubes in my preamp from the stock ones, Vostok ones off Ebay, Siemens ones from another specialist US dealer, to this current mix of Mazdas and Mullards.
Not only is noise well down, but musicality is right up, a somewhat harsh sound before (dynamic but gritty) replaced by something altogether more musical and smooth (tone colours and textural depth in spades).
So, your stress on "honing" is fully understood here, and Brent's amazingly good advice has been integral to me getting a result currently that was out of reach even a few years ago.
I loved NOS E88cc Telefuken in my First Sound preamp. Then I got some old Siemens and liked them too for other reasons. Then Emmanuel the maker of First Sound updated my preamp. Darned if the $40 a pair tube he provides isn't better than my $500 a pair Tele or $350 a pair siemens.

My new amps do have old stock drivers, voltage regulators and rectifiers. The KT88 is a Shuguang 50 year Black Treasure. Thinking of also trying the Psvane ACME.

Only saying a tube matters.
 
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