Arrakis speaker is a biamped speaker with an electronic crossover. It presents a different load to an amp than the Altair. I had the VAC 450 on the 2 ohm tap and it did not drive the Altair. Like I said no tube amp including the single ended will drive it properly. I don't care what kind of power supply the NAT has. I will gladly like to be proven wrong as I love tube amps.
Triodes and Tetrodes and SET, Oh My!
- Thread starter Ron Resnick
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I knew this was going to be a complicated thread!
I was hoping one or more members might have directly compared N.A.T. single-ended tetrode to VTL push-pull triode mode on a familiar system.
Of course, to make it more complicated, different tubes sound different, even separate from the different circuit types.
I wish Dr. Gizmo were still here - he might have a lot of things to say.
If you haven't read his texts, Ron, they're well worth it, even re-reads with his particular sense of humour, and the deep knowledge is scattered among several texts.
I'm sure you're right! It's been many years, and I'm likely "remembering" triode-mode sonics that were great for their day, but, no longer great.
Hi Ron,
I have some experience with NAT and some other really good SET amps from Eastern Europe. I have heard the NAT SE1 MKI, MKII, SE2SE MKI, MKII and SE3 as well as the Transmitter. I think the Transmitter can be run in Triode mode, which I believe is how I heard it being used. We did some direct comparisons between the NAT SE2SE MKII and the CAT JL2 Signature, which is widely regarded as one of the best sounding push/pul Class A triode amps (it handily beats what I have heard so far from VTL anyway). We did the comparison on a pair of Apogee Grands that were being run only with the panels and passively (using a Diva crossover). This worked fine because the Grand is essentially an updated Diva on top of a big sealed box subwoofer; howver, with active xover and partial amplification (specially designed by Krell). The result of that comparison was that while both were very good the NAT brought an extra degree of midrange purity as well as top to bottom coherence. It was pretty close but in the end the clear advantage to the NAT.
Now, I heard the Grand again with a full NAT rig (SE 1 MK I on the tweeters, SE2SE on the midrange and the SE3 on the bass panel...Krell on the subs) and later with 4 NAT transmitters (bass panel and midrange ribbon...tweeter Krell, sub Krell). To be honest there was not a huge difference between the two setups but perhaps the a bit more resolution with the Transmitter rig and a bit better tone on the SE211 rig. Unfortunately, IMO, the Apogee active X-over imposes too much of its own signature on the sound and it is a bit grainy and harsh. The passive setup, even though it was not an optimized xover, was better sounding tonally at least.
I have also owned a NAT hybrid, the Symbiosis SE, for something really different and it has both strong and weak points but overall a tube output SET sounds better than a MOSFET one. I have a NAT preamp now (Plasma SE) that sounds excellent.
I would have to say though, that I find KR Audio products to give better sound than what I have heard from NAT up to now. They are one of the best amps on the market despite being a "reverse" hybrid. They nail tonality and dynamics.
Another contender that I am reviewing now is Aries Cerat. I have the Diana integrated (25 watts but 110KG!) that uses Direct heated Pentodes wired in triode (814 tube for input and driver and 813 for the output). This has perhaps even better microdynamics than KR, which surprised me, with a very nice and quite accurate tonality. Spatial is also superb. KR seems to have more powerful bass at this point but that aside the Diana is really impossible for a push/pull amp to beat, IMO.
Something else to consider are indirect heated triodes like the 6C33C as used in Lamm and some others. Amps with this tube have a very solid image density from what I have heard with my own Wall Audio Opus M50 monos (they use two per channel in a PSE config). Midrange and bass is quite special sound with this tube in most designs I have heard.
We have done many direct comparisons with push/pull pentode amps (Octave MRE 230 with black box), push/pull triode amps (VAC 30/30 MKII, PureSound A30 in triode and tetrode), hybrid SE(Transistor) (NAT Symbiosis SE), Hybrid (Lamm M1.1) and SET (KR Audio VA350i, Wall Audio Opus M50, JJ 322, Cayin 9084 monos on Thiel CS3.7 speakers. The best sound was coming from the KR VA350i and the best push/pull sound from the VAC 30/30 but the KR was quite a bit better than the VAC. Actually, pretty much all of the SETs (including the NAT hybrid) were better than the VAC ultimately. However, the VAC is still a pretty satisfying amp.
I hope to be able to put the Diana up against the KR VA350i and/or the KR Kronzilla SXi. A friend has both. On my Odeon horns, the Diana beats my Wall and JJ in everything except deep bass at this point. I had a VAC 30/30 before and the NAT hybrid was better so I sold it.
I used to run ribbons and electrostats on KR amplifiers and it was a superb sound, natural and effortless despite the lowish power. NAT also drives these kinds of speakers well...just not quite as good sounding, IMO but still quite satisfying.
I don't think comparing with Symbiosis is a fair comparison. It will have to be a shootout between Transmitter (with lower power) and Kronzilla.
I loved what I heard on tone and air from Christoph's V350i but I think for Apogees more power, with that quality, is required.
I owned the Vac 30/30 too, btw
Same with Aries - great sound, but 30w is for horns.
Grands are easier to drive, and Flo's Transmitters with the Grands were fine, fast and loud in his current room, but to do a proper test you need a bigger room.
The Apogee active crossover needs to be properly restored or eliminated. Neither Henk nor Graz or Rich Murry are fans of original Apogee crossovers
I loved what I heard on tone and air from Christoph's V350i but I think for Apogees more power, with that quality, is required.
I owned the Vac 30/30 too, btw
Same with Aries - great sound, but 30w is for horns.
Grands are easier to drive, and Flo's Transmitters with the Grands were fine, fast and loud in his current room, but to do a proper test you need a bigger room.
The Apogee active crossover needs to be properly restored or eliminated. Neither Henk nor Graz or Rich Murry are fans of original Apogee crossovers
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fwiw, I spoke with the US importer for KR at Newport and for my 91db speakers he was recommending Kronzilla only. I've wanted to try the VA350i for some time as I prefer the tube complement and don't like Kronzilla aesthetics, but he didn't feel it was enough.
What do you think of the KR vs. latest Jadis stuff, Bonzo?
Jadis are very different from KR and NAT. The latter two are more neutral, transparent. My experience is more with NATs which are more powerful and dynamic and high on SS qualities of separation, bass, without giving up tone. KR is great too.
I normally don't like coloured valves like AN and Kondo (the extremely expensive Kondo is good). But Jadis is one of the pretty sounding things I love. It is like opening a window and letting the sun in - but lovely, involving. On paper, it has negatives compared to NAT, it is muddier and slower, but if you like it it could become your top choice. Someone told me it distorts a lot and the distortions make it sound more natural. Possible. Also the range is from 30w to 500w.
I have always found the power designs and implementation makes more of a difference in the quality of the sound coming from the tube amp regardless of the mode used.
Ie. Ron you mentioned the Arrakis system in Austin using PP. He and another super system in Dallas both biamp with flagship VTL amps. Both speakers (Arrakis and Focal) are fairly efficient speakers and would be fine with a decent SET amp. Both owners are of like mind and consider that stressing a SET amp to the max vs using the bottom 20-25% of a PP amp is the better way to go. Given that both amps sounded the best I have ever heard them sound on each respective system I would concur they are on to something.
That being said it helps that both amps have massive power designs which is not something I can say for most tube amps on the market. This I find makes the most impact on the "color" of a tube amp through any given speaker SET or PP. Weak power designs are common and when a tube amp has a high demand put on it you hear coloration for days. The expectation is SET amps will have >95db efficiency speakers so the load presented to the speaker wont require a very good power supply design. At least that is the only conclusion I have come to...
As far as PP or SET when an amp does gives the option of switching modes SET always sounds better to me regardless of the tube complement
Ie. Ron you mentioned the Arrakis system in Austin using PP. He and another super system in Dallas both biamp with flagship VTL amps. Both speakers (Arrakis and Focal) are fairly efficient speakers and would be fine with a decent SET amp. Both owners are of like mind and consider that stressing a SET amp to the max vs using the bottom 20-25% of a PP amp is the better way to go. Given that both amps sounded the best I have ever heard them sound on each respective system I would concur they are on to something.
That being said it helps that both amps have massive power designs which is not something I can say for most tube amps on the market. This I find makes the most impact on the "color" of a tube amp through any given speaker SET or PP. Weak power designs are common and when a tube amp has a high demand put on it you hear coloration for days. The expectation is SET amps will have >95db efficiency speakers so the load presented to the speaker wont require a very good power supply design. At least that is the only conclusion I have come to...
As far as PP or SET when an amp does gives the option of switching modes SET always sounds better to me regardless of the tube complement
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Thank you very much, morricab, for conveying your extensive experiences with all of these amplifiers!
Did it ever occur to you, that he could prefer to sell you the Kronzilla over the 350i because it's double the price
The 350i drives my Studio Grands with 86 dB per watt in 3 meters with ease in my huge living room, as it did the Thiel 3.7 (i think it's below 90 dB per watt in 1 meter and has a nasty impedance dip). Even on the 82 (?) dB Acoustats it sounds VERY good in my upstairs system. In fact, the 350i sounded wonderful on every speaker we hooked up except from the Scintillas 1 Ohm, where it just farted
With your 91 dB speakers, I would not hesitate a second to use the 350i (as ong as the impedance stays above 3 ohms).
Why don't you just try it.
Btw. I have both, 350i (integrated and poweramp) and the Kronzilla SX poweramp
Does anyone have experience driving a big Genesis 1 Series midrange/tweeter panel with a medium or high power SET amplifier?
Flo's active xover is properly restored but it is not high end, IMO, and acts as a bottleneck in the ultimate potential of that system. Eliminated would be what I would do and use a good tube crossover or digital crossover (digital out to good DACs).
He is maybe right and maybe wrong. How loud do you listen and what size is your room and what distance from the speakers do you listen? If you are not more than 3-4 meters from the speakers and the room is not huge than a VA350 should be sufficient.
I once compared the VA350i to the Jadis Defy 7 MKIII with special Siltech wiring. The speaker was the Focal Maestro Utopia BE and the source was a Mark Levinson 390s cd player. The difference between them was surprisingly small, the Jadis is a very fine sounding PP tube amp, but the KR was overall more holographic, better controlled on the bass and a tad more coherent from top to bottom. More continuousness.
I had Magma Special Edition + Magnetostat Special Edition (much more expensive than normal Magmas and Magnetostats) as well as Jadis JPL and Jadis JA 100 in my room at the same time. The JA 100 had basic electroharmonix. Even then, though technically they sounded wrong, musically you could not prefer one over the other. Speakers were 93db sensitive Verity Leonores.
No but I made DIY ribbon hybrids using the same BG planar magentic driver that Genesis uses (just shorter) and drove the whole thing with two KR Audio VA350s (one for the planars and one for the woofers) connected with an Accuphase F25 crossover. That worked really well and the KRs had no problem at all with the 4 ohm 87db planar driver.
Again, I don't really agree. People said the same thing about big Acoustats (my Spectra 4400s were taller than a Fullrange and about as wide as one on the top). I actually had the Spectra 4400s running as subs and the Spectra 2200s running above 100Hz for a while and that worked amazing in a 20 square meter room.
Do you like the Verity speakers? I find them to sound generally not quite right. Only once I liked the Parsifals driven by the Nagra 845 monos.
Morricab, my Apogee of choice likely to be Graz Divas
Rich of True Sounds absolutely says nothing less than 200W on the bass ribbons is acceptable, triodes fine on mids and treble ribbons, the whole lot running via an active crossover, Pass Labs or First Watt
He is adamant the bass ribbons are bitches, and need absolute control
Now, I currently run, and love, my NAT SE2SEs (using the twin 211s, not the GM70s), and would love your take as someone who has run a slew of NATs on Apogees
Should the Divas be run actively bi amped, and am I better going non NAT iron control on the bass ribbons as Rich advises, or do you think Transmitters could work here, with SE2SEs on the mids and treble?
Rich of True Sounds absolutely says nothing less than 200W on the bass ribbons is acceptable, triodes fine on mids and treble ribbons, the whole lot running via an active crossover, Pass Labs or First Watt
He is adamant the bass ribbons are bitches, and need absolute control
Now, I currently run, and love, my NAT SE2SEs (using the twin 211s, not the GM70s), and would love your take as someone who has run a slew of NATs on Apogees
Should the Divas be run actively bi amped, and am I better going non NAT iron control on the bass ribbons as Rich advises, or do you think Transmitters could work here, with SE2SEs on the mids and treble?
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