SET amp owners thread

[213Cobra]

OK, I just pulled the Edicron 6922 that it came with. I replaced it with my Telefunkin E88cc that cost $360 each now. Hands down, tubes play a big part with these amps. I am now playing 3 DB louder on my stepped ladder attenuator and its absolutely glorious. I was stopping 3 db lower with the Edicron because it was topping out for me. Starting to hit the point where you go, ok, that too loud. I'm 3 db higher now and could go up, but why. Its dam good right where it is.

I have had them running all morning. These amps slay. I am actually 6 db higher and could keep going up. They are just crushing it on my vinyl STST Motus II, Hana, Allnic – A Tribute to Duke – Concord Jazz 1977. I'm kind of shocked how much I like these amps.

Edicron 6922 tubes are actually Russian 6H/N23. Some people love them more than any other 6922 family, except for CCa, but it is a kind of tight-sphincter tube compared to the Euro 6922 variants. It's usually a good place to start when coming from a p-p amp, but sooner or later you discover there's more available from the amp when you move on from the clean restraint of the 6H23. Good progress!

Phil

 

[morricab]

OK, I just pulled the Edicron 6922 that it came with. I replaced it with my Telefunkin E88cc that cost $360 each now. Hands down, tubes play a big part with these amps. I am now playing 3 DB louder on my stepped ladder attenuator and its absolutely glorious. I was stopping 3 db lower with the Edicron because it was topping out for me. Starting to hit the point where you go, ok, that too loud. I'm 3 db higher now and could go up, but why. Its dam good right where it is.

I have had them running all morning. These amps slay. I am actually 6 db higher and could keep going up. They are just crushing it on my vinyl STST Motus II, Hana, Allnic – A Tribute to Duke – Concord Jazz 1977. I'm kind of shocked how much I like these amps.

Tube quality is critical particularly with SET due to no negative feedback and the limited number of stages (my Aries Cerat Genus has only 2). I have heard similar transformations with all my SETs over the years.

 

[morricab]

For more reasonable money, I have JAN Philips 6922s and NOS Tesla 6922s to be quite good sounding. Siemens and Dutch made Bugle Boys are really good on the next price ladder up for that tube type.

 

[Ron Resnick]

Many years ago, I had the VTL MB450 PP mono blocks. Very nice amps, used them on my Apogee Stage speakers.

I bought an Antique Sound Labs 50 watt 805 SET, because I was in the process of going towards an active crossover. I was experimenting and trying out different things.

This was high power PP vs. medium power SET.

I had an 805 tube go bad, so while the new tube was on it’s way, I tried an experiment and put the MB450 on one channel and the SET on the other, equalized the volume, and listened.

The general dynamic open-ness of the SET was apparent right away, and I could change the imaging from one amp to the other in emphasis by shifting my ears back and forth from one speaker to the other. The SET pointed out compression and grit in the upper midrange of the MB450 PP, something I had not been aware of. The general open and natural sound quality of the SET won.

I sold the VTL MB450 and tube amps in my system since have been SET.

This isn’t to say the VTL was in any way a bad amp, or that aren't great sounding high power tube PP amps, I just found my ears preferred the SET presentation.

This is very interesting. Thank you for conveying this report.

Did you find 50 watts were sufficient to drive the Stages? Putting the question another way, were any aspects of the sonic presentation compromised when you switched to the low power amplifier?

 

[Kingrex]

I would agree there is much less grit. Its far more clean. SET via my Black Shadow is dam nice. I played quite a few album yesterday. Now I'm plagued over getting another pair of 6922 e88cc Telefunken. I went through my tubes yestersay. I have 3 sets of Tele. I use to have a set of Siemens and Amprex. I know I sold the Siemens. I can't find the Amprex. I also have a set of ifi. Emmanuel with First Sound Audio got me to buy them. They are probably the most quiet tube out there. They just lack emotion. I went through a bunch of other 6922 I got from upscale audio. In my preamp, Tele is hands down best. I will have to play with the amp and see what it really wants.

 

[cjfrbw]

This is very interesting. Thank you for conveying this report.

Did you find 50 watts were sufficient to drive the Stages? Putting the question another way, were any aspects of the sonic presentation compromised when you switched to the low power amplifier?

That's a good question, but I didn't listen to them like this much, and rapidly moved on to active three way crossover. I eventually had the two Wavac 50 watt amplifiers with one 50 watts on each ribbon and the bottom crossed over to subwoofer.

50 watts is marginal at best for a Stage by itself @86db efficiency and a power gobbling passive crossover, and I seriously doubt that a single 50 watt SET would have been satisfactory in the long run at anything but rather low listening levels if powering the whole speaker by itself. That is one of the reasons that I got the VTL MB450 in the first place.

Analysis Epsilon is an 'easier' speaker to drive than the Apogee Stage, even though the efficiency is nominally the same.

However, with the active crossover arrangement and multiple amps/subwoofer/surrounds, many people who heard the result really liked the active crossover/Stage arrangement and it could get loud in my room.
(As a note, I estimated that 50 watts on each ribbon with an active crossover bypassing the passive crossover and passing off the lower two octaves to subwoofer, was somewhat equivalent to having 200 watts of power on the panels if using a single amplifier with the 3db power sapping passive crossover).

I still miss the wonderful sound of those original Stage speakers, but they succumbed to the known impedance drift in the bass panels and there was no good fix.

 

[Kingrex]

Does an active crossover detract from the SET sound. Or do you think it makes it better.

 

[cjfrbw]

Does an active crossover detract from the SET sound. Or do you think it makes it better.

A fraught subject of controversy, so I wouldn't state anything outside of personal preferences.

In that context, I would say it makes it better. The power proposition is better as stated, because bypassing a passive crossover automatically makes for better power distribution to the speaker elements. You also get the 'direct report' over the selected frequency range from the amp without passive crossover elements.

Power is precious with most SET amps, and, of course, they might never work well on truly current hungry speakers, but they worked great with the Apogee Stage (and the Analysis Epsilon that I presently own).

SET amps also have most of their distortion in the lower frequencies, so using one on the midband from 200 Hz to upper midrange can give you the 'magic' without the problems of relying on the SET for bass.

I currently use solid state amps for the lower three and a half octaves and SET for the broader midrange, and the effect is magical.

A benefit of passive crossovers could be that they make the sound more uniform across the entire bandwidth through some kind of averaging process, but that single feature doesn't really sell me in exchange for the loss of efficiency.

I will now cover my head to get stomped by enraged passive crossover fans.

 

[Ron Resnick]

Hi cjfrbw,

Thank you for these very interesting comments.

My thinking when you first reported
that "[t]he SET pointed out compression and grit in the upper midrange of the MB450 PP, something I had not been aware of. The general open and natural sound quality of the SET won," and that you "just found my ears preferred the SET presentation," was "sure -- that's why many people prefer SET over high-power push-pull, including me, but the reason all tube lovers don't drive all speakers with SETs is because of incompatibility with insensitive speakers in the areas of drive, dynamics, control, headroom, etc."

This is why I like the idea having a high-power SET in house (NAT Magma New SE or Audio Music 833 Ultima) to compare and contrast the SET presentation with the presentation of the main high-power push-pull VTLs.

 

[cjfrbw]

Certainly worth a try on a trial basis.

 

[Ron Resnick]

My curiosity is the same as why MikeL was fascinated to try low power SETs in his system

 

[bonzo75]

SETs unmatched to the speaker make the whole system sound pretty bad. Might be good enough for a change but should be let go pretty quick like Mike did

 

[cjfrbw]

My own useless but fun You Tube video. Probably about 4.5 watts/6a5g tubes on the BG75 midrange ribbons (Sylvania indirectly heated triode 300Hz-7Khz ribbon). Microphone rolls off at 70hz, so little deep bass on recording. Vinyl quality maybe G minus.

 

[cjfrbw]

Another with same rig (isn't Covid 19 sheltering boredom wonderful?). Original in system sounds much better and more vibrant, but not too bad facsimile for You Tube.

 

[morricab]

That's a good question, but I didn't listen to them like this much, and rapidly moved on to active three way crossover. I eventually had the two Wavac 50 watt amplifiers with one 50 watts on each ribbon and the bottom crossed over to subwoofer.

50 watts is marginal at best for a Stage by itself @86db efficiency and a power gobbling passive crossover, and I seriously doubt that a single 50 watt SET would have been satisfactory in the long run at anything but rather low listening levels if powering the whole speaker by itself. That is one of the reasons that I got the VTL MB450 in the first place.

Analysis Epsilon is an 'easier' speaker to drive than the Apogee Stage, even though the efficiency is nominally the same.

However, with the active crossover arrangement and multiple amps/subwoofer/surrounds, many people who heard the result really liked the active crossover/Stage arrangement and it could get loud in my room.
(As a note, I estimated that 50 watts on each ribbon with an active crossover bypassing the passive crossover and passing off the lower two octaves to subwoofer, was somewhat equivalent to having 200 watts of power on the panels if using a single amplifier with the 3db power sapping passive crossover).

I still miss the wonderful sound of those original Stage speakers, but they succumbed to the known impedance drift in the bass panels and there was no good fix.

Stages were something special alright. They had a double layer bass panel that was unlike other models. I drove my Caliper Signatures with a nice sounding hybrid (Sphinx Project 14mkiii) but got my first SETs during that period (Cary CAD572se monos...20 watts). Those 20 watt SETs sounded nearly as powerful as Sphinx, which was rated 280 watts into 4 ohms (and could deliver at least 500 into 2 ohms...Calipers were 3-4 ohms)! A nice sounding intro to the SET world.

 

[Tbzc]

Hi cjfrbw,

Thank you for these very interesting comments.

My thinking when you first reported
that "[t]he SET pointed out compression and grit in the upper midrange of the MB450 PP, something I had not been aware of. The general open and natural sound quality of the SET won," and that you "just found my ears preferred the SET presentation," was "sure -- that's why many people prefer SET over high-power push-pull, including me, but the reason all tube lovers don't drive all speakers with SETs is because of incompatibility with insensitive speakers in the areas of drive, dynamics, control, headroom, etc."

This is why I like the idea having a high-power SET in house (NAT Magma New SE or Audio Music 833 Ultima) to compare and contrast the SET presentation with the presentation of the main high-power push-pull VTLs.

Ron,

I own VTL Siegfried II (for 3 years) and NAT Transmitter (3 months) and have been comparing them quite intensively for the last 3 months. Like many members here I have also been lusting for SET since many years. I have actually had one PSET system in another apartment but that system just didn’t work in my dedicated room in my new house. So I have tried many combinations in the last few years and learned lot.

My speakers are Sigma Acoustics MAAT with duelund crossover which are quite easy to drive (you need above 50w). Compared to VTL, my first impression of NAT was that the sound is more open and clear. More air. Midrange is presented a bit forward. But, after I had NAT for several weeks I did the comparison again and asked my wife to join me. Our conclusion (after two sessions): VTL plays more full, organic. You do miss that meat on the bones with Transmitter, especially in low bass. But not only there.

After that I played with VTLs again and tried additional tweaks. I have already changed 12AT7 tube to Mullard which certainly helps to increase musicality a lot. Then I used Neodio B1 antivibration feets. And then I put them on granite plate. With all the tweaks VTL gained in musicality and transparency which is now almost on par with SET. With all of VTLs advantages retained. Very happy with improvements.

After many years of experience with different amp topologies and speakers I do not believe in one holy grail only. There are different ways how to achieve musical nirvana but the key factor IMHO is your music preference. Mine is very wide: from old to new rock, electronica, jazz (mainly modern) and classical. Therefore I have - at least temporarily - gave up dream of combining low watts SET and horns. My nirvana is all tube system, based around DHT preamp, lots of tube power and big sensitive cone speakers.

 

[bonzo75]

The Nat however is not the same comparison as a low watt SET. I did prefer the jadis when I had both at my place on Verity. In an application where Nat is required (high power, more drive) I might prefer a good push pull or a good SS depending on the speaker. However, low watt SETs around 10w and below, is totally different. Even there it is possible to prefer an EL84 push pull or a PSET, but even that will be around 10 watts.

 

[spiritofmusic]

Ron,

I own VTL Siegfried II (for 3 years) and NAT Transmitter (3 months) and have been comparing them quite intensively for the last 3 months. Like many members here I have also been lusting for SET since many years. I have actually had one PSET system in another apartment but that system just didn’t work in my dedicated room in my new house. So I have tried many combinations in the last few years and learned lot.

My speakers are Sigma Acoustics MAAT with duelund crossover which are quite easy to drive (you need above 50w). Compared to VTL, my first impression of NAT was that the sound is more open and clear. More air. Midrange is presented a bit forward. But, after I had NAT for several weeks I did the comparison again and asked my wife to join me. Our conclusion (after two sessions): VTL plays more full, organic. You do miss that meat on the bones with Transmitter, especially in low bass. But not only there.

After that I played with VTLs again and tried additional tweaks. I have already changed 12AT7 tube to Mullard which certainly helps to increase musicality a lot. Then I used Neodio B1 antivibration feets. And then I put them on granite plate. With all the tweaks VTL gained in musicality and transparency which is now almost on par with SET. With all of VTLs advantages retained. Very happy with improvements.

After many years of experience with different amp topologies and speakers I do not believe in one holy grail only. There are different ways how to achieve musical nirvana but the key factor IMHO is your music preference. Mine is very wide: from old to new rock, electronica, jazz (mainly modern) and classical. Therefore I have - at least temporarily - gave up dream of combining low watts SET and horns. My nirvana is all tube system, based around DHT preamp, lots of tube power and big sensitive cone speakers.

Tbzc, I've been running the Nat SE2SE 70W triodes since 2015. Totally love them in every way on my 101dB eff Zus in an 18x48 room.
I have heard the Transmitters a couple of times, incl on Analysis Omegas ribbons, and I do detect a glassier tone, less tonal saturation.
Now, they are tetrodes, so unsure if that's the reason. For me if I wanted "more" Nat than these SE2SEs, I'd jump to the Magmas New, triodes again. 170W v my 70W.

 

[bonzo75]

Marc did you hear the 60 or the 120 watts on the analysis?

 

[morricab]

Tbzc, I've been running the Nat SE2SE 70W triodes since 2015. Totally love them in every way on my 101dB eff Zus in an 18x48 room.
I have heard the Transmitters a couple of times, incl on Analysis Omegas ribbons, and I do detect a glassier tone, less tonal saturation.
Now, they are tetrodes, so unsure if that's the reason. For me if I wanted "more" Nat than these SE2SEs, I'd jump to the Magmas New, triodes again. 170W v my 70W.

I found the 211 based amps from NAT better sounding than what I have heard from the transmitter.
That said, NAT is not the only high power SET game in town with Aries Cerat, KR Audio, Ayon and others with 60+ watt amps in their lineups.

We found your SE2SE to sound superior on Apogees than a CAT JL2 Signature, a very good sounding PP Class A Triode amp. The CAT is probably the best sounding amp of that type I have heard (Modded Jadis Defy 7 and JA30 were also very nice) but the NAT was better...and it’s not the best SET of that power I have now heard!