SET amp owners thread

[Ron Resnick]

Would you expect 60w of SET power to be worth checking out, or is this just not enough power, end of story.

For me, that would be not enough power, end of story, unless, maybe, you were limiting your music to girl with guitar and small chamber music. But for me, no, end of story.

I do think that in both tube and solid-state amplification amplifiers with fewer tubes and fewer solid-state devices generally sound better than larger amplifiers with massed devices. But, once you are dealing with an insensitive speaker, where SET amp levels of power are inadequate, then I believe in throwing a lot of power at the speaker.

 

[Ron Resnick]

is the lack of ultimate soundstaging/depth and instrumental separation fundamental to SET

No, not at all, in my experience. My suspicion is simply that you have a speaker/amp mismatch.

 

[morricab]

First time for me in this thread, or with a SET amplifier for that matter.
My setup was (and might be again) a Pass Labs xp22 preamp, a long 40 foot run of mogami balanced cable, Ayon Triton monoblocks running in triode mode (tetrode mode loses the magic), 10 ft synergistic research tungsten speaker cables to Nola metro grande II speakers.

I love the Nola speakers, which image well even close to a back wall on either side of my fireplace (I have no flexibility in placement at all, they must go between the fireplace and the windows, shooting the short way across the living room), and they are visually pleasing so they are a fixed variable here. With a TotalDAC/Taiko Extreme front end, the sound is wonderful, with 3D sound, oodles of low level detail without ever sounding harsh, good dynamics and a very low noise floor.

However as our species is want to do, I went with an audio buddy, who was looking for new equipment, to Bacche Audio where I heard their top of the line speaker driven by 300Bs. The SET sound was intoxicating (I'm preaching to the choir here) and I started looking around (always a dangerous sign). I came across a good deal for a pair of Viva Aurora monoblocks, which would (should) have enough power for the Nola speakers, and voila, I was an SET owner. After a kluge of an installation (picture a plywood ramp covered with a soft blanket, and pushing the amps up the ramp onto my stands), I was in business.

Then a couple of weeks of listening, critical assessment, I had an audio buddy come over for a listening session. In the past, we've had very similar responses to equipment so I tend to trust his judgement (particularly since he so often agrees with what I hear) even if he values some aspects of sound differently.

Compared to the Tritons, the Viva amps have more upper bass and the upper bass through midrange is magical, the best I've ever heard here. Where I really feel vexed is the soundstage and detail. The soundstage is wide but has little depth (great 2D, but not 3D) which I find acceptable on some tracks but a serious limitation on others. I also hear less space and silence between instruments, so that subtle details don't surprise me and bring a smile to my face like the Tritons do. I don't hear the voices and instruments as separated as before, though the mix is still very good sounding. If I hadn't heard what the Tritons could do with 3D imaging and subtle detail, I might not be as finicky. But I'm an audiophile, and therefore I want it all!!!
I want that intoxicating midrange, plus the subtle detail and 3D soundstage.

Certainly one possibility is that the Nola and Viva are not a match made in heaven (where I could in fact have it all).
I am running my pre-amp around 90+ which can get it pretty loud but perhaps I need to be running the amplifiers less hard?
Since the speakers are a done deal here, horns or any other speakers are not an option. Would more power help? The Ayon Vulcan Evo perhaps?
Or maybe my cables or something else is limiting and keeping me from the nirvana I'm searching for.

Any and all advice would be welcome.

edit: as another calibration point, I love Stax headphones, which will give you some insights into my preferences.

Try a SET from Ayon?? They make very good ones like the Ayon Crossfire Evo monos. Ayon products have very good soundstage and detail...not sure about the Vivas. I have owned (and reviewed) 4 Ayon amps (owned: Crossfire III integrated, Helios stereo and Spark integrated. Reviewed: Ayon Titan Evo monos) and they all did excellent soundstage: both width and depth with great separation in the images within the soundstage. They all sound tonally nicer than the Ayon PP tube amps (even in triode mode).

There are some other truly excellent SETs that will drive your speakers like KR Audio Kronzillas, Amplifon SET 42 SE, Aries Cerat Genus etc. that will have great tonality and the soundstage/imaging you desire.

 

[cat6man]

Thanks everyone! I also spoke with a dealer who sells Nola and he concurred with the group consensus that a 30w set is a mismatch.

Well it seemed worth a try since 60 triode was adequate. Of course not all watts are created equal and synergy is everything.

I'll put my Ayon amps back in this weekend. If anyone is interested in purchasing Vivid Aurora monoblocks, please contact me.
I'll be advertising them for sale in the coming week.

Thanks again

 

[bonzo75]

field coil Lowther with Shindo 300b, Thomas Mayer 45/2a3, custom PX4.



Mayer 10y + D3a Vs Shindo Monbrison, PTP lenco with audionote field coil

 

[Argonaut]

field coil Lowther with Shindo 300b, Thomas Mayer 45/2a3, custom PX4.

Mayer 10y + D3a Vs Shindo Monbrison, PTP lenco with audionote field coil

Any audio vids of the Lowther / Mayer combo

 

[bonzo75]

Any audio vids of the Lowther / Mayer combo

No videos but generally the speaker needed the higher power and drive of the Shindo 300b. If we had something more powerful that would have worked too. The Mayer phono pre combo was quite better. The lowther's are an overall a long listen, fit into big living room, musical sound. There were some Voight corner horns from the 30s that had potential but were not set up for demos. Also a long mono horn with Lowther

 

[christensenleif@msn.com]

I went back through and read the old emails again. Yes, they of course have the original spec but are they meeting that spec in manufacturing? That was the question from Audio Tekne. I showed them a bunch of measurement sheets from people’s for sale ads and it didn’t seem to be the case. Audio Tekne also mentioned the importance of the filament and if you dig inside the WE site they mention using a new secret sauce coating for the filament.

as far as I know they had specialised suppliers of certain parts of the 300B tubes: eg Sylvania were supposed to deliver the filament wires

 

[christensenleif@msn.com]

also you´re all so hung up in SET watt ratings
to put it in perspective:
my DIY all out 300Bs 8 watts had far better control over my dual FLH from 65-600 than the Nagra VPA PP 845s 50watt
bet it´s due to my extremely stiff LC-LC psu

 

[Argonaut]

The Mayer phono pre combo was quite better. It is overall a long listen, fit into big living room, musical sound.

Phnoe’s for the win then …

 

[morricab]

also you´re all so hung up in SET watt ratings
to put it in perspective:
my DIY all out 300Bs 8 watts had far better control over my dual FLH from 65-600 than the Nagra VPA PP 845s 50watt
bet it´s due to my extremely stiff LC-LC psu

THe VPA's are weak in the output transformer...not just the power supply... A friend of mine has them and he is thinking of moving on...

 

[bonzo75]

Nagra SS amps have weak drive too.

 

[christensenleif@msn.com]

THe VPA's are weak in the output transformer...not just the power supply... A friend of mine has them and he is thinking of moving on...

I sold mine to a Scot living in Sweden.....

 

[remdeck]

View attachment 76334

FIRST: BE VERY VERY CAREFUL!!!!! High Voltages inside!!

Turn the KR Audio up side down. I took some books, as the T100 tubes are bigger than the transformer cases. Don't let the amp rest on the tube(towers)
Open the coverplate. When you power on the amp, make sure that the speakers are connected. Volume completely down.
Hook the voltage meter on ground (Black cable) and on Con 2 in the red circle. When the tubes are cold you will measure 1,3V - 1,5V which will slowely go down. After around 10 minutes adjust the pot in the yellow circle to 1,1V. Don't overdo it, but it can take some turns as the pot is a 10 turns one. Repeat on Con 10 and the pot besides it.
Recheck after 20 minutes.
The negative bias PSU voltage ist -199V (violet circle)

If the protection is on all the time, you cannot adjust as the amp doesn't have bias then.
If that is the case, you can disable the protection for this short (!) time to get to the values needed. This is done when pulling LM339 in the black circle:
View attachment 76335
Put it back when you adjusted the bias.

Here is the T100 tube socket :
View attachment 76336
The drilled red/black cables are the 5V filament voltage. You will measure 6,1V and 1,1V here, referenced to ground.

Remco

NEWS FROM THE KR AUDIO VA350 PURITY

In november 2022 my VA350 once in some days, went into protection. Waiting 30 seconds, it was working again for lots of hours.
I measured the bias again. It was a liitle low, but my biaspot was almost on its end. I was suspecting the T100 tubes would be done.
I somehow got the email adress of the designer of the KR audio amps, Marek Gencev. I wrote him an email at sunday evening, which he answered on monday morning at 7.30h (!):
The bias for VA350 is 1.10Vdc. If the amplifier goes into a protection even with correct biasing you should check thermal stability of TL431
(-30Vdc), which I did:


The TL431 is in the blue circle.
The -30Vdc can be measured at the Tantal cap, the yellow blob left to the TL431.



You can see the measure-probe on the left side of the Tantal cap. The blue arrow markes the TL431. As I heated the TL431 with a hairdryer, it was clearly visible that the voltage got from 29Vdc (cold), to 26Vdc (warm).

So, I ordered the TL431 and all the caps on the main PCB, as one of the 450V caps looked strange (see first pic, left to the TL431)
These are 4x 47uF/ 450V (RM7,5mm , H31,5mm, Ø16mm)
6x 47uF/200V (RM5mm, H20mm, Ø12,5mm)
2x 10000uF/16V (RM7,5mm, H40mm, Ø18mm)
All together some €15....

After I'd changed all, the bias was good again. I adjusted it and checked for several days if the bias was drifting. All was as should be.
When I got to do the listening, I was very surprised at how much better the VA350 now sounds!! More dynamics and the soundstage opened wide now with lots of layering and soundstagedepth... Very very nice!! A friend of mine who was here just before and direct after the modification said it has transformed my system. I was still thinking, it would be my room-acoustics and my speakers, not being able to layer well, but here it is
So, when someone has a KR Audio amp (the main pcb is almost the same in all amps. The TL431 is in all of them) he should check the bias and look for the drifting TL431.

Also, I had one T100 tube, which was making ticking noises sometimes (once in a few weeks) Sounded like playing a record, even when not playing anything. I asked Marek, what it could be. His answer:
"With a noisy tube, try to play the amplifier at maximal volume with disconnected speakers for few seconds.
Likely there is an impurity on mica holders or a grid and you can clean it with a transient signal."

This is really scary, as the amp itself makes all the musik-noise
This I had to do twice within a week and is now gone.

So, as I can say, I'm very happy to have it solved and that my system is sounding so incredible now!!

Disclaimer: don't do this yourself if you are not familiar with electronics! LETHAL VOLTAGES INSIDE!!!
but it is really easy to do

Thx for the mail support from Marek, who helped me a lot and answered my many questions!

Regards, Remco

p.s. One surprise when I turned over the main PCB:

Nice silver mica caps over the already very good Mundorf Mcap Supreme Silver/ Gold!

 

[bonzo75]

At Bill’s, experimenting with Audio Detail GM70 and 300b and comparing to existing 801a amp. The 70 was excellent, very transparent and gets the musical lines with letting out just flow. those who listen to my also heard this on recent hORNs universum videos



Dava on the horning SATI Dynavector arm, vdh master strad on SME V on a TD160 that Bill put a wooden plinth on.

the white horn colour integrates very well with the light floor and light wall colour and the glass door

 

[the sound of Tao]

At Bill’s, experimenting with Audio Detail GM70 and 300b and comparing to existing 801a amp. The 70 was excellent, very transparent and gets the musical lines with letting out just flow. those who listen to my also heard this on recent hORNs universum videos View attachment 104000

View attachment 103999

Dava on the horning SATI Dynavector arm, vdh master strad on SME V on a TD160 that Bill put a wooden plinth on.

the white horn colour integrates very well with the light floor and light wall colour and the glass door

View attachment 104001

Typically inspiring stuff from Bill, that’s awesome thanks Ked…

 

[Argonaut]

Bill could’t hold you off any longer then Ked … Audio vids ?

 

[marslo]

Before I switch to the upgraded Circle Labs A100 here is my Crossfire III SET , Archie Shepp , vinyl from SteepleChase recording studio.
Ked said this one sounds good so I am bit more keen to post it here
No hocus-pocus, just simple Iphone 12 mini .

 

[morricab]

Before I switch to the upgraded Circle Labs A100 here is my Crossfire III SET , Archie Shepp , vinyl from SteepleChase recording studio.
Ked said this one sounds good so I am bit more keen to post it here
No hocus-pocus, just simple Iphone 12 mini .

Cool.

 

[morricab]

At Bill’s, experimenting with Audio Detail GM70 and 300b and comparing to existing 801a amp. The 70 was excellent, very transparent and gets the musical lines with letting out just flow. those who listen to my also heard this on recent hORNs universum videos View attachment 104000

View attachment 103999

Dava on the horning SATI Dynavector arm, vdh master strad on SME V on a TD160 that Bill put a wooden plinth on.

the white horn colour integrates very well with the light floor and light wall colour and the glass door

View attachment 104001

And the 300B amps?