SET amp owners thread

[Amir]

I believe this debate (debate of A vs B or which sound is better) never ends but there is a simple method that can help.

I invited some audiophiles to my showroom and they listened to two transports :
1- CEC TL0 Transport
2- TAD D600 Transport

The DAC was TAD D600, the digital cable was Acrolink 6300 between CEC and TAD.

50% of listeners preferred TAD Transport for more organic sound. TAD was more natural more beautiful more velvet texture more lovely sound for long term listening, more image depth.
In short listeners believe the TAD was more musical.

50% of listeners preferred CEC transport for more dimensional sound, more image height, better bass, better pace and more separation in complex music.
In short listeners believe the CEC was more accurate/real.

This is an example of A vs B debate in audio and I think these debates never ends between audiophiles. More than 1000 posts are here about natural sound of David but those who are against this idea did not accept it yet.

I think audiophiles could not convince each other because of different taste. Group A prefer TAD and Group B prefer CEC. Which group idea is right?

I think the key is finding a proper method for judgment.

My solution is :

Step one : Sound analysis method
In step one you should ignore your taste and just check which sound/component shows more contrast.

Are You On The Road To... Audio Hell? Article By Leonard Norwitz And Peter Qvortrup

Are You On The Road To... Audio Hell? Article By Leonard Norwitz And Peter Qvortrup

www.enjoythemusic.com

Better audio component shows more contrast between different records.

Step two : Music Enjoyment
In step two again you should 100% forget the sound and put 100% of your focus on music listening enjoyment.
This process takes more time because your brain needs time to fully ignore effects of sound on your judgment. More music enjoyment more music expression means better audio.
Romy has videos about this topic and describe why musical expression is important.

 

[bonzo75]

Hi this is not a subject for SET amps owners thread. Please move CEC TAD CD to a digital thread and the David K posts to Peter’s thread or American sound threads, lamm discussions fit into the subject of this thread.

 

[Rob181]

I already have SET on my secondary system. I have now swapped to SET on my main system as well with the Phasemation MA-5000 which should be delivered in a few weeks time. 2 X 45 Watts which are plenty enough for my efficient Stenheim Reference Ultime Two.

View attachment 149429

For the time being, I have their little brothers MA-2000 on loan. Together with the CSPort GM70PA, they are on my short list for replacing the LM-805 IA in my secondary system.

View attachment 149430

I am really looking forward to hearing your thoughts on the CS Port GM70PA....

 

[morricab]

I am really looking forward to hearing your thoughts on the CS Port GM70PA....

27 KG is pretty light weight for a GM70 amp. I have a 2A3 amp that weighs more. My precious GM70 amp from Amplifon was more than double this weight. Makes me skeptical about power bandwidth if OPTs are too small.

 

[bonzo75]

27 KG is pretty light weight for a GM70 amp. I have a 2A3 amp that weighs more. My precious GM70 amp from Amplifon was more than double this weight. Makes me skeptical about power bandwidth if OPTs are too small.

If it has in interstage transformer it will be heavier than cap coupled, does not necessarily mean better

 

[mtemur]

I have now swapped to SET on my main system as well with the Phasemation MA-5000 which should be delivered in a few weeks time. 2 X 45 Watts which are plenty enough for my efficient Stenheim Reference Ultime Two.

Very nice-sounding amplifiers — congratulations! I’m pretty confident they will drive the Stenheim Reference Two very well, since they already performed great with 50 SET watts. They’re a relatively easy load in my opinion; I’ve also heard them sounding good with 20-watt push-pull amps. The only downside is that they’re very expensive for pro drivers and aluminum blocks.

 

[dcc]

I had the demo pair for 8 days in my system and indeed they drive the Stenheim Reference Ultime Two with ease. I currently drive them with the 25 watts MA-2000 that I have on loan without any problem.

 

[Lagonda]

I had the demo pair for 8 days in my system and indeed they drive the Stenheim Reference Ultime Two with ease. I currently drive them with the 25 watts MA-2000 that I have on loan without any problem.

Are you going to bi-amp like you did in your previous system ? Or just one mono amp per side ?

 

[dcc]

No bi-amping anymore. The Stenheim don't need a lot of power.

 

[Rob181]

27 KG is pretty light weight for a GM70 amp. I have a 2A3 amp that weighs more. My precious GM70 amp from Amplifon was more than double this weight. Makes me skeptical about power bandwidth if OPTs are too small.

CS Port make excellent equipment & quality Japanese Hi Fi equipment producers generally don't stuff up tube based products...

 

[morricab]

CS Port make excellent equipment & quality Japanese Hi Fi equipment producers generally don't stuff up tube based products...

I just know what high powered SETs require to have clean bass. Aries Cerat Diana has 18kg output transformers…that’s 36kg just for the OPTs! Compare to 27 kg for the whole CSPort amp…

 

[bonzo75]

I just know what high powered SETs require to have clean bass. Aries Cerat Diana has 18kg output transformers…that’s 36kg just for the OPTs! Compare to 27 kg for the whole CSPort amp…

Dcc has had a lot of AC exposure as he lives nearby flyer who was a distributor

 

[mtemur]

I just know what high powered SETs require to have clean bass. Aries Cerat Diana has 18kg output transformers…that’s 36kg just for the OPTs! Compare to 27 kg for the whole CSPort amp…

I don’t know many things about output transformers but I know tightly wound, compact transformers are better compared to loosely wound, big ones. The goal is to concentrate magnetic flux in a small area. In OPT world being bigger doesn’t mean being better. Of course OPTs you mentioned might have been wound tightly while also being huge.

 

[Atmasphere]

Isn’t negative feedback unnatural?

No!

Improper application of feedback is!

Most amps in the last 60 years got this bit wrong, as the feedback is applied to a non-linear node, such as the cathode of a tube or the base of a transistor in a differential pair. Since the device is non-linear, the feedback is distorted before it can do its job and so adds higher ordered harmonics (unpleasant to the ear) and intermodulations (also unpleasant to the ear). The solution is actually simple: don't do that; instead apply the feedback in the same manner as seen in opamps, where the audio is mixed with the feedback in a resistive divider network (which is far more linear than any active device) instead.

Many here probably know that solid state amps and opamps share a lot of topology but this is one of the ways in which they differ.

Obviously in both the case of the tube amp or solid state you must have a provision to make sure the phase of the feedback signal is correct.

In a tube amp the feedback is applied to the grid of the input tube rather than its cathode. The impedances of the feedback loop will be much higher since the input impedance of the amplifier is much higher.

Yes, as I wrote above this is one of David's maxims. It makes some sense to me. My quibble with Peter was that it does not mean everything else automatically falls into place, if something else is unbalanced or emphasized or unnatural.

When David's disciples repeat any of his maxims I think it's appropriate to give David credit for the point -- as you are doing here -- and not allow it to seem like it is original thinking.

As I mentioned in my comment that started this, the ear has a sort of tone control built in. If bass is lacking, treble is emphasized. If too much bass, the treble sounds muddy or rolled off. So its important to get everything right. This is why I'm a big fan of Distributed Bass Arrays, since getting the bass right in most rooms is the biggest challenge, and if the room has regular dimensions, standing waves can cancel bass notes at certain frequencies and locations (such as the listening position) in the room. A Distributed Bass Array can break up standing waves (something you can do with DSP room correction) allowing you to get the bass right anywhere in the room.

Yup agree , the nature of its implementation into some circuit topologies can be used to benefit integrity of the signal , Interestingly PYE introduced an interesting design feature Into their PF91 back in the early 50’s by the provision of adjustable positive feedback (in addition to the main negative feedback) in order that the effective output impedance may be reduced to zero to improve loudspeaker damping.

That said however … for my part negative feedback has a questionable place within a Purist SET circuit application .

Actually rather than positive feedback, what was happening in that amp (as well as a few others) is it employed current feedback (which raises output impedance) as well as Voltage feedback (which reduces it). By adding a control that varied one vs the other, the output impedance could be varied so the exact damping for a given speaker could be achieved. But that introduced a set up variable; to enhance plug and play, MacIntosh and ElectroVoice introduced the idea of using enough feedback to allow the amp to behave as a Voltage source and then have speakers designed to expect this kind of 'Voltage drive'. At that point the amps with a 'Damping control' went away.

. The whole point of SET is being purist, avoiding the alleged problem of crossover distortion (which, as Ralph would argue, isn't one).

Correct! You can have a class B amp that has no hint of crossover distortion (ElectroVoice made such amps in the 1950s), and most class D amps are immune to that too. IOW that is not a property unique to SETs.

When an amplifier cannot properly control a bass driver, it can sometimes be mistaken for greater bass extension because the driver continues to move

That's just simply a low damping factor and is independent of bass response.

I'm a huge fan of Lamm electronics, so I think Lamm would likely be amazing on any appropriate sensitivity and appropriate impedance speaker.

Its Ok but you can find low power PP class A amps that can do better on those speakers, while doing just as well in the mids and highs.

Is the Karma Exquisite "appropriate sensitivity and appropriate impedance"?

No. The impedance is too low along with the efficiency and the phase angles too obtuse.

 

[dcc]

I just know what high powered SETs require to have clean bass. Aries Cerat Diana has 18kg output transformers…that’s 36kg just for the OPTs! Compare to 27 kg for the whole CSPort amp…

I had the chance to listen to the CSPort GM70 and its matching preamp in my secondary system about 18 months ago and I was highly impressed. CSPort is using switched mode power supplies as its founder is the former CEO of COSEL, a leader in that field. I would like to test the CSPort against the Phasemation MA-2000 in a near future.

Compared to Aries Cerat which has always sounded too coloured for my taste, I would take the CSPort any day. I don't give a damn about the sheer weight and the bulky enclosures. And believe me that I had my fair share of listening sessions of Aries Cerat gear as the former distributor for my country is a very close friend.

 

[morricab]

I don’t know many things about output transformers but I know tightly wound, compact transformers are better compared to loosely wound, big ones. The goal is to concentrate magnetic flux in a small area. In OPT world being bigger doesn’t mean being better. Of course OPTs you mentioned might have been wound tightly while also being huge.

Without sufficient iron you will get saturation in a SET for bass frequencies…this is because of the high standing DC current passing through it at all times. Winding affects how extended the bandwidth of the transformer is in the high frequencies. AC transformers use a very sophisticated winding to give wide bandwidth and a lot of iron for superior bass response. If your transformer saturates you will have a poorly controlled bass because distortion will be high.

 

[morricab]

I had the chance to listen to the CSPort GM70 and its matching preamp in my secondary system about 18 months ago and I was highly impressed. CSPort is using switched mode power supplies as its founder is the former CEO of COSEL, a leader in that field. I would like to test the CSPort against the Phasemation MA-2000 in a near future.

Compared to Aries Cerat which has always sounded too coloured for my taste, I would take the CSPort any day. I don't give a damn about the sheer weight and the bulky enclosures. And believe me that I had my fair share of listening sessions of Aries Cerat gear as the former distributor for my country is a very close friend.

AC too colored? They are probably the lowest distortion SET in existence…including ones using negative feedback. As someone who has owned a whole bunch of SETs and heard at length many many more (from friends who are SET owners) I can’t agree with your assessment. I haven’t heard the CSPort and for sure some of the weight reduction is the use of switch mode power supplies, but I am skeptical when I see a SET this light with this power output, knowing what is required for good bass from a SET.
I have a fantastic sounding 2A3 SET from Silvercore that weighs over 30kg to make 3.5 watts. On 98dB Horning speakers it sounds incredible with punchy tight bass. However, it’s not trying to make 30 watts.

 

[Argonaut]

AC too colored? They are probably the lowest distortion SET in existence…including ones using negative feedback. As someone who has owned a whole bunch of SETs and heard at length many many more (from friends who are SET owners) I can’t agree with your assessment.

I must say that this comment raised an eyebrow ( Roger Moore Styleee) , As I have yet to come across AC SET ‘s as being considered “coloured” before on any of the forums that I visit … Until now , In fact quite the opposite , in that a few 300B , 2A3 , 10Y , 45 , etcetera aficionados have found them a little too linear and ‘clean’ for their taste …. And I appreciate both viewpoints and own a number of SET amplifiers that cover the gambit from coloured / warm / saturated midband …. To more linear / accurate to source / less forgiving of poor recordings .

 

[dcc]

Making statements without having listened to the gear is not the way I contribute to WBF. And I stand by my word regarding Aries Cerat. I had plenty opportunities to acquire gear from them and never wanted to. Case closed.

 

[Argonaut]

You are on a different path , No worries , Bona fortuna, I am sure that the owner/designer of AC is not loosing any sleep at night wondering !

Likewise I have no knowledge or personal experience of CSPort front end electronics by way of comparison with AC so cannot comment , other than the apparent build quality , and circuit design ethos which I quite like , and that were one to have found a SET noticeably less “coloured” than AC one might as well go SS and not bother with valves at all.

Perhaps I will have the opportunity to hear their amplification at Munich this year .