SET amp owners thread

[morricab]

If they had a facepalm emoji I'd use that.

So it doesn't matter to you when I say that Soundstage grounded a speaker terminal, so got incorrect results?

How that can happen is if you apply a sine wave from a signal generator, and that signal generator is grounded by its AC cord, and then you connect a distortion analyzer at the output which is also grounded, unless you take care using a differential probe or isolation transformer, as soon as you connect the analyzer, one speaker terminal will be at ground. I explained what happens earlier.

Do you not read what I write or do you choose to ignore it?

No, it doesn't matter what you say now. What you said then was...nothing, which indicates you didn't have an issue with the measurements at the time they were made. Where is the manufacturer's response? Also, it is the only independently published set of measurements that is available on the internet for one of your amps.

So, I did not ignore you but I disregard what you say because it contradicts the facts available.

 

[Atmasphere]

No, it doesn't matter what you say now. What you said then was...nothing, which indicates you didn't have an issue with the measurements at the time they were made. Where is the manufacturer's response? Also, it is the only independently published set of measurements that is available on the internet for one of your amps.

So, I did not ignore you but I disregard what you say because it contradicts the facts available.

Its not the only published set of measurements as I said earlier. I didn't figure out what had happened until we got the amps back.

Apparently you don't allow me credibility and your 'technical' posts either as they are either sniping, trolling or complete red herrings.

I hate to do this, but since you refuse to read or use logic, reason or those sorts of things, since this is about you trying to make me wrong any way you can, you're now on ignore too. If at some point you finally see reason, we are both active on other forums, if you wish to apologize I'm open to it, as I''m not taking this personally other than the complete waste of time.

 

[Solypsa]

I am guessing this little sub topic is losing steam.

If it is to be continued, imho, we need to look at ( pictures of ) real measurements of distortion from real, specific, and relevant amps of each type. ( SET, PP, OTL; high quality and not kits or vintage stuff ). Doesn't have to be an amp manufactured by any of the participants if that eases the conversation.

What that data ' means ' can of course be debated but at least there is a set of data that can form a concrete basis for the debate...

My 2c.

 

[christoph]

Guys!
Pretty please, with sugar on top, take this conversation somewhere else!

I opened a dedicated thread for you:

What are the advantages/disadvantages of different amp topologies?

Hi Guys Please carry on with your interesting discussion here in this dedicated thread and NOT in the SET-owners thread. Knock yourselves out.

www.whatsbestforum.com

This thread is about SET-owners and nothing else.

 

[morricab]

Guys!
Pretty please, with sugar on top, take this conversation somewhere else!

I opened a dedicated thread for you:

What are the advantages/disadvantages of different amp topologies?

Hi Guys Please carry on with your interesting discussion here in this dedicated thread and NOT in the SET-owners thread. Knock yourselves out.

www.whatsbestforum.com

This thread is about SET-owners and nothing else.

Couldn't carry on...even if we wanted to...Atmasphere ignored everyone who owns a SET .

Anyway, it will always be a source of discussion why people like the sound of SET despite it's obvious objectively worse performance...I see nothing wrong debating that on this thread, but I agree that discussion was going nowhere.

 

[Atmasphere]

Guys!
Pretty please, with sugar on top, take this conversation somewhere else!

I opened a dedicated thread for you:

What are the advantages/disadvantages of different amp topologies?

Hi Guys Please carry on with your interesting discussion here in this dedicated thread and NOT in the SET-owners thread. Knock yourselves out.

www.whatsbestforum.com

This thread is about SET-owners and nothing else.

Sorry- I had thought it was about SETs and not their owners.

Since I have put the ones who really aggravated this conversation on ignore, its not likely to continue on this thread FWIW. Also FWIW I am an SET owner.

 

[acousticsguru]

Couldn't carry on...even if we wanted to...Atmasphere ignored everyone who owns a SET .

Anyway, it will always be a source of discussion why people like the sound of SET despite it's obvious objectively worse performance...I see nothing wrong debating that on this thread, but I agree that discussion was going nowhere.

My understanding of tube amplification is limited, but my gut instinct says I'm hearing the same (or similar) as with loudspeaker drivers: timbral qualities. There are drivers that objectively show lesser distortion, lower dynamic compression, faster settling times etc., but once one uses a magnifying glass (measuring equipment), it often turns out the seemingly negligible distortion they have is of the nastiest sort (e.g. metal and other hard material breakup), whereas drivers built using e.g. cone materials one can knock on and that make a pleasant sound tend to have a benign behavior and sonic characteristics that may be only marginally less "revealing", yet cause no listening fatigue (major pet peeve: in particular for classical music aficionados, longterm listening "side" effects are key). Grossly generalizing, of course, as I could compile a near endless list myself to try and prove the contrary, but it's been my impression for decades now, that what "little remains" may have greater impact qualitatively than quantitatively, in particular as we're often looking at decimal digits after the comma. Nothing new and revolutionary, just rambling thoughts…

Greetings from Switzerland, David.

 

[matsurus]

My understanding of tube amplification is limited, but my gut instinct says I'm hearing the same (or similar) as with loudspeaker drivers: timbral qualities. There are drivers that objectively show lesser distortion, lower dynamic compression, faster settling times etc., but once one uses a magnifying glass (measuring equipment), it often turns out the seemingly negligible distortion they have is of the nastiest sort (e.g. metal and other hard material breakup), whereas drivers built using e.g. cone materials one can knock on and that make a pleasant sound tend to have a benign behavior and sonic characteristics that may be only marginally less "revealing", yet cause no listening fatigue (major pet peeve: in particular for classical music aficionados, longterm listening "side" effects are key). Grossly generalizing, of course, as I could compile a near endless list myself to try and prove the contrary, but it's been my impression for decades now, that what "little remains" may have greater impact qualitatively than quantitatively, in particular as we're often looking at decimal digits after the comma. Nothing new and revolutionary, just rambling thoughts…

Greetings from Switzerland, David.

I have same experience with beryllium and other metal drivers, they can be made more ear friendly but it need a lot more "tricks" (progressively dampening listening room, oil caps crossover, 2-3db minus slope on hearing problem regions, downhill sloping fr, higher crossover 3 or 4th, etc..) in order to achieve this, compared to softer materials.

 

[acousticsguru]

I have same experience with beryllium and other metal drivers, they can be made more ear friendly but it need a lot more "tricks" (progressively dampening listening room, oil caps crossover, 2-3db minus slope on hearing problem regions, downhill sloping fr, higher crossover 3 or 4th, etc..) in order to achieve this, compared to softer materials.

Cone materials are fascinating. There are compression drivers in which membranes hardly move, but where diaphragms can be swapped out (e.g. mylar, aluminum, titanium and beryllium) and I find it flabbergasting how the sound changes from plasticky to perky (if not slightly nasty) to slightly soft and sometimes diffuse yet pleasant. Once one starts checking frequency response and decay, it turns out that the seemingly greater treble extension of the former only appears to be that - the upper range may be entirely filled in with breakup modes/distortion, begging the question if the apparent “softness” of the latter is at all a function of beryllium itself, or simply the tru(er) character of the respective horn. Anyway, my point was that materials do have their sound, it’s undeniable, and yes of course a good designer is going try and compensate for this, as the end result (to me anyways) is to build a coherent speaker, and not one with attributes, however pleasant these may be. Loudspeaker building is where I know my way best, so as not to be off-topic, overall coherence and timbral accuracy is what I look for in all audio gear, hopefully coupled to dynamics, liveliness, bandwidth, musicality and a lack of listening fatigue. I basically don’t like anything that’ll stick out like a sore thumb over time, doesn’t matter whether good or bad, it detracts from the musical experience.

Greetings from Switzerland, David.

 

[acousticsguru]

Needless to say, the old phrase “to err on the[…] side” (take your pick among positive attributes) applies to audio as to all imperfection (life itself?) - and this to me applies to SET perhaps more than anything else in audio. Of the three I currently have, one sounds overtly tubey, one noticeably, and the third sounds just right, so much so that after over two years and almost a thousand hours of attentive listening (I don’t like background music), there’s still nothing in particular garnering my attention other than the music itself.

Greetings from Switzerland, David.

 

[WBF Team]

On behalf of the Moderator Team, I'd like to inform you that any further off-topic postings in this thread will be deleted without notice.

Please carry on with your discussion about amp topologies in the thread that was opened for this purpose:

What are the advantages/disadvantages of different amp topologies?

Hi Guys Please carry on with your interesting discussion here in this dedicated thread and NOT in the SET-owners thread. Knock yourselves out.

www.whatsbestforum.com

 

[Atmasphere]

My understanding of tube amplification is limited, but my gut instinct says I'm hearing the same (or similar) as with loudspeaker drivers: timbral qualities. There are drivers that objectively show lesser distortion, lower dynamic compression, faster settling times etc., but once one uses a magnifying glass (measuring equipment), it often turns out the seemingly negligible distortion they have is of the nastiest sort (e.g. metal and other hard material breakup), whereas drivers built using e.g. cone materials one can knock on and that make a pleasant sound tend to have a benign behavior and sonic characteristics that may be only marginally less "revealing", yet cause no listening fatigue (major pet peeve: in particular for classical music aficionados, longterm listening "side" effects are key). Grossly generalizing, of course, as I could compile a near endless list myself to try and prove the contrary, but it's been my impression for decades now, that what "little remains" may have greater impact qualitatively than quantitatively, in particular as we're often looking at decimal digits after the comma. Nothing new and revolutionary, just rambling thoughts…

Greetings from Switzerland, David.

When I play my SETs, I play them on my Classic Audio Loudspeakers T3.3s, which employ beryllium diaphragms in the midrange. The first breakup is at about 35KHz so the driver is both fast and smooth. It also has a Kapton surround suspension, which helps prevent breakups due to out of band low frequency information messing with it otherwise.

The CALs aren't really efficient enough (98dB) to work with the type 45 SETs I have (nor will they really be enough for the 300b amps I'm building up), but as long as its not over conversational levels they work alright. CAL makes a Heartsfield reproduction which is more in the ball part at 105dB, and uses the same diaphragm.

 

[bonzo75]

When I play my SETs, I play them on my Classic Audio Loudspeakers T3.3s, which employ beryllium diaphragms in the midrange. The first breakup is at about 35KHz so the driver is both fast and smooth. It also has a Kapton surround suspension, which helps prevent breakups due to out of band low frequency information messing with it otherwise.

The CALs aren't really efficient enough (98dB) to work with the type 45 SETs I have (nor will they really be enough for the 300b amps I'm building up), but as long as its not over conversational levels they work alright. CAL makes a Heartsfield reproduction which is more in the ball part at 105dB, and uses the same diaphragm.

so if SETs are fine with classic audio, what’s the issue?

 

[morricab]

When I play my SETs, I play them on my Classic Audio Loudspeakers T3.3s, which employ beryllium diaphragms in the midrange. The first breakup is at about 35KHz so the driver is both fast and smooth. It also has a Kapton surround suspension, which helps prevent breakups due to out of band low frequency information messing with it otherwise.

The CALs aren't really efficient enough (98dB) to work with the type 45 SETs I have (nor will they really be enough for the 300b amps I'm building up), but as long as its not over conversational levels they work alright. CAL makes a Heartsfield reproduction which is more in the ball part at 105dB, and uses the same diaphragm.

With my 98dB speakers, my 2A3 amp, which is mid-way between a 45 and 300b in terms of power, it will play way above conversation level cleanly. Maybe you sit far away or your speakers are in a big room? If so, then i can imagine needing more power...or if you listen well above 100dB.

 

[Atmasphere]

so if SETs are fine with classic audio, what’s the issue?

The T-3.3's I have are flat to 20Hz; they sacrifice some efficiency for low frequency bandwidth. 98dB isn't enough for most SETs, since at that level in my space its nice to have 50-60 Watts. Even with the (Moth) 2A3 amps I had, you could hear how easily the OTLs I used to run had more bass extension and impact. The Heartsfields are too big for my space and don't go as low.

When there is a 6dB/octave rolloff, which most amps have at either end of their bandwidth, phase shift is introduced and extends to 10x the cutoff frequency (if in the bass) or to 1/10th the cutoff (-3dB) point if high frequencies. So if you cut off at 20Hz you have phase shift to 200Hz. In the bass the ear perceives this as a lack of impact. The ear is no good at individual tones of course, but over a spread of frequencies its a different matter. If there is a rolloff in the highs, say at 50KHz, phase shift will exist down to about 5KHz. This can be heard as a darkness or a slowness. It might not seem obvious but when you compare to an amp that lacks this kind of phase shift its easy to hear.

If the amp has no feedback, which is most SETs, then it can't compensate the phase shift. Now with most high efficiency speakers over 100dB, bass reproduction isn't good anyway (my old Altec corner horns with dual 15" horn-loaded woofers were only good to 60Hz when sitting in the corner of a room). So often SET OPT transformers are designed to get the highs right rather than the bass, since over about 7 Watts you have to make a decision about that. This is why the 2A3 was recognized as the natural successor to the 300b in the late 1990s and why the 45 ascended the throne a few years later. Its not because any of those tubes sounded better, its because the bandwidth issue of larger OPTs is easily heard, even if its not recognized outright as such since it manifests as phase shift. A 45 based SET has very nice wide bandwidth if it has a good OPT. But at 0.75Watts you might be limited to headphones to really hear what its about.

 

[DasguteOhr]

The T-3.3's I have are flat to 20Hz; they sacrifice some efficiency for low frequency bandwidth. 98dB isn't enough for most SETs, since at that level in my space its nice to have 50-60 Watts. Even with the (Moth) 2A3 amps I had, you could hear how easily the OTLs I used to run had more bass extension and impact. The Heartsfields are too big for my space and don't go as low.

When there is a 6dB/octave rolloff, which most amps have at either end of their bandwidth, phase shift is introduced and extends to 10x the cutoff frequency (if in the bass) or to 1/10th the cutoff (-3dB) point if high frequencies. So if you cut off at 20Hz you have phase shift to 200Hz. In the bass the ear perceives this as a lack of impact. The ear is no good at individual tones of course, but over a spread of frequencies its a different matter. If there is a rolloff in the highs, say at 50KHz, phase shift will exist down to about 5KHz. This can be heard as a darkness or a slowness. It might not seem obvious but when you compare to an amp that lacks this kind of phase shift its easy to hear.

If the amp has no feedback, which is most SETs, then it can't compensate the phase shift. Now with most high efficiency speakers over 100dB, bass reproduction isn't good anyway (my old Altec corner horns with dual 15" horn-loaded woofers were only good to 60Hz when sitting in the corner of a room). So often SET OPT transformers are designed to get the highs right rather than the bass, since over about 7 Watts you have to make a decision about that. This is why the 2A3 was recognized as the natural successor to the 300b in the late 1990s and why the 45 ascended the throne a few years later. Its not because any of those tubes sounded better, its because the bandwidth issue of larger OPTs is easily heard, even if its not recognized outright as such since it manifests as phase shift. A 45 based SET has very nice wide bandwidth if it has a good OPT. But at 0.75Watts you might be limited to headphones to really hear what its about.

Change your woofer of the altec with acoustic elegance td 15. In the same horn go easy 20hz lower. A other league of performance promise.

Acoustic Elegance TD15M high efficiency bass/midbass driver

The TD15M is designed for high efficiency bass/midbass applications. Featuring the Full Copper Faraday Sleeve (FCFS) for incredibly accurate reproduction.

aespeakers.com

 

[Atmasphere]

Change your woofer of the altec with acoustic elegance td 15. In the same horn go easy 20hz lower. A other league of performance promise.

Acoustic Elegance TD15M high efficiency bass/midbass driver

The TD15M is designed for high efficiency bass/midbass applications. Featuring the Full Copper Faraday Sleeve (FCFS) for incredibly accurate reproduction.

aespeakers.com

Yes- that would be nice if I still had them. I've heard there are lots of nice updates in that regard.

 

[Nutsfortubed]

Assemblage SET300B built by me.

 

[acousticsguru]

Assemblage SET300B built by me.

Wow, that seems to have been around forever - is the kit still available?

Greetings from Switzerland, David.

 

[Nutsfortubed]

Sadly no. I am in the process of saving to replace caps with Audio Notes.