If anyone has a link to the relevant DIYaudio page, I'd greatly appreciate it.
SETs and Horns
- Thread starter Al M.
- Start date
For anyone else interested in tracking down the information, here's a link to Peter's posts over on diyA: https://www.diyaudio.com/forums/members/petavgeris.html
Hi,
I am fond of both 45 and 46 tubes. It is obviously very tricky to draw a credible comparison without keeping many other important aspects constant, which I have not done. That being said, if you asked me to choose and explain my decision I would opt for 46 based on the fact that it is highly nuanced, lightning fast, and very expressive. As the other gentleman states on this thread - it just delivers music in a compelling way.
Clearly this is all moot if your system isn’t efficient enough to allow the use of such low power.
From what I can see it can make double the power of the type 45. And it doesn't need as high plate load in the output transformer to make its power, so the output transformer can have more bandwidth owing to lower distributed capacitance.
Yeah I believe it can be run in a higher power configuration but the way I have it in my Mayer amps it produces a whopping 1.25 watts only. I have only seen one other 46 amp but that was also running just over 1 watts.
So ever so slightly less than double the power. But at that power level, that's still significant. I think there are other similar tubes, like the 6A4, which is a pentode with its suppressor grid tied to the center of the filament as it is directly heated.
Have you ever considered using something like a 6BL7 or 6BX7? They would make about the same power, and you could use just one for stereo if you are uncomfortable with the idea of paralleled sections. They have a really nice family of curves looking very similar to that of the 45. It has the advantage of being indirectly heated, which can help with circuit design in a number of ways. I know this might be considered blasphemy by some but the linearity of the tube is more important than where its directly or indirectly heated. The reason DHTs are so revered is that many of them have very good linearity.
I you're playing around with tubes like this, I have a box of prewar audio tubes that would love a good home.
Hi!
In single ended operation you can't get more power from a 46 than from a 45. 1.25 is about the max which can be achieved. It also requires a higher plate impedance than the 45. So is more demanding on the output transformer
Very nice tubes indeed and also very linear. But I yet have to see a indirectly heated tube which can really match a DHT in linearity. I do use IDHTs and yes they simplify circuit design, but the DHTs are just a notch better and are the only choice for me in the top amps. It is worth the extra circuit complexity needed for the filament supplies to get them totally quiet
Stevie Bench ran some interesting measurements years ago which showed that the amplification factor remains more constant in DHT as in IDHTs. The latter showed a slight compression effect while the DHTS mu remained constant with signal amplitude. Stevie was the first to analyse this AFAIK. Interestingly the thoriated tungsten filament tubes were best in that regard, followed by oxide coated DHTs and then indirectly heated tubes. Kind of matches what I hear.
No using IDHTs is not blasphemy. This has nothing to do with religious beliefs but experience. I am happy to use IDHTs and they have their place. For example I used a lot of 6CB5As TV tubes in amplifiers as output tube. But it is a compromise IMHO and my best amps only use DHTs, also as driver.
All just IME and YMMV
Thomas
In single ended operation you can't get more power from a 46 than from a 45. 1.25 is about the max which can be achieved. It also requires a higher plate impedance than the 45. So is more demanding on the output transformer
Very nice tubes indeed and also very linear. But I yet have to see a indirectly heated tube which can really match a DHT in linearity. I do use IDHTs and yes they simplify circuit design, but the DHTs are just a notch better and are the only choice for me in the top amps. It is worth the extra circuit complexity needed for the filament supplies to get them totally quiet
Stevie Bench ran some interesting measurements years ago which showed that the amplification factor remains more constant in DHT as in IDHTs. The latter showed a slight compression effect while the DHTS mu remained constant with signal amplitude. Stevie was the first to analyse this AFAIK. Interestingly the thoriated tungsten filament tubes were best in that regard, followed by oxide coated DHTs and then indirectly heated tubes. Kind of matches what I hear.
No using IDHTs is not blasphemy. This has nothing to do with religious beliefs but experience. I am happy to use IDHTs and they have their place. For example I used a lot of 6CB5As TV tubes in amplifiers as output tube. But it is a compromise IMHO and my best amps only use DHTs, also as driver.
All just IME and YMMV
Thomas
Why do the curves not reflect that?
I was unaware that you made IDHTs. We asked you about making one about a year and a half ago and it sounded like that was not possible.
I don't *make* IDHTs. I use IDHTs in some of my amplifiers (separate company) In the tube factory I only make directly heated triodes and rectifiers
Thomas
See attached excerpts from GE data sheets. One shows a DHT. See the ruler straight curve for the mu. This is a 842. The other is the 6BL7 see how the mu varies. Unfortunately they started late to include this curve
Attachments
If I am to choose a low power tube for an audio amplifier, among the classic tube variants, I would definitely go for 45. I am not experienced at all with 46, so I can't comment on this. As soon as Bill declares his preference, I cannot comment on this,logically it has many pros.
I had played with 45 12-13 years ago. It was my favorite. My favorite piece among audio tubes, before migrating to the transmitters' sound. Since I crossed the forbidden territories of 801 and then vt-25, I never came back. My last step was (and still is) RS241, a truly amazing tube. And of course the British variant of 834, named STC 4304, along with the UFO 316a.
In my opinion, these tubes are the best sounding valves ever made. They have somewhat higher distortion but their sound is so dynamic, glossy and thrilling that you forget everything else. And of course combined with mercury vapor rectifiers and tube rectified filaments, with Tungar bulbs.
I am now designing my new loudspeakers from scratch, field coiled of course, powered with mercury vapor tubes. I will report as soon as I have reached a good point of progress.
I had played with 45 12-13 years ago. It was my favorite. My favorite piece among audio tubes, before migrating to the transmitters' sound. Since I crossed the forbidden territories of 801 and then vt-25, I never came back. My last step was (and still is) RS241, a truly amazing tube. And of course the British variant of 834, named STC 4304, along with the UFO 316a.
In my opinion, these tubes are the best sounding valves ever made. They have somewhat higher distortion but their sound is so dynamic, glossy and thrilling that you forget everything else. And of course combined with mercury vapor rectifiers and tube rectified filaments, with Tungar bulbs.
I am now designing my new loudspeakers from scratch, field coiled of course, powered with mercury vapor tubes. I will report as soon as I have reached a good point of progress.
(Edit. Getting my second vaccination shot in two weeks... and then) Going to hear a pair of Avantguarde Duo XDs next month, and then the Sadurni Staccatos in June. Looking forward to seeing whether either hits all the right notes and allows for the pursuit of a low power SET. Currently leaning towards the 46 if that does happen.
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I have some experience with Thomas amplifiers, though not with the specific one equipped with these 46 tubes. These amps are among the best machines or there for sure. Don't consider my words as a praise for Thomas amps, I never do so. If they were bad sounding, I would openly comment against them, some folks around know me quite well...
But I can't tell the same for Avant-garde speakers. Mainly for one reason. They just don't do justice to the amplifiers. We need speakers that are open to the amplification units, transparent and with lack of this 'horny' coloration. If you want to experience what these amplifiers are really capable of, you need different speakers for sure,no question about it.
But I can't tell the same for Avant-garde speakers. Mainly for one reason. They just don't do justice to the amplifiers. We need speakers that are open to the amplification units, transparent and with lack of this 'horny' coloration. If you want to experience what these amplifiers are really capable of, you need different speakers for sure,no question about it.
Could you pls explain what do you mean by "coloration " ?
400 Hz played by AGs is 400 Hz or something else ? How do you measure the "coloration" ?
Of course the material used for the construction of the driver and the speaker influence the way we perceive the music reproduced by this specific speaker. When one Iisten to the same music reproduced by Wilsons, Magicos , Cessaros, Accapella, AGs with even the same amp and the source - synergy aside- they all sound different . All of them reproduce the music with a specific " colour " , but which one is the "right" one ? Does it really exist ?
Or is it just a matter of personal preference ?
400 Hz played by AGs is 400 Hz or something else ? How do you measure the "coloration" ?
Of course the material used for the construction of the driver and the speaker influence the way we perceive the music reproduced by this specific speaker. When one Iisten to the same music reproduced by Wilsons, Magicos , Cessaros, Accapella, AGs with even the same amp and the source - synergy aside- they all sound different . All of them reproduce the music with a specific " colour " , but which one is the "right" one ? Does it really exist ?
Or is it just a matter of personal preference ?
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I suppose one's choice is by definition a personal preference. While different components and systems will sound different I don't believe there is one that is singularly "right" - just as there is no singular performance of Beethoven's 6th Symphony that is the right performance - there is no one true example that is right.
If you have no goal or intent then it can be whatever strikes your fancy on any given day. And that's fine for some people. However if you have a reference against which you are assessing, then the "right one" may be a function of that - how close to your reference is what you hear from what you have?
If your reference is the sound of live acoustic music how similar is your sound to that? Granted that reproduction wil be distinquishable, how close does your system's sound get to your reference? Different systems can come closer or further. Two different systems can be credibly natural and still sound different.
While there may not be a singular example of a performance of Beethoven's 6th that is the right performance, that, imo, doesn't mean its all subjective. After all, there is a score, the most basic reference. Maybe not the best way to say this but think of a performance as an implementation of a score. Some are better than others. Is it different for reproduction?
I am not looking for the reproduction closest to the live music because I assume that in reality that is not possbile .
Instead, I select the equipment which make possible to feel the same emotions as during live performance. Our preferences come from education, experience and probably even from our genes.
And some speakers present better small jazz trios, some reproduce very well human voices and others big scale symphonic orchestra .
I may like all of them whilst they are different . I do not strive for the one 'best of the best' but 'good enough' gear because I have more modest and realistic expectations. I am willing to accept some downsides as long as the general presentation gives me the touch of the music I like.
For example I like my Trios ( very good for Beethoven or Mahler btw ) but in the same time I like my second system with PS 5.1 - 27 years old monitors ( perfect for small jazz trios and human voices ) . I was impressed by big Wilsons , Acapellas , cabinet size Kawero and even small Reimyo monitors - among others.
Instead, I select the equipment which make possible to feel the same emotions as during live performance. Our preferences come from education, experience and probably even from our genes.
And some speakers present better small jazz trios, some reproduce very well human voices and others big scale symphonic orchestra .
I may like all of them whilst they are different . I do not strive for the one 'best of the best' but 'good enough' gear because I have more modest and realistic expectations. I am willing to accept some downsides as long as the general presentation gives me the touch of the music I like.
For example I like my Trios ( very good for Beethoven or Mahler btw ) but in the same time I like my second system with PS 5.1 - 27 years old monitors ( perfect for small jazz trios and human voices ) . I was impressed by big Wilsons , Acapellas , cabinet size Kawero and even small Reimyo monitors - among others.
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Speaker color is one thing, lack of coherence, bad alignment between different drivers, boom boom bass, volume mismatch between highs and lows, and lack of tone is another. I am referring to some of the speakers mentioned in your list
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