SET amp owners thread

morricab

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96 db Brad. I play a lot of large scale music as well as smaller and have a largish space so for me reasonable headroom is important.

I’m planning on (post Covid if the world rights itself) putting together a horn OB with supravox woofers and BMS co-axial CD aimed at an early 100+ db efficiency so then will consider PX25 or 45 as full range amp option.
My Supravox/horn system is working on 11 watts (on Supravox) and 5 watts (horn) respectively. The horn could work on much less, the Supravox could perhaps be fine with mid-high single digits (8 watt 300B for example).
 
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the sound of Tao

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I have heard nice things about those amps, by someone i really trust.
Milan I’m loving mine. I have one LM set on the Harbeth 40.2s and the other on the Pap trio horns. I have Microzotl as preamps on both. Am so sold on these as they just do everything I musically want. The exploration into another amp to check out various low watt valves is just a function of having longevity in this hobby. The fact that I’m completely happy already points to an early end for me so I thought I could extend my usable life by giving myself another challenge :)

Everyone who currently uncovers nirvana is asking for a very early end... and that is such a very dangerous move in this current environment. Best to look quite unfinished with much more to discover atm otherwise you are just tempting fate to come visit.
 
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the sound of Tao

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My Supravox/horn system is working on 11 watts (on Supravox) and 5 watts (horn) respectively. The horn could work on much less, the Supravox could perhaps be fine with mid-high single digits (8 watt 300B for example).
What sensitivity do you figure your horns and woofer are approximately at Brad? I was thinking I’d double up on the 15 inch silver voice coiled supravox woofers which are @99db... or could go FLH and that would still get me in the ballpark I would like to be in a range between 102db or maybe up to near 105db approx. depending on configuration. Thinking 102db might be a nice balance in sensitivity and just not requiring impossibly quiet amps to make work as I don’t have the budget to play in that exalted amp league.
 
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morricab

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What sensitivity do you figure your horns and woofer are approximately at Brad? I was thinking I’d double up on the 15 inch silver voice coiled supravox woofers which are @99db... or could go FLH and that would still get me in the ballpark I would like to be in a range between 102db or maybe up to near 105db approx. depending on configuration. Thinking 102db might be a nice balance in sensitivity and just not requiring impossibly quiet amps to make work as I don’t have the budget to play in that exalted amp league.

The Supravox in TQWT loaded cabinet is rated at 99db. The horns are either 110db (big Beyma CP755Ti) or 105db (smaller CP350Ti). I adjust the volume at the amps (not digitally) as both amps are integrateds. So, overall system sensitive should be 99db or thereabouts.
 
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the sound of Tao

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The Supravox in TQWT loaded cabinet is rated at 99db. The horns are either 110db (big Beyma CP755Ti) or 105db (smaller CP350Ti). I adjust the volume at the amps (not digitally) as both amps are integrateds. So, overall system sensitive should be 99db or thereabouts.
That strikes me as near ideal. Somewhere around there is a good balance between options on valves and sensitivity to system noise.
 

Kingrex

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I'm not sure I fully understand headroom. I have never sat for a session with it, without, then with again to get the ahhhh, now I hear it. What I do know is Thomas with PAP told me the Whammerdyne 2A3 at 4.5 watts is as good as it gets at low volume. But, Thomas prefers 200 watt Pass monoblocks as they walk away from the Whammerdyne as the volume goes up. Ease, headroom, dynamics etc.

I guess I need to keep looking and reading.

If you dont mind Tao, I might PM you about the crossover. I don't see any way to modify the PAP crossover outside getting rid of it and wiring 2 completely independent crossover for biamping. Do you see something different.
 

morricab

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I'm not sure I fully understand headroom. I have never sat for a session with it, without, then with again to get the ahhhh, now I hear it. What I do know is Thomas with PAP told me the Whammerdyne 2A3 at 4.5 watts is as good as it gets at low volume. But, Thomas prefers 200 watt Pass monoblocks as they walk away from the Whammerdyne as the volume goes up. Ease, headroom, dynamics etc.

I guess I need to keep looking and reading.

If you dont mind Tao, I might PM you about the crossover. I don't see any way to modify the PAP crossover outside getting rid of it and wiring 2 completely independent crossover for biamping. Do you see something different.

There is an intesting article in Stereophile from Peter Van Willenswaard from maybe 20 years ago, showing how tube amps have significantly more dynamic power than SS amps and it seems that they can swing voltage much more freely without hard clipping. However, he wasn't sure from a physics explanation why it was the case. Of course once you reach the real limit of the amp it will start to clip/compress (tube amps start to compress in early clipping rather than a hard clip) it will sound like it is running out of dynamics (if the signal demands it get louder but it really can deliver more power then dynamics could get flattened.). I would take a whammerdyne at moderate levels over a 200 watt Pass any day of the week and twice on Sunday. The whammerdyne no doubt sounds far more lively and realistic at lower levels, where it is still within its deliverable power envelope, than the Pass, which to my ears sound relatively flat and lifeless compared to a good SET at moderate power delivery...particualrly the more powerful Pass amps.
 

morricab

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That strikes me as near ideal. Somewhere around there is a good balance between options on valves and sensitivity to system noise.
Yeah, interestingly, the noise on the EL84 amp is surprisingly modest given how high the horn sensitvity...the Mastersound EL34 SEP is quite a bit noisier...I will roll tubes in it to see if it just tired tubes...on the horn it was quite audible at the listening position.
 

Kingrex

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I would take a whammerdyne at moderate levels over a 200 watt Pass any day of the week and twice on Sunday. The whammerdyne no doubt sounds far more lively and realistic at lower levels, where it is still within its deliverable power envelope, than the Pass, which to my ears sound relatively flat and lifeless compared to a good SET at moderate power delivery...particualrly the more powerful Pass amps.[/QUOTE]

Fully agree. I just don't find the life I seek in SS amps.

I have had my fair share of ahh moments. If you look up RP6 Hot Rodded With Remote Mount Motor, you will see my Rega journey. When I bought the STST Motus II and did a direct swap. Everything stayed the same except my table changed. It was a jaw dropping experience. Same with my suite of Mojo Audio digital gear. I was stuck on Windows as my friend Alrainbow was so adamant it was better. I finally took the switch to the root ram Linux Mojo Audio advocated. Another holly mother of god, what an improvement.. Before I got my noisy Casablanca, I was using an equally noisy Altec 1570B modded by Transition Audio. The Altec is quite rich and thick. All full of nice bloom. But as soon as the Casablanca went in, I knew all the accuracy and nuanced tonality that makes an instrument sound real was missing in the Altec. Ultimately I want to find that happy medium. The place where the truth of the recorded instruments are captured and come to life. I want more body and depth to make the picture engaging in a relaxing manner. More than I am getting from the Pentode KT88 push pull. Not a sit and analyze. Just a sit and enjoy. I feel like this amp move is close to the end for me. The rest of my system is as good as I need it to get.
 
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bonzo75

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There is an intesting article in Stereophile from Peter Van Willenswaard from maybe 20 years ago, showing how tube amps have significantly more dynamic power than SS amps and it seems that they can swing voltage much more freely without hard clipping. However, he wasn't sure from a physics explanation why it was the case. Of course once you reach the real limit of the amp it will start to clip/compress (tube amps start to compress in early clipping rather than a hard clip) it will sound like it is running out of dynamics (if the signal demands it get louder but it really can deliver more power then dynamics could get flattened.). I would take a whammerdyne at moderate levels over a 200 watt Pass any day of the week and twice on Sunday. The whammerdyne no doubt sounds far more lively and realistic at lower levels, where it is still within its deliverable power envelope, than the Pass, which to my ears sound relatively flat and lifeless compared to a good SET at moderate power delivery...particualrly the more powerful Pass amps.

Putting SS amps into some high sensitivity woofers leads to bass roll off, if you damp it too much. These woofers have high damping and are best run with low watt tubes to get better bass
 
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Joao@altheamusica

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Putting SS amps into some high sensitivity woofers leads to bass roll off, if you damp it too much. These woofers have high damping and are best run with low watt tubes to get better bass

Please explain your comment, and once more I like to see a technical explanation
 

cjfrbw

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I think that if you could do the 200th watt as well as the first watt, Nelson Pass would never had spun off his First Watt enterprise to begin with. I think the summary caveat was 'current sharing' amongst multiple devices, which seems to impose some perceptible limit to sound quality. Of course, the first watt anthem is a much beaten dead horse, too.

The notion that a system should have massive power reserves to be able to capture the elusive, theoretical 120db transient with perfection, but sacrificing the quality of the majority of the signal, is a stubborn one, which seems to combine with the audiophile love of monster truck heavy metal and display.

Having a Lambo for a daily driver on city streets may be flashy, but you may look awkward putting the groceries in it.

My own recent experiences with the flea powered amps show me that they do, in fact, still have unique and desirable qualities that elude the big guys. Why, I don't know, they just hit that pleasure and involvement spot. Whether these are qualities you want every day in every way in the system is up to the individual, I suppose.
 

morricab

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I would take a whammerdyne at moderate levels over a 200 watt Pass any day of the week and twice on Sunday. The whammerdyne no doubt sounds far more lively and realistic at lower levels, where it is still within its deliverable power envelope, than the Pass, which to my ears sound relatively flat and lifeless compared to a good SET at moderate power delivery...particualrly the more powerful Pass amps.

Fully agree. I just don't find the life I seek in SS amps.

I have had my fair share of ahh moments. If you look up RP6 Hot Rodded With Remote Mount Motor, you will see my Rega journey. When I bought the STST Motus II and did a direct swap. Everything stayed the same except my table changed. It was a jaw dropping experience. Same with my suite of Mojo Audio digital gear. I was stuck on Windows as my friend Alrainbow was so adamant it was better. I finally took the switch to the root ram Linux Mojo Audio advocated. Another holly mother of god, what an improvement.. Before I got my noisy Casablanca, I was using an equally noisy Altec 1570B modded by Transition Audio. The Altec is quite rich and thick. All full of nice bloom. But as soon as the Casablanca went in, I knew all the accuracy and nuanced tonality that makes an instrument sound real was missing in the Altec. Ultimately I want to find that happy medium. The place where the truth of the recorded instruments are captured and come to life. I want more body and depth to make the picture engaging in a relaxing manner. More than I am getting from the Pentode KT88 push pull. Not a sit and analyze. Just a sit and enjoy. I feel like this amp move is close to the end for me. The rest of my system is as good as I need it to get.[/QUOTE]

Now get a good SET since you will be on the amp hunt again...

THat STST TT is an interesting one...I love DD done right!
 

bonzo75

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Please explain your comment, and once more I like to see a technical explanation

Woofers like Altecs, for example, do not do well with high damping. I understand from montesquieu and people experienced with Tannoy its the same...Tannoys need power, but not a high damping factor.

In the case of Altecs, every time there is an SS amp, I hear poor lower midbass and bass. The speaker seems choked. Leif also mentioned to me how he got better bass with his JBL woofers from his own 300b than from a Pass (I forget which one).

The technical reason that a person explained was the low QTS that leads to a highly damped woofer, does not do well with SS amps which have low output impedance. This results in the rolloff. They do better with low valves of higher output impedance. I am not a techie who measures, but my ears tell me that horns breathe bass best when driven with valve amps. There are certain woofers which will benefit from SS amps on the midbass front, as used with Trios. Lower bass active woofers will benefit from SS amps.
 

Exlibris

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Yes, I completely agree with this. Over more than 20 years of continuously having various 300B amplifiers in my amps rotation, I've tried every significant tube. Like overdosing your Manhattan with too much red vermouth so the vermouth steps on the whiskey, most of today's 300B tubes rewards a palate that likes a sweet, sticky midrange with a little bloat in the bass. Now I don't have any argument with someone who chooses that sound, knowing that's what they want and are getting. But if you are seeking more objective sound, with agile articulation, speed and definition in the bass region and a not-euphonic top end so you get music that is harmonically complete, there's really only the KR 300B. Everything else, including the various Sophias, the TJ equivalents, the Shuguangs, Treasures, Psvane, neo Gold Lion, JJ, Takatsuki, EML, WE, WE replicas, etc. sound comparatively colored, all in various attractive ways, but also in ways that are both additive and subtractive to a more neutral musical truth. Easily the most disappointing was the Takatsuki, after all the hype, audiophile worship on various forums, and reviews. A superbly-crafted valve that in the half dozen amps I tried it in, yielded that old-school, oversmooth, edges-sanded, lifeless, boring sound. At twice the price of the KR in the US. One thing I haven't heard is the USA special edition KR 300B that sells for about 50% more than the standard balloon glass tube.

Now you can give me a voicing profile you might want to attain through 300B amp tube selection, and I can probably recommend something specific. But if you want open, honest, broadband sound from a 300B, with bass discipline, shove, spatial projection, energy, definition, snap, top end harmonic completeness yet still deliver the 300B midrange magic. the KR is pretty much in a class of one. For a much cheaper step-down but very competent tube (and I surprise myself when I write this) I'd probably go with the Electroharmonix Gold Grid 300B.

Phil
I'm wondering if anyone has compared the KR 300B Balloon to the KR 300BXLS.
 

Joao@altheamusica

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Woofers like Altecs, for example, do not do well with high damping. I understand from montesquieu and people experienced with Tannoy its the same...Tannoys need power, but not a high damping factor.

In the case of Altecs, every time there is an SS amp, I hear poor lower midbass and bass. The speaker seems choked. Leif also mentioned to me how he got better bass with his JBL woofers from his own 300b than from a Pass (I forget which one).

The technical reason that a person explained was the low QTS that leads to a highly damped woofer, does not do well with SS amps which have low output impedance. This results in the rolloff. They do better with low valves of higher output impedance. I am not a techie who measures, but my ears tell me that horns breathe bass best when driven with valve amps. There are certain woofers which will benefit from SS amps on the midbass front, as used with Trios. Lower bass active woofers will benefit from SS amps.

well that is the lowest explanation I'll accept.... and yes, Tannoy needs power and like push-pull amps. My Eminence woofers I used before needed solid state amplifiers and the problem of them is that the frequency range goes very high (over 1KHz) - some people use to add another magnet and then the sensitivity rises but frequency range extends as well: result is very high slopes in the crossover....

BTW, I ran my Altec 416 in a BR enclosure with 12W :)
 
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bonzo75

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well that is the lowest explanation I'll accept.... and yes, Tannoy needs power and like push-pull amps. My Eminence woofers I used before needed solid state amplifiers and the problem of them is that the frequency range goes very high (over 1KHz) - some people use to add another magnet and then the sensitivity rises but frequency range extends as well: result is very high slopes in the crossover....

BTW, I ran my Altec 416 in a BR enclosure with 12W :)

Yes that's why I don't plan to use eminence except for lower bass where I don't mind an active bass solution driven by some SS amp or Crown etc
 

213Cobra

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I'm wondering if anyone has compared the KR 300B Balloon to the KR 300BXLS.
I've used them both for comparative purposes in a 300B amp, KR 300B Balloon vs. KR 300BXLS. The only reason to use the XLS is if you have an amp that is designed to exploit the XLS tube's potential for greater power output. And if you have one of those, you can't just throw a 300B into it. To compare the two according to their performance at full respective potential, you'd need an amp that has switched bias and B+ settings, and an OPT able to handle the higher output of the XLS.

There are some subtle differences between using the B and the BXLS tube in a standard issue 300B amp. The essential KR traits are in both at 300B bias and B+. The XLS delivers a trace more top end snap and a trace more bass depth and texture. The midrange tone of the B carries a little more texture. I also found the XLS slightly noisier than the B Balloon in standard circuits. If you have an amp with the bias and B+ to uncork the XLS' higher output potential (15-25w XLS v. 8-10 B), it becomes a 300B on steroids, more like an 845 but retaining 300B nuance, though somewhat less brute drive than a good 845.

Phil
 

Exlibris

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I've used them both for comparative purposes in a 300B amp, KR 300B Balloon vs. KR 300BXLS. The only reason to use the XLS is if you have an amp that is designed to exploit the XLS tube's potential for greater power output. And if you have one of those, you can't just throw a 300B into it. To compare the two according to their performance at full respective potential, you'd need an amp that has switched bias and B+ settings, and an OPT able to handle the higher output of the XLS.

There are some subtle differences between using the B and the BXLS tube in a standard issue 300B amp. The essential KR traits are in both at 300B bias and B+. The XLS delivers a trace more top end snap and a trace more bass depth and texture. The midrange tone of the B carries a little more texture. I also found the XLS slightly noisier than the B Balloon in standard circuits. If you have an amp with the bias and B+ to uncork the XLS' higher output potential (15-25w XLS v. 8-10 B), it becomes a 300B on steroids, more like an 845 but retaining 300B nuance, though somewhat less brute drive than a good 845.

Phil
Thank you. Yes I believe my amp is designed for use with the EML 300BXLS. It puts out 60 watts using xls tubes and 50 without. The manual says, however, that the amp can be run using any 300B.

The manual:
http://www.allnicaudiousa.com/manuals/Allnic A-6000.pdf

From the manual:
"50 watts of pure class A high power output. The A-6000 is a double parallel single ended power amplifier. Almost all other 300B amplifiers are under, and distortion, driven. This is a result of the use of conventional "Resister-Capacitor" circuits, which give only up to around a 70V swing voltage, with high distortion. This means that an already distorted signal of a lower than optimum swing voltage is directed to the deep biased 300B grid. Allnic’s powerful "Inductor Drive" circuit gives up to a 150V swing voltage, with very low distortion (about 0.3%). It is this drive delivered to the A-6000 that allows for a significantly higher output (50w) than the approximately 27 w output that could be expected from standard 300B circuits."

"You may use any 300B type tube in the A-6000, including the newer higher voltage varieties."
 

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