What are the Sonic Trade-offs in Using Low/ High and Tube vs. SS with High Efficiency Speakers?
- Thread starter caesar
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I use a relatively high-power tube amp, pentode class A/B (100 W/ch into 8 Ohms) for my 92 dB efficient monitors. Trade-offs: none that I can hear.
Before that, I powered my speakers with low-power tube amps, triode class A (15 W/ch). Trade-off: a certain level of distortion on some complex material while still retaining dynamics. No advantages over my current amp.
If I had the money and I heard a worthwhile difference (to be determined, not sure) I might go with a Spectral high-power SS preamp/amp combo (which unfortunately requires its own cables). Spectral impresses me, and I love it.
I am not dogmatic about topologies.
My subs are high-power class D.
Caesar, using 70W Class A 211s into my 101dB eff Zus (incorporating 350W Class D downfiring subs), into an 800 sq ft/5500 cub ft room is a match made in Heaven, room energises at moderate volume levels, does not thin out and die at lower levels.
You know I’m a fan .
You know I’m a fan .
I've used 1000W monoblocks and then 35W tubes into the same 89dB and 92dB speakers. The tube amp into the inefficient speakers was limited in volume, but nothing else.
The best combo is the current 35W monoblocks driving the 92dB speakers, but they are exceptional high-efficiency speakers, the Vapor Nimbus.
I have also heard big SS amps at shows driving the Nimbus. Very good results. The less effort an amp needs to drive the speaker, the better IME.
Steve N.
Empirical Audio
The best combo is the current 35W monoblocks driving the 92dB speakers, but they are exceptional high-efficiency speakers, the Vapor Nimbus.
I have also heard big SS amps at shows driving the Nimbus. Very good results. The less effort an amp needs to drive the speaker, the better IME.
Steve N.
Empirical Audio
The bogeyman is zero crossing distortion. With Single ended class A DHT, it pretty much simply doesn't exist. Given high sensitivity speakers lay all bare, they are peanut butter and jelly. The drawback is often the bass. Woofers are always less sensitive than compression drivers in their unhoused states and when finally loaded need A LOT of cabinet or horn length. To borrow from Jaws, You're gonna need a bigger house.
That said there are SS amps these days that have very low to next to no ZCD. In these cases it comes down to bias and biasing implementation and faster switching on the rails. Some like the Valvet A series which were built for horns use only 1 pair of output devices and are class A all the way. As such they are extremely resolving of low level detail but also have considerable if limited grunt (50w) putting them in Single ended Parallel land but at lower cost. The PASS First Watts also come to mind. I owned Aleph 0s for some years and these were very low in ZCD but still had that SS grain that was much diminished later with the XA series.
Those that bias into A/AB have another bogeyman because of the temp variations at the transistors rails. They can run too cold even after many hours. That actually happened to me. My amps just wouldn't warm up with the 99dB speakers I was babysitting. That would be thermal bias drift. Designers deal with this in many different ways from electronic to mechanical heat exchange and combination thereof so the transistors work within their optimal thermal operating window. CH uses a simple thermal tracking chip set while companies like Edge (are they still around?) went as far as using laser bias tracking. One guy even put in a heater. Directly heated transistors! Made me laugh then but it kinda made sense. Cold SS simply sucks and that is basically what we have on the mass market. I think people who don't like SS associate SS with COLD SS. They would be right for the most part. Tubes warm up one their own and rarely take more than 40 minutes do so regardless of load. With high efficiency, SS can take from never to many hours. With my fairly efficient VR 11s I would begin the warm up cycle with the Air conditioning off and turn it one only when I'd come back in to listen after an hour. It would take my M2.2s another 3 albums for the system to really hit its stride. Overheating amps both SS and Tube both suck so no need to go there.
As for speed, it is a bit of a misnomer because of how they are measured. It is actually more about the size of the voltage steps between on and off positions. The smaller, the smoother the transition but the harder to time. Those that do this well while remaining bedrock stable tend to be complex, have stupid high parts counts and are thus expensive. The upside is knowing that the power is there should you need it granted that we probably don't need it 9 times out of 10, but still...
It is also an alternative to those like me that have PTSD from exploding valves and B+ fuses. LOL
That said there are SS amps these days that have very low to next to no ZCD. In these cases it comes down to bias and biasing implementation and faster switching on the rails. Some like the Valvet A series which were built for horns use only 1 pair of output devices and are class A all the way. As such they are extremely resolving of low level detail but also have considerable if limited grunt (50w) putting them in Single ended Parallel land but at lower cost. The PASS First Watts also come to mind. I owned Aleph 0s for some years and these were very low in ZCD but still had that SS grain that was much diminished later with the XA series.
Those that bias into A/AB have another bogeyman because of the temp variations at the transistors rails. They can run too cold even after many hours. That actually happened to me. My amps just wouldn't warm up with the 99dB speakers I was babysitting. That would be thermal bias drift. Designers deal with this in many different ways from electronic to mechanical heat exchange and combination thereof so the transistors work within their optimal thermal operating window. CH uses a simple thermal tracking chip set while companies like Edge (are they still around?) went as far as using laser bias tracking. One guy even put in a heater. Directly heated transistors! Made me laugh then but it kinda made sense. Cold SS simply sucks and that is basically what we have on the mass market. I think people who don't like SS associate SS with COLD SS. They would be right for the most part. Tubes warm up one their own and rarely take more than 40 minutes do so regardless of load. With high efficiency, SS can take from never to many hours. With my fairly efficient VR 11s I would begin the warm up cycle with the Air conditioning off and turn it one only when I'd come back in to listen after an hour. It would take my M2.2s another 3 albums for the system to really hit its stride. Overheating amps both SS and Tube both suck so no need to go there.
As for speed, it is a bit of a misnomer because of how they are measured. It is actually more about the size of the voltage steps between on and off positions. The smaller, the smoother the transition but the harder to time. Those that do this well while remaining bedrock stable tend to be complex, have stupid high parts counts and are thus expensive. The upside is knowing that the power is there should you need it granted that we probably don't need it 9 times out of 10, but still...
It is also an alternative to those like me that have PTSD from exploding valves and B+ fuses. LOL
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The 2A3 valves in my old amps never exploded, they shorted. I have had my share of amp damages and almost-damages. I have PTSD from that
. Fortunately, my current Octave amp has an electronic (SS regulated) shut-down safety mode if tube failure should ever happen. Tube made foolproof. One of the attractions that factored into my purchase. But I've heard the KT150 tubes in it are exceptionally reliable. Nonetheless, it is good to never have to worry. The amp also has an 'eco mode' that leaves it on but shuts off the tubes after 10-15 min without signal. Beautiful when you want to go out for dinner, worry free.
The bogeyman is zero crossing distortion. With Single ended class A DHT, it pretty much simply doesn't exist. Given high sensitivity speakers lay all bare, they are peanut butter and jelly. The drawback is often the bass. Woofers are always less sensitive than compression drivers in their unhoused states and when finally loaded need A LOT of cabinet or horn length. To borrow from Jaws, You're gonna need a bigger house.
That said there are SS amps these days that have very low to next to no ZCD. In these cases it comes down to bias and biasing implementation and faster switching on the rails. Some like the Valvet A series which were built for horns use only 1 pair of output devices and are class A all the way. As such they are extremely resolving of low level detail but also have considerable if limited grunt (50w) putting them in Single ended Parallel land but at lower cost. The PASS First Watts also come to mind. I owned Aleph 0s for some years and these were very low in ZCD but still had that SS grain that was much diminished later with the XA series.
Those that bias into A/AB have another bogeyman because of the temp variations at the transistors rails. They can run too cold even after many hours. That actually happened to me. My amps just wouldn't warm up with the 99dB speakers I was babysitting. That would be thermal bias drift. Designers deal with this in many different ways from electronic to mechanical heat exchange and combination thereof so the transistors work within their optimal thermal operating window. CH uses a simple thermal tracking chip set while companies like Edge (are they still around?) went as far as using laser bias tracking. One guy even put in a heater. Directly heated transistors! Made me laugh then but it kinda made sense. Cold SS simply sucks and that is basically what we have on the mass market. I think people who don't like SS associate SS with COLD SS. They would be right for the most part. Tubes warm up one their own and rarely take more than 40 minutes do so regardless of load. With high efficiency, SS can take from never to many hours. With my fairly efficient VR 11s I would begin the warm up cycle with the Air conditioning off and turn it one only when I'd come back in to listen after an hour. It would take my M2.2s another 3 albums for the system to really hit its stride. Overheating amps both SS and Tube both suck so no need to go there.
As for speed, it is a bit of a misnomer because of how they are measured. It is actually more about the size of the voltage steps between on and off positions. The smaller, the smoother the transition but the harder to time. Those that do this well while remaining bedrock stable tend to be complex, have stupid high parts counts and are thus expensive. The upside is knowing that the power is there should you need it granted that we probably don't need it 9 times out of 10, but still...
My NAT Symbiosis SE took 2 hours to really warmup and lose nearly all of the transistor character...and this was SINGLE ENDED transistor (only 1 big one per channel...not many in parallel)...so there was no crossover distortion. Tubes also sound a bit thin until warmup as well.
However, for SS there is more going on than just crossover distortion for most amps. For PP there is cancellation of even harmonics and the application of negative feedback (even with most Class A amps), which changes the harmonic structure of the distortion and then there is the inherent distortion of the devices themselves. Mosfets and especially bipolar transistors are less linear than triodes and as a result have a more complex distortion pattern.
IMO, many of these artifacts are simply more audible on high sensitivity speakers. Horns are a microscope compared to the unaided eyesight of a normal sensitivity speaker...
Hard to say as the First Watts and the Valvets are both really good. The Valvets are a bit fuller sounding but that doesn't make them automatically better depending on the speakers and taste. If I were to multi-amp I'd probably go with FW, one pair the Valvets because the latter has more energy storage.
True. SS and horns are indeed big in Japan. If I'm not mistaken, the specific noise in question is hum.
The 2A3 valves in my old amps never exploded, they shorted. I have had my share of amp damages and almost-damages. I have PTSD from that
Fortunately, my current Octave amp has an electronic (SS regulated) shut-down safety mode if tube failure should ever happen. Tube made foolproof. One of the attractions that factored into my purchase. But I've heard the KT150 tubes in it are exceptionally reliable. Nonetheless, it is good to never have to worry. The amp also has an 'eco mode' that leaves it on but shuts off the tubes after 10-15 min without signal. Beautiful when you want to go out for dinner, worry free.
Those Octave amps look really good. I'd love to hear them one day. Do you have a thread where you compare your former PP 2a3s with BP PS vs the Octaves? Link please
Those Octave amps look really good. I'd love to hear them one day. Do you have a thread where you compare your former PP 2a3s with BP PS vs the Octaves? Link please
Unfortunately nothing yet. I may write a review someday.
I am incredibly amazed by the Octave amp. Just yesterday evening and this morning my jaw was on the floor with the Trio of Doom (John McLaughlin, Jaco Pastorius, Tony Williams). I may never have heard this specific kind of animal forward rhythmic drive before in music / the reproduction of it. The dynamics and quick impact of the drums were to die for as well. I was a few times laughing out loud for joy and amazement, no kidding. Of course, the source is where it starts, and the Yggdrasil DAC again proved what a true rhythmic monster it is. Digital used to always literally lag behind analog in rhythm (in its early days, painfully so), but not anymore. Now it is analog (vinyl) that needs to prove itself to me if it can do rhythmically what I hear from Redbook digital.
I used Cary Audio 2a3 SET mono blocks to power the midrange and super tweeter horn drivers in my DIY, fully horn loaded, triamplified speakers. I had been having trouble finding affordable 2a3 bottles that I liked and had began wondering if any solid state amp might sound as good as my SETs. Then I read the 6Moon's review of the First Watt F3 single ended, single gain stage, class A stereo amplifier with JFET output transistors. The reviewer proclaimed the F3 to be the first solid state amplifier to have all the immediacy, warmth, texture, various other SET traits, etc. of the best SET Triodes. Knowing how foolish it was to buy one unheard and unseen I bought one from Reno HiFi. I was astounded how good it sounded driving the midrange driver, an AER BD3 in my Oris 150 horns. It also fared well driving the super tweeter. I bought a second F3 and sold the 2a3 SETs This was back a number of years ago and I have never regretted the change.
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To me it's come down to a contrasting of two approaches: one of using passively configured high efficiency speakers with low(er) wattage tube amps, and the other using actively configured high eff. speakers with solid state amps. From my chair the potentially best sounding option is that of the latter scenario.
Remove the passive filter and the amps are given a much easier job optimally controlling the drivers being connected to them directly, which effectively lessens the importance of the amp. Proper amp matching is also about load independency, and very often the current draining complex passive filters of expensive high-end speakers call for über-expensive amps with massive power supplies to have those speakers "come alive." Not looking into a passive filter will have a given amp perform closer to its full potential and make much more effective use of its power. Which is also to say: less power is typically needed with actively configured speakers compared to their passive equivalent, all of which adds up to cheaper amps necessitated.
Moreover the active approach, apart from having one dedicated amp channel controlling its respective and directly connected driver, can make effective use of amp differentiation; use the better sounding amp for where it matters most, i.e.: from 500-1kHz on up, and more "brute," higher power below that range where it's in more outright need. Added to that a digital cross-over/DSP can more readily accommodate bandwidth limited horns (typically used in high eff. speakers) in need of steeper filter slopes, as well as elaborate delay settings and corrections for notches and peak suppression. Trying to achieve the same with a passive filter is impossible, period.
I've heard great sounding passively configured high eff. speakers with low wattage SET's, but the most impressive sounding high eff. and horn-loaded systems I've heard have been DSP-actively configured with SS amps. They didn't have any distinct SS-amp sonic imprinting, but rather came close in some respects to the sound of SET's, while adding other traits.
I have passive horns with SET and active horns...with SET...I would never put a SS amp on them...again.
Never heard the actively configured, horn-loaded speakers with SET's combo, but can only imagine it being wonderful sounding.
Which SS amps did you try using on your horns, and which horns? Passively, actively? Speaker cables? Myself I use a Belles SA30 pure Class-A solid state amp on the MF/HF horn covering ~600Hz on up with 1mm Mundorf Silver/Gold cables - actively, i.e.: sans passive XO components between the amp and DH1A compression drivers. Smooth, enveloping, extremely dynamic, visceral and effortless, but aspects of this of course also comes down to the specific DSP implementation.
Agreed, but this microscopic tendency of horns as very revealing instruments also applies to the adverse effects of the passive filter components themselves, as well as cables, overall filter implementation, etc. Maybe that's implied in what you write, but I certainly find active config. with SS amps and DSP to be a boon with horns. Should SET's in that mix prove an even better combo, well, that'd just be a bonus.
That microscopic tendency in horns is exactly why I would never use SS with them.
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