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Post by audiobill on Jun 4, 2015 15:39:21 GMT -5
IMO, all the technical analysis and specs in the world don't come close to explaining the spatial magic a good tube amp is capable of....and I've had 'em all!
Kind of like buying a guitar based on wood types used, scale length, pickup type and impedance, width at the nut, name on the headstock, warranty and color rather than how it SOUNDS!!
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Post by jmasterj on Jun 4, 2015 20:45:12 GMT -5
Two of my system configurations contain a tube pre amp mated with solid state power. My Bada DC-222 Hybrid Tube integrated amp has a tube preamp section mated to a solid state power amp with 95 watts/channel it really sounds great. It was my first tube amp. I upgraded the preamp tubes when I purchased it in 2010. I haven't changed a thing since. It's sound has been very consistent.
It was so nice that when I purchased my XPA-100 mono blocks I had to have a tube preamp to mate with them. I chose the entry level Xiang Sheng 728A. It has six tubes, three sets of two, four of them I could change, the other two you can only get the Chinese version so no need to change them. Before I rolled the two pairs of preamp tubes that I could change I was not happy with the sound. The new tubes really opened up the sound. I still believe this combo is the least tube sounding of my three tube amp configurations.
I have been listening to the XPA-100's and 728A combo for several months now, the more I listen to it the more I like it. This preamp power amp combo works well with all three sets of speakers. I love my Yaqin MC-30L tube integrated amp. But make no mistake about it, the tube pre with solid state power amp is just as good. Keep in mind what Keith said you can get a solid state amp and choose a tube preamp that has the sound you prefer, or you can roll the tubes to find a sound you like. It works for me.
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Post by ocezam on Jun 5, 2015 7:54:37 GMT -5
Another thing worth mentioning is damping...Also, as a general statement, it means that, if you connect many modern speakers to a tube amp, you can expect "lots of not especially tight sounding bass that doesn't seem to go very low". Agreed. I do not particularly care for most bass made with tube power, even that produced from my350 watt monoblocks. Therefore I choose to go to the expense and trouble of bi-amping. Best of both worlds IMHO. |
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Post by pedrocols on Jun 5, 2015 8:40:52 GMT -5
Another thing worth mentioning is damping...Also, as a general statement, it means that, if you connect many modern speakers to a tube amp, you can expect "lots of not especially tight sounding bass that doesn't seem to go very low". Agreed. I do not particularly care for most bass made with tube power, even that produced from my350 watt monoblocks. Therefore I choose to go to the expense and trouble of bi-amping. Best of both worlds IMHO. Using subwoofers is also an alternative. However, it takes time to properly integrate a subwoofer(s) to a stereo system but once you do it will be hard to erase the smirk off your face...  |
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Post by Canuck_fr on Jun 5, 2015 9:01:08 GMT -5
I am old enough to have used old tube amps (MAC). For those who think that tube power performs differently, I think that Keith's explanation is very clear and it explains what I we hear.
For those who think you need less power with a TUBE AMP, I suggest you compare your low power tube amp to a Mini-X. You will be surprised to see how good the Mini-X amp will sound even when compared to a XPA-2.
To me headroom is very overated.
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Post by pedrocols on Jun 5, 2015 9:15:29 GMT -5
I am old enough to have used old tube amps (MAC). For those who think that tube power performs differently, I think that Keith's explanation is very clear and it explains what I we hear. For those who think you need less power with a TUBE AMP, I suggest you compare your low power tube amp to a Mini-X. You will be surprised to see how good the Mini-X amp will sound even when compared to a XPA-2. To me headroom is very overated. If you measure how many watts you use at home you will be surpeised at how little watts you actually using. |
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KeithL
Administrator 
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Post by KeithL on Jun 5, 2015 11:53:37 GMT -5
Yes - and no. With many speakers, the difference in how the bass sounds caused by different amounts of damping extends up to several hundred Hz - which is above the frequencies that a sub will be handling. If I were bi-amping with a tube amp for the mids and highs and a solid state amp for the bass, I would want to cross them over at about 250 Hz or so - or maybe even higher.... at the highest frequency I could without the crossover falling into the critical range of voice frequencies. Agreed. I do not particularly care for most bass made with tube power, even that produced from my350 watt monoblocks. Therefore I choose to go to the expense and trouble of bi-amping. Best of both worlds IMHO. Using subwoofers is also an alternative. However, it takes time to properly integrate a subwoofer(s) to a stereo system but once you do it will be hard to erase the smirk off your face... |
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Post by pedrocols on Jun 5, 2015 12:08:09 GMT -5
Yes - and no. With many speakers, the difference in how the bass sounds caused by different amounts of damping extends up to several hundred Hz - which is above the frequencies that a sub will be handling. If I were bi-amping with a tube amp for the mids and highs and a solid state amp for the bass, I would want to cross them over at about 250 Hz or so - or maybe even higher.... at the highest frequency I could without the crossover falling into the critical range of voice frequencies. Using subwoofers is also an alternative. However, it takes time to properly integrate a subwoofer(s) to a stereo system but once you do it will be hard to erase the smirk off your face... Precisely! |
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Post by bluemeanies on Jun 5, 2015 12:33:20 GMT -5
I am not as TECH savvy as many here appear to be on this thread.
The bottom line that I would like to put in motion here via my thoughts on tube performance has nothing to do specs, or spread sheets and diagrams of total harmonic distortion. For me it is totally the listening experience. I can only compare my experience in music recreation by past systems I have owned and there performance levels from over the years past..
My escape from the chains of rationalizing that more power is better and you can never have enough power was hard to cut lose. This was especially hard since I had B&W speakers that CRAVE power. The more you can throw at them the better performance reliability you will achieve. The better midrange, the better effect in audio frequencies in the tweeter and let's not forget less distortion.
My recent dive into the pool made me walk away with experiencing the tube effect centering around the m125's, a tube amplifier from tubes4hifi/Dynaco. The m125 Is a 16 gauge brushed stainless steel chassis. The amplifier comes with switch for Pentode mode or Triode mode. In Pentode mode @125 watts and Triode mode 65watts. All this information and more can be found on their website tubes4hifi. Talk about best bang for the buck...in the tube area hands down for price and performance IMHO these tube amplifiers can go neck to neck with the best of them.
My experience with the m125 performance and I will admit I am still in the infancy stage has been one of throwing out all of the OLD SCHOOL RULES of more the more power the better. Since the debut of these amplifiers in my system I have experience a much smoother sound along with a definitive clarity that I did not acquire with previous SS amplifiers. Soundstage and midrange has also stepped up a notch and the little nuances in those special recordings...depression of a piano pedal, the artists' breathing on the microphone are all qualities that should enhance a quality recording and playback from any source and those qualities are extenuated with the m125's.
Of course this is my own experience and opinions but I do encourage everyone and anyone who is considering a change in their system to accent their music libraries to test drive a tube amplifier...and seriously consider a well made, not mass manufactured, and 100% American made amplifier...the m125.
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Tube power
Jun 15, 2015 13:33:48 GMT -5
via mobile
Post by ocezam on Jun 15, 2015 13:33:48 GMT -5
Yes - and no. With many speakers, the difference in how the bass sounds caused by different amounts of damping extends up to several hundred Hz - which is above the frequencies that a sub will be handling. If I were bi-amping with a tube amp for the mids and highs and a solid state amp for the bass, I would want to cross them over at about 250 Hz or so - or maybe even higher.... at the highest frequency I could without the crossover falling into the critical range of voice frequencies. Using subwoofers is also an alternative. However, it takes time to properly integrate a subwoofer(s) to a stereo system but once you do it will be hard to erase the smirk off your face... I CROSS AT 9OO Hz. |
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Post by sounder on Jan 14, 2016 18:21:32 GMT -5
Watts are watts, that much is true. However, watts alone are not a measure of the power of any amplifier. There is current, voltage, amperage, all of which are part of the measure of "power" of any given amplifier. And, there is the power reserve which relates to the power tranformer, capacitors and much more.
I have B&W 803s which are supposed to be "power hogs" and only sound best with high power SS amplifiers. The efficiency rating is 90db. I run them with my Primaluna Integrated tube amp. It runs 18w in triode mode, or 36w in Ultralinear mode. Anyone who understands SS amps would tell me it isn't enough power... not even close. I'm here to tell you they sound better with this amp than any high power SS amp could possibly make them sound. It's awesome. You would never listen to them and assume the power is too low.
On the other hand, if I got a 150 watt Radio Shack amp, I'm certain any of us would immediately say they sound thin and need more power. Same if I hooked them to a 150 watt Sony receiver. The reality is, even when you say SS watts are SS watts, it isn't the whole picture. I would pose that a 75wpc Rotel or Parasound amp will always sound better than the 150 watt Sony.
In the case of the Primaluna, a big part of the reason is that the PL integrated has massive output transformers. This amp weighs like 70 pounds. Most of that weight is the transformers. So it has huge amounts of power in reserve and can push these speakers just fine, even with the "measly 18 watts" triode mode.
So, I don't think there really is any blanket statement you could make as a generalization to say how much power is relatively. I think some 10 watt tube amps (with good tranformers) may drive a difficult speaker like the 803s, while others (with weak transformers) may not. While your 100 watt tube amp may seem to be in the ballpark with a 200 watt SS amp, the 36 watts in the Primaluna seems to my ears to be more equivalent to a 150 watt SS amp. So, that's maybe a factor of 4X. I don't think there really is an easy generalization you can make.
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Post by garbulky on Jan 14, 2016 18:46:32 GMT -5
As someone already said, "power is power" - and the rated power is simply the rated power. Therefore, "75 clean watts" is going to be exactly the same whether it's coming out of a tube amp or a solid state amp. If we were to follow your "horsepower and torque" analogy, then the tube amp has neither more horsepower nor more torque. However, tube amps do have rather different distortion characteristics.... and this affects how they sound in several ways.... 1) Tube amps don't clip suddenly like virtually all solid state amps. If you overdrive a solid state amp, once you reach its limit, it will start sounding very bad very suddenly. In contrast, a tube amp will start sounding gradually worse and worse as you exceed its ratings. Since music is very dynamic, the average amount of power you use when playing music is typically 1/10 to 1/20 of the average power, with peaks only occurring a few percent of the time. This means that, with music, the peaks will start clipping long before you're anywhere near their actual maximum average output power. If you turn a solid state amp up too loud, it will start clipping the peaks very harshly, which will sound nasty. If you turn an equivalent tube amp up equally too loud, the occasional clipped peaks will be distorted, but the distortion will not be as obvious or as nasty. So, the tube amp and the solid state amp will start clipping at the same point but, if you keep turning them both up, the tube amp will let you go a lot further into clipping before it starts sounding really bad. 2) Solid state amps tend to have an overall distortion profile such that their distortion remains very low as you increase the power until you reach their limit, at which point the distortion rises very suddenly. In contrast, many tube amplifiers have what's called "a monotonic distortion curve". What that means is that the distortion rises gradually as they produce more power. (With some SET amps, the distortion actually rises linearly with power; with most pentode and ultralinear amps, while their distortion stays reasonably low at low power levels, it still rises more or less linearly at higher power levels until they reach clipping.) Now, interestingly, our human brains tend to interpret distortion as "loudness" (probably because it's annoying). Just think about how "loud" a cheap table radio seems to be able to play - because your brain interprets the annoying distortion it produces as "loudness". So, as you turn up that tube amp, not only does it really play louder, but the rise in distortion as it delivers that higher power makes it sound proportionally "even more louder". As you turn it up, the solid state amp delivers: 1 watt @ 0.01% THD, then 5 watts @ 0.02% THD, then 20 watts @ 0.05% THD In contrast, a typical SET 20 watt amp may deliver: 1 watt at 0.1% THD, then 5 watts @ 2% THD, then 20 watts at 10% THD You can think of the distortion almost like a "multiplier" on how loud it "sounds" - or like a "psychoacoustic dynamic range expander". A 75 watt solid state amp playing music at an average level of 20 watts will probably be clipping a few percent of the time - and will sound rather harsh. A 75 watts tube amp playing music at the same level will probably be clipping the same percentage of the time - but it will distort just enough to make it seem like it's playing louder, while still avoiding sounding harsh enough to be perceived as sounding really bad. 3) I should also mention that, fifty years ago, many companies under-rated their equipment more than is common today (so "a 50 watt amp" may really have been able to deliver 75 watts). This was true partly because some were simply rated very conservatively, but partly due to that gradual distortion characteristic I mentioned. (If a given amplifier could deliver 50 watts @ 1% THD, and 75 watts @ 10% THD, and you wanted to rate it at 1% THD, then your rating was "50 watts". However, it still had lots of headroom which it could use to deliver much louder peaks while only distorting them somewhat rather than clipping them outright.) Therefore, to be precise, with tube amps - as compared to solid state amps - there tends to be a "disconnect" between "how much clean power they can deliver" and "how loud they can play before they start outright clipping" - but that disconnect is really due to how they distort at various power levels and not to how much actual clean power they can deliver. I have been trying to expand my knowledge on Tube amps. Obviously a common question is "why is the rated power so low, and will they drive my speakers as good as X solid state." I am in the same boat, I'm a numbers guy. The other day I decided I was going to put it to the test and hooked the Olympicaiii up to our Mcintosh MC275 amp (2 channel 75 watt tube). My finding was that they sounded FANTASTIC and the lower end had a robust, full sound. The olympica prior were hooked up to a 5 channel 200 watt Mcintosh amp with only the two channel driven. The tubes didn't seem to get taxed at all. We also keep the ML Montis hooked up to our MC275 and they sound sublime without feeling taxed at all. So here is my question to someone who has previously jumped heavily into this question. Assuming the amps are in the same family. What is a general power rating from tube to solid state?. Ex: 75 watt tube = 200 watt solid state. Is this even an assumption that can be made? I'm looking for a general blanket statement. "Generally 75w tube amp will compare in power to a 200 watt solid state" Would you use 75Wx2 to power your high end, not very sensitive speakers? I have a general understanding on the distortion qualities of tubes being more gradual hence not sounding as harsh as solid state amps, and also the increase voltage making the tube seem more powerful. I interpret this as horsepower and torque working together. Let's discuss, and as always thanks for the insight! What about the amounts of negative feedback used in solid state versus tubes to get this lower distortion? |
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Post by audiobill on Jan 15, 2016 8:35:08 GMT -5
Gar, depends on the circuit topology.....
For example, Balanced Audio Technology's all tube designs use zero negative feedback, while other designs use a lot, and can be stage local or global Although this is just an example, understand the level of engineering, parts quality and cost required to achieve their designs:
"Zero Feedback Topology
There is another aspect to designing a low restriction gain stage – the elimination of negative feedback. Put simply, high feedback circuits are restrictive circuits. Empirical evidence confirms this to be the case.
In any zero-feedback configuration, the user listens to the unique voices of each individual component. These voices come through totally free and uncorrected, like solo dancers in a ballet theater. As with solo dancers, these components also must meet the most demanding performance requirements. The proper choice and application of each component are now of paramount importance. The individual parts selected for all BAT products, from the signal capacitors to the power tubes and the output transformers are well qualified for such a mission. Their characteristics are linear and well controlled. The 6C33-B output tube, for example, is an ideal vacuum tube for audio power application due to their low plate impedance and high current capability. The linear operating range for the REX II Power amplifier’s oversized output transformers extend far beyond their specified output power rating.
In order to evaluate the effects of negative feedback on sound characteristics, a prototype BAT amp was equipped with feedback controls that provided an adjustment range from 3 dB to 10 dB. We soon discovered that as little as 3 dB of negative feedback was detrimental to the sound. The insertion of negative feedback generally reduces the sound stage as well as lessens the air around the reproduction of the human voice. The sound becomes constricted - no longer breathing like the live event. Thus, notwithstanding the improvements that negative feedback brings to an amplifier’s measured performance, every listener preferred the zero feedback position."
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Post by audiobill on Jan 15, 2016 8:44:54 GMT -5
Watts are watts, that much is true. However, watts alone are not a measure of the power of any amplifier. There is current, voltage, amperage, all of which are part of the measure of "power" of any given amplifier. And, there is the power reserve which relates to the power tranformer, capacitors and much more. I have B&W 803s which are supposed to be "power hogs" and only sound best with high power SS amplifiers. The efficiency rating is 90db. I run them with my Primaluna Integrated tube amp. It runs 18w in triode mode, or 36w in Ultralinear mode. Anyone who understands SS amps would tell me it isn't enough power... not even close. I'm here to tell you they sound better with this amp than any high power SS amp could possibly make them sound. It's awesome. You would never listen to them and assume the power is too low. On the other hand, if I got a 150 watt Radio Shack amp, I'm certain any of us would immediately say they sound thin and need more power. Same if I hooked them to a 150 watt Sony receiver. The reality is, even when you say SS watts are SS watts, it isn't the whole picture. I would pose that a 75wpc Rotel or Parasound amp will always sound better than the 150 watt Sony. In the case of the Primaluna, a big part of the reason is that the PL integrated has massive output transformers. This amp weighs like 70 pounds. Most of that weight is the transformers. So it has huge amounts of power in reserve and can push these speakers just fine, even with the "measly 18 watts" triode mode. So, I don't think there really is any blanket statement you could make as a generalization to say how much power is relatively. I think some 10 watt tube amps (with good tranformers) may drive a difficult speaker like the 803s, while others (with weak transformers) may not. While your 100 watt tube amp may seem to be in the ballpark with a 200 watt SS amp, the 36 watts in the Primaluna seems to my ears to be more equivalent to a 150 watt SS amp. So, that's maybe a factor of 4X. I don't think there really is an easy generalization you can make. This is consistent with what many of us hear with other tube designs - |
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Post by bluemeanies on Jan 15, 2016 9:33:47 GMT -5
Watts are watts, that much is true. However, watts alone are not a measure of the power of any amplifier. There is current, voltage, amperage, all of which are part of the measure of "power" of any given amplifier. And, there is the power reserve which relates to the power tranformer, capacitors and much more. I have B&W 803s which are supposed to be "power hogs" and only sound best with high power SS amplifiers. The efficiency rating is 90db. I run them with my Primaluna Integrated tube amp. It runs 18w in triode mode, or 36w in Ultralinear mode. Anyone who understands SS amps would tell me it isn't enough power... not even close. I'm here to tell you they sound better with this amp than any high power SS amp could possibly make them sound. It's awesome. You would never listen to them and assume the power is too low. On the other hand, if I got a 150 watt Radio Shack amp, I'm certain any of us would immediately say they sound thin and need more power. Same if I hooked them to a 150 watt Sony receiver. The reality is, even when you say SS watts are SS watts, it isn't the whole picture. I would pose that a 75wpc Rotel or Parasound amp will always sound better than the 150 watt Sony. In the case of the Primaluna, a big part of the reason is that the PL integrated has massive output transformers. This amp weighs like 70 pounds. Most of that weight is the transformers. So it has huge amounts of power in reserve and can push these speakers just fine, even with the "measly 18 watts" triode mode. So, I don't think there really is any blanket statement you could make as a generalization to say how much power is relatively. I think some 10 watt tube amps (with good tranformers) may drive a difficult speaker like the 803s, while others (with weak transformers) may not. While your 100 watt tube amp may seem to be in the ballpark with a 200 watt SS amp, the 36 watts in the Primaluna seems to my ears to be more equivalent to a 150 watt SS amp. So, that's maybe a factor of 4X. I don't think there really is an easy generalization you can make. Agree 1000%! Without distortion! |
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Post by sonicseeker on Jan 15, 2016 10:35:01 GMT -5
Going to try the tubes myself, and I know there are a lot of ways to argue the merits of different types of stereo electronics but the only one that matters is what I actually hear and weather it fits my perception of what qualifies as a pleasing experience.
My choice will be a Decware Zen triode integrated amp model SE34I.5(aka Rachael).
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Post by sounder on Jan 15, 2016 10:49:11 GMT -5
I know there are many options out there. But if you get a chance, listen to some Primaluna gear. IMO it hits a sweet spot, with very good performance without spending Mcintosh money. Their web site has a dealer locator to see if there is one nearby.
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Post by milsap195 on Jan 15, 2016 12:31:24 GMT -5
Come to the dark side!   |
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Post by sonicseeker on Jan 15, 2016 18:06:51 GMT -5
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