tube fanatic Posted August 15, 2015 Share Posted August 15, 2015 I knew that would get everyone's attention! Nelson Pass is brilliant. I can't imagine anyone in the audio field thinking otherwise. Given his respect in the audio field, one would think that he wouldn't give the sonic attributes of SETs (due to their distortion characteristics in particular) a second thought (no pun intended!). That obviously isn't the case. This article makes an interesting read and further cements the fact that low power tube amps combined with high efficiency speakers make a winning combination:http://www.enjoythemusic.com/magazine/viewpoint/1013/set_sit_nelson_pass.htmSteve Deckert is also an accomplished engineer whose Zen Triode amp is one of the most popular tube amps out there in its price range. I rarely see one for sale and have never seen any negative comments about them. Here are Deckert's comments about why they work so well with high efficiency speakers:http://www.decware.com/paper43.htm Lastly, here's a little discussion on an audio forum about using the Zen Triode with Heresys and La Scalas. It is very informative as well:http://www.pinkfishmedia.net/forum/showthread.php?t=159270To add my own comments to those above on Pinkfishmedia, I have been involved with a number of SET driven near-field systems using CWs, LSs, and Reference Series speakers. The result has to be heard with one's own ears. I can't properly express the musical involvement possible with that arrangement.Maynard 1 Quote Link to comment Share on other sites More sharing options...
Guest thesloth Posted August 15, 2015 Share Posted August 15, 2015 Can someone explain to me what time smear? I have a feeling its something people that don't understand feedback systems invented. F A triode has internal feedback. I linked a paper with the math in another thread on here. Quote Link to comment Share on other sites More sharing options...
Luv_sum_Horns Posted August 15, 2015 Share Posted August 15, 2015 Re: Nelson Pass - If he can voice a transistor to sound like a tube amp, just imagine if he sat down to make the best tube amp evar. Regarding Decware, about a third of the page down Steve convinced me to by the Rachael. I have tried to explain this in my own words but the figures he shows really top it off: http://www.decware.com/newsite/TORII.htm Quote Link to comment Share on other sites More sharing options...
Luv_sum_Horns Posted August 16, 2015 Share Posted August 16, 2015 Re: Nelson Pass - If he can voice a transistor to sound like a tube amp, just imagine if he sat down to make the best tube amp evar. Regarding Decware, about a third of the page down Steve convinced me to by the Rachael. I have tried to explain this in my own words but the figures he shows really top it off: http://www.decware.com/newsite/TORII.htm I was thinking the exact same thing about Mr. Pass but he has commented before that SS is his game. I believe he has said he owns and listens to an SET amp. He mostly uses mosfets in his Firstwatt amps because of the pentode like curves and his very own Pass SIT's have a triode like curve and he likes to use these active parts with as simple circuit as possible. The one I am listening to right now is the single stage amplification F6 which is a push pull amp. I also own two SE Firstwatt amps. Every one has a different sound. My next build is going to be a SET though. Any one have any thoughts about this schematic? http://diyaudioprojects.com/Tubes/6EM7-SET-Amplifier/ Where do you find the 8H 150ohm choke and the 1H 50ohm chokes? I have found a 10H 262ohm choke at Parts express and a 1.5H 56ohm. I am thinking the values would work with maybe a R1 resistance change for L1. I see beautiful real walnut furniture with a nice tub amp inside! I don't know what it is about walnut. Sweetens my tubes somehow. Makes me want to make some walnut bridges for my cables Quote Link to comment Share on other sites More sharing options...
moray james Posted August 16, 2015 Share Posted August 16, 2015 I knew that would get everyone's attention! Nelson Pass is brilliant. I can't imagine anyone in the audio field thinking otherwise. Given his respect in the audio field, one would think that he wouldn't give the sonic attributes of SETs (due to their distortion characteristics in particular) a second thought (no pun intended!). That obviously isn't the case. This article makes an interesting read and further cements the fact that low power tube amps combined with high efficiency speakers make a winning combination: http://www.enjoythemusic.com/magazine/viewpoint/1013/set_sit_nelson_pass.htm Steve Deckert is also an accomplished engineer whose Zen Triode amp is one of the most popular tube amps out there in its price range. I rarely see one for sale and have never seen any negative comments about them. Here are Deckert's comments about why they work so well with high efficiency speakers: http://www.decware.com/paper43.htm Lastly, here's a little discussion on an audio forum about using the Zen Triode with Heresys and La Scalas. It is very informative as well: http://www.pinkfishmedia.net/forum/showthread.php?t=159270 To add my own comments to those above on Pinkfishmedia, I have been involved with a number of SET driven near-field systems using CWs, LSs, and Reference Series speakers. The result has to be heard with one's own ears. I can't properly express the musical involvement possible with that arrangement. Maynard take a look at Susan Parker's amplifier design. http://www.susan-parker.co.uk/zeus.htm 1 Quote Link to comment Share on other sites More sharing options...
Luv_sum_Horns Posted August 16, 2015 Share Posted August 16, 2015 I knew that would get everyone's attention! Nelson Pass is brilliant. I can't imagine anyone in the audio field thinking otherwise. Given his respect in the audio field, one would think that he wouldn't give the sonic attributes of SETs (due to their distortion characteristics in particular) a second thought (no pun intended!). That obviously isn't the case. This article makes an interesting read and further cements the fact that low power tube amps combined with high efficiency speakers make a winning combination: http://www.enjoythemusic.com/magazine/viewpoint/1013/set_sit_nelson_pass.htm Steve Deckert is also an accomplished engineer whose Zen Triode amp is one of the most popular tube amps out there in its price range. I rarely see one for sale and have never seen any negative comments about them. Here are Deckert's comments about why they work so well with high efficiency speakers: http://www.decware.com/paper43.htm Lastly, here's a little discussion on an audio forum about using the Zen Triode with Heresys and La Scalas. It is very informative as well: http://www.pinkfishmedia.net/forum/showthread.php?t=159270 To add my own comments to those above on Pinkfishmedia, I have been involved with a number of SET driven near-field systems using CWs, LSs, and Reference Series speakers. The result has to be heard with one's own ears. I can't properly express the musical involvement possible with that arrangement. Maynard take a look at Susan Parker's amplifier design. http://www.susan-parker.co.uk/zeus.htm Very nice, thanks for the link Moray. So many circuits, so many tubes. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted August 16, 2015 Author Share Posted August 16, 2015 Re: Nelson Pass - If he can voice a transistor to sound like a tube amp, just imagine if he sat down to make the best tube amp evar. Regarding Decware, about a third of the page down Steve convinced me to by the Rachael. I have tried to explain this in my own words but the figures he shows really top it off: http://www.decware.com/newsite/TORII.htm I was thinking the exact same thing about Mr. Pass but he has commented before that SS is his game. I believe he has said he owns and listens to an SET amp. He mostly uses mosfets in his Firstwatt amps because of the pentode like curves and his very own Pass SIT's have a triode like curve and he likes to use these active parts with as simple circuit as possible. The one I am listening to right now is the single stage amplification F6 which is a push pull amp. I also own two SE Firstwatt amps. Every one has a different sound. My next build is going to be a SET though. Any one have any thoughts about this schematic? http://diyaudioprojects.com/Tubes/6EM7-SET-Amplifier/ Where do you find the 8H 150ohm choke and the 1H 50ohm chokes? I have found a 10H 262ohm choke at Parts express and a 1.5H 56ohm. I am thinking the values would work with maybe a R1 resistance change for L1. Thanks for posting that SIT amp. I'll have to look it over when I have the time. Who knows, maybe I'll become a solid state convert some day!!! Regarding the 6EM7 amp, it is always enjoyable to see how creative some designers are. Don't worry too much about the choke inductance or its dc resistance. Hammond makes many which will get you in the ballpark of the values specified. It isn't overly critical- a couple of henrys above or below the specified value won't affect ripple all that much; same for the dc resistance since a few volts variation is also not critical. Lots of designs floating around out there depending on the tubes a person wants to use. https://www.hammfg.com/electronics/transformers/choke/153-159 Mouser usually stocks the whole Hammond line: http://www.mouser.com/ Maynard Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted August 16, 2015 Author Share Posted August 16, 2015 Can someone explain to me what time smear? I have a feeling its something people that don't understand feedback systems invented. F A triode has internal feedback. I linked a paper with the math in another thread on here. You really don't know what "time smear" is? Well, I don't either! Deckert gets a bit flowery with his descriptions sometimes, but in this case I think he's referring to phase distortion. Not quite sure... Maynard Quote Link to comment Share on other sites More sharing options...
Don Richard Posted August 16, 2015 Share Posted August 16, 2015 AFAIK, the big problem with high feedback designs that are stable is TIM distortion. That issue was dealt with long ago and does not seem to be an issue today. Crossover distortion is a larger problem with PP designs, whether SS or tubes. IMO. Quote Link to comment Share on other sites More sharing options...
Fjd Posted January 16, 2016 Share Posted January 16, 2016 (edited) http://www.circuitdiy.com/product/2sj28-sony-p-ch-vfet-for-ta-n88-class-d-amp These are the real thing and not fakes as most are on Ebay. Nelson has said he will consider designing an amplifier with just the 2SJ28 transistor when he gets time. It will be a design without OPT. He has 2 designs on his website using 2SJ28 and 2sk82 in a push pull amplifier but after publishing the VFet2 design the 2SK82 sold sold out in a matter of days. I bought an extra pair to sit on. SIT transistors are the only ones that I am aware of that have the Triode curve response and the Triode sound. Which of the two designs are you collecting parts to build? I just received two pair for my parts bin from a friend that bought genuine from circuitdiy and now doesn't think he will have a chance to build. . Edited January 16, 2016 by Fjd Quote Link to comment Share on other sites More sharing options...
WMcD Posted January 16, 2016 Share Posted January 16, 2016 So, what if anything, is going on with testing of impulse response of amplifiers. Feedback is said to cause a hall of mirrors effect. Maybe Dr. Who can tell us. WMcD Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 16, 2016 Share Posted January 16, 2016 Can someone explain to me what time smear? I have a feeling its something people that don't understand feedback systems invented. Perhaps, but there are circuit components that change behavior with temperature. Music isn't a constant level signal, so the dynamic bits in music can be affected by thermal hysteresis. There can be other time domain factors too, like temporary bias shifts on AC coupled stages. Sure, on average over a long time they settle down, but music isn't necessarily symmetric for short periods of time. Speaking in generalities, feedback systems are not immune to these behaviors, but to discuss them in detail would require a very specific analysis of each circuit topology independently. All I'm trying to say is that "time smear" could very likely be referring to something real. Due to the complex technical nature of the subject, I wouldn't be surprised if an audiophile attributed sonic artifacts to the wrong thing. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 16, 2016 Share Posted January 16, 2016 So, what if anything, is going on with testing of impulse response of amplifiers. Feedback is said to cause a hall of mirrors effect. Maybe Dr. Who can tell us. WMcD Impulse response and frequency response are the same thing....especially when talking about devices like amplifiers. Any "hall of mirrors" effect is happening at the speed of light, and the distances here are very short. There is no way I the world that the "propagation delay" of the electrical energy is an audible facet here. We design circuits all the time where that matters, so it's not like we don't know how to deal with it. The magnitude of the effect is way smaller than the random vibrations of the molecules in your circuits. There is the whole TIM subject, which could be thought of as a "slow feedback" circuit, but that doesn't behave like "reflections" - which is what I think is implied by the mirror analogy. TIM is more like someone trying to keep their head still while balancing on one leg on a chair sitting on a ball. If the ball moves too quickly, then their head is going to move slightly to maintain balance....even if the ball is moved just as quickly back to its starting location. The head movement is the distortion added to the output. There's probably a million things wrong with the analogy so don't take it too far, but it has very little to do with how quickly the ball position gets transmitted through the chair and person's leg. It has to do with how far/fast the person's body can react to the stimulus. An older slower person's head will move further than a young fast kid. Quote Link to comment Share on other sites More sharing options...
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