anarchist Posted March 29, 2007 Share Posted March 29, 2007 On paper, the pCats should dominate.Not on my paper [] Perhaps I should clarify my statement. The PCats operate in true triode which (a true triode implementation) is claimed to be superior to implementations which switch from UL to Triode but aren't close to optimized. The PCats operate in class A. Again, theoretically superior in sound to amps running in AB or B. As I mentioned, I look forward to a real world comparison. Unfortunately, I agree with gary - the results are likely to be polite and state both are phenomenal and are different so you can't compare. "There is no winner - depends on preference" An objective analysis might indicate whether the two items I mentioned above actually impact the sound in a significant manner. I pay little attention to the 25 watt vs 60 watts - that amounts to 3db? Hardly significant IMO. Regardless, we have two guys on the forum who are producing tube amplifiers any of us would be happy to own. I could/should have purchased VRD's when I had the opportunities previously from Scott and Smilin. In any case, I was able to purchase my Dynaco's from Dee and have enjoyed the process of upgrading them further; with VRD's I never would have done that. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 29, 2007 Share Posted March 29, 2007 No actually neither the VRD or the PCat is a true triode amplifier that would require a true Triode output tube. They are both faking it. Besides the superiority of Triode is completely debatable if you ask me 100% personal preference. On just about all klipsch speakers the VRD will make your ears bleed before switching out of class A. So IMHO your paper is thin. Quote Link to comment Share on other sites More sharing options...
SilverSport Posted March 30, 2007 Share Posted March 30, 2007 ...but they sound Deeeeeeeeeluxe! Bill Quote Link to comment Share on other sites More sharing options...
anarchist Posted March 30, 2007 Share Posted March 30, 2007 On paper, the pCats should dominate. I look forward to a real world comparison... An objective analysis might indicate whether the two items I mentioned... actually impact the sound in a significant manner. Not my paper. I simply listed differences and indicated I was interested in how it translated to real world performance. I would defer to Mark to explain the differences between his triode implementation and the typical triode implementation which switches from UL to triode. The fact remains the PCats are pure class A and VRD's or Dynaco's for that matter are not... I understand your point about the switching from class A to class B but that is also dependent on bias setting, no? In any case, the amps are built differently as I explained and my only interest was in whether it makes any difference in the real world. You suggest no. I appreciate your observations. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted March 30, 2007 Share Posted March 30, 2007 No excuse needed. I appreciate your knowledge and experience with this, Mark. Consistency in design and sonic attributes from one stage to the next makes sense, and as you say, some will like it; others might not. Erik Quote Link to comment Share on other sites More sharing options...
maxg Posted March 30, 2007 Share Posted March 30, 2007 So it is a triode using a pentode tube not operating in single ended mode - right? Its a parallel implementation? If the VRD is running at, say, 10 wpc and operating in triode mode this is different? When we say mock triode isnt that what ulta-linear does anyway? Damn but this stuff gives me a headache. Quote Link to comment Share on other sites More sharing options...
LeeW Posted March 30, 2007 Author Share Posted March 30, 2007 Damn but this stuff gives me a headache. I'll second that[8-)] Quote Link to comment Share on other sites More sharing options...
anarchist Posted March 30, 2007 Share Posted March 30, 2007 Max, My understanding, I will let Mark or others do the technical thing, is if it is switchable you will not have a full triode implementation. An optimized triode implementation involves making some additional changes beyond merely disconnecting the UL taps and sticking a resistor between pins 3 and 4 on the output tubes. Sure you can say it is triode, but its like eating sugarfree cookies instead of the real thing. Quote Link to comment Share on other sites More sharing options...
maxg Posted March 30, 2007 Share Posted March 30, 2007 So you built a push pull triode using a Pentode tube? Yes? Please? Help? Huh? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 Max, My understanding, I will let Mark or others do the technical thing, is if it is switchable you will not have a full triode implementation. An optimized triode implementation involves making some additional changes beyond merely disconnecting the UL taps and sticking a resistor between pins 3 and 4 on the output tubes. Sure you can say it is triode, but its like eating sugarfree cookies instead of the real thing. Absolutely wrong the switch has nothing to do with it! strapping in triode is strapping in triode. I think the main point Mark is trying to make is he designed from the floor up with triode in mind. I put it in as a added little feature. I personally do not care all that much for quasi strapped triode output tube sound the tube was never designed to be run that way hell I feel the same about Class A its main benefit in are application is reduced tube life. I still say if you want a true class A triode then use a true class A triode, plenty of them to choose from (IMHO which is my right I believe). I don't care for the distortion triodes produce in the output tube location they just seem to have trouble tracking the load of a full range speaker. Preamps are a different world then amplifiers. I personally do not think the triodes are superior to Ultra Linear when dealing with the output section in fact more similar then different. But your going to get a different story based on each designer or users preference. By the way Anarchist your little Dynaco slam is not going un-noticed... grow up dude. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 Without getting too involved here, any tube can be configured into "single-ended" or "push push". You can have a single-ended triode (SET) or a single-ended pentode (SEP) or push pull models of either. If you choose push-pull, there are four basic "hookups." 1. Triode. 2. Pentode. 3. Ultra Linear. 4. McIntosh. "UltraLinear" is a word invented at Dynaco and it means in English: "Cross between triode and pentode." It was invented many years earlier by another fellow. But in essence, it seeks to gain the advantages of triode with the power of pentode. Attached here is a general diagram of the plate and mutual characteristics of pentodes and triodes. The visual should make it easy to see the difference in what means a "triode" and what means a "pentode." But why did you use Pentode as an example rather then Ultra Linear??? There is a difference and also more to what were discussing then just raw plate curves. Of course in the end I have no way of winning this discussion but your just slipping in small tid bits and not including all pertinent information. This is kind of akin to a Infomercial. Quote Link to comment Share on other sites More sharing options...
anarchist Posted March 30, 2007 Share Posted March 30, 2007 Absolutely wrong the switch has nothing to do with it! strapping in triode is strapping in triode. By the way Anarchist your little Dynaco slam is not going un-noticed... I suggest you are confused or eager to find a reason to be defensive when there is none. My point is not the switch. The point is there is more to optimizing a triode circuit and such an implementation precludes or severly hinders your ability to switch on demand between triode and UL. It is more complex than disconnecting the UL taps and sticking in the resistor which is what most implementations (whether using a switch or not) are doing. As far as a Dynaco slam, I don't know what you are talking about. I have Dynacos and enjoy them. Any slam you perceive is your own doing not mine. Quote Link to comment Share on other sites More sharing options...
anarchist Posted March 30, 2007 Share Posted March 30, 2007 This is kind of akin to a Infomercial. Now, that, is a slam. A great line though; I will have to use it when the opportunity presents itself. My only point again - which seems to have been missed - was how will a optimized triode implementation compare to the run of the mill triode conversion and how will a true class A amplifier compare to a class AB. Is the difference is sound significant or theoretical. On paper, it sounds great... in practice... will it make a difference. I look forward to Lee's review. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 Absolutely wrong the switch has nothing to do with it! strapping in triode is strapping in triode. By the way Anarchist your little Dynaco slam is not going un-noticed... I suggest you are confused or eager to find a reason to be defensive when there is none. My point is not the switch. The point is there is more to optimizing a triode circuit and such an implementation precludes or severly hinders your ability to switch on demand between triode and UL. It is more complex than disconnecting the UL taps and sticking in the resistor which is what most implementations (whether using a switch or not) are doing. As far as a Dynaco slam, I don't know what you are talking about. I have Dynacos and enjoy them. Any slam you perceive is your own doing not mine. [bs] Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 Ummm, well I see this is taking a nasty and very antagonistic turn already, so I am going to drop it, as it has no import to me other than correcting what was originally a mis-statement a few posts back about the pCAT not being a true "triode" amplifier. It is a triode amplifier. Some people will like that, other people won't. There's something for everyone. Max---yes, a pCAT uses two pentodes wired as triodes in a Class A push-pull arrangement. Manufacturers of pentode tubes regularly publish their specifications for use as a triode and this practice dates back over 60 years. If anyone has any other questions about pCAT amplifiers, just email me, or perhaps start a different thread or whatever. Nothing nasty about it. But the discussion was comparing Ultra Linear to Triode. Tetrode or Pentode operation is not Ultra Linear you know it and I know it but most here would have no clue. So your graph was hugely misleading in this context or in the tube amplifier world today. Just about zero pentode amplifiers are built in this day and age because of what is on your graph. Ultra Linear was designed to relieve the pentode/tetrode short coming you presented. My next three attachments will explain it to some degree. Ultra linear is very similar to Triode while relieving some of the triode short comings and presenting a few of its own short comings. It's all trade offs. Personal preference rules. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 Click to enlarge Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 Click to enlarge Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 30, 2007 Share Posted March 30, 2007 This is kind of akin to a Infomercial. Now, that, is a slam. A great line though; I will have to use it when the opportunity presents itself. It was meant to be a slam and in my opinion the exact truth. The graph was hugely misleading in the context of this discussion. Quote Link to comment Share on other sites More sharing options...
anarchist Posted March 30, 2007 Share Posted March 30, 2007 Absolutely wrong the switch has nothing to do with it! strapping in triode is strapping in triode. By the way Anarchist your little Dynaco slam is not going un-noticed... I suggest you are confused or eager to find a reason to be defensive when there is none. My point is not the switch. The point is there is more to optimizing a triode circuit and such an implementation precludes or severly hinders your ability to switch on demand between triode and UL. It is more complex than disconnecting the UL taps and sticking in the resistor which is what most implementations (whether using a switch or not) are doing. As far as a Dynaco slam, I don't know what you are talking about. I have Dynacos and enjoy them. Any slam you perceive is your own doing not mine. [bs] I am not sure what your response applies to but if you think it is my statement about triode (I have no interest in your accusations about attacks) perhaps you can explain how you deal with the Miller effect and global negative feedback in the simple switched circuit I described above. Otherwise, I have no further need to comment or participate in the discussion and will simply wait for Lee's review. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted March 30, 2007 Share Posted March 30, 2007 no pressure Lee Quote Link to comment Share on other sites More sharing options...
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