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  1. Well, deftly avoiding the 300B/2A3 argument, I will say that since it's a 300B amp, and given the choice of 300B's available today, I'd go with the TJ mesh or even solid plates, over anything else. Charlie G ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  2. Before you blow $500 on 300B's, you might try the rather highly thought of TianJin 300B's. The globe meshplate is $275/pair, and it has been extremely well received, many place it above current production WE ($900/pair). I've heard these and they are excellent. There is an even cheaper 300B by the same guys, the coke bottle solid (non-meshplate). It is only $150/pair, and while not as sweet as the meshplate, it is still an excellent-sounding, well-built 300B tube. Quite impressive to see these coming out of China. Most of the tube factories there do not have such a great reputation. Anyway, check these out. Be sure to get the TianJin, NOT the FullMusic tubes, as they have been specially matched & burned in. I believe diyhifisupply and bottlehead both have them. Good luck. ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  3. James, I have never been good with using vague wording to describe sound, and I will not attempt to here. And I'd stress again that low THD numbers doesn't mean the amp doesn't present other types of distortion (such as intermodulation products, also problems with the harmonic spectra and other things caused by global feedback). As for local feedback, it is unavoidable. The plate resistance in a tube is a sort of local feedback that is essentially instantaneous and does not suffer any of the ill effects of global feedback. I guess I would ask why exactly you feel that SS presents a more 'neutral' sound because it has (for instance) lower 2nd order harmonic products, if other distortion products are present and ultimately also have a negative effect on the sound. Does this other stuff not matter? While Person A might hear a big SS amps as very neutral & clean, but a SE tube amp as colored, Person B might hear the SE tube amp has having the most neutral & clear harmonics, while the SS is colored by a grainy treble and a poor midrange. Or are your ears the ones by which neutral & eupohic should be judged? Obviously nobody would say 'yes' to that question (except explicitly in reference to thier own system). So we tend to fall back on objective measurements, which are important. But then we can't suddenly say that some kinds of distortion & the common problems with SS are unimportant. Or perhaps they just go hand-in-hand with HiFi? Basically what I'm saying is that I reject that people who prefer tubes do so only because it adds some kind of euphonic distortion. Part of it might just be the fact that tubes are just plain BETTER at some things than solid state. For an example of some of these things, see my previous posts in this thread, and see Colin's other thread "tube vs SS part two; zero feedback," the stuff by Lynn Olson. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  4. James, The big triodes are more linear than BiPolar or FET devices. In and of themselves, they are among the most linear amplificaiton devices ever created. As I said in my first post, which you obviously did not even read, SS devices almost always require the use of feedback when actually applied, in order to achieve decent distortion numbers. Take something like the Zen circuit and remove the feedback, and it will have higher distortion than a good tube. It's interesting that some people utterly reject the colorations and distortion products of a tube amp, and then readily accept the colorations and distortion products of a big SS amp, and say one is Hi Fi and the other is not. It's even more interesting when you consider which types of distortion actually have a negative effect on the sound. You say that people who like tubes just like the way it colors the sound? Perhaps they just ACCEPT the limitations of a tube amp, because they are unwilling to accept those of solid state? I would love an amp w/ bandwidth from DC to 100khz, and super-low output resistance, and hundreds of watts of power on tap, and so on. The proverbial 'Straight Wire With Gain,' but if getting specs like that means switching to solid state and using lots of feedback, well... no thanks, because it just plain SOUNDS BAD. As I said previously... if that's Hi-Fi, if Hi-Fi means sacrificing sound for specs, well then I want nothing to do with it. But that doesn't have to be the case; what is really important is what specs you are measuring, you can measure those that look great in a brochure, or you can measure the specs that have been shown to actually have an impact on the subjective quality of the sound. Charlie G ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  5. Well, it's good to hear that someone has recognized the importance of these other factors. It's unfortunate though, that since I'm guilty of not having looked at Crown's brochures, that I no longer have any credibility. In which case I'd urge anyone to investigate on their own the effects of the ear's distortion on hearing & the results of SE operation of triodes and transistors (in terms of distortion). As these are the important things I was trying to convey, not the fact that IMD & TIM specs are not commonplace. (The fact that I have not seen them doesn't mean they don't exist, it means they aren't commonplacein Hi-Fi, and I maintain that.) Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  6. James: Objectively, Tubes are considerably better than solid state. A solid state device has inherently MUCH, MUCH higher distortion than a tube. In fact, the bigger triodes, when operating at high cathode current, are possibly THE MOST LINEAR AMPLIFICATION DEVICES EVER CREATED. I'll give you a minute for that to sink in Because SS does not do very well on its own, it is almost always used in conjunction with feedback. (Of course there are exceptions, I'll get to those in a sec.) When you use feedback with a tube amplifier, it is possible to obtain pretty great THD numbers too, but never as high as SS, because the gain is much lower. Now, while I'm not going to go into a long discussion of feedback, a basic fact is that while feedback can be used to lower THD & improve output impedance, ultimately other problems can manifest (especially IMD). IMD & TIM are almost *never* measured, and I've never seen a production SS amp w/ IMD & TIM specs. NEVER. Instead we always see THD (quite possibly the most meaningless specification ever recorded) specs AT FULL POWER. *Always* at full power... why do you think that is? It is measured at full power because Push-Pull SS amps have much higher THD at low power levels. A SE tube amp, on the other hand, has decreasing distortion levels at low power. This is why THD at X power level is such a worthless specification. Even looking at a graph of THD vs Power isn't much help, as it often doesn't extend all the way down. Given this, we must be VERY CAREFUL what we are comparing. Tubes in and of themselves are much more linear, SS *AMPS* have better THD because they use lots of feedback. Also we can compare Push-Pull vs SE. SE Solid State amps (like Pass Lab's designs) have many things in common w/ SE tubes, like decreasing distortion with decreasing power. And again, you must be very careful as to what SORTS of distortion you are talking about, and what subjective effects they have on hearing. Harmonic distortion is generated in absolutely *MASSIVE* ammounts by your ear. In fact, w/ a 90db input signal, your ears generate 80db of 2nd order harmonic distortion, 60db of 3rd order harmonic distortion, and 50db of 4th order harmonic distortion. Your brain filters it out. Your brain is TRAINED to filter out a sloping 2nd, 3rd, 4th, etc... harmonic distortion profile. Taking the very generalized case of SE Tubes vs PP SS operating at EQUAL POWER, the SS Amp will have lower THD and lower output impedance, but the tube amp will have much lower intermodulation distortion products, because of the lack of feedback. The tube amp will also be generating a distortion profile similar to that created by the ear. Saying that tubes are not Hi-Fi because of the THD specs is panamount to saying that THD is the *only* spec important to Hi-Fi! Heck, Harmonic Distortion isn't even the only form of distortion! If there was any one distortion product that did the LEAST harm to the sound (subjectively), harmonic distortion would be it! (Especially when in this sort of sloping profile.) Charlie G EDIT: In fact, studies have shown a THD of as high as 10%, in the proper profile, and at certain SPL levels to be *completely inaudible*. The brain simply doesn't hear it. Again, what I'm saying here is that THD is only part of the story, we must consider the profile of the harmonics, and we must consider THD vs Power. If 'Hi-Fi' is nothing but the quest for the lowest THD numbers possible, then I want nothing to do with it. I'd rather search for the best sound possible. Just one last time, in case anybody missed it: The THD spec at full power for an amplifiers tells you absolutely NOTHING about the subjective sound quality of the amplifier. This message has been edited by Spider124 on 10-23-2001 at 07:00 PM
  7. It is a tough recommendation, since they are only available as a kit (but you can get the PCB assembled, and most of the extra parts you need, except for the transformers, since they ship from Australia); but you really will not beat the sonics of the AKSA by Printed Electronics. (55w/ch 8 ohms) Well, you might beat it, but I expect you will pay well over a thousand dollars to do so. Careful replacement of some of the capacitors with boutique 'audiophile' grade caps lend the amp a sound somewhat close to tubes, but with effortless power and dynamics, and a noise floor that few tubes can match. The amp is not Class A, but crossover distortion is pretty much eliminated. Unlike most SS, the first watt is just as good as all the rest. You'd need to know someone who could assemble it, but if you can get it figured out, it would DEFINITELY be worth trying. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  8. Welborne doesn't sell assembled amps anymore. They are kits-only now. If you contact Bottlehead, they know a guy who will assemble thier kits (But really they are very easy if you so much as know which end of a soldering iron to hold) and does a great job, but it is somewhat expensive. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  9. Is that a 5-channel amp? If so, you should consider replacing the Sony Receiver with a true Preamp/Processor. I think Outlaw Audio has one in the works, should be pretty good and will go for about $800, I think. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  10. You should just buy whatever DAC you think sounds good As I said, most of them have jitter reduction circuitry, and I'm sure it will sound great. The parts in my long letter on digital audio discussing what works best didn't neccesarily mean you HAD to have one of those methods As for my setup, the data is converted from simple PCM format to I2S IN THE DAC, by a special chip I designed specifically to do that. The PCM data is buffered in the DAC before being converted to I2S, so the timing of the PC's transmissions to the DAC are irrelevant, and have no effect on jitter. The audio does not HAVE to be compressed beforehand, I just chose to do so. You could just as easily stick a CD in there and rip it in realtime. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  11. disco, yes, I know that each has advantages and disadvantages. However, I am not talking about specs or performance as measured by Hewlett & Packard, I'm talking about sound. It MAY be possible to build a single-bit DAC that sounds as good as multibit DAC's. There were a couple single-bit DAC chips that sound very very good, but are so old and hard to find that I have only gotten to hear one or two, and never in ideal setups. Here I am making a blantantly wide-reaching statement, but it is absolutely true: ALL new 1-bit DACs sound absolutely awful compared to the good multibits (BB PCM63 and Phillips TDA1541, especially) and the good old 1-bit's. There has been a growing trend to throw analog stages and other junk into the DAC chip, and the result is absolutely dreadfull. IF someone made a 1-bit DAC that handled the newer formats w/o all the nasty analog stages on-chip, I would certainly try it out. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  12. The VTL IT-85 is a push-pull EL34 amp. Pretty standard design, although I'm sure they use rather high-quality components. If you are looking for something more affordable you might try the AES AE-25 Superamp (Push-pull KT88's with triode mode) at $1200 assembled ($1000 kit), or the regular AE-25 at $800 assembled ($600 kit) (Push-pull EL34's). Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  13. Prana, you can upsample/oversample any sample rate to any other sample rate with a computer. The problem is that upsampling w/o application of a filter (oversampling), doesn't really give you any advantage (except perhaps for the sin(x)/x rolloff of a multibit DAC, but that can be compensated for w/o upsampling). However, the problem is that oversampling with a filter sounds pretty awful. This accounts for 50% of the nasty sound of digital, I'm convinced. (The other half is poor analog stages, especially opamps.) For playing back any PCM audio (From redbook to 192khz DVDA), the absolute best-sounding system will always be a non-oversampling multibit DAC. Period. End of Story. If I rebuild this DAC instead of moving to SACD (which is tempting), it is very likely I will keep my digital front-end (obviously) and change the DAC's & Analog stages to those of the Adagio DAC by Thorsten. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  14. Randy, In the DAC prototype I am currently using, a clock (essentially idential to the Audiocom Superclock, measured performance is about <10ps jitter) is driven DIRECTLY to the bit clock of the PCM1702. There is not a single logic chip or anything in between. That is, plain and simple, the jitter the DAC sees. I'm not really ready to go into excessive detail in how the signal is buffered/isolated/converted in the DAC, but the Computer->DAC communication is completely asynchronous and has no effect whatsoever on the timing of the clock. I'd really have to see the thread to know what exactly I said and under what circumstances. Also, I truly did not believe really good playback was possible from a PC for awhile until I came across this method. It is not an exceptionally new idea, but this is the first implementation I know of, and there are no readily-available commercial designs. (All the firewire stuff uses this sort of asynchronous communication with the actual clock's located on the receiving side, instead of vice-versa. But none of the firewire stuff is out yet.) As I said, I'm looking to convert the design to firewire and upgrade the DACs & analog stages, but ultimately I am losing interest, instead looking towards SACD. Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling."
  15. Randy, every single time I mentioned the quality of a clock, I was specifically speaking about jitter. Sorry I was not clear on this. I'll say it again: The quality of a transport in terms of jitter is dependant 100% on the quality of the clock (and it's power supply), NOT the mechanism or laser pickup. EDIT: What I'm saying here is that a transport, even an extremely high-end one, has no sort of 'inherent' advantage over a regular CD Player, it is completely dependant on the quality of the clock, and the various parts of the DAC (as I said in my post there). A Transport/DAC combo has some advantages (upgrading one at a time) over a single CDP unit. But if the Transport/DAC combo is using S/PDIF or similar, it will almost ALWAYS have worse jitter than a combined unit with a good clock (like the Audiocom Superclock or the LCAudio XO). Charlie ------------------ "What's that noise?" "It's the carpet, it kinda mutes the speakers." "No, it sounded more like the chandalier falling." This message has been edited by Spider124 on 07-18-2001 at 05:35 PM
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