recstar24 Posted July 19, 2009 Report Share Posted July 19, 2009 To my ears, the ZD is about the best I've heard so far across a broad spectrum for general listening. (There may be others that do certain things better) Do you think the ZDT 'sounds' better, or is it that it 'measures' better? I only care about the former. I believe that the ZD/ZD SE also measures better as well. In the same review I mentioned Craig stated "The Zana Deux distortion, square wave response and bandwidth are better than any transformer-coupled amp." I haven't heard the ZDT but would imagine it to provide similar performance. I think if your happy with the ZD then that is just fine, unless you specifically needed the extra power. Quote Link to comment Share on other sites More sharing options...
Icarium Posted July 19, 2009 Report Share Posted July 19, 2009 I think it sounds better.. no idea how it measures. Quote Link to comment Share on other sites More sharing options...
recstar24 Posted July 19, 2009 Report Share Posted July 19, 2009 I think it sounds better.. no idea how it measures. Which one are you referring to that sounds better, ZD or ZDT? (Excuse grammar nazi for coming in as the pronoun "it" is not clear enough:p) Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 19, 2009 Author Report Share Posted July 19, 2009 I can also see myself as using the ZD as a pre-amp to a traditional stereo system in the not so distant future as well. Has anyone done this? How does it sound? I wonder if the ZDT is better for that, or if it only allows the ability to drive a small set of efficient speakers... Quote Link to comment Share on other sites More sharing options...
Sherwood Posted July 19, 2009 Report Share Posted July 19, 2009 You could drive a large set of efficient speakers, too... Quote Link to comment Share on other sites More sharing options...
dsavitsk Posted July 19, 2009 Report Share Posted July 19, 2009 Axiom Project Doug I sent you a link to that a while back, I would love to hear your comments. In theory, theory and practice are the same, but in practice ... Yes, I basically like a high load for a tube and no cap in the cathode. The design is clever in a lot of respects, and there is much about it to like, but in a cost for sound calculation, I'm not sure I agree with their choices. Here are some issues ... Chokes present a load to the tube that is 2*pi*Frequency*Inductance. There are two things to note about that. The first is that the load is rising with frequency. This is not necessarilly a problem so long as the choke is sufficiently large, but at the margins it can be an issue, particularly with high rp tubes. The second is that the choke is just too small for the tube in the first stage. They are loading a 6J5 with a 200H choke. The 6J5 has a rp of ~7K. The higher the load on a tube the better, but you really want it to be at least 4 to 5x rp. At 60 Hz, that choke gives a load of ~75K which seems pretty good. However, at 20Hz, it is only 25K which is a lot less good. Moreover, that diode has an impedance of around 200 ohms at these currents. This, as you know, is multiplied by mu and added to rp. So, rather than 7K, rp is actually ~11K meaning that that 25K load is really on the borderline, and deep bass is likely to suffer considerably. In contrast, the LEDs in yours (which are diodes as well) have an impedance or about 8 ohms, and the load that we put on the tubes is about 10M, even at 20Hz. In fact, the limit to yours comes fro the Miller capacitance of the output tube which is a different issue altogether. Anyhow, this really comes down to the 6J5 being a poor choice of valve -- a D3a, for instance, solves much of this. The advantage of a choke over a CCS is that it can swing above B+, but that does not seem to be the issue here, at least in the first stage, as the grid will hit cutoff long before that point. So, a CCS on the first stage with a better biasing scheme would likely be a good thing. Oh, and the PS has a little more ripple and a lot more sag than I think you'd want -- and in simulations, it might destroy the rectifier. Why they didn't use damper diodes there instead of in the cathodes is a bit of a mystery. Edit: I should also add that iron resonates, and that much iron is likely to resonate in unpredictable ways. It may not be an issue, but it is likely not an amp that you could just build as drawn without some sophisticated measurement equipment and just expect it to work. Quote Link to comment Share on other sites More sharing options...
digger945 Posted July 19, 2009 Report Share Posted July 19, 2009 Slightly off topic, but I've always wanted to understand a bit more about this tube v. transistor argument. Copied from whytubes "If you ask enough people (particularly audiophiles), you'll start to discover some truly metaphysical theories on why tubes sound better. Some explanations utilize quantum theory, some are simply wrong, while others are just plain bizarre. But in my own circuit designs I've encountered some odd phenomena that I can't explain. For example, in a mic preamp prototype, I discovered that performance measurements were different if the unit was upside down. After I tried to eliminate all possible environmental factors, the difference persisted, even with a variety of tubes, and in different buildings. It was audible, too, though subtle. Was it caused by gravity slightly shifting the internal tube elements? The earth's magnetic field? I still don't know. Tubes sound better because their distortion products are more musical. Tubes provide a more appropriate load to transducers. Those are the fundamental reasons why tubes sound better, but is there more?" Found googling "input capacitance vacuum tubes" w/o the quotes. Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 19, 2009 Author Report Share Posted July 19, 2009 You could drive a large set of efficient speakers, too...Wow! He's single, isn't he. I wonder how it sounds! I would think that'd be better served by doing a REAR loaded straight line exponential... Quote Link to comment Share on other sites More sharing options...
HeadphoneAddict Posted July 19, 2009 Report Share Posted July 19, 2009 Doesn't Blutarsky still have ZD #40 for sale? I know the Melos is gone and the first ZD sale fell through when a resistor was damaged in shipping (now fixed). I heard it after the repair and it sounded just like before. I for one feel the ZDT must have a deeper wider soundstage than the ZD even though I haven't compared the two directly - my logic is as follows - I compared the ZD to my maxed WA6 with PDPS mod and Sophia 274B rectifier and they were similar in many ways including soundstage. Then with my more recent ZDT vs WA6 comparison it is very clear that the WA6 sounds more forward with a less deep/wide soundstage than the ZDT. Without having ever heard the ZDT I would have recommend the ZD easily, but for now the ZDT has won my heart. I should also add that I heard the ZD SE and Balancing Act at CanJam, and thought they were both very good with HD800 and HP-1000. The working ZDT didn't make it to CanJam, so there was no comparison. I will note - the HP-1000 sounded like someone wired the 4-pin XLR wrong, and crossed over the ground wires to the wrong channel, so they only sound right when used with the single ended adapter (but that will be fixed soon). Quote Link to comment Share on other sites More sharing options...
Icarium Posted July 19, 2009 Report Share Posted July 19, 2009 Which one are you referring to that sounds better, ZD or ZDT? (Excuse grammar nazi for coming in as the pronoun "it" is not clear enough:p) ZDT. Yeah I went with "it" because I thought I had quoted oatmeal's post which was in response to my post which indicated which I thought sound bettered. Oops. Quote Link to comment Share on other sites More sharing options...
atothex Posted July 20, 2009 Report Share Posted July 20, 2009 EC stuff makes me hot. Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 20, 2009 Author Report Share Posted July 20, 2009 Doesn't Blutarsky still have ZD #40 for sale? Don't know, is he here or on the other? I'll look through the classifieds here, but if anyone knows him could they ask?... I heard the ZD SE and Balancing Act at CanJam, and thought they were both very good with HD800 and HP-1000. I heard them too, I really liked the BA as well, but I didn't get a chance to really listen with Senn's. I think I heard the HP-1000 as well, so not a real good comparison for me. Off the top of my head though, I'd say there wasn't enough of a difference to me personally to warrant the extra cost. I'm really gonna have to scrape for the ZD, I just got laid off. Quote Link to comment Share on other sites More sharing options...
penger Posted July 20, 2009 Report Share Posted July 20, 2009 On the other site... the search function in the for sale forums is your friend. Quote Link to comment Share on other sites More sharing options...
Dreadhead Posted July 20, 2009 Report Share Posted July 20, 2009 Don't know, is he here or on the other? I'll look through the classifieds here, but if anyone knows him could they ask?I heard them too, I really liked the BA as well, but I didn't get a chance to really listen with Senn's. I think I heard the HP-1000 as well, so not a real good comparison for me. Off the top of my head though, I'd say there wasn't enough of a difference to me personally to warrant the extra cost. I'm really gonna have to scrape for the ZD, I just got laid off. Sorry about the job man Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 20, 2009 Author Report Share Posted July 20, 2009 Sorry about the job man Thanks. It's gonna be tough! Quote Link to comment Share on other sites More sharing options...
atothex Posted July 20, 2009 Report Share Posted July 20, 2009 Thanks. It's gonna be tough! I don't recall ever seeing 2 Zanas for sale at the same time, until now, but I really really don't think you should do it. Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 20, 2009 Author Report Share Posted July 20, 2009 I don't recall ever seeing 2 Zanas for sale at the same time, until now, but I really really don't think you should do it.Why? Quote Link to comment Share on other sites More sharing options...
atothex Posted July 20, 2009 Report Share Posted July 20, 2009 Why? Well, I don't know how much you have saved up, but if you're gonna be scraping for it, then I'd say a big amp purchase is rather fiscally irresponsible. Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 20, 2009 Author Report Share Posted July 20, 2009 Oh! Forgot a tidbit of information - I already have over half saved for the down I thought I was going to pay on a new one. (I found a used one over on the other site!) I will have to sell stuff and scrounge so as not to tap into what I have to get me by. It's a risk, but not a huge one. I knew the layoff was coming for about 3 months, so I've been saving for it. it just means ramen noodles, and no PS Audio DLIII DAC for a while. It is bad here though. We're at 15% in LA county, and everywhere you look, vacancies, business spaces for rent, etc. Quote Link to comment Share on other sites More sharing options...
HeadphoneAddict Posted July 21, 2009 Report Share Posted July 21, 2009 Don't know, is he here or on the other? I'll look through the classifieds here, but if anyone knows him could they ask?I heard them too, I really liked the BA as well, but I didn't get a chance to really listen with Senn's. I think I heard the HP-1000 as well, so not a real good comparison for me. Off the top of my head though, I'd say there wasn't enough of a difference to me personally to warrant the extra cost. I'm really gonna have to scrape for the ZD, I just got laid off. If you just got laid off you should be saving money, not buying a ZD. Quote Link to comment Share on other sites More sharing options...
Dusty Chalk Posted July 21, 2009 Report Share Posted July 21, 2009 x3 -- assume it's going to last 10 times as long as you expected it to. This is a really bad time to be looking for a job. That said, two (formerly unemployed) people I know just got jobs, so it's not impossible. Quote Link to comment Share on other sites More sharing options...
oatmeal769 Posted July 21, 2009 Author Report Share Posted July 21, 2009 Thanks you guys. For a minute I was like "Why don't they mind their business.." But now I figure it's just other audiophiles who know the urge and are looking out for a fellow nutcase in an awful economy. *sniff* I really think I'm okay though. I work for an Electric Utility, and shuffling around a lot in temporary stuff is kind of normal. As long as people need electricity, I'll be ok. Besides, I got it barely used at a great price, I think if I really had to I could sell it for about a hundred bucks less easily. Unfortunately though, My plans to buy a good DAC to go along with it at the same time would have come out of my 'primary fund' and yeah, that'd be foolish. So now I have a huge bottleneck in my system. Oh well, good motivation to start pestering them for another assignment! I didn't think a DAC made such a huge difference until I heard what I did a couple weeks ago. It's really just as important as the amp isn't it? Quote Link to comment Share on other sites More sharing options...
Icarium Posted July 21, 2009 Report Share Posted July 21, 2009 I think so. Some people feels it plateaus real fast though, but my personal experience is that I've heard quite a bit of variance between several sources that I thought were all good and could be considered top tier. Quote Link to comment Share on other sites More sharing options...
n_maher Posted July 21, 2009 Report Share Posted July 21, 2009 If you just got laid off you should be saving money, not buying a ZD. Sorry, the irony here is to f'ing thick. Quote Link to comment Share on other sites More sharing options...
Voltron Posted July 21, 2009 Report Share Posted July 21, 2009 Beat me to it. Quote Link to comment Share on other sites More sharing options...
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