Jump to content

the NEW Zana Deux, ZDT and Balancing Act thread


Recommended Posts

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.

Link to comment
Share on other sites

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...

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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).

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.
Link to comment
Share on other sites

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 :(

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.