[Dr.J]

Dallen, what problem?

 

[dallan]

Right channel cutting out and some static on that side. Cleaned pins and went away but now and then hours later it threatened to come back. I probably need to find a cleaner for my tube pins.

 

[Clayton SF]

I get static when I turn the amp on and start switching inputs from I to II to III. Channel cuts out to when switching from L to H. I just fiddle with both knobs until the static goes away and the channel returns. It happens every time I turn on the amp.

 

[dallan]

This happens in mid listening, but like I said it appears to be tube pins.

 

[BobMajor]

I had a similar problem and localized it to the input selector. By moving the selector back and forth to the other 2 positions it generally goes away right a way. I haven't figured out any way to clean inside the selector switch as it appears closed.

 

[dallan]

Yeah i'm not sure Bob, but i actually think it may have been a bad piece of coax in the end.......

 

[telecaster]

I've been curious about the TH900 and ZD matching interested in acquiring both. And more in general about low impedance phones with the OTL deux. As I seem to understand, the output coupling capacitors (the two sticking out of the Zana) are handmade by the maker with paper in oil and is custom tailored at 250uF?
The Zana Deux is an OTL, so the output load being low like the TH900 25ohm will suffer from high pass cutoff filter? Or Im mislead somewhere?

 

[songmic]

Quote:

I've been curious about the TH900 and ZD matching interested in acquiring both. And more in general about low impedance phones with the OTL deux. As I seem to understand, the output coupling capacitors (the two sticking out of the Zana) are handmade by the maker with paper in oil and is custom tailored at 250uF?
The Zana Deux is an OTL, so the output load being low like the TH900 25ohm will suffer from high pass cutoff filter? Or Im mislead somewhere?

 
Normally, I would never recommend an OTL amp for the TH900 due to the impedance mismatch and damping factor issues you've described above. The ZDSE is an exception, however, as it has an output impedance of only 3 ohms at low gain setting, which is *very* low for an OTL amp - the lowest I know, in fact - and even lower than most transformer-coupled tube amps. With the TH900 at 25 ohms, it satisfies the so-called 1/8 rule, so one will not suffer from any distortions theoretically.
 
With that out of the way, I can easily say that the ZDSE is one of, if not the best, headphone amp for the TH900. The synergy between the two is extraordinary, almost as if they were made for each other. Here's why.
 
1. TH900 has slightly rolled off, laid-back mids compared to treble and bass, producing a somewhat colored V-shaped curve. Although this is not a weakness of the TH900 per se, I'm sure many listeners, myself included, prefer the mids to stand out more. The ZDSE complements this shortcoming(?) by bringing the mids forward, as the ZDSE is best known for its rich mids.
 
2. Although the TH900 has one of the widest soundstage for a closed headphone, it is still a closed-back design and doesn't boast a wide soundstage as those of open-back flagship headphones such as the HD800. There is no single-ended headphone amp I know that does soundstage better than the ZDSE, not only in width but also depth. With the TH900 and ZDSE, you will forget that you're listening to closed headphones.
 
3. The euphonic touch of ZDSE makes the TH900 one of the most musical headphone I've ever heard that works gloriously with virtually every genre I throw at it.
 
The TH900 is undisputably the best closed-back headphone available in the market today, but it truly shines with a top-of-the-line amp like the ZDSE.

 

[telecaster]

Wow this setup makes me so envious it must sound glorious! I'm a big fan of OTL AMPS as I believe bad iron can only deteriorate the magic sound of tubes. Although I don't believe mismatched impedance to be detrimental to the sound that much, I understand rhetoric can create slight frequency changes.

I don't believe in damping factor. It is propaganda to me And heard high damping factor sound like crap and low damping factor sounding exquisite. The headphones membrane is to little and light and damping factor play zero weight on it's control. I'm entitle to Personal opinion of course!

What I referred to above is not the output impedance it is the size of the output coupling capacitor that is 250uF per channel. I guess if the bass is deep with th900 then the value of capacitance work well!
I think the sound if OTL could be described as transparent dynamics with deep separation and layering. Lack of distortion and utterly musical medium range that is so pleasing.to the ears.
The zana deux is surely the best Headphone OTL AMP!

I have completely upgraded my lafigaro339 it's an OTL with 265uF ouput film cap per channel. I will first buy the th900 to see if it drive it as well as my hd650. As I understand the first Zana was designed around the hd600 as a cost no object best amp ever. I can only deduct that the so called OTL mismatch for the th900 is false if the output coupling capacitance is of enough value and quality as to not deteriorates the magic of OTL.

atmasphere make one of the best sounding loudspeaker tube amp and that is of course OTL!!!

I believe that current driving capabilities instead of voltage is where all the magic lies...

 

[ValentinHogea]

I'll never regret selling the La Figaro 339 and eventually buying a Zana.
The difference is amazing...

 

[telecaster]

V, thanks for making it even more harder

Of course the Zana is a beauty! But please don't put down the 339 like that, it's a good amp!

 

[Mr.Sneis]

OG Zana Deux #3 is headed overseas to AnakChan to join his th900.  Hope the amp arrives safe and sound! 
 
In its place is ZDT #12.  This is a whole different beast altogether which is now succeeded by the Eddie Current 2a3.  The driver tube is a 12ax7 which seems to also go by 5751.  If anyone has any info about this particular amp and or tube recommendations please let me know!

 

[AnakChan]

Thank you Mr.Sneis for the fast shipment & am anxiously awaitIng for its arrival. I'm very much looking forward to joining the Zana Deux family. Now to make room for it as I've never owned a desktop amp of that size before .

There'll be lots of questions from me to this community as its my first time owning a tube amp, so please do be gentle with me.

 

[telecaster]

If my memory is intact the 12ay7 is 70% of the gain of the 12ax7. The 5751 is 50% or slightly less of 12ax7 gain. Those are classic fencer amp tubes and good one are relatively pricey. Less gain favors Mellowness high gain attack and dynamic.

 

[AnakChan]

Quote:

Thank you Mr.Sneis for the fast shipment & am anxiously awaitIng for its arrival. I'm very much looking forward to joining the Zana Deux family. Now to make room for it as I've never owned a desktop amp of that size before .

There'll be lots of questions from me to this community as its my first time owning a tube amp, so please do be gentle with me.

 
Mr. Sneis, you're a star . I've not even modified the PSU for 100V nor the OI to 3 ohm, but it's already working very nicely with the TH-900. Next to open it up, take some pix and ask Craig what to change for the voltage and OI.