Where are the ZV9 builders???

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Some new pics :

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Soft start module
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The output cap are RIFA PEH169 22000uF + RIFA PEG124 1000uF + MKP 0.47uF as base.
Today I did some bypass testing, found that one Mcap MKP supreme 4.7uF + one Bennic XPP 39uF to get the superb result.
Will keep on testing....

cheers

Coffin:smash:
 
By the way...

I've been fiddling with my ZV9, again. I used to run it as a transconductance amplifier, with no feedback and with disconnected Aleph CS. I had loaded the output with various resistors-values from 7.5-15 ohms worked best.

But, I got an itch and some free time, and opened it again...

I decided to go back to feedback variant...but I wanted just a little bit...

Inserted feedback resistor 31.7 k (27 k+4.7 k). Input resistor 2.7 k. Also put a 330 nF capacitor to hi-pass it at around 180 Hz. Fed by a "passive" preamp, it has enough gain for Visaton B200's in 2-way Open Baffle...

Now, which variant sounds better? I don't know. Non-feedback variant sounded more "lively" but it got unpleasant at high volumes. With feedback, it is more "shy" but a bit cleaner.

Just a matter of taste....
 
Downside: It costs more, more capacitance takes up more space
Upside: Better filtration, better dynamics
Bear in mind that most electrolytics have really wide tolerances. It's nothing to see +-20%. If you think in terms of 15000uF and add 20%, you're almost half-way to 22000uF. Unless you go really nuts, there won't be a problem. If you do go nuts, stick a resistor or inductor in front of the cap bank to slow the pulse it draws from the diodes. Problem solved.

Grey
 
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GRollins said:
Downside: It costs more, more capacitance takes up more space
Upside: Better filtration, better dynamics
Bear in mind that most electrolytics have really wide tolerances. It's nothing to see +-20%. If you think in terms of 15000uF and add 20%, you're almost half-way to 22000uF. Unless you go really nuts, there won't be a problem. If you do go nuts, stick a resistor or inductor in front of the cap bank to slow the pulse it draws from the diodes. Problem solved.

Grey


Grey .......... yes ;

but - output cap was/is in question .
 
Most of what Grey say's is true until you get to the goin nuts part. :D But, bigger tends to improve low freq performance. Gives less phase shift. Lower Damping Factor. Lower Xl, lower ESR, quite likely higher ESL. Even if only an infinatesmally small amount of improvement is to be gained, someone will go for it. :xeye: And of coarse, listening to it wins out every time.
One suggestion I've read regarding caps effecting your signal path. When they are out of the passband by a wide margin, their bad effects are less noticeable or effect the signal less. But then, I've also read, never use a bigger cap than necessary too. :confused:
 
Vix said:
By the way...

I've been fiddling with my ZV9, again. I used to run it as a transconductance amplifier, with no feedback and with disconnected Aleph CS. I had loaded the output with various resistors-values from 7.5-15 ohms worked best.

Hi Vix. Me feedling again, too;) I know its a while back you said this, but...Did you find it necessarry to load the output? I will be using Z9 on the ABBY clones, so I might not need the little DF it brings. Just curious, since I am setting mine up as a transconductance amp, right now. One more thing, did you jumper out R18? The schematic in Fig 4 shows it like that.

:)
 
Hi Steen!

Yes, I found it absolutely necessary to load the output. I started with 30 ohms and went down, until I reached 7.5 ohms. In my experience, around 10 Ohms was the best value driving Visaton B200 's in an Open Baffle. While I had the Visations in a box (ML TL, with a closed port, so effectively a sealed one, around 66 L volume) I needed less damping, so I used values between 15-22 Ohms.

Since I had disconnected Aleph CS, I also jumpered out R18.

However, after a while, I found that a little feedback sounds better with the OB speakers...

IMHO, ABBY clones will definitely benefit from a no-feeback option. Then just use a load resistor to tune the "tone" you like . Just like a Guitar tuning ;)

Regards

Vix
 
steenoe said:
Thanks for great advice, Vix:) Looking forward to play around with the Zv9 again. I have also made a dualmono kind of audiophile version of the J-fet BoZ. Dualmono is affordable when the psu is 2 duracell's:D

:)

You're welcome. Concerning the preamp: When you remove the ZV9 feedback, gain will go up. If your source has enough output, and with efficient speakers, you may find that you don't need an active preamp at all. At the moment, I am using just a Cathode Follower with a single 6922 tube as a preamp/buffer. J-fet Boz also works fine, but it is not as "liquid" as a tube...

Downside of the tube follower is that you can't push ZV9 to max levels, there will be instances when you'll want it just a bit louder, (Zv9 has the reserve) but the "follower"preamp can't provide more voltage...

I'm thinking about building a tube preamp...(maybe a simple SRPP)....or...who knows...

Vix

P.s. Just noticed in the tube thread that some folks dislike the SRPP...:eek:
 
Peter Daniel said:
Today I connected the tweeter (Aurum Cantus ES G1) directly to the amp through 6.8uF Siememns MKV cap only (the midrange was connected through BG N 1000/50 cap), no other electrolytics at amp's output have been used.

If you run your tweeters through those large electrolytics, you really don't know what Zv9 is capable of ;)

The focus, delicacy, definition and resolution of highs are truly impressive.


Thats a very cool idea, I'll be testing that.

:cool:
 
I am not finished yet, I decided to solder a new pair of boards, with some better part. Black Gate caps and so on. I am quite sure about what to use for the outputcap. I have some of the usual Panasonics, but I might try some Elna's that I have. Another idea would be to parrallel Pana FC's to get to 10000uF. Any other suggestions?

:)
 
steenoe said:
I am not finished yet, I decided to solder a new pair of boards, with some better part. Black Gate caps and so on. I am quite sure about what to use for the outputcap. I have some of the usual Panasonics, but I might try some Elna's that I have. Another idea would be to parrallel Pana FC's to get to 10000uF. Any other suggestions?

:)

Yes, smaller caps than 10mf works better and if you include a 330 uf -or so- on that group plus a small film like MPK you will hear the diference.

Cheers ;)
 
Thanks Tony. I will try smaller ones in parallel. I just found some Nichicon Muse 2200uF caps in the drawer, they will fit much better on the board than the FC's, which will have to be raised. I think I will try with those first. Paralleling 4 of them per channel can be just squeezed in, on the board.

:)
 
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