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EQUIPMENT FORUMS >> ZP3 / ZMC1,2,3 >> Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
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Message started by marcvs66 on 02/16/19 at 02:56:22

Title: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by marcvs66 on 02/16/19 at 02:56:22

I've been running Denon DL-103s as my cart of choice for a while now. Which is the reason why I have an AUDITURIUM 23 step-up MC transformer (specifically for DL-103) coming my way shortly. I am considering switching my phono stage to a ZP3 to match my Mini Torii. My question is: will the A23 step-up transformer work w/ the ZP3?

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by Acetone on 02/16/19 at 16:16:03

Hey Marcvs, the ZP3 likes to see 47K ohm 2V input (2V for full gain).
So if your SUT will output the above all should work very well together.

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by marcvs66 on 02/16/19 at 18:08:08

Thanks for the comment!

This A23 is specifically voiced for Denon DL-103 carts (there's also a version for Ortofon). Auditorium 23 seems to be somewhat secretive about the specs for this little step up transformer - at least I can't find any info?

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/18/19 at 12:26:53

The ZP3 HAS a 47K input impedance and likes to see 4-5mv input voltage to output a 2V source (which your Mini would want), it does not want a 2V input voltage like Ace said. He is mostly likely think about a Dec. amp. not the Phono.
Most all SUTs assume a 47K load at the input of the Phono because that is the de-facto standard MM input load on all MM Phono's. I would have to assume the a23 is no different.
I tried to look up the transformer specs used in the A23 but they are no where to be found, as you said. Regardless, I'm going to say that the A23 will work just fine with the ZP3. The only area you could possibly have any issue with is gain (output from the ZP3 to Mini). Depending upon the how much the A23 'steps up' the output of your cart (unknown with knowing the coil ratio), running the ZP3 directly into the Mini it may not be enough.
For example, I run a SoundSmith Zephyr MIMC that has a .04mv output. It connects into a SUT that is configured to give me about ~20db of gain. If I were going directly into my Dec. amp (requiring ~2V for full output), it would NOT be enough to get full volume out of the amp (close but not enough). However I run into a Pre first and it is able to make up the extra gain I need, so this could easily be your case as well, especially since the DL-103 is a little bit lower output then my Zephyr.
Hope this helps, unfortunately not a clear cut answer since the winding ratio on the A23 is unknown. Just know it will def. work, you just may not be able to drive the amp to full volume (most likely wont be able to).

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by Archie on 02/18/19 at 17:46:21

jslateiv,

Just a side note. When I do the calculations, a 5mV input to the ZP3 gives only 0.6V+ out. I've wondered if I have a problem with my math. Are you sure of the 2V out? I note that the ZMC1 specs say both a 20X and 61db with a ZP3. By similar calcs, my .05mV cart with my ZMC1 SUT gives about 0.6V out of the ZP3 when using the 61db figure and more like 1V when using the 20X figure. I'm not sure which is correct but I'm guessing the latter since I seem to get more gain with the SUT and a .05mV cart then with just the ZP3 and a 5mV cart. For my calcs I'm using a formula that I found here: http://www.theabsolutesound.com/articles/taking-the-guesswork-out-of-phonostage-gain-1/

And a further side note. When I was waiting for my ZMC1 a couple years ago, I ran my .05mV cart directly into my ZP3 and boosted the output of that with my CSP3. I got got results except for the added noise. I'm sharing this not as a recommendation but rather as an example of what sort of works.

There must be gain specs for that A23 somewhere but I too guess it will play well with the ZP3.

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/18/19 at 19:36:25

Hey Archie, I did not look at the ZP3 output spec before I posted (but should have),. It is posted as 41db of gain (not a specific V out which would certainly be dependent on the source driving it). I guess I was assuming that since most of Steve's amps are in the 1.5-2V sensitivity range that for a typical 5mv cart input you would get an output in the ~1.5V range. Should have done my math first.
Regardless though, you are correct with your math. I do get .56V for a 5mv input at 41db of gain. Not a 100% sure on your discrepancy though. Possible that the carts are outputting a slightly different amount than the pub. spec.
I too ran my .04mv cart straight into the ZP3 (just to see) and yes, while the gain can be made up with a traditional Preamp, like you found out there is a lot of inherent tube/circuit noise that gets revealed in the process. Like everything in this hobby, especially when your components have sensitivity specs, working or not depends on a lot and on match up those sensitivites. Speaker, amp, pre sensitivity are all going to play a big role.
My thought is that the ZP3 will work best with carts @ 5mv of output and an amp that is on the higher sensitivity side, certainly no lower than 1.5V (ie, <1.5V) for full output. In so many cases, we rarely listen to 'full' output though so I imagine that the less than ideal or matching specs on paper don't really always come into play, though if you can match it up proper then it will definitely benefit the noise floor coming from the ZP3 as we both know. Check out the following link. It has some good calculators and ratio descriptions,..
http://www.sengpielaudio.com/calculator-gainloss.htm

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/18/19 at 19:42:05

Crazy, but I can't find A23 specs anywhere, and I've done a lot of digging! LOL I too think it'll work just fine with the Mini as the Mini has a lower sensitivity of 1V . marcvs66 may possibly need a pre depending upon how sensitive his speakers are but I think that would really be the only 'gotcha',.. speaker sensitivity being possibly low,..

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by Archie on 02/18/19 at 23:33:43

I'm out of my element with most of what your link was about. I wouldn't be surprised if Steve would have like the ZP3 to higher output but from reading his development papers I think he was happy to get 42db with low noise. I think the ZP2 may have been more like 35db. I find having the CSP3 very important to make up some of the deficiency, especially since my cart of choice is putting out only 0.35mV. Without it I couldn't run my ZMA at full output.

If I understand the ZMC1 correctly, the variable impedance really makes it nice since there doesn't need to be a close match between SUT and cart. I've only used mine with 3 different Ortofon MC carts but they've all sounded great with it.

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/19/19 at 12:12:12

I imagine he would have loved more gain but didn't want it at the expense of noise. I'm in the same boat, with out my BHK-Pre I wouldn't get near full output.

Various carts will like to see a different but specific 'load' or load range as it were. The load reflected back to the cart from the transformer/phono connection is the Phono impedance divided by the Sq.root of the transformer 2ndary.,.. so say you have a 1:10 ratio on the trans your using,.. 47,000/(10x10) = 470ohm,.. The ZMC has a variable resistor across the sec. and that in turn is in parallel with the load of the ZP3, allowing you to 'tune' the imp. to the cart between the 470ohm down to something much lower (for the carts that like to see a lower imp.).

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by NormD on 02/19/19 at 13:05:32

I use a ZSTAGE to boost my ZP3 to match other inputs into my ZTpre.

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by marcvs66 on 02/23/19 at 16:43:15

Thanks everybody for the detailed answers to my question - much appreciated! Sorry - too busy w/ work this week... didn't have a chance to check this thread until the weekend...

I have to admit - being new to the hobby - a lot of the technical detail mentioned above, is a little too advanced for me to fully understand. I did however take the plunge and got myself a used ZP3 at this point (thanks to one of the members of this forum).

The seller turned out to be somewhat local and he was nice enough to offer to come over to my house and let me try the ZP3 in my system with his step-up transformer (Bob's Devices 10x/20x).

The result: the ZP3 with my (ZU) DL-103 sounded REALLY good! My speakers are ZU Omen MkIIs (high efficiency) - so, even at 10x setting: plenty of volume for my smallish living room.

The A23 is on its way from Germany currently - but - I have no doubt that it will work quite well in my current set-up.

Thanks again everybody for running the numbers and trying to figure this out for me.

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/25/19 at 13:57:58

That's great Marcvs66. Always nice when you can try something out like that. The Omens are great speakers. I have a highly modified pair that I LOVE! Their high sensitivity really helps when things like the sensitivity of other equipment is maybe not as matched as you would like. I have no doubt that the A23 will work great for you. If I had to guess I would say the ratio is at least 1:10 but probably a touch higher which will certainly be in your favor!

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by marcvs66 on 02/25/19 at 21:38:19

The A23 is on its way. I'll report once I have it in hands and have had a chance to try it out. My friend in Germany - who is sending me the A23 - found out that it (supposedly) uses HAUFE T-890 transformers. The step-up ratio of the HAUFES is 1:10. So, it should do the trick.

What modifications did you do to your Omens?

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/26/19 at 16:50:43

I had the original Omens, so some of these mods are already incorporated into your MKII's. (asd1001, t-nuts, foam padding behind FRD) what I did was all at Sean Casey's direction....

1. 1" Oak dowel between the 2 drivers & back wall (weak spot on the front baffle)
2. Druid V/Def. drivers (FR103ND) & ASD1001 and added the t-nuts to the cabnet.
3. replaced woolish driver damping with foam blocks
3. Event cabling harness (internal)
4. full length Fiberglass wrapped dowels (ZU R&D from Druide VI) epoxyed/glassed into all 4 verticle corners
5. attached/gapped butcher blocks to the base

All in all I would have to say the FR103ND Drivers, front>back dowel, and ridigly attached butcher block base made a tremondous difference. Alot of this was done over years of time. The f>b dowell between the 2 drivers really helps alot. and was one of my first mods.. The last was the attachment of the bases. I had been sitting the speakers on them to good effect but attaching them really tightened up the low end. Cummlatively everything really compliments the speakers as a whole and I couldn't be more pleased. I had toyed with buying a pair of Soul Supremes and when talking to Sean, he said 'if you don't mind doing a little work, I can get you 95% there for 1/4 of the $',.. that last 5% being the Radian tweeter used in the Druids and Supreme's,.. The 'Super' Omens now are really notthing like an Omen and are more of a cross between a Druid V/Soul Superfly in an Omen shaped box that makes them pretty unique!

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by jslateiv on 02/26/19 at 16:57:44

I had posted some pics of the Butcher block bases on the 'ZRock2' thread you posted on a while back,.. not sure if you ever saw them,...

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by marcvs66 on 02/26/19 at 22:59:25

jslateiv.

thanks for above posts - extremely interesting! I sent you a PM.

Title: Re: Can I run a ZP3 with A23 STEP-UP MC TRANSFORMER???
Post by marcvs66 on 03/14/19 at 14:17:55

So, the A23 step-up-transformer finally made it from Germany - and I've been living w/ it for about 10 days or so. It does do a wonderful job negotiating between my turntable and the ZP3. I am running a ZU Audio modified DL-103 - and to me - in combination with the A23, the DL really does an amazing job for what I paid for it. I couldn't be happier.

The A23 step-up did introduce some hum into my system and it took a while for me to figure out, how to remedy that problem. I read through a number of posts (regarding ZP3 hum) here on the board and ended up moving the step-up as far away from all the power-sources/power cable/etc. as I could - and that took care of the hum almost completely. I'm down to a very acceptable hiss - which one can only hear when I turn the volume up past the half-way mark. I can live with that.

Conclusion: I am happy to report that there is really nice synergy between the Auditorium 23 step-up and the ZP3. If you are running any DL-103-type cartridge, I would recommend looking into the A23 step-up.