Phono 2 feedback

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WireNut

Re: Phono 2 feedback
« Reply #40 on: 18 May 2017, 02:23 pm »

That's using the assumption that all off leaves it at 47 k as with the  Phono I.  If all off is in fact zero the just get the resistor equal to the load you want. I haven't looked at all the switch combos so don't know if you can get close that way.














     
        Is C11 and C12 for capacitance loading ?

JackD

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Re: Phono 2 feedback
« Reply #41 on: 18 May 2017, 11:56 pm »
Yes.  Then account for the value of your TT's wiring plus 50 pf for the unit itself.

WireNut

Re: Phono 2 feedback
« Reply #42 on: 19 May 2017, 06:28 am »

Yes.  Then account for the value of your TT's wiring plus 50 pf for the unit itself.



I tried measuring the capacitance of my tonearm wiring and interconnects with a DMM just yesterday but my test failed :scratch:.
Meter set to caps, removed head shell and set aside, probed each head shell pin in the end of the tonearm while probing the hot and ground pins at
the end of each interconnect. No luck trying that, the DMM barely registered any thing  :dunno:.
 

Audiovista

Re: Phono 2 feedback
« Reply #43 on: 19 May 2017, 09:53 am »
Hi guys,

Sorry for being AWOL. I was on the road, and was not getting notifications on my email. Have to check out why. I just came back, and checked Vista circle. Please do not hesitate to use my email if you need prompt answers - that is something I check multiple times during the day, wherever I am!

Thank you Jack for helping!!

To answer the original question about 34.5k loading. Best thing to do is to move all DIP switches to the OFF position, and insert resistor 37.5k into R11 and R12 positions. There is internal default resistance of 1.5Mohm (1500 kohm) and the combination with 35.7k will yield 34.87kohm... close enough :)

The resisotr should be metal film, something like this one: https://www.digikey.com/product-detail/en/yageo/MFR-25FRF52-35K7/35.7KXTR-ND/15036


JackD

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Re: Phono 2 feedback
« Reply #44 on: 19 May 2017, 12:17 pm »
Wirenut

Closest you will get is to do what you've done and then disconnect TT's leads from Vista.  Then with cable as straight as possible measure the pin and shield of one of the RCA's.

bacobits1

Re: Phono 2 feedback
« Reply #45 on: 19 May 2017, 12:24 pm »
Good to know, "0" then or practically with deeeps off.
Makes it very easy to custom load, no calculations.
Very versatile Phono Pre!!

Audiovista

Re: Phono 2 feedback
« Reply #46 on: 19 May 2017, 05:11 pm »
 :D

WireNut

Re: Phono 2 feedback
« Reply #47 on: 20 May 2017, 02:39 am »
Know problem Boris. I figured you were traveling.
When you say "Turn off all external switches" do you mean ALL loading, gain, and Low-Pass filters if I'm going to set the loading internally?
Or, can I set the loading internally, but use the external switches for gain and low pass filter's?
 
I'm trying to learn how to set up the phono-2 for future cartridge's.

Also, regarding C11 and C12 can you give me a cap series/brand/example for my reference?
My current cartridge suggest 150-300 Pf.

I've had no luck trying to measure my TT's tone arm and interconnect wiring so far. I'm obviously not checking it correctly. :scratch:.

This is a learning process for me. Thanks for your help.

Steve
     
 
 

 

JackD

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Re: Phono 2 feedback
« Reply #48 on: 20 May 2017, 03:24 am »
To change the loading internally just turn all the resistance switches to off and leave the rest as normal.  I suspect once you get a measurement for your tonearm cable and leads you will be within the parameters for capacitance without doing anything else.  To measure the cable it is easier with alligator clip leads but if you don't have them and only probes lay one of the cables out straight and put the positive lead from the DMM on the pin and the negative on the shield.  Don't let them touch each other or both parts.  If your TT is a vintage one with original leads it will be somewhere around 100 pf.  I measure almost a dozen JVC, Denon, Sanyo and Techinics tables and got between 90 and 125 pf on all of them.  That is why I ordered my Phono I Mk II with 50 pf instead of the standard.  Just FYI the resistance will make far more difference than the capacitance if you are even close.  The only cartridge I ever put any effort in to capacitance loading with was Felix's beloved Shure m97xe and I found it dead sounding at any setting.  Also make sure you meter is reading pf and not nf.

Audiovista

Re: Phono 2 feedback
« Reply #49 on: 20 May 2017, 07:48 am »
Thanks for understanding Steve! Jack is correct, only loading switches need to be OFF, gain and filtration still need to be set as required. I should have been clearer in my post (darn jet lag).

What instrument are you using to measure cable capacitance? Many standard DMMs cannot measure low capacitances accurately. They may use 1kHz frequency for measurements, and for the cables 10kHz or higher will be better. I have just ordered a very inexpensive RLC meter to test, will let you know how it works when I receive it (I do not expect miracles, intended use is just for quick incoming inspection of power transformers).

You are measuring cables only, right? Cartridge is disconnected?


WireNut

Re: Phono 2 feedback
« Reply #50 on: 20 May 2017, 01:27 pm »

What instrument are you using to measure cable capacitance? Many standard DMMs cannot measure low capacitances accurately. They may use 1kHz frequency for measurements, and for the cables 10kHz or higher will be better. I have just ordered a very inexpensive RLC meter to test, will let you know how it works when I receive it (I do not expect miracles, intended use is just for quick incoming inspection of power transformers).

You are measuring cables only, right? Cartridge is disconnected?


 Thank you both for all this great info  :thumb:. I should have stayed in electronics in high school  :duh:.
My meter is a Southwire 10040N. I just read It will only check capacitance in auto range from nF and uF.

 Later today I’m going to make some test leads with clips and I’ll try and see if I can get a measurement in nF doing what Jack suggest.
If I can get a stable reading I’ll convert the numbers to pF. It's worth a try. I have to do something in my retirement :D.

 I’m checking my table’s capacitance with the cartridge disconnected and with the power off.

Audiovista

Re: Phono 2 feedback
« Reply #51 on: 22 May 2017, 09:41 am »
I checked the specs of your DMM (http://www.southwiretools.com/tools/file.get.do?file_id=244).

Minimum range is 40nF with 10pF resolution (0.01nF), ±5% and ±7 digits accuracy ... not great for what you want to do.

For example, if the actual capacitance is 0.10nF (100pF), the DMM can display any value between 0.03 and 0.17nF (that's the ±7 digits part which becomes the most critical for those low values).

rickmusicman

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Re: Phono 2 feedback
« Reply #52 on: 16 Jun 2017, 07:05 pm »
Is the Vista Audio website down permanently? I have been trying to access it for the last 2 weeks and it comes up with a server error message. Verty Audio does not even show the Phono 2 yet. Are they still in business?

Audiovista

Re: Phono 2 feedback
« Reply #53 on: 16 Jun 2017, 10:18 pm »
Hi everyone, we are having a problem with web hosting service, something got messed up with Vista's site during service upgrade (Verty site is using the same service buf it is not affected). I hope to resolve the issue within couple of days.

All is good with Vista, we are all well and busy!

Thank you,
Boris

rickmusicman

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Re: Phono 2 feedback
« Reply #54 on: 16 Jun 2017, 10:33 pm »
That's great news, not about the web site, but that you are busy and doing well. I will be ordering a Phono 2 in the next few weeks. Rick

Audiovista

Re: Phono 2 feedback
« Reply #55 on: 17 Jun 2017, 12:10 am »
Thank you Rick!

Audiovista

Re: Phono 2 feedback
« Reply #56 on: 20 Jun 2017, 01:59 pm »
After I had to learn much more than I ever wanted about web hosting and servers, two problem escalations and several weeks, the site is functional again....

I'm super happy to go back to working with hardware. :)

rickmusicman

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Re: Phono 2 feedback
« Reply #57 on: 27 Jun 2017, 07:05 pm »
I ordered the Vista Audio Phono 2 a few days ago. A little frustrated because after the payment, I have sent 2 emails to Verty Audio to verify they received the payment as well as spec information on the turntable, cartridge and pre-amp. I have not received an email back, has anyone else experienced this when ordering a product from them?

Audiovista

Re: Phono 2 feedback
« Reply #58 on: 27 Jun 2017, 08:55 pm »
Hi Rick,

Thank you for the order. I checked with Verty. Apparently they received PayPal notification yesterday evening and your last email with preamp info about two hours ago. The input impedance will not have any adverse effects on the preamp operation. Your Phono-2 is ready to ship. I think that Phono-2 will be set for your cartridge. The optimization is always done with Phono-1, but not with with Phono-2 as it is easy to set with the DIP switches.

Thanks again,
Boris

rickmusicman

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Re: Phono 2 feedback
« Reply #59 on: 27 Jun 2017, 09:55 pm »
Boris, Thanks for the update. Sorry I seemed a little worried. I didn't realize it took so long for the paypal payment to go through. I had sent it 2 days ago, and sent an email the same day asking for payment verification. I then sent a 2nd email today because I hadn't heard back and was afraid the paypal transaction had an issue. Thanks for your quick response. I can't wait to get the phono 2! Rick