[jupiterboy]

My Phonomena II has bit the dust for the second time this year. I don’t know if Mr. Yee is going to be as generous in repairing it this time, so I am wondering about low cap phono pre's, preferably with some loading options for MMs.

I like what I have read about the LCR circuits, and the Budgie would bring more valves into the mix, but with a dose of negative feedback and an odd output impedance.

What else should I be considering?

[rodge827]

The iPhono is a good one to look into at $399.99.

http://ifi-audio.com/portfolio-view/micro-iphono/

[WireNut]

Vista Audio phono preamp. Great phono pre for $299.00.

 

[jupiterboy]

The iPhono is a good one to look into at $399.99.

http://ifi-audio.com/portfolio-view/micro-iphono/

So for MM, the lowest cap is 100pF and 47K is the only loading? I can’t find a large/readable version of the jumper settings.

[bacobits1]

What was the problem with  the Phonomena II? Under warranty?
Interesting because such a low powered device usually does not develop problems.

The two Pres mentioned the Vista MKII and the iFI could give a "NOVA" Phonomena a run for the money.
I have had all 3.

If you go to the Review "enjoy the music" published it will give you a better pict of the settings.

http://www.enjoythemusic.com/magazine/equipment/0313/ifi_audio_iphono.htm

[jupiterboy]

What was the problem with  the Phonomena II? Under warranty?
Interesting because such a low powered device usually does not develop problems.

The two Pres mentioned the Vista MKII and the iFI could give a "NOVA" Phonomena a run for the money.
I have had all 3.

IDK. This is Michael’s prototype. It did fail in Feb., so anyone's guess. He said it was a resistor that time, and I see some yellowing in two positions on the board in the right channel side. He has made all the mods himself, but the unit is years out of warranty. I don’t expect him to fix it for free forever. Two failing in a year signals some sort of issue to me.

[jupiterboy]

Vista Audio phono preamp. Great phono pre for $299.00.

 

I see how this works, you get custom cap and loading from the factory. My wires measure at 33pF, and I have never measured the cart's response with only 33pF, so I would be guessing at what loading to have it set for. An interesting choice. Op amps?

[bacobits1]

On the Vista the capacitance is not user adjustable you would have to state what you want  when you order. Gain and Resistive loading is adjustable to any resistance you might possibly need.
Resistors supplied should cover most settings. I will say the Ifi is very convenient. But this all depends on how much you change cartridges.

[jupiterboy]

On the Vista the capacitance is not user adjustable you would have to state what you want  when you order. Gain and Resistive loading is adjustable to any resistance you might possibly need.
Resistors supplied should cover most settings. I will say the Ifi is very convenient. But this all depends on how much you change cartridges.

I don’t swap out much. 440MLa is what I am using, so zero cap and probably something around 30K with 38db gain is going to be ideal. Hard to know how to load it without measuring with 33pF total cap.

[neobop]

If you need custom loading Vista is the way. 
http://www.vista-audio.com/products/phono-1mkII/index.htm

For AT MMs something around 150pF total seems ideal.  Does 33pF include the internal tonearm wire?  If so, then 100pF should be fine.  If not, then 75pF might be better.  The standard unit comes with 47K as default and resistors are loaded in parallel.  But you can order it however you want.  You can order it without default resistors and whatever value you select becomes the load.  I think 4 or 5 sets of resistors are supplied.  You load them in little slots like cart clips. 

Seems there's an abundance of riches these days for great inexpensive phono stages, but Vista is the adjustability champ.
neo

[jupiterboy]

If you need custom loading Vista is the way. 
http://www.vista-audio.com/products/phono-1mkII/index.htm

For AT MMs something around 150pF total seems ideal.  Does 33pF include the internal tonearm wire?  If so, then 100pF should be fine.  If not, then 75pF might be better.  The standard unit comes with 47K as default and resistors are loaded in parallel.  But you can order it however you want.  You can order it without default resistors and whatever value you select becomes the load.  I think 4 or 5 sets of resistors are supplied.  You load them in little slots like cart clips. 

Seems there's an abundance of riches these days for great inexpensive phono stages, but Vista is the adjustability champ.
neo

33pF is just my cables—cart to RCA. The loading sounds ideal. I could put any resistors in I wanted and no soldering. I would probably get one set up with zero cap in the unit and just let it fly with 33pF.

[neobop]

33pF is just my cables—cart to RCA. The loading sounds ideal. I could put any resistors in I wanted and no soldering. I would probably get one set up with zero cap in the unit and just let it fly with 33pF.

AT recommends 100 - 200pF.  Sometimes if there's too little capacitance mid-treble droop can be worse and response is more erratic.  It could work though, you never know.  The problem is that Vista default capacitance is a fixed value that can't be changed.  Maybe you could order one with sockets where the default resistors normally go and use them for resistance loading.  Then you could buy some caps to use in the resistor load sockets if necessary.
Tell Boris what you want to do and I'm sure he'll fix you up.
neo

[jupiterboy]

AT recommends 100 - 200pF.  Sometimes if there's too little capacitance mid-treble droop can be worse and response is more erratic.  It could work though, you never know.  The problem is that Vista default capacitance is a fixed value that can't be changed.  Maybe you could order one with sockets where the default resistors normally go and use them for resistance loading.  Then you could buy some caps to use in the resistor load sockets if necessary.
Tell Boris what you want to do and I'm sure he'll fix you up.
neo

This is a very interesting topic. The lowest total cap I have been able to get and measure frequency response is 100pF. The AT carts have a bump at the top. People tame this with lower loadings. My measurement and ears confirm a persistent top end bump even with 38K loading and 100pF total cap. Problem with the lower loading is that you take the top end sparkle away from the cart. Some, IMO wisely, point out that AT probably sets there spec without consideration of the cable capacitance, assuming most users won't add this in and can’t control it anyway.

Hagerman calc shows ideal loading with 33pF total cap to be more than 120K—wow.

I was under the impression from the responses that cap was one of the variables that could be adjusted on this unit. I need to talk with the designer and find out.

Thanks for the input!

[neobop]

Vista standard configuration is adjustable gain and resistance loading.  Capacitance is normally a fixed value - whatever you want.
I believe Boris can accommodate you with plug in caps, in the manner I described.  I don't know if plug in caps is doable in their standard location because it might be physically prevented.   Here's Vista Circle and phono thread:
http://www.audiocircle.com/index.php?topic=114404.0

"Hagerman calc shows ideal loading with 33pF total cap to be more than 120K—wow."

Hagerman is a talented designer, but the calculator is rather useless for MM loading.  Mechanical function is the main determinant of response and combined with electrical resonance (LCR) determines final response.  Virtually all carts have a naturally rising high end that's tamed with mechanical damping and flattened out with judicious manipulation of electrical parameters.  That bump in response you refer to might be cantilever resonance + the rising high end of the cart.   Does it look like this?
https://sites.google.com/site/zevaudio/turt/cartridge-comparison-list/audio-technica-at440mla

I think you could get a better explanation if you converse with Dlaloum here:
http://www.audiocircle.com/index.php?topic=88878.msg1358218#new

He's very good at explaining these things.
neo 

[jupiterboy]

Thanks for the thread links. Most charts of the AT carts show something similar, but I take my measurements after the phono pre. My Hi-Fi test record, oddly, has a disparity between the left and right channel that is not reflected in other test LPs with pink noise. The averaging tends to emphasize the hump a bit. At any rate, I have done months of listening at 62.5K, 50K, 38K, 24K and 21.5K. I've also taken measurements at those loadings, and compared in-room response as well, since that is where the rubber meets the road, so to speak.

Here is an example that I believe is 38K loading with 100pF total cap.




I only find the Hag calc interesting from a theoretical perspective, as real world results deal with so many other factors.

Sounds like I can do zero pF and 100K native to decrease the load from that point. When I get down to it, I will ask about the possibility of a mono switch.

[neobop]

That's the HFN test record?  If so, the pink noise is flawed.  All test carts show a severe roll off around 15K.  This was reported a few years back by an EE, and it seems to be so:
http://www.bm.rs/Micro%20Benz/Benz%20Micro%20Ace%20-%20HiFi%20News%20July%202012.pdf

Good luck with 100K and the stock 440.  Keep the volume down when you start, you might get an ear bleed.  I have a 440ML OCC, and with the stock stylus mine was unlistenable at 100K, any capacitance.  At the time I was using a Sonus Formula 4 arm and 1 foot of VDH silver arm cable going directly into a 50pF AHT stage.  Maybe you'll have different results.  I had to substitute a stylus with a boron or beryllium cantilever to get acceptable response at 47K let alone 100K. 

A mono switch is normally on the line stage.  It's usually not recommended to have those extra connections on a phono stage and it might not be physically possible.  Vista is tiny.  For mono you could strap your cart or combine channels at the output.  Other than that, you'll have to ask.
neo

[jupiterboy]

Good luck with 100K and the stock 440.  Keep the volume down when you start, you might get an ear bleed.  I have a 440ML OCC, and with the stock stylus mine was unlistenable at 100K, any capacitance.  At the time I was using a Sonus Formula 4 arm and 1 foot of VDH silver arm cable going directly into a 50pF AHT stage.  Maybe you'll have different results.  I had to substitute a stylus with a boron or beryllium cantilever to get acceptable response at 47K let alone 100K. 

I would load it around 32-38K, but with 100K native, I could produce a match for any cart. 100K, as you note, does not sound good with the AT carts.

[JackD]

Both of my Vista's were ordered with 50 pf of native capacitance and that covers cartridges from well over a dozen brands and 40 years.  Though the photo show seven different values of resistors shipped, mine both came with nine and you can buy whatever you want for about $2 a pair from even RS.  Use this calculator to figure out what you need. 

http://www.electronics2000.co.uk/calc/series-parallel-resistor-calculator.php

[jupiterboy]

Both of my Vista's were ordered with 50 pf of native capacitance and that covers cartridges from well over a dozen brands and 40 years.  Though the photo show seven different values of resistors shipped, mine both came with nine and you can buy whatever you want for about $2 a pair from even RS.  Use this calculator to figure out what you need. 

http://www.electronics2000.co.uk/calc/series-parallel-resistor-calculator.php

Thanks. Being able to choose what resistors to use is a big draw for me. I have used a few—Vishay, Tantalum etc. in loading plugs and find they all sound a bit different. I would be lost without the online calcs.

[bajaed]

Wonder how the Vista would work with my Dyna 10x5? What settings would be recommended? In my system the cart seems to need all of the 55db gain the Jasmine has for MM.