[GregC]

I have an Ambrosia preamp with a phono board that allows both MM and MC inputs.  The MC input has a fixed 1000 Ohm load, so I was thinking about loading resistors in parallel at the RCA inputs to reduce the loading impedance.  I am going to use 133 Ohm RCA loading plugs, so with the 1000 Ohm load I will have a 117 Ohm effective load which is about perfect based on the manufacturer's recommendation.   

I also own a 1:20 step up that I can plug into the MM input.  My cartridge has a 4 Ohm internal impedance, so the 117.5 Ohms shown by the step up to the cartridge may be too high of an impedance.  Everything I have read suggests a load of 10 to 20 times the internal cartridge impedance load when it comes to step ups.  I was wondering if I could use the same 133 Ohm resistor plugs in parallel at the turntable input of the step up to lower the impedance seen by the cartridge from 117.5 Ohms down to 62 Ohms?  That would be a better impedance match for the 4 Ohms internal impedance on the cartridge. 

I am confident in my calculations for the MC direct input, but am I correct that I can use the same loading plugs on the turntable input of the step up to reduce the load seen by the cartridge?

[AvFan]

I had the same questions about loading with a SUT in the chain.  I spent some time researching loading on MC carts and found that as long as the load exceeds the 10 to 20 times the internal impedance there was little or no change in the cartridge's performance.  And if you look at the specs for many MC cartridges they say the load should be at least a spec'd load.  My dedicated MC preamp is set at 10kOhm so I put a 100ohm resistor in parallel to test what I read.  I couldn't hear a difference between 100 Ohms and 10,000 Ohms.  Maybe my system can't reveal the subtle differences but now I just make sure I've achieved at least the 10 to 20 times the cartridge's internal impedance, regardless of whether there is a SUT in the chain, and I don't worry if it is many times more.

[GregC]

I had the same questions about loading with a SUT in the chain.  I spent some time researching loading on MC carts and found that as long as the load exceeds the 10 to 20 times the internal impedance there was little or no change in the cartridge's performance.  And if you look at the specs for many MC cartridges they say the load should be at least a spec'd load.  My dedicated MC preamp is set at 10kOhm so I put a 100ohm resistor in parallel to test what I read.  I couldn't hear a difference between 100 Ohms and 10,000 Ohms.  Maybe my system can't reveal the subtle differences but now I just make sure I've achieved at least the 10 to 20 times the cartridge's internal impedance, regardless of whether there is a SUT in the chain, and I don't worry if it is many times more.

I definitely meet the criteria of being above the minimum recommended loads using my MC step up or MC direct.  I just read that if your impedance is too high the tonal balance can be skewed towards being too bright.  Even though I think both my MM and MC inputs sound outstanding, I want to test simple options to assure that I am able to eek out the best performance from my vinyl playback chain.   

[sunnydaze]

I seriously doubt you can hear a difference between 117 and 62 ohms.  Even with larger differences, you'd likely not hear it.   IMO...don't worry about it!

[GregC]

I seriously doubt you can hear a difference between 117 and 62 ohms.  Even with larger differences, you'd likely not hear it.   IMO...don't worry about it!

Based on my ears being closer to sows ears than golden ears I bet you are right.  The resistor plugs would make more of a difference on my MC direct, where the fixed 1000 Ohm load will be loaded down to 117 Ohms.  A simple tweak does not hurt and puts my mind to rest I have the best potential sound from my setup.

[sunnydaze]

I hear ya about the nervosa, and trying to maximize potential.....

But my other thought is that the loading plugs may do more damage to the signal (eg: another link in the chain theory)  than the "potential benefits"  of achieving the "theoretically correct"  loading.

Try it both ways, I'd be curious to hear the results.

[woodsyi]

I hear differences between 10 and 1k Ohms.  I got 8 stops in that range and I am usually at 121 Ohms with my primary pick up having 5 Ohms internal impedance.  At 75 Ohms or below (40.2, 20, 10) music gets loose.  I will sometimes go to 242 if I want to go brighter on some recordings.  I have gone as far as 475 for some recordings but never stay there too long.  1K, 4.75K and 10K did not work out.

Frankly,  I don't know why a phono preamp with gains for LOMC would not go to at least 100 Ohms for impedance setting.  I think the sweet spot for most upscale LOMC is between 50 and 500.  I really don't know how good your phono card is in your Ampzilla pre but a pick up of Universe II's stature deserves to be tried with a phono section that will allow you to try different impedance settings between 50 and 500. 

I agree about the suggested plugs possibly causing more harm than good.  I think you owe to yourself to try in home a stand alone phono section with adjustable impedance loading.  Dan has a good one at Modwright, ph150.  I know he had a tester for beta trials.  Maybe he still has it around to try?

IMHO and YMMV of course. 

[AvFan]

I definitely meet the criteria of being above the minimum recommended loads using my MC step up or MC direct.  I just read that if your impedance is too high the tonal balance can be skewed towards being too bright.  Even though I think both my MM and MC inputs sound outstanding, I want to test simple options to assure that I am able to eek out the best performance from my vinyl playback chain.

I'd agree that with MM cartridges the higher the load the tone skews towards the higher frequencies. I have loaded down a Grado to 10k and an Ortofon 2M Blue to 32k to get them where I wanted but I didn't hear any real change with different loading on MCs.  Of course this may not be true for you and others have noted they can hear a difference.  If I'm going to load a MC cartridge I typically aim for 100ohms as a starting point (of course taking into account the manufacturers recommendation and the 10-20x rule) and let my ears be the judge.  The best thing about load plugs is they are a fairly inexpensive way to dial in the sound of your cartridge/system to your preference and easy to remove if they are altering the sound in an unacceptable way.

[bacobits1]

I agree you might think your hearing changes but if you have to listen that hard you are kidding yourself.
Just being anal about it for a period I understand. Settings here are usually between 100 and 300 Ohms most of the time. I wouldn't buy a Phono unless it is completely adjustable.

But my other thought is that the loading plugs may do more damage to the signal (eg: another link in the chain theory)  than the "potential benefits"  of achieving the "theoretically correct"  loading.

 John, I also agree with that.

[GregC]

I hear differences between 10 and 1k Ohms.  I got 8 stops in that range and I am usually at 121 Ohms with my primary pick up having 5 Ohms internal impedance.  At 75 Ohms or below (40.2, 20, 10) music gets loose.  I will sometimes go to 242 if I want to go brighter on some recordings.  I have gone as far as 475 for some recordings but never stay there too long.  1K, 4.75K and 10K did not work out.

Frankly,  I don't know why a phono preamp with gains for LOMC would not go to at least 100 Ohms for impedance setting.  I think the sweet spot for most upscale LOMC is between 50 and 500.  I really don't know how good your phono card is in your Ampzilla pre but a pick up of Universe II's stature deserves to be tried with a phono section that will allow you to try different impedance settings between 50 and 500. 

I agree about the suggested plugs possibly causing more harm than good.  I think you owe to yourself to try in home a stand alone phono section with adjustable impedance loading.  Dan has a good one at Modwright, ph150.  I know he had a tester for beta trials.  Maybe he still has it around to try?

IMHO and YMMV of course. 

The Ambrosia phono stage is superb, being good enough for me to sell a Whest PS 30RDT SE and have no regrets.  The Absolute Sound raved about the MC stage on the Ambrosia, even with the fixed 1000 Ohm load.  At the time I got the Ambrosia I had a Miyajima Labs Shilabe cartridge, and it sounds great loaded at 1000 Ohms. 

I recently upgraded to a ZYX Universe II so it works best if loaded down to 100 Ohms.  I was looking at trying loading plugs because I want to see if the ZYX tonal balance is better when loaded to the manufacturer's specification.  With the SKY 20 the gain is perfect, and the load shown to the ZYX is 117.5 Ohms, but it does not match the guideline that a step up should show a cartridge a load of 10 to 20 times the internal impedance of the cartridge.  I can have the fixed load changed in the MC direct on the Ambrosia if I find the ideal loading.

I owned a Modwright SWP 9.0 SE and I am a fan of Dan's work.  Unfortunately I do not have the space on my rack for the PH150 and its power supply. 

I agree with you regarding the ZYX deserves the best.  I have an Origin Live Sovereign deck, Origin Live Conqueror MK2 arm with upgraded silver hybrid  cable, and the ZYX Universe II so I value high quality vinyl playback.

I appreciate your time to comment and provide your insights.

[GregC]

My Ambrosia has two separate circuits on the phono board, MM at 42 DB gain with a 47K load and MC direct that can be loaded 52/58/64 DB gain and it has a fixed 1000 Ohm gain.  So far I am preferring the step up into the MM input.

[THROWBACK]

The answer may be system dependent. I was running my Miyajima Madake into a DSA Phono II with a (selectable) input impedance of 450 Ohms. I added a super tweeter to my setup and found the system sounded much better at 200 Ohms.

You might try cheap resistors to get the frequency balance where you want it, then switch to a high-quality resistor for sound quality.

[GregC]

The answer may be system dependent. I was running my Miyajima Madake into a DSA Phono II with a (selectable) input impedance of 450 Ohms. I added a super tweeter to my setup and found the system sounded much better at 200 Ohms.

You might try cheap resistors to get the frequency balance where you want it, then switch to a high-quality resistor for sound quality.

You are correct that everything is system dependent.  The Shilabe sounded great at 1000 Ohms and that was actually the load the distributor said he liked in his system. 

I had a hard time deciding between a Madake and the ZYX Univerese II for my recent cartridge upgrade, especially after a few years of happy ownership with my Shilabe.   I think each of the distributors are awesome people to deal with and both products offer excellent performance and quality. 

Your Madake into a DSA Phono-2 is a very nice setup you must be happy with it.

[GregC]

I thought I would report back my findings regarding parallel loading.  I bought some 133 Ohm RCA plug resistors from DB Systems.  David from DB Systems is a great guy to deal with, I was very impressed with his customer service. 

I asked for as close to 125 Ohms as possible, while using just one resistor per plug.  David said that 133 Ohms was available and close to my desired load.  I also asked for Teflon RCA plugs in an effort to have the least impact on sound quality. 

I plugged the 133 Ohm resistor plug into a Vampire Y adapter in one RCA input and the phono cable into the other RCA input and the Y adapter into the step up transformer input jack.  The 133 Ohm plug along with the 117 Ohms (effect load shown to the cartridge from the 1:20 transformer) yielded 62 Ohms load shown to my cartridge.  That is much closer to the theoretical 10x to match the internal impedance load of the cartridge.

What I found was the sound was still dynamic, detailed, and musical; however, the highs were smoother without being rolled off.  For a small outlay of cash for some high quality RCA resistor plugs I am very happy with the results.  I now know that matching load impedance can yield positive and audible results.
 

[THROWBACK]

to: GregC

"Your Madake into a DSA Phono-2 is a very nice setup you must be happy with it"

Yes, I am: VERY! I had a chance to compare it directly to the top Ortofon cartridges (MC Anna and MC A95); also using the DSA Phono II, but in a different room, with different speakers, etc. Clearly, they are wonderful cartridges as well. But IN MY SYSTEM, I prefer the "richer" sound of the Madake.

[AvFan]

What I found was the sound was still dynamic, detailed, and musical; however, the highs were smoother without being rolled off.  For a small outlay of cash for some high quality RCA resistor plugs I am very happy with the results.  I now know that matching load impedance can yield positive and audible results.

That is good news!  I couldn't agree more that cartridge load plugs are an inexpensive modification that can yield great results.  And I can second your comment about David Hadaway at DB Systems.  I use a DB-1B preamp and a DB-8HG MC phono preamp and David has been very helpful in the past. 

[TomS]

I have a Miyajima Kansui running into a Vinnie Rossi LIO phono stage. It uses internal step ups for MC and has remote control cart loading in very small increments. It's fascinating to play with the loading from your listening chair, but I still tend to set and forget it. Once in a while I'll think "that's a little bright" and drop it down on the fly, but it's very rare. Both the Kansui and my previous cartridge, a Soundsmith Hyperion, suggest somewhat unorthodox loading, so the remote made this easy to dial in, then I left it.

Glad you found a setup that works for you and that DB Systems is still great to work with.

[GregC]

I have a Miyajima Kansui running into a Vinnie Rossi LIO phono stage. It uses internal step ups for MC and has remote control cart loading in very small increments. It's fascinating to play with the loading from your listening chair, but I still tend to set and forget it. Once in a while I'll think "that's a little bright" and drop it down on the fly, but it's very rare. Both the Kansui and my previous cartridge, a Soundsmith Hyperion, suggest somewhat unorthodox loading, so the remote made this easy to dial in, then I left it.

Glad you found a setup that works for you and that DB Systems is still great to work with.

I had a Shilabe and it worked great with either my 1:20 SUT with no resistors or my MC direct with 1000 ohms fixed load.  The ZYX is low impedance and low output.