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  #61  
Old 02-02-17, 05:59 PM
andyr andyr is offline
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Originally Posted by RossB View Post
With an active gain stage the input impedance changes the tonal character of the cartridge significantly.
Absolutely! And I would say the majority of LOMC users do not hear the best their cart can deliver because they are limited in the loading they can apply.

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Originally Posted by RossB View Post
Loading via SUT is very different from loading via headamp or active MC stage.
Absolutely! And the loading they can apply with a SUT is very limited.

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Originally Posted by RossB View Post
With a SUT, the primary goal is to step the voltage up to around 5mv - the loading is far less critical to the sound quality.
Sure, the purpose of the SUT is to multiply the output of the LOMC by the turns ratio. So with a nominally 0.28mV Benz LP, the output becomes 2.8mV with a 1:10 SUT.

But I suggest it is a complete non-sequitor to say "the loading is far less critical to the sound quality". The issue with a SUT, IMO, is that there is little ability to get the optimal loading for the cart - so you put up with what you can get.

Sure, if you have a LOMC that really does sound its best at 100 ohms loading ... then with a 47K MM phono stage and a 1:10 SUT, the cart normally sees 470 ohms. But if you put a 12K resistor on the output side of the SUT, this will change the loading seen by the cart to be 96 ohms (47K in parallel with 12K, divided by 100).

But if you have a Benz LP, for instance, there is no way to get it to be loaded at 3K3 (the value which sounds best to me, anyway) with a SUT - unless you replace the 47K default loading in the MM phono stage to 330K (330K / 100 = 3K3). Which will probably have implications for the sound of the phono stage's 1st gain stage.

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Originally Posted by RossB View Post
There is a good explanation of this on the Rothwells site, which explains it better than I can: http://www.rothwellaudioproducts.co....rs_explai.html.
Mmmm, IMO this is a very biased 'white paper' - IMO full of half-truths. But I'm sure all SUT devotees think it is on a par with one of Moses' tablets - ie. God's truth.

For instance, on the 1st page:

1. More importantly, IM distortion tends to be lower in transformers than it is in transistor amplifiers.

That is an absolutely true statement. But, although I am not an SME in solid-state electronics, my understanding is that IM distortion occurs in Class AB amplifiers - which have a +ve DC rail and a -ve DC rail ... there is none in a single-ended circuit (which has just a +ve DC rail).

So IM distortion is not an issue with a single-ended, JFET-based headamp, for instance.

2. Does the cart's tonal balance change with load impedance? It certainly does if the cart is a MM type but LOMCs are much less sensitive to changes in the load impedance.

That is completely A-about-T, IMO. MM carts are very sensitive to load capacitance ... not so sensitive to load impedance. LOMCs OTOH sound very different at different loadings.


Andy
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  #62  
Old 02-02-17, 06:22 PM
merlin merlin is offline
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Originally Posted by Tim Jones View Post
I think the net effect of these (very helpful) answers is that, unless I can somehow arrange a dem, I'm going off the Koetsu idea a bit, and veering towards a Benz LP or perhaps a Lyra. 3 or 4k is a lot of money for something whose character might limit me to particular musical choices.

I do admire timbre and resolution, but neutrality is probably a better idea in terms of how I feel about my system atm...
I was of very similar mind Tim and moved to Lyra. To be fair I'm lucky enough to know Jonathan but the qualities of the Lyra are exactly what I was looking for on the SME. A richness of timbre combined with a passable level of neutrality which made the results of archiving my vinyl more rewarding to listen to on various sources and systems.
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  #63  
Old 02-02-17, 11:01 PM
daytona600 daytona600 is online now
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Quote:
Originally Posted by mjw View Post
While on the subject of Koetsu, can any knowledgable, long term users advise on stylus cleaning, please. I still treat mine like the first baby, so afraid am I of damaging it. It gets a pass with a (otherwise unused, of course) sable artist's brush after every play (a la ESCO) but what about a drop of cleaner or the putties available? I live in fear of the tip falling off and can't even find a web page to tell me if the diamond is glued, wedged or whatever to the cantilever.
Thanks
RCM reduces stylus cleaning to once in a blue moon
anybody using a high end MC like a koestu without a RCM is throwing away hundreds of hours of stylus life
usually get 2500-3000hrs out of my koetsu over the last 30oyears
once in a while use a ultrasonix stylus cleaner or a dust buster to clean the stylus
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  #64  
Old 02-02-17, 11:50 PM
andyr andyr is offline
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Originally Posted by daytona600 View Post

RCM reduces stylus cleaning to once in a blue moon
Absolutely disagree. Using a wet/vac or ultrasonic RCM is a fundamental prerequisite for playing vinyl ... but you should still clean the stylus every side. As well as using a CF brush (on the LP) before and after play,

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Originally Posted by daytona600 View Post

anybody using a high end MC like a koetsu without a RCM is throwing away hundreds of hours of stylus life
As well as suffering record noise that can generally be eliminated with use of a wet/vac or ultrasonic RCM.

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Originally Posted by daytona600 View Post

usually get 2500-3000hrs out of my koetsu over the last 30 years
once in a while use a ultrasonix stylus cleaner or a dust buster to clean the stylus
Despite having used a Nitty Gritty for over 20 years (and recently swapped to an ultrasonic RCM) I would not take the stylus on my Benz LP beyond 1000 hours (2800 sides).

I agree an ultrasonic stylus cleaner is a good thing to have.

Andy
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  #65  
Old 03-02-17, 01:41 AM
G T Audio G T Audio is offline
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Originally Posted by andyr View Post
Not sure I agree with your comment how mfrs arrive at their 'recommended" value ... the specs for my Benz LP merely say "500 ohm to 47K ohm"!

IMO, there is an optimal load for any cart - it is not logical that this value should change when a SUT is suddenly introduced in front of a MM phono stage (ss or valve) instead of using a pre-pre amp (aka ' headamp').

Why a mfr might suggest 2 different values, to me is because of the way a SUT modifies the default 47K loading which most MM phono stages have. As I'm sure you know, when a SUT sits between the cart and the MM phono stage, the cart 'sees' 47K / sq of the turns ratio. So with a 10:1 turns ratio, the load becomes 470 ohms ... with a 20:1 turns ratio, the load becomes 118 ohms.

This, IMO, is the weakness of SUTs.
You might not agree Andy but that is what cartridge manufacturers do. I know because I have asked them...

It is rare that a solid state phono stage is MM only. Therefore the extra gain required for an MC cartridge is normally done activity. It is here that loading is more critical than with a valve/tube phono stage because the only way to load a cartridge (if you have too load) is with a resistor and in 99.99% of phono stages these resistors are cheap and cost about 10pence each. So now you have a very precise coil of wire in the cartridge generator often made from precious metals (silver or gold) and is then connected to a cheap loading resistor which is a disaster from a sonic POV. Often when using a solid state phono stage and a hot cartridge (early Lyra's spring to mind) is where loading helps to tame the higher frequencies to give a more pleasing audible result.

I have found that when using a good MC cartridge with precious metal coils that matching it to a SUT also with precisely wound coils of wire gives the best sonic result.

Loading: IMO the last thing you should be doing is to try to load a cartridge which effectively is a way to restrict or limit its performance. A bit like adding weight to a race car to restrict its performance, or running down the road with a rucksack full of bricks on your back. However I understand this is a way of tuning the sound to give the user a more pleasing or desirable result.

When using a valve or tube phono stage the most important thing is getting the correct amount of gain and good signal to noise performance. This should be No1 on the list and if you must load or try to reduce the cartridges performance then do this by carefully adjusting the input resistor on the secondary side of the SUT. Experiments and careful listening tests done many years ago proved that loading the secondary side of the SUT has very little impact on the performance of the cartridge. There are a couple of cartridges where great care is needed to achieve the best results and these usually have either very low internal impedance or very high internal impedance.
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Last edited by G T Audio; 03-02-17 at 02:25 AM.
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  #66  
Old 03-02-17, 02:51 AM
andyr andyr is offline
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Originally Posted by G T Audio View Post
You might not agree Andy but that is what cartridge manufacturers do. I know because I have asked them...
And I get back to what Mr Lucaschek (Benz) writes in his specs for the LP ... 470 to 47K. IOW - roll your own! In fact, Benz's own phono stage offers 47K - so I'm happy to agree that's what he thinks sounds best.

I myself don't like the sound at 47K - I find the bass is too flabby (although the 'air' around the instruments is wonderful). So I like it much lower.

Quote:
Originally Posted by G T Audio View Post
It is rare that a solid state phono stage is MM only. Therefore the extra gain required for an MC cartridge is normally done activity. It is here that loading is more critical than with a valve/tube phono stage because the only way to load a cartridge (if you have too load) is with a resistor and in 99.99% of phono stages these resistors are cheap and cost about 10pence each. So now you have a very precise coil of wire in the cartridge generator often made from precious metals (silver or gold) and is then connected to a cheap loading resistor which is a disaster from a sonic POV.
Not quite sure what you 're trying to say here? That the default 47K resistor is typically a 10 pence res ... or the loading reses which modify the 47K default are 10 pence reses?

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Originally Posted by G T Audio View Post
Often when using a solid state phono stage and a hot cartridge (early Lyra's spring to mind) is where loading helps to tame the higher frequencies to give a more pleasing audible result.
Let me give you a simple example which explains where I'm coming from. A guy who had a Benz LP contacted me because:
* he knew I had one, and
* he knew I loaded it at 3K3.

He had a very expensive US tube phono stage (BAT?) which was MM/MC ... but the MC input was courtesy of a 1:10 SUT. So the load shown to the Benz LP was 470 ohms.

I lent him a headamp which had a 2nd (parallel) pair of input RCAs and a whole stack of 'loaded' plugs - so he could play with loadings. He found - as I had found - that the Benz sounded best at 3K3 (not 470 ohms) ... so he bought a head amp and now uses his phono stage's MM input.

So, yes, this might well have tamed the Benz LP's "hot higher frequencies" - but it made made it sound much more pleasurable than the sound he was able to achieve using a SUT, with a 470 ohm loading.

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Originally Posted by G T Audio View Post
Loading: IMO the last thing you should be doing is to try to load a cartridge which effectively is a way to restrict or limit its performance. A bit like adding weight to a race car to restrict its performance, or running down the road with a rucksack full of bricks on your back...
Mmmm, yes, obviously. But all we are trying to do is make a cart sound its best by loading it optimally. Which you cannot do with a SUT.

Quote:
Originally Posted by G T Audio View Post
When using a valve or tube phono stage the most important thing is getting the correct amount of gain and good signal to noise performance. This should be No1 on the list and if you must load or try to reduce the cartridges performance then do this by carefully adjusting the input resistor on the secondary side of the SUT. Experiments and careful listening tests done many years ago proved that loading the secondary side of the SUT has very little impact on the performance of the cartridge. There are a couple of cartridges where great care is needed to achieve the best results and these usually have either very low internal impedance or very high internal impedance.
Or you can do what my friend did - use a headamp which allowed extremely flexible loading to optimise the sound of his cart with the MM input to his phono stage. He got great gain and great signal-to-noise performance and he achieved the best sound from his Benz LP.

Andy
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  #67  
Old 03-02-17, 03:56 AM
abbydog abbydog is offline
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In fact, Benz's own phono stage offers 47K - so I'm happy to agree that's what he thinks sounds best.
If you are referring to the Lukaschek PP-2 I have one and it is - how you say - not a shining example of the breed. In particular, the bottom end is awol with a Benz LP whatever the loading.

In fact, it rather amuses me that many dealers selling very expensive cartridges who boast about having 57 varieties of turntable have no phono stages of suitable quality to exploit them. Typically you'll find a couple of afterthought transistor examples from the usual suspects and even a PP-2 would be a bonus!
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  #68  
Old 03-02-17, 04:32 AM
Mike Reed Mike Reed is online now
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All the foregoing is very interesting if slightly technical for me. Interesting because I've just gone from a m/c only s/s phono stage with plug-in loadings to inbuilt valved stages within my pre.

All three of my cartridges (Proteus 1 ohm imp., K. Urushi 5 ohms and Benz Ebony 5 ohms (?)) changed 'character'. It was much more than a slight improvement in dynamics etc., but it was beneficial on all three.

The loading positions on the pre. seem to vary with record as well as cart., although the gain is roughly the same. In other words, the loadings (3,6, 12 and 40 ohms) don't seem to correspond with the internal cart. impedances (although I never use 40). I find it baffling after s/s but am more than happy with the transition. The Transfig. and Koetsu have identical output, with the Benz being slightly higher.
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  #69  
Old 03-02-17, 10:09 AM
G T Audio G T Audio is offline
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Originally Posted by andyr View Post
And I get back to what Mr Lucaschek (Benz) writes in his specs for the LP ... 470 to 47K. IOW - roll your own! In fact, Benz's own phono stage offers 47K - so I'm happy to agree that's what he thinks sounds best.
If you look at my first post on this you will see "Published loading figures are based on a "recommendation" from the cartridge manufacturer and is arrived at by listening in the cartridge manufacturers system, using their test electronics and in their listening room. It is done by ear and not by measurements. Obviously their value could be, and often is, very different from what works best in your system".

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Originally Posted by andyr View Post
myself don't like the sound at 47K - I find the bass is too flabby (although the 'air' around the instruments is wonderful). So I like it much lower.
The Benz LP and LPS fall into the "high impedance" category I mentioned in my first post. These have high internal impedance at 38ohms so I am not surprised that owners prefer it when a higher load impedance is used. The best performing cartridges normally have an internal impedance of less than 6 ohms.

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Originally Posted by andyr View Post
quite sure what you 're trying to say here? That the default 47K resistor is typically a 10 pence res ... or the loading reses which modify the 47K default are 10 pence reses?
What I am saying is the cartridge coils are very precise and intricate and are similar in quality to the transformer windings of an SUT. Basically in a solid stage phono stage cartridge loading is achieved by changing the value of a resister (>47K ohms) that sits directly across the cartridge windings whether in parallel with another resistor or not. To connect an expensive cartridge to a phono stage where a cheap resister is used is very poor IMO as there could be significant audio degradation due to the cheap quality part, something that could have a bigger effect on the sound than changing the loading value itself! The design of the phono stage also has a significant effect of the performance of the cartridge so the whole phono stage including the MC stage, whether head amp or SUT, should be considered as one.

Quote:
Originally Posted by andyr View Post
Let me give you a simple example which explains where I'm coming from. A guy who had a Benz LP contacted me because:
* he knew I had one, and
* he knew I loaded it at 3K3.

He had a very expensive US tube phono stage (BAT?) which was MM/MC ... but the MC input was courtesy of a 1:10 SUT. So the load shown to the Benz LP was 470 ohms.

I lent him a headamp which had a 2nd (parallel) pair of input RCAs and a whole stack of 'loaded' plugs - so he could play with loadings. He found - as I had found - that the Benz sounded best at 3K3 (not 470 ohms) ... so he bought a head amp and now uses his phono stage's MM input.

So, yes, this might well have tamed the Benz LP's "hot higher frequencies" - but it made made it sound much more pleasurable than the sound he was able to achieve using a SUT, with a 470 ohm loading.
Quote:
Originally Posted by andyr View Post
Mmmm, yes, obviously. But all we are trying to do is make a cart sound its best by loading it optimally. Which you cannot do with a SUT.
l'll simply say that there are SUTs and SUTs. Not many audio manufacturers use good SUTs because they are expensive and not many transformer manufacturers know how to make good ones these days. I suspect your example above is more to do with the quality of the SUT used than any loading applied to the cartridge.
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  #70  
Old 03-02-17, 10:23 AM
G T Audio G T Audio is offline
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Originally Posted by Mike Reed View Post
All the foregoing is very interesting if slightly technical for me. Interesting because I've just gone from a m/c only s/s phono stage with plug-in loadings to inbuilt valved stages within my pre.

All three of my cartridges (Proteus 1 ohm imp., K. Urushi 5 ohms and Benz Ebony 5 ohms (?)) changed 'character'. It was much more than a slight improvement in dynamics etc., but it was beneficial on all three.

The loading positions on the pre. seem to vary with record as well as cart., although the gain is roughly the same. In other words, the loadings (3,6, 12 and 40 ohms) don't seem to correspond with the internal cart. impedances (although I never use 40). I find it baffling after s/s but am more than happy with the transition. The Transfig. and Koetsu have identical output, with the Benz being slightly higher.
The EAR 912 uses different turns ratios on a pair of internally mounted input step up transformers providing 30, 26, 23, and 20dB of MC gain before the MM phono circuit. The loading switch just selects the different turns ratios i.e. different MC gains and the front panel just shows the associated load presented to the cartridge on that setting. Basically its just a gain switch.
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  #71  
Old 03-02-17, 11:32 AM
Mike Reed Mike Reed is online now
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Originally Posted by G T Audio View Post
The EAR 912 uses different turns ratios on a pair of internally mounted input step up transformers providing 30, 26, 23, and 20dB of MC gain before the MM phono circuit. The loading switch just selects the different turns ratios i.e. different MC gains and the front panel just shows the associated load presented to the cartridge on that setting. Basically its just a gain switch.
Thanks. Sounds as though it's not really a loading (i.e. impedance) switch, then.. However, there's a gain switch as well, starting at zero and reducing by - 6 and -12 dB. The -6 setting is more or less de rigeur for all my cart's regardless of where the loading (called 'adjustment') switch is pointing.

My Superline stage had capacitance plugs as well, which were needed, but there's no such facility on the 912; presumably because valves or valve circuit designs render capacitance a non-issue. Or because, unlike the Superline, the signal ends up going through a m/m circuit.

It would have been preferable to have mastered the abacus before investigating higher mathematics but it's a bit late for that; knowledge is never wasted, however !

B.t.w., my Ebony L's internal impedance is 5 ohms, whereas I see that the LPS is the 38 ohms you mentioned above. Seems odd for a manufacturer to have such a discrepancy in their range although the Ebony does have the not insignificantly lower output.

Last edited by Mike Reed; 03-02-17 at 11:47 AM.
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  #72  
Old 03-02-17, 01:14 PM
andyr andyr is offline
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Originally Posted by G T Audio View Post

l'll simply say that there are SUTs and SUTs. Not many audio manufacturers use good SUTs because they are expensive and not many transformer manufacturers know how to make good ones these days. I suspect your example above is more to do with the quality of the SUT used than any loading applied to the cartridge.
I agree there are SUTs and SUTs ... but I would think that with the high price of the LAMM phono stage (which is what the guy who changed to headamp+MM input had), they would not be using the cheapest one they could find.

Andy
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  #73  
Old 03-02-17, 04:04 PM
pmac pmac is offline
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AFAIK Lamm use Jensen transformers
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  #74  
Old 03-02-17, 04:14 PM
andyr andyr is offline
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Originally Posted by pmac View Post
AFAIK Lamm use Jensen transformers
So from GT's PoV - these must be cheap rubbish (given that the sound with a properly-loaded Benz LP into the Lamm's MM input is so much better)!

Andy
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  #75  
Old 04-02-17, 09:46 AM
G T Audio G T Audio is offline
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Originally Posted by andyr View Post
So from GT's PoV - these must be cheap rubbish (given that the sound with a properly-loaded Benz LP into the Lamm's MM input is so much better)!

Andy


Not so much cheap rubbish, but I doubt Jensen use exotic core materials or oxygen free copper and oxygen free silver in their transformers which is why I wouldn't use them in my high-end designs...
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