Running LOMC with MM (47K) loading


This is the way I run my Zyx 4D and my Benz Ebony L before it. I have a JLTi phono preamp which allows me to do this. I have been satisfied with this pre since buying it new. Yet I may be in the market for a new (Different) one. However some I have seen may not offer this ability. One that has great reviews also  has the loading and gain all tied together. Not sure about Herron but it may be out of production. Not sure about others. 
 
The question comes  with @Atma-sphere comments on loading and circuit stability. He contends that the loading  damps (stops) the cartridge cantilever from moving as freely as it was designed (my words) And it is better IF you can run with no loading. But that requires a stable circuit which not all have. Apparently my JLTi has a stable circuit because I have been running LOMC's this way for a 10-15 yrs. 

That said, should I require this attribute to my next phono preamp? And might I be better off to send the JLTi to Joe Rasmussen  (Allen Wright's partner) for upgrade to Pre and new Power supply?. That will be the cheapest and that is likely to be the step I take. However the question still exists. If the damping is as per Ralph's assessment, it would seem that the stability of the  circuit is of greater importance than the ability to have a lot of loading options with unstable circuitry. Another question, Is loading a band aid for a  circuit which is not at an optimum? I am not an electronic tech so I am not  looking to stir the pot but  for my own  understanding  Thanks
artemus_5

Showing 4 responses by pindac

I have used a LMOC on a Valve Input/Output MM Phonostage.
From a Audible Perspective, the marriage of the Two Devices delivers a prentation that is Rich and Voluminous.

As for a Presentation it suits 'IMV' non complex music combined with female volcals.
It also worked quite nicely with a Male Harmony with Harmonica and Acoustic Guitar.
With ECC81 Valves as a Input, it was Volume Control Hungry to achieve the Listening Levels I prefer, and on a few tracks, the Volume was not enough and the replay was a little wanting for extra Volume.

Put the SUT in place and the same Cartridge becomes a very airy detailed device, that lends itself to all Music Types.
The Volume Control is happiest when set at at approximately half rotation and this leaves ample more for when required.

I have not got a Problem with the MM Stage minus SUT.
I have got a Cartridge that can wear two costumes.
One version is a MM only Cob Horse with a Cart in Tow, and the other version a SUT enhanced performance Flat Race Horse released from the Stalls.     
The reference was made to ECC81 to help explain why there may have been a need to use the VC at a full rotation.
The arrangement of Tubes and Brand Selection of Tubes used with the Phonostage are a result of it being Bespoke Produced for me with trials on other Tube Configurations and Brands having been undertaken.
ECC83's were rejected by myself as a Input Valve.
The design allows for the usage 83's, and I knew that the 83 would allow for more Gain with the LMOC.  
As said, the outcome of using the Cart Direct to Phonostge or via a SUT
has not created anything unwanted, when it comes to Sound Quality.
There are Two Presentations available from one Cartridge. 
 
@larryi 
             I have a long experience with Valve Equipment.
For a person like myself, with sesitivities to certain perceived sounds that are catergorised as detractors as a result of a Sonic Trait.
I am very careful not to produce a Sound that draws my attention to a Sonic Trait that is noticeably present and not an attractor to the Sound Quality.
The Phonostage I was having produced was a ECC83 Input/Output as a Prototype.
It had a lot to offer and I heard it evolve with a couple of design changes to the Power Supply and exchanges of the Internal Components to Matched Boutique Parts.
I heard the model,that in the words of the designer / builder was a finished model, without much more to be done.

I informed the designer that it was possibly one of the best all Valve Phonostages I had heard.
I made it known that the ECC83 was causing me a concern.
There was something overbearing as a Sonic Trait and the Perceived Weight Underpinning the Music and Vocals are too much for my liking.
The Weight was quite noticeable, and the projection of the Mid's and Highs were subdued as a result.

There was a friction between myself and the designer, that had a very constructive conclusion.
Shortly after the last audition, I was offered a audition of the same Device with ECC81 Valves at the input stage.
I accepted this offer and the rest is history, with a couple of twweaks to the components and the ECC81's the Phonostage was now where I wished for it to be.

As a follow up to my receiving the Phonostage, another friend kindly offered to extend the fledgling experience, by making available a very attractive collection of Vintage Matched ECC81/ECC83 Configurations.

It was agreed the Phonostage would receive approx' 200 Hours of use, which was done through a Reverse RIAA and CDP on repeat.
 
The Designer /  Builder,  myself and a selection of members of my local HiFi Group were present on the day, to take part in the Vintage Tube Rolling experience on the Phonostage. 

The Tubes in use today by myself were unaminously agreed by the attendees, that from the permutations produced, the combination of the Valves I have in use were a stand out over the other arrangements.
The options on permutations on this day were quite vast, so not all were achievable. 
One thing that is recollected quite strongly, is that particular valves that were thought to be quite capable, did not Pop into the Limelight with a
 X Factor during this Tube Rolling session. 

As said I can use ECC83's at the Input without any concern for the Phonostage.
I have not felt the need to return to a configuration I struggled with at an earlier date.    
I am not a EE minded person.
My Trust was with the Engineer for the design / prototype builds.
As is, with all my other Amplification.

My contribution to the prototypes was to supply a quantity of Boutique Components from Brands the designer did not usually use, as well as supply ears to help with assessments as the design was developed.
This was done more under the guise of further learning, rather than believing a improvement could be achieved through exchanging components.
The designer had Two Identical schematics for 83Input / 83 Output Prototypes.
The Models only differed, as one model was a Single Input, and the other Model has Three Switchable Inputs. 
A Brand of Copper Cap's I chose are exchanged from the designers selected ones in my Phonostage,  these are allowing a Lighter Airier Presentation more aligned to my preference.
A lesson learned one can say.

As for the Phonostage as a development, I heard it with 83's Input Output, 81 Input/ 83 Output and a ECC82 Version .
The Power Supply has been produced in a couple of versions,
the second version is a very noticable improvement over the first edition.
I have the second version Power Supply.
I also know there was a surprise moment about the measurements, and in Layman Terms, the quietness of the Phonostage was extremely impressive.

Recently I have learned there is now another version Three of the Power Supply.
A friend who has been in the company of this Phonostgae on a few occassions has been impressed by this design, which has resulted in them now purchasing one with the Version Three Power Supply.
I am yet to learn whether it will be the same as mine or a 83/83.
This will be determined when the COVID restrictions are altered to allow non family members into anothers home, and the evaluations can start.

The restrictions with COVID over the past year has prevented the HiFi related 'get together' experiences I enjoy.
Hopefully I can get out and meet very soon and hear some of the
Lock Down developments that took place.