What innovative, unconventional cartridge designs can you recommend?

@pindac 

each design will be bespoke to each Cartridge, to produce the correct reverse RIAA

I don't think you actually mean "each Cartridge"? 

Maybe you really mean "each Cartridge Model"?

Since all DS Audio's current Cartridge Models use the same LED and photo-electric sensors. that implies that "all current DS Audio Cartridges" only need one 'custom' design of Equalizer.  Fortunately. there are more than a score of these so-called 'custom' designs presently on the market. 

Since the circuit schematic has been placed in the public domain by DS Audio, I think we should immediately drop the word 'custom'.  We don't use it for phono stages.

I note that one of the Equalizers you favour does not even include RIAA equalisation.

The SoulNote Equalizer one model up from mine supports dozens of emphasis curves to support a plethora of records cut by record companies before RIAA became the standard.

As far as your unsubstantiated allegation that photo-receptors are non-linear (you use transistors as an example of non-linearity) you have to understand what is being varied to get a response. 

With DS Audio, what varies is only the fraction of the area of the photo-receptor exposed to the same frequency and intensity of infra-red light.  It varies from a little bit to a lot more, but unlike a transistor it does not cross a null point.  What comes out is current in direct proportion to the exposed area.  If you like, it responds in a linear fashion like a transistor biased in a pure Class A amplifier. 

I am pretty sure I have given you a reference which includes graphs, though it is the distance between the multiple lines that has to be the same for linearity.  Straight line graphs are so boring, there is no point publishing one.

@audphile1 

You described what I am hearing better than I ever could.  Thank you.

As it happened, the first record I played was an Original Master Recording of Adrian Boult conducting Elgar's transcription of a Bach organ work.  MoFi is on the cover.

Next was a direct-to-disk-master of two Beethoven piano sonatas. Like most audiophile recordings, this did not do much for me with Moving Magnet, but when the optical cartridge bit deep into the guts of the piano - transformative.

I had to play my 60-year old copy of Bruno Walter playing Mahler 9.  It came up like new.  Even the used Boult recordings (in quadrasonic sound) of the Elgar symphonies came up a treat.

The other DS Audio component I own is getting a work-out too.  The gel stylus cleaner.

@richardbrand you will be rediscovering your entire collection now. And the sound will only get better as the cartridge breaks in. I noticed with the Hana the first signs of improvement at around 30hr mark. But it really blossomed at close to 100hrs. 

Thanks for the music recommendation! I will have to listen to that Adrian Boult album on streaming if it’s available. Might get an LP later. 

Is this the record?

Only The TOTR DS Audio Cartridge Model is what I have a experience of, from the time of receiving the Demonstration. Resulting in an assessment being made, and not limited to myself only, where for me the TOTR DS Audio Cartridge Model was not making an impression that was enough to pursue the experience any further for my own systems needs. Others present were openly expressing their lack of being impressed, maybe even being kind about how they were disappointed, but what do I know, it was a fun day overall, and the DS Audio Cartridge demonstration was not the entirety of the experiences to be had.

I have shown to others within this Thread an Option for a Energizer that was not being referred to when the Energizer was the common topic in the Thread, this is a a model that I certainly do not favour as I have no direct experience of it in use, therefore I do not purport it has such a quality that it should be valued. The earlier posts within the Thread are with content that is purport from the OP about a Cartridge that is not demonstrated in any system, they speak as authority without any prior experience. The response to " rauliruegas " by the OP shows a realised  experience of their analogue experience attained by the OP. 

I have done enough within this thread, there is plenty to consider if willing or desired by those who are interested in a Cartridge change and have the funds to consider the Electromagnetic Induction Design or a modern Optical Read Cartridge.

I know I have now learnt enough to day I have a Magnet Attraction to a Technology with 50ish years of R&R behind it.

Maybe just Maybe, Jonathan Carr from Lyra, who is openly documented as being an advisor to the Founders of DS Audio prior to first production, has not produced his own version, because his understanding of the Upstream non Linear Issues beyond Stylus > Cantilever and attachment to the Shading Plate would undermine his hard work carried out with the alternate Cartridge technology.

I apologise if this is getting ahead of myself, maybe Mr Carr himself has another view of the Technology used for the Cartridge design. That would be very nice to be introduced to.