MMC20 Genetic manipulations…

[chartz]

Yes it is glued, but it can be opened with some care. Not for the faint of heart though.

[Glitch]

I’ve run some similar experiments using the same dirt cheap replacement cantilever/stylus…

My approach is a bit different than matador’s. Instead of using an “internal” wire to connect the new cantilever to the old cross, I reamed out the new cantilever to fit over the collar on the cross. This (theoretically) has a performance advantage of only having one interface connection (i.e. where glue is needed) instead of two.

The picture above shows a couple examples of the FrankenCartridges compared to the original.

The FrankenCartridges track a record groove just fine and make music. I’ve noticed some distortion in the high frequencies. My initial thought was that this was caused by a bad suspension in the donor cartridge. I’ve since repeated the experiment on a few other cartridges to try to identify a pattern. My sample size is admittedly small, but the two “best sounding” cartridges that have nearly identical distortion. I also have cartridges where it is obvious that the suspensions are shot. Based on this, I’m guessing that the distortion is caused by bad tip geometry, bad interface connection (currently just using a friction fit), or that the new pink styli are simply crap. I’m not ruling out all three ;-).  Does anyone have any theories?

I’m not sure what I’ll try next. Has anyone tried this with a better quality replacement cantilever/stylus?

Glitch

[auric]

Hi:

There is a short video interview of Axel Schürholz plying his craft. Some of the footage shows his approach:

Derek

 

[Dillen]

Sure you got the tracking angle correct?
I think it looks very steep.

Martin

[Glitch]

Derek:  Thank you for posting the video. I was able to pick up at least one tip as well as confirm that some of the methods that I already figured out are on the right track.

Martin: Yes, the tracking angles in the first picture are pretty unsatisfactory, especially the FMMC2. The FMMC20 isn’t nearly as bad. I didn’t do a good job at lining up the cartridges for the picture. For the first attempts, I didn’t try any adjustments to the geometry. I was just happy to complete the transplant without destroying either the replacement cantilever or broken cartridge. 😉

Here are today’s results that include adjusting the tracking angle and better cartridge alignment for the picture.

The tracking angle in the top left was purposefully altered. The bend in the bottom right is a result of damage from the reaming process in one of my earlier attempts. I’ve learned that it is pretty easy to damage the components while working on them.

One advantage to Matador’s approach is that it should be easier to adjust the tracking angle simply by bending the inner wire.

Glitch

[Glitch]

The latest experiment was to make several cantilevers with different tracking angles. The picture above is the one that, by eye, has the best geometry. The bad news is that all of the candidates exhibit a very similar distortion. The good news is that my cantilever bending jig seems to work and I found a record track where the distortion is easy to hear (i.e. the issue is easily repeatable).

Please let me know if you are interested in hearing a recording of the distortion, would like to see any other views of the cartridges, or have any suggestions of what to try next. Thanks.

Glitch

[Glitch]

The latest (and last for now) Franken-MMC (FMMC) experiment. The donor cantilever is aluminum with a conical, bonded diamond stylus.

My cursory evaluation of the cartridge performance on a 1 to 20 scale, where 1 through 5 map to B&O’s MMC1 through MMC5, respectively, and 20 is something put together from sewing needles and twigs…

The FMMC with the $2 pink ceramic stylus is about a 17. The grafting is relatively easy to do, but the playback is muddy and suffers from distortion on some recordings.

The FMMC with the conical, bonded diamond stylus is about a 12. The playback distortion exhibited by the pink ceramic FMMCs is gone. In general, the highs and lows are there, but the fine detail is not. It sounds like a tired, inexpensive cartridge. This isn’t surprising since it actually IS a tired, inexpensive cartridge.

My overall conclusion is that this type of DIY grafting isn’t very practical. There is a learning curve where one will certainly destroy some donor cantilevers and/or target cartridges. The overall performance could certainly be improved upon by buying a higher quality donor cantilever/stylus. However, the risk/reward ratio just isn’t there. Botching just one reasonably nice donor cantilever and having to replace it puts the overall price in the ballpark of a new SMMC4 (that has a fresh suspension).

My future plans are to use the grafted cantilevers for evaluation of cartridge suspensions. I have a handful of cartridges with missing cantilevers. I got these with various used turntables and have no idea of their history. If I happen find a suspension that still has life in it, I’ll be remotivated and graft it. Maybe some sort of nude elliptical?

Yep, none of this made sense. Wound I do it again? In a heartbeat!

Glitch

[Peter]

Just come across this thread which made me examine the cartridges I still have.

SP15 – interesting square diamond with edges parallel to cantilever – cut to a shape which looks down my microscope to be spherical – supposed to be elliptical – this is the first of the MMC range and became the MMC4000.

I then have 2 MMC5000s

1. Square diamond – quite a bit smaller and set with sides 45 degrees to cantilever and cut with a Shibata profile – elliptical with leading edges cut away. Blue dot on mating face of cartridge.
2. Round diamond, smaller and darker but with similar Shibata tip. Green dot on mating surface.

MMC6000 – square diamond again edges set to 45 degrees and both front and back surfaces cut away – Pramanik profile.

MMC20CL – lovely transparent sapphire cantilever with tiny diamond, edges parallel to cantilever , both leading and trailing edges cut away though leading edge deeper – the 6000 seemed more symmetrical.

MMC20SH (!) – this the relevant one really – pretty sure Axel did this one for me – the cantilever has a cut close to the body and there seems to be a sleeve almost but very smooth and no ridge but a graduation down to the rest of the cantilever. There is a diamond which I think is square, sides 45 degrees to side of cantilever though looks about a degree out. The diamond seems to be contact line rather than shibata as cut on four sides though not as well finished on the trailing edge compared to the B&O versions (being a bit picky here!) Attaching a picture for the cantilever.

I confess to rarely using them these days and my ears are not what they were! I remember to 20CL being temperature sensitive – came alive in a warm room. The 6000 was quite bright and made a superb record cleaner – could clear dust out of a pristine looking record! I rather liked the SP15 and that one stays on the BG4000!

I do have a memory of having an MMC4 rebuilt – it involved the suspension being replaced and the front of the cartridge cut off and then reattached but a line remained to show the process. No longer have any of the newer cartridges as either sold or gave away all the relevant decks. I never liked them as much as the 4000 series, not even the 8002 I had.

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