Shure V15 mk2 - Internal Cartridge Cleaning

[Mark_in_Lex]

Hi all, I was given a V15 Mk2 that sat in a Hot/Cold attic for 20 years. I pulled the stylus assembly out and the shaft was very dirty. Question: Should I try to clean the inside of the cartridge body? I did test the cartridge with the old stylus and it sounded very worn but had both channels. Have a new Jico (not SAS) ready to install.
Thanks everyone. Mark

 

[thomo57]

What do you mean about the inside of the body?
Doesn't sound like a good idea to me

 

[wualta]

Dirty or not, the V15 Type II's operation doesn't depend on an electrical contact between the shaft and the interior of the cartridge. Go ahead and install the Jico and let us know how it sounds.

 

[BrocLuno]

Clean the outside, but be very careful of doing anything on the inside...

If there was a stylus in there during teh storage, it is likely that nothing happened internally...

 

[Mark_in_Lex]

Thanks everyone,

Thomo57, what I was talking about is the 1/2" shaft from the stylus that goes into the body of the cartridge. That was dirty making me think the inside of the cartridge body itself needed cleaning.

 

[Mark_in_Lex]

Dirty or not, the V15 Type II's operation doesn't depend on an electrical contact between the shaft and the interior of the cartridge

Interesting..... How is the signal passed from the stylus? Thanks, Mark

 

[bhebbel]

This does not sound like a good idea.

 

[thomo57]

Thanks everyone,

Thomo57, what I was talking about is the 1/2" shaft from the stylus that goes into the body of the cartridge. That was dirty making me think the inside of the cartridge body itself needed cleaning.

Gday Mark
I'd probably give the removable styli part a very careful light clean but be a bit dubious about getting anything inside the body

 

[wualta]

Interesting..... How is the signal passed from the stylus? Thanks, Mark

Sorry for the delay in replying. The answer is: magnetically. There's a tiny wiggling magnet on the back end of the cantilever, inside that brass-colored tube, and just inside the stylus hole are four little flat soft iron "fingers" that pick up and carry the varying magnetic flux to the four coils inside. The magnet thus induces a small current in the coils, which pass the signal to the four pins on the back of the cartridge and on to the RIAA stage. You could make the brass-colored tube out of nonconductive plastic if you wanted, and some cartridges (Empire 600 LAC family, many Nagaokas) do just that.

 

[savatage1973]

Correct me if I am wrong, but the biggest concern of the hot/cold attic storage (with respect to the cart) would be the effect on the stylus suspension, which on a MM cart with replaceable stylus is incorporated into the stylus unit. There should be no effect on the cart body itself, and if the cart was stored with a stylus on it, there should be no dirt/dust on the internal contacts, so you should be able to just clean off the outside of the body and plug in the new stylus and be good to go.

 

[Starquest]

Sorry for the delay in replying. The answer is: magnetically. There's a tiny wiggling magnet on the back end of the cantilever, inside that brass-colored tube, and just inside the stylus hole are four little flat soft iron "fingers" that pick up and carry the varying magnetic flux to the four coils inside. The magnet thus induces a small current in the coils, which pass the signal to the four pins on the back of the cartridge and on to the RIAA stage. You could make the brass-colored tube out of nonconductive plastic if you wanted, and some Japanese cartridges (Osawa, for one) do just that.

Excellent explanation, thank you! Is that basically how all MM carts work? I had wondered previously if swapping styli on a cart too much could 'wear out' the connection, but from what you're saying, it sounds like there is no risk of that.

 

[ripblade]

Corrosion would also be a concern. The pins might need special attention...a pencil eraser plunged in and twirled around the pin usually works. Hopefully corrosion is not an issue inside the body as that really can't be fixed by the lay person.

 

[bobins08]

Correct me if I am wrong, but the biggest concern of the hot/cold attic storage (with respect to the cart) would be the effect on the stylus suspension, which on a MM cart with replaceable stylus is incorporated into the stylus unit. There should be no effect on the cart body itself, and if the cart was stored with a stylus on it, there should be no dirt/dust on the internal contacts, so you should be able to just clean off the outside of the body and plug in the new stylus and be good to go.

Correct.

I think the odds are extremely high that the cartridge body is fine. I would not attempt to clean inside the cartridge body. Just wipe off dust on the outside of the body, maybe clean the pins that the tone arms connects to, install the new stylus and enjoy!

 

[wualta]

Is that basically how all MM carts work?

Almost by definition, yes. The magnet wiggles, spraying magnetic flux as it does, in what it thinks is empty space. The socalled pole pieces, which are made of permalloy/soft iron-- iron alloy that by design passes on but does not retain magnetic flux (it's magnetically soft)-- act on magnetic force the way copper wire conducts electricity. You can think of a magnetic phono cartridge as very similar to a playback head in a tape recorder, if that helps at all.

I had wondered previously if swapping styli on a cart too much could 'wear out' the connection, but from what you're saying, it sounds like there is no risk of that.

Correct. Now, if the stylus and body fit together too tightly, and it does happen, you can slightly change the shape of the mating pieces such that a random example of the same stylus will fit too loosely, but this is rare, and that's what poster putty is for.

 

[Mark_in_Lex]

There's a tiny wiggling magnet on the back end of the cantilever, inside that brass-colored tube, and just inside the stylus hole are four little flat soft iron "fingers" that pick up and carry the varying magnetic flux to the four coils inside.

Thanks Wualta, I learned a lot from your post. I also appreciate the overall conversation. I plan to NOT clean the interior of the V15 mk2. Thanks guys. Mark