Life After Technics SL1200 Mk5

@dsper 

Tonearm cable is Cardas Double Litz 1 X 21.5 coax that is supposed to be 33 pF per foot.

OK- so 3 feet of that is 100pf. If the cartridge spec is for 150pf the phono section should be set to 50pf.

@dsper I think you are doing well.


You might try dialing in even less capacitance, since the tonearm cable is part of the overall capacitance that is a load on the cartridge. If its an actual tonearm cable and not a generic audio cable then it might be 60 to 100pf on its own (a generic cable might be 4-5 times that amount!). By decreasing the load capacitance by 50pf you effectively raised the resonant frequency by 3 or 4KHz. This probably puts it right outside the audio band. The further you can get it from the audio band the better- it will open up your bandwidth without increasing brightness. 

Better bass/foundation, better drive, and the treble is much better. It is a little bit shrill on a couple of albums but I suspect that it needs more time to break in or it could just be the albums.

@dsper  Good- glad to hear it!

Since this is a high output MM cartridge its really a good idea to look into cartridge loading. This is because there is so much inductance with the cartridge; that in conjunction with the capacitance of the tonearm cable results in an electrical peak. If the cable has high enough capacitance this peak could easily be just at the top of the audible range!

For this reason loading is essential. I think you'll find that takes out the shrillness and it should sound smoother than the digital once you've sorted it out.


The first step might be to find out the capacitance per foot of your tonearm cable. If its over 22pf and if you have more than about a meter of cable I would consider alternatives. Its essential that the cable be low capacitance and this is why you usually don't see longer tonearm cables since the longer they are the more total capacitance.

Actually I don't buy MM cartridges all that much; when I do they are new. I see them on turntables that we service. I've also experienced the phenomena with my own cartridges as they've aged. It does not seem to matter whether they are MM or LOMC. I examine the stylus with a microscope to see if there's any wear and then make sure its set up properly in the arm. If it doesn't sound right (tinny) then I replace the stylus. No need to set it up again- just change it and the unit immediately sounds better. Since its not wear, not dirt and not a bent cantilever, the only thing I can attribute this to is a perished suspension. Given the size of the suspension, its not hard to imagine that it will perish like a lot of other polymers that also perish in a similar amount of time. If the customer is a smoker then usually the suspension has melted (just like the rubber parts in a tape machine might in a similar situation). But otherwise when the suspension is gone I've found it more likely that its gone stiff. I've been able a couple of times to restore some suppleness to the suspension by using a tiny amount of brake fluid (which is a trick I learned from antique motorbike restoration for vintage irreplaceable tires) and letting the cartridge sit upside down for about a month. That restored things for a while, but then the sound went back downhill as the fluid worked its way down the cantilever and began collecting dirt. So really the only way I know to deal with this is to simply replace the stylus which isn't that hard (or expensive) with most MM cartridges.

So two anecdotes, contradicting each other. But we do know that polymers perish; for me its more than a bit of a stretch that somehow the polymers used in all cartridges won't perish where they do so commonly elsewhere in the world. Occam's Razor solves this one nicely!

I've seen it happen quite often! I'm sure some might make it but you would be lucky indeed to see any cartridge last 30 years!

@dsper The one thing that isn't getting mentioned here is that your cartridge is beyond its freshness date.

The cantilever has a suspension which fails over time. It perishes and might get really stiff or might simply melt. Either way the cartridge will sound wrong- no bass, harsher highs, possibly poor tracking. If the cartridge has a replaceable stylus you replace it. If not you get the cartridge rebuilt or replaced.


It ***DOES NOT MATTER*** if the cartridge was stored for a while- that's a pretty good guarantee that it won't sound right years on! Sort this matter out before any other investments, else you'll be dealing with the same issue as you've already seen.


Its also worthy of addressing how the cartridge is loaded and that sort of thing, but not worth discussing now since the cartridge has to be dealt with right now.