cafe latte wrote:Been trying to tweak my sure m97xe with loading, I am running it at 62k input impedence, but the difference to 47k was not great. I really like the cart but it needed something, spoke with and I decided to try 75k and still there was not much change, but of course it is not just impedence that is important, but also capacitance and the ideal combined capacitance of the arm leads and phono leads should be about 150pf assuming that the internal cap in the phono preamp is 100pf. This gives an 'ideal' for loading the sure of 250pf. All good so I removed the cart and headshell IMPORTANT!! Then using a capacitance meter measured the leads back to the arm and to my amazement the combined lead and arm wire capacitance was 305pf, adding this to the internal pre amp cap I arrived at 405pf!! Next i did a bit of experimentation using high quality interconnect cable I use to make up leads and measured DOUBLE the length of the sl1210 leads and the capacitance was just over 100pf. After that is only a short run of arm wire, and experiments with thin wire even a bit twisted showed it should onlt be a few pf's. I am not a great believer of the benefits of really high quality interconnects, but all the same it has been demonstrated in the past that high capacitance values when connected to a cart can alter the frequency response positively and in this case very negatively. Safe to say when I get five mins the stock cables are coming off!! Anyone any thoughts, I am wondering if these values may be doing my dl160 no favours??
Thanks to for all his advice.
Some ordinary digital multimeters do have a capacitance measuring range, but I think it's better to have a stand alone digital capacitance meter as I have. The one I have is not very expensive yet accurate and reliable. It is a bit of test equipment well worth having if one dabbles with turntables! Regards, .
cafe latte wrote: (...) Anyone any thoughts, I am wondering if these values may be doing my dl160 no favours?? (...)
G'day mate, this is the one I have. http://www.jaycar.com.au/productView.as ... rm=KEYWORD Regards, .
(...) capacitance loading only affects the treble frequency response and only when substantial coil inductance is present in the cartridge (typical MM's and high output MC's). (...)
G'day mate, well if you mean optimum capacitance loading, it varies. Over the recent years, the general trend with typical moving magnet cartridges has been within the range of 200 to 300 picofarads (overall, including tonearm wiring, interconnect and phono preamp input capacitance).
However in past years, cartridges like the Shure V15typeIII and M91ED specified a somewhat higher capacitance load in the range of 400 to 500 picofarads.
Yes most manufacturers specify an optimum capacitance load range. Essentially, capacitance loading only affects the treble frequency response and only when substantial coil inductance is present in the cartridge (typical MM's and high output MC's).
This website pretty well tells the story, although the 'real world' of cartridges can be somewhat different at times! http://www.hagtech.com/loading.html Regards, .