Cartridge loading explained

[carlosfm]

I suggest something that reminds me the lettering of low-fi from the 70's/80's:

"Linear Skating Auto-Stop Continuous Resistive/Capacitive Loading".

:shock:

[kcc123]

What about CCFF guys??

Compulsive Cartridge Fiddlers Facility :lol:

Have fun Chairguy, and post us some pics!!

For those of you wanting to experiment similarly
but at much reduced cost: One still can buy the
Pioneer C21 preamp, no tonecontrols, fantastic
build quality at less than US$200 on US eBay.

Facilities there include switchable:
C21: 100, 150, 200, 300, 400, 500pf
C21: 100, 10k, 25k, 50k, 75k, 100k
(see: https://www.hifiengine.com/manuals/pioneer/c-21.shtml )

as well as one of the best volume controls I ever
used.

Other HiQ Japanese preamps from that era (e.g.
Yamaha, Kenwood & Sony) did include similar
controls so my guess is that at least some hifi nutters
from that era had at least a vague idea what proper
loading could achieve....

I also have a Pioneer C21 preamp which has been modified by me with Blackgate capacitors and pure silver wires. It sounds excellent in all areas.

[carlosfm]

Hi-Fi News this month has MM cartridge measurements and they all show problems due to incorrect cartridge loading.
And then they listen and judge those carts that way - serious mistake.
Who has this mag and a scanner?
It would be great to post that page here.

[bauzace50]

Hello carlosfm,
Which edition of Hi Fi News are you referring to? For which month?
Thankyou.
bauzace50

[carlosfm]

Hi-Fi News, October 2008.

[carlosfm]

Is this some kind of lost knowledge, like how to build a pyramid?

Probably.
I've seen a line preamp with MM/MC phono inputs that had pots for MM loading too, on the back.
Most amazing, it had variable resistance (with a dual gang linear pot) and variable capacitance (with a dual gang variable capacitor!).
If my memory doesn't fail me, it was an Audio Research. I don't remember well...

You'd think Hi-Fi News would have enough sense to listen or measure at standard and optimal loading.

They used the load that each manufacturer recommends.
It's a review of 4 MM cartridges.
When you look at those graphs (some are nasty) you'll realize that it's just the way those cartridges sound - with the recommended load - and they pretty much confirm what happens with incorrect loading, like my simmulations have indicated.

:mrgreen:

[clarke68]

Is this some kind of lost knowledge, like how to build a pyramid?

I've seen a line preamp with MM/MC phono inputs that had pots for MM loading too, on the back.
Most amazing, it had variable resistance (with a dual gang linear pot) and variable capacitance (with a dual gang variable capacitor!).

Ray Samuels makes one...'tain't cheap, tho:

http://www.raysamuelsaudio.com/products/xr-10b

[clarke68]

My Bay Audio Budda' Clarke...for about 1/10 the price and good performance (along with a line stage and FM tuner, too)

http://soundofthewood.com/preamptuners.html

Ahhh...much better example (or at least more appropriate to my end of the budget spectrum). Thanks!

[bauzace50]

@ carlosfm,
the Hi Fi News for October 2008 has a review of four MM cartridges. There is no article on the effects of different loading on cartridges. Could you verify your information please. I would like to get the correct article.
Thankyou,
bauzace50

[carlosfm]

@ carlosfm,
the Hi Fi News for October 2008 has a review of four MM cartridges. There is no article on the effects of different loading on cartridges. Could you verify your information please. I would like to get the correct article.

It's exactly that article, the four MM cartridges review.
Yes, there is no article on the effects of different loading on cartridges - I didn't say there was.
The last page of the review (the relevant one) is the measurements and conclusion.
The conclusion goes in line to what you see in the graphs - it's more likely that you prefer the sound of a cartridge when you don't have a big peak in the treble.
It is the lack of testing other loading options that saddens me - probably the prefered cartridge is not the best one.

[disko]

If you already have a preamp or phono stage, that you like, it shouldn't be too big a deal to have a 100K stereo pot wired in, to replace the input resistors.

The problem with commercial grade stereo pots is channel balance. 40% difference is not hypothetical. What about a linear stepper pot?

[carlosfm]

Carlos, How did you source your pot?

Oh, I've been using Alpha pots (from Taiwan) for some years, I love them - small, really smooth running and very good sounding.
I buy them at Jaycar UK, but since the UK office is virtual, they send directly from Australia and then I have to pay the customs office to release the package. (!)
These pots are small, 9mm, green body. You should find them easily at Jaycar.
What you need in this case is 100K linear dual pot.
Buy a bunch and measure for best channel matching.

Btw I use these Alpha pots on line preamps too (which have a much heavier use -volume control - than on the input of a phono pre) and they are working silky smooth and reliably for years.
It is so precision and smooth running that an Alps Blue feels like cheapo stuff.

[carlosfm]

Good afternoon all, I've often been tempted to wire in a dual gang 100k pot but on every occasion I've talked myself out of it for these reasons.

Namely, the rotational inaccuracies between the pots (a big problem based on personal experience with volume controls), the carbon resistance track (in most pots) contributes noise especially at higher impedance settings, and the almost inevitable 'noisy pot' syndrome...but if someone can tell me where to obtain a good 100 k dual gang pot free of these issues, and if it isn't too expensive, I use one. :) Regards, .

Hi ,

Your worries are more than justified.
For a volume pot I always keep in the range of 10K to 20K log. Going higher is just adding noise and in some cases (depending on the circuit) a lower frequency low-pass filter.

No such worries in the input of a phono pre, as you will wire the pot as a variable sunt resistor (joining two pins), you will not have series resistance with the signal.

[carlosfm]

Good afternoon all, well I've done it.

Already? 8)

Did you find those small green Alpha pots I recommended?

http://www.jaycar.com.au/productView.as ... &SUBCATID=

[SuperDaveKzoo]

I have read this thread from top to bottom. Valuable information. I am very interested in determining the correct (starting) load for my cart. I cant for the life of me find an inductance spec for a Denon DL-103R. Any suggestions? Thanks........!