The range of input loads for MC
 

Firstly, if any of you frequent the Audio Asylum (Bernhard) then my apologies for the cross posting...

Can you folks please tell me what MC you use and what input load it seems happiest with?

I'm in the process of designing/building an MC phono amplifier for a friend and wanted to know what range of impedance options I ought to make available for cartridge loading. If I'm building in flexibility, I might as well design to allow for all the likely MC contenders.

The gamut seems to run from AudioNote Io at 10R through to Benz Micro at 1K. These appear to be the extremes with most (Clearaudio, Dynavector, Wilson Benesch, Denon) falling at the 100R point. Some (Ortofon) seem happier at around the 33R point. I've seen very few cartridges requiring loads between 1K and 100R, (200R to 750R loads seem almost non-existent).

Does the info above correspond with your experiences?

Thanking you in advance for your inputs (pun intended)
Drew

Drew,

it depends if your MC input is a transformer or an active stage withan input resistor.

For resistive input your info is quite correct. Ii is long ago that i used resistive input for MC and my impedances were:

Supex 1000, 30R
VdH DDT, 100R
Elac EMC2, 100R
AT OC9, 100R
Spectral Reference, 1k
ShinonRed, 600R->1k
Koetsu Rosewood Sig.MkIII, 100R
Koertu Urushi, 100R
Ortofon X3-MC, 100R
Ortofon Rohmann 30R resistive. 47Ohm inductive.
I use a Jensen JT-346-AX input trannie, loaded with 6k8 at the secondary, ratio 1:12 reflects 47 Ohm at the trannies primary.

not yet tried out or hearsay:
Accuphase AC3, 100R
Denon DL103, 400r->1k
hearsay:
Clearaudio, 40R
vdHul Kolibri, 500R
Allaerts, 100R
Ortofon SPU, >100R

Thanks Bernhard. Looks like I'm on the right track then.

at present the plan is to fit an 8 bank dip switch with the following values:
27R
39R
56R
110R
180R
330R
470R
1K

All in parallel will give 9.8R which will suit the A.N. Io 1K//330 is 247 1K//180 is 150.

This should give a pretty wide range of matching options such that we're not locked into a dead end.

The help is appreciated

Drew

Hi Drew,

don´t forget 47k as an option.

I ran my Lyra Lidian and run my Micro Benz L04 @47k

william

Are these are high output MC's similar to Sumiko BPS?

Just to set the record straight, the 47k input impedance will be standard for MM as will the lower gain setting. The extra 10dB of gain and the lower impedance values will come into play as and when selected by the user

Thanks for the heads up.

drew

drew,

no they are normal low output MC´s. There are quite a few manufacturers who recommend 47k input impedance for low output MC´s (Lyra and Benz for example)

william

see also this link_

www.audiophilia.com/hardware/l04.htm

Drew,

Why don't you take a look at the X-Ono Owners Manual.
I'm sure you'll get all the answers you need.
BTW:
my Jubilee is happy with 40R load.
my MC7K5 with anything between 80R and 100R
Haven't tried my v.d.H. WB/SPX with my Ono yet, anyway it's custom made with 0,25 mV output and should work with 100R instead of 500R as recomended by the "Dutch" for the standard version.
Anyway, cartridge loading is not going to be a problem if you go for something like the thresold M1.

Regards,
Nick

Re: The range of input loads for MC
 

I'm very interested in your ideas, can you present them. Sorry for the threadjacking. Please start a new thread if/when you will answer me.

Don't forget the capacitive load
 

When I had the Denon 103 and was using an active MC stepup, I tried a lot of values, and got the impression, that 100R gets fine treble, but overdamps the basss, and that 1k gets free and powerful bass, but a bit harsh treble. So I then tried an RC-combination of 1k and parallel to that a series combination of 10nF and 100 Ohms. Bingo.

If you have a look at ad pages of Swiss company FM Acoustics (they sell very expensive phono stages, their top of the line model even with adjustable EQ), or their manual, you see, how you can influence the frequency response in treble and overall region when setting resistive and capacitive load independently. Very interesting.

regards,
Hartmut

I am still using an old Ortofon MC20 and I tweaked around with
different resistors many years ago and eventually settled on
10 Ohms. However, I am under the impression that all (?)
modern MCs are of the higher-voltage type, so perhaps such low
values are no longer of interest.