Few technical questions about an Ortofon MC cart on a Scout 2...


Non-technical enthusiast here, facing a bit of a conundrum...

I picked up a Scout 2 today, and the previous owner was kind enough to throw in a high end Ortofon X5-MC, albeit "possibly broken". During handling he knocked the cantilever. It’s perfectly centred and the stylus appears in tact, but when the cartridge makes contact with vinyl the cantilever recedes or "lifts" a hair...as in, it gets pushed back into the body by about 1-1.5mm.

The record player itself is in beautiful shape and appears to be functioning perfectly, but every record I’ve played so far sounds sluggish and rather muffled in the low end - particularly as compared to my spritely Rega P3.

Adding to the confusion is my phono preamp - a Sonneteer Sedley, which has all kinds of resistive and capacitance switches for MM/MC carts. I’ve tried about 3-4 settings so far, in the ballpark for a high output MC cart, but none has remedied this basic "sluggishness".

Can you kind folks help me diagnose this? Is the cartridge definitely kaput? If so, can it be repaired? Is it possibly a tracking/force issue?

I won’t bore you with the Sedley’s switches and X5’s technical specs unless it comes to that...

pupil
So...I launched YouTube and found a VPI walkthrough on basic setup...

Major improvements! The cartridge was way too recessed and not correctly aligned. Still not as coherent a presentation as I'd like, but already much, much better.

As I continue to refine my setup skills, I wonder if I could trouble you ladies and gentlemen with the following boring technical information?

Here's what Ortofon says about the X5:

Internal impedance, DC resistance -   80 Ohm
Recommended load impedance   - 47 kOhm / < 500 pF

And here are the Sonneteer's possible parameters:

Switch Function

  1. 1  1kΩ

  2. 2  47Ω

  3. 3  100Ω

  4. 4  220Ω

  5. 5  47pF

  6. 6  10pF

  7. 7  100pF

  8. 8  220pF

  9. 9  MM/MC

  10. 10  RIAA/IEC


1-4 are resistive loading...and 5-8 for capacitance. 9-10 are self-explanatory, I figure.

Any suggestions? 




After looking at the manual for your phono stage I suggest the following:

1) Switches 1 through 4 for the left channel should absolutely/definitely/positively be set to the up position, which will provide the 47K load impedance your cartridge requires. If you have had any of those switches in the down position it would certainly result in major sonic degradation with this cartridge, and probably with nearly all other high output cartridges regardless of whether they are MC or MM. The corresponding settings should of course be made for the right channel, but BE SURE TO NOTE that those are controlled by switches 7 through 10, as the switch numbering is mirrored for the two channels (i.e. left 1 = right 10 and left 10 = right 1).

2) I suspect that left channel switch 9 (corresponding to right channel switch 2) would work best in the down (low gain) position, but depending on the design of the phono stage and the gains and sensitivities of the rest of your system it is possible that the up (high gain position) might be preferable in terms of noise levels and with respect to the positions of the volume control that you will find yourself using. It is also possible, though, that using the high gain setting would result in an obvious increase in distortion, due to overloading of the phono stage or the input circuit of your preamp or integrated amp.

3) The manual recommends that left channel switch 10 (corresponding to right channel switch 1) be left in the down (RIAA) position unless there is a problem with "cone flap" (i.e., woofer pumping) due to record warps.

4) After all of the foregoing settings have been optimized you can experiment with different settings of left channel switches 5 through 8 (capacitive loading), corresponding to right channel switches 6 through 3, which will affect tonal balance in the treble region. The unknown capacitance of your phono cable and tonearm wiring will affect what setting is optimal, which makes the optimal setting hard to predict. As does the vagueness of the "<500 pf" spec. But in any event be sure that the capacitive loading of the two channels is set to the same value; setting the values to be unequal would be an easy mistake to make given the mirrored numbering of the switches.

Regards,
-- Al
Al, I'm touched that you took the time to look into this. That is extremely gracious of you. 

I note your absolute/positive/definitive suggestion that switches 1-4 on the left side be UP. That is curious, because switch 2 on the left side is the 47ohm resistive load, which is the only dip I have in the down position. 

Regardless, I'll take your advice and let you know! 
... switch 2 on the left side is the 47ohm resistive load, which is the only dip I have in the down position.

That’s the problem, or at least most of it!!

The 47K load that is recommended for the cartridge means 47,000 ohms, not 47 ohms (which would only be suitable for some low output moving coil cartridges).

When you put left channel switches 1 through 4 and right channel switches 7 through 10 to the up position you’ll be applying the proper 47,000 ohm load to the cartridge, and I’m sure you’ll notice a dramatic improvement.

Regards,
-- Al


P.S:  When you make that change, though, you'll be significantly increasing the signal voltage that is received by the phono stage, so per my earlier comments you may find that the low gain setting of the phono stage (left channel switch 9 and right channel switch 2 both set to the down position) works better than the up position you are presently using.

Regards,
-- Al