CONUNDRUM

Bruce (Bifwynne), good points about load capacitance. I don't recall offhand the particular discussion you are referring to, but let me clarify a little further.

For cartridges having high inductance, such as most MM's, the load capacitance seen by the cartridge will directly affect tonality in the upper part of the audible spectrum. Too much or too little capacitance for the particular cartridge will adversely affect frequency response flatness. 100pf is recommended by the manufacturer for the OP's Maestro.

For cartridges having low inductance, such as most LOMC's, load capacitance will have insignificant direct effects on the cartridge's behavior at audible frequencies. However, high capacitance will lower the frequency and increase the amplitude of the ultrasonic resonant peak which results from its interaction with cartridge inductance. That in turn can result in the phono stage being required to process excess ultrasonic energy that it may not be able to handle gracefully. In general, therefore, the lower the capacitance the better, for LOMC's.

For HOMC's, such as the Dynavector you referred to, my suspicion is that the second of those two effects will generally be the most significant. But I don't have a precise feel for that, as inductance specs for that cartridge (and most others, for that matter) don't seem to be available. Perhaps Jonathan will comment further, with respect to HOMC's.

Handymann, I'm surprised that the attenuators you tried had such adverse effects. What model did you use, how much attenuation did it provide, and where in the signal path did you place it?

Best regards,
-- Al

Thanks Al. BTW you may have picked up on something about the Maestro that that I d/n focus on when I fiddled with it on my VPI Classic. As I reported in many posts to the point of ad nauseum, I had a bass ringing/resonance that Mike at VPI and I could not fix. At the time, Mike and I focused on optimizing the set up to manage the tone arm/carty resonance from a mechanical perspective.

In retrospect, I question outloud now whether there might have been a mismatch with the PH-7 by reason of capcaitance: Maestro - recommended 100pF vs. PH-7 - 200pF (not even including I/Cs of another 100pF).

I think this point is relevant to the OP because he has the same front end as I did. Any thoughts??

As an aside, I currently use a SS VPI Zephyr, a MI carty. I checked the SS web site. FWIW, nothing mentioned about capacitance that I could find????? Oh, the Zephyr sounds great to my shriveled ears.

Hi Bruce,

I wouldn't expect load capacitance to be relevant to issues at bass or subsonic frequencies.

Yes, the Maestro isn't optimally loaded by the capacitance of the PH-7 + cabling, but I have no way of knowing how significant the resulting sonic effects may be with that particular cartridge. And of course it is an issue that is separate from the overloading problem.

With respect to the Zephyr, Mr. Ledermann does provide a load capacitance recommendation, 100 to 200 pf. See page 2 of this datasheet. Again, I don't know how critical that may be.

Best regards,
-- Al

Al, I got us off topic, but I'll close the "capacitance" loop fast. Thanks for the info on the Zephyr. To my untrained journeyman ears, the Zephyr souns great, cables and all. I thought the Maestro did too. Something to be said for ignorance -- if I feel happy, then I guess I am. :)

I agree that the primary problem is line stage clipping. Al, do you agree with my suggestions above, particularly those relating to calling Tom Tutay and ARC???

Handyman...I don't believe you are correct when assuming that the output can not be reduced without sacrifice. Call Audio Research, and I am quite positive that by substituting a resistor, (an easy procedure...but you need the right kind and value and position in the circuit which Audio Research will provide) your system will sing.