CONUNDRUM

Handyman,

It's a shame you ended up with a mismatched cart and phono stage, but that certainly sounds like the problem. Adding a transformer is a terrible idea IMHO, and clearly avoids the root cause.

If the PH7 is designed for LOMC cart, then get one or sell the phono stage and get something with more flexibility. When evaluating carts, you need to consider the combo of the cart & phono stage for gain; you also need to consider the combo of arm/cart for compliance compatibility.

By reading about what carts PH7 owners use, you will probably be able to quickly get a sense of what output range to consider. Then you can use online interactive chart(vinylengine? somebody help me here, please) to evaluate compliance compatibility for various arm masses vs. carts. Now you will have a list of viable candidates, and you can narrow it down by price and the sonic attributes for each model vs. your goals/preferences.

Perhaps ph7 owners can chime in...cheers,
Spencer

Spencer, As I have already mentioned 3 times, I own the PH-7 and owned at one time the Maestro. By itself, the PH-7 has no problem with the Maestro. The real problem here is that the PH-7 is overloading the line stage and the PH-7 does not provide for gain attenuation.

IMHO, the real solution and the best solution is that the PH-7 -- which btw is a very very good phono stage -- would do a great job with pretty much any carty (except those with outputs less than .5mV) IF the PH-7 was matched with an ARC line stage. The synergy is perfect, as would be expected.

I will not repeat the advice I gave above, other than to say that I would ditch the PH-7 and/or the Maestro as a last resort, of course taking cost/benefit into account. This is a practical problem that demands a practical solution.

One last point. Almarg mentioned in another OP that capacitance may be an important and possibly choice limiting factor when selecting MC carties. As I recall, MC carties are sensitive to aggregate capacitance of the phono stage and I/Cs between the TT and phono stage.

The ARCDB web site reports that the input capacitance of the PH-7 is 200 pF. That may be the upper limit of some MC carties. If so, very low capacitance and short I/Cs would be called for.

I had this problem when using a DV 20Xs H carty. I was using long (12') cheapo Radio Shack I/Cs. The DV didn't sound very good -- almost listless and dull. I bought a shorter pair of custom I/Cs from Tom Tutay (16pF/ft) and the TT/carty combo was much improved after break-in.

I reiterate for the last time that a converation with Tom Tutay may be worthwhile. A call to Calvin at ARC may also be warranted.

Good luck. If Almarg catches this thread, perhaps he can weigh in with better advice.

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