CONUNDRUM

Addendum: Tom Tutay is very solid. I used him to build a very custom impedance buffer that summed L/R channels and corrected an asymetrical loading problem. That's about as "custom" as it gets. I reiterate my suggestion to call him. Perhaps other folks who know Tom could weigh in with approbations.

Handymann: In the event of signal overload, I sometimes use interconnect cables that have a built-in two-resistor network that attenuate the signal by a fixed amount. Since only two resistors are used (one series, one shunt), and the attenuator is built into the RCA connector plug right before the line stage input, there isn't much degradation in sound.

You need to determine by how many decibels you need to attenuate the signal from the PH-7, figure out (or ask someone) a resistor network pair that attenuates the signal by the desired amount without stressing the PH-7, then build (or have someone build) that resistor pair into the RCA connector of a decent-quality interconnect cable.

Since the modification will be to the interconnect and not to the phono stage or line preamp, the work should be fairly simple, and won't affect the resale value of the ARC or Aesthetix.

hth, jonathan carr

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