Cary SLP98P not working with Audio Research VT100

Hi guys,

The power amp has no way of "knowing" whether the output of the preamp is in or out of phase with the input of the preamp. The statement in the manual about not using a phase inverting preamp makes no sense to me, unless they are envisioning the possibility of the amp's AC current draw somehow affecting the preamp via its effects on the AC line voltage. Similar to the effect Ralph once described in this post, and his post just below that one. But it would seem far fetched that phase inversion in the preamp would have anything to do with that possibility.

Also, I recall it being mentioned in another thread a few months ago that the manuals for some ARC tube amps say in bold face type that "ARC tube amps must be used with ARC preamps or damage will occur." Which would seem to further reinforce the notion that cautionary statements in their manuals should be taken with several grains of salt.

Mac, your last post makes it pretty clear that the APC conditioner is somehow a factor. Looking at the photo of its rear panel shown on page 17 of the pdf of the manual, the one very speculative suggestion I have at this point, and it's just an intuitive guess, is to try plugging the preamp into the outlet designated for connection of a subwoofer (with the amp continuing to be plugged into the outlet designated for "amplifier"). Perhaps the separate filtering the APC has presumably been applying to the preamp and the amp is somehow involved; making that change would apparently put the two components on the same filter.

If you are using the APC's turn on/turn off sequencing provisions, keep in mind that that would be affected if you try this experiment, and you would want to manually turn the amp on last and off first.

Not sure what else to suggest at this point. Weird problem.

Regards,
-- Al

Have you tried connecting the speaker wires up (from the amp) red to red and black to black? Instead of red to black and black to red?

Ok ... I admit not being a techie, so take this with a grain of pepper. If the problem with the amp is presenting in both channels, there could be a common power supply problem that is causing some type of oscillation (e.g., pulsing output power tubes). If all the output power tubes are affected, it seems more likley a problem in the power supply.

The problem is doubly weird because you say it does not occur if your Oppo 105 is directly hooked up to the VT100. Does the Oppo attenuate the signal presented to the VT100??

I have two suggestions. One -- if possible try to borrow another linestage/pre and see if the problem persists. Two -- even if the problem seems to resolve itself by changing out the linestage/pre, I would check in with Kal in ARC Customer Service. I think this situation deserves better advice than just a grain of pepper (or even a whole pepper shaker) from a know-nothing like me.

Please let us know how you make out.

Good luck.

If your preamp is SE, you need to have the pins in the balanced input on the amp for SE to work.

ZD542, what is meant by SE?