Audio Research amps - balanced & non


Ideas/suggestions anyone?
I have an original ARC SP-10 pre-amp (perfect, re-tubing once in a blue moon but totally reliable after ~25 yrs so reluctant to replace) but I would like to replace my original D-115 amp with VTM 200's (i.e. balanced) or get a VT-130SE (also balanced) to bi-amp alongside the D-115 to drive the bass end, assuming that's even possible.

Question - can balanced power amps work with a 'pre-balanced' pre-amp like the SP-10, or even work in a bi-amp arrangement as the only balanced component? I suspect not but would like some user comments.
Thanks!!
westchr
The VT-130SE does not have a phase splitter and requires a true balanced input to operate correctly. If the SP-10 is not a balanced design you can't run it directly into a VT-130 SE.

Good Luck

Marty
Sorry, I didn't see the bi-amp part of your post. Some active x-overs will output a true balanced signal even if the input is single ended. The NHT x-2 is an example. If you bi-amp as follows: Source -> ARC sp-10 -> NHT x-2 -> ARC vt-130 se/main speaker (via NHT balanced main out) + subwoofer (via NHT subwoofer out), you should be okay.

Marty
There is a way to create a quasi-balanced output from a single-ended source. Ashly (pro sound equipment) uses it, and it works.

From the single-ended signal ground connect a resistor equal to the output impedance of the signal to the (-) wire of a balanced interconnect. Since the (-) impedance matches the signal (+) impedance both wires will pick up the same noise, and this will be canceled in the balanced input circuitry of the power amp.
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By adding all this junk to the signal path, you significantly defeat the major strengths of the SP-10 and the VT-130.....and this is portrayal of space. These both were at the top of their class in this key area. Keep things simple and you will be rewarded by what these products can do.