Time to upgrade the pre-amp.

I've been very interested in the AR preamps as well.

I'm curious, what parts in the older reference models are of concern as far as potentially not  being available?

OP,

generally, what volume level is your ARC preamp set at for normal listening?

What about the amp's GAIN? OP's Speakers sensitivity are 94 db/w/m

found this pecking about:

https://www.audiocircle.com/index.php?topic=176890.0

"It might be useful in the specifications section to inform the buyer of what the overall gain of the amplifier is since you are stating that it has too much gain for your 108dB horn system.

The specs state a power output of 6 watts. I am going to assume that this is RMS and also that it is at an impedance of 8 ohms. The specs also state a 400mV input sensitivity. I am going to assume that this input sensitivity is what is needed to pump out 6 watts RMS (clipping).

So let's do the math.

Using P=V (squared)/R; where P is wattage and R is impedance. V then works out to 6.93 Vrms.

If the maximum output power is 6.93 Vrms and to reach that maximum power you need to input 400mV rms (or 0.4V rms), then gain is calculated by:

gain = 20 *dB log (X) where log X is equal to log (6.92/0.4) or 1.24.

gain = 20*1.24 = 24 to 25 dB.

So gain works out to be 25 dB, which indeed might be too much for a 108dB horn system (power being a separate issue of course). I would aim for 12 to 16dB of overall gain in a system that is that sensitive.  This is of course relative to what your source (dac, vinyl, others) is producing and if you have a preamp in the system as well. It requires a careful balance.

Pretty amps though! GLWS!

Best,
Anand."

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I've visited OP's home, heard his wonderful system.

One of the issues with the ARC SP16L Preamp is each 'step' in the volume is too much of a jump, not smooth like normal remote volumes. We thought it was inherent to that model, a motivation to change. Are the steps 'heightened' by the amp's gain? Avoid any 'stepped' volume control in an alternate unit?

Anyone have experience with this one?: https://www.decware.com/newsite/ZTPRE.html

I am of the mind that if a system is passive friendly, and I think that the OPs, like mine is, then a very good passive linestage is hard to beat. I have plenty of gain from both digital and analog sources. I understand that an analog front end can be challenging, but with my SS Carmen II (2.2 mV) into an SPL Phonos using the 50db of MM gain, I have plenty of volume.

I know some think only active preamps can give the body and slam to the music they prefer. But I contend that in the right system, this is not so. I suggest anyone interested in a good passive give Hattor Audio a look.

http://www.hattor.com/dualmono_preamp_the_big.html

I’ve had an ARC SP6B since 1981, and most of the repairs needed on it were for cold or cracked solder joints. Nothing serious. I imagine the same would be true for an SP10 or 11. But my preamp has needed repairs once every 5 years or so since 2000.