Pairing my new Bartok with power amps

Hello everyone, my first entry on this forum. I got my new Bartok in February and I’m still getting used to it. I’d really like to hear some comments from others about my experience so far, particularly when pairing with power amps.

This is my first significant upgrade for many years and things have moved on. I was using an Audio Research LS7 and 300.2 pre/power combination driving Quad ESL63 electrostatic speakers with a Copland CDA288 as source, all bought many years ago. In 2017 I bought a Cambridge Audio 851N to add internet radio and use of AirPlay and TV etc.

Since February it is Bartok with Tidal HIFI, ARC 300.2 using balance output, and ESL63. But also, I use the Bartok RCA output to a Cambridge Audio 651W and long cables to my study with Monitor Audio PL100 speakers.

I have to upgrade some cables, but so far things are already good. I am amazed by the sound in the study despite the relatively humble amp and small but good speakers, and this with 10 metre long cables; a real bonus for a second room. However, the main room has been a little disappointing. I love the ESL63s which I had since new in 1994 but I’m told they present a tough impedance. When running both power amps at the same time the volume in the study is way too high while the main room volume is just okay. And the sound in the main room lacks body. I switched out the ARC300.2 for my old Quad 606 (from 1994) and it is transformed with great weight and volume and about the same volume as the study. I then changed back to the ARC300.2 and changed the Bartok output from 2v to 6v. A real improvement in performance in my main room, but then of course the study volume is ridiculous.

So the preferred setup is ARC300.2 (better clarity that the Quad 606), with Bartok set to 6v.

Does the ARC 300.2 have a low input sensitivity? I’m wondering if I should look out for an ARC 100.2 on eBay to run the study setup to get a better match between the two power amps But the 100.2s are also getting old and apparently unrepairable now.

Any thoughts?

One final comment: the overall sound I’m getting now is great and I suspect will improve further with use and some cable upgrades.


Hi Simon,

Audio Research Corporation 300.2

Input sensitivity
2V RMS for rated output (28 dB Gain) single-ended or balanced

Cambridge Audio 651W

Sensitivity 1.5V rms unbalanced 1.5 + 1.5V rms balanced

Quad ESL63

Sensitivity: 86dB SPL for 2.83V rms at 1 meter
Nominal impedance: 8 ohms (6.2 ohms minimum)

Monitor Audio PL100

Sensitivity (1W@1M) 88 dB
Nominal Impedance 4 Ohms

So, Bartok at 6V out into both ARC 300.2 and CA 651W will cause the CA to go louder, because of its higher input sensitivity (1.5V, vs 2V for ARC). Please note that with 6V out you can cause distortion in both amps when playing loud.

The Quads work at 8 ohms, the Monitor Audios at 4 ohms. Again the MAs play louder. Anyway, the Quads are known for their low sound pressure.

The best you can do here is to use 2 separate pre-amps, one for each setup and room, to attenuate the 2 different setups, when the 6V out from Bartok is given. Better even, set Bartok to 2V out at 0.0dB unity gain, and attenuate with the 2 pre-amps to get the desired listening level in each room. Unless you use pre-amps that can handle 6V in.

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Thanks for your very helpful comments. I had not appreciated that the input sensitivities of various power amps could be so different. I also looked up the ARC 100.2 which is 1.3 v so that wouldn’t work out in combination with the 300.2, in fact it would be worse than the 651W. I also looked up the Quad 606 which is 0.5 v for 140 W output, which explains a lot. I always thought it was rated conservatively power wise.

So I hooked up the Quad 606 on RCA to the ESL63s and ARC 300.2 on balanced output to the PL100s. Great sound all round and a balance of volumes. I’ve just sent the 606 back to Quad for a service, the first since 1998. It would be good if it comes back with improved sound, but I doubt it will quite match the 300.2 sonically, though a better match to the speakers. Also, the 606 does not have balanced inputs which would be preferred for the main listening room (and I have a higher quality balanced interconnect cable than the RCA). I’ll wait to see the results.

It’s been an interesting learning process and it’s great that the Bartok has selective output voltage. I’m about to get Sennheiser 800s headphones too, to add to the fun.