Matching the sensitivity of two amps for bi-amping

Thank you fellow audiophiles for your input. I didn't reply for a couple of days for the purpose of getting more opinions. It looks like the passive bi-amping is a contradictory approach. Will try to gain some experience by using amplifiers from friends and at that point i will refrain myself from buying. The specific requirements needed for the second amplifier(s) further limit the possible choices. Yes, I do have Y-splitters - two Audioquests that I am using from my CD player for sending the signal to two different set-ups - one for a higher quality system and one for a conventional system used when I am doing fitness. I do have also balanced and unbalanced outputs from the CD player (Esoteric DV 50 S) but the preamp has only unbalanced inputs, so I am not using the XLR's. Some Mcintosh amps have gain knobs, should I try this?
Regards to all of you and happy listening.

"Some Mcintosh amps have gain knobs, should I try this?"

Yes this is the way to get the right balance between the amps so long as the Mac is higher in sensitivity than your AN amps, and then use your CJ preamp for the master volume.

Cheers George

Hello Nik,

First, to be sure it's clear, "higher sensitivity" = a lower sensitivity number, assuming that sensitivity in each case is defined as the input voltage required to drive the amp to its maximum rated power.

Second, per my earlier comments you don't necessarily need higher sensitivity. What you need is higher gain (assuming the amp provides a volume control). Assuming that the low frequency amp will be considerably more powerful than your present 8W amp, having higher sensitivity (defined as the input voltage required to drive the amp to its max rated power) would also assure that the higher powered amp has higher gain. However, you would be unnecessarily limiting your choice of amplification by choosing based on sensitivity rather than gain. Perhaps severely limiting it.

Finally, I suspect that any McIntosh amp you might choose would be far more powerful than your present 8W amp. If you were to passively biamp such a combo (i.e., without a crossover "ahead" of the amps), using the Mc's volume control to gain match, as I indicated earlier you would not be able to turn the preamp's volume control up high enough to utilize most the the Mc's power capability without driving the 8W amp into clipping, resulting in severe distortion.

Although passive biamping (i.e., with no crossover ahead of the amps) relieves the high frequency amp of having to supply current and power at low frequencies, it does not relieve that amp of having to output voltages corresponding to the full frequency range of the signal, including the deep bass content. Your 8W amp would almost certainly not be capable of outputting nearly as much voltage as a much more powerful McIntosh. So you would be paying for a lot of watts in the Mc that you wouldn't be able to use, and that would not increase the overall power capability of your system as much as you might expect.

Best regards,
-- Al

Nikmilkov

I ran 20watt single ended (SET) tubes on the mids and highs of esl's and then used a 300watt transistor with input gain pots for the bass driver.
Then for the master preamp I use a passive pre to drive both amps. (In your case you'll be using you active CJ pre which is no trouble maybe even better load wise)
This was very successful, because the transistor amp was higher in sensitivity than the tubes and therefore able to be gain matched with its own input pots to the same volume of the lower sensitivity SET tube amp, and then the passive pre became the master volume control.

Cheers George