2 amps for 4 speakers and other Amp related

judas_rising said:

Hello,

I have the Rega Elicit R amp, driving the Tannoy XT8F all rigged up in a main setup (rack).

I also have the Dynaudio Emit M20 - 4 Ohms / 86 dB, which I plan to use for another room, but do not have space for the amp/dac etc., Can place another amp on my main rack only.

Intention is to take the pre-out from Rega and feed it into Amp 2, which can be an integrated or a power amp. Long speaker wires to the M20 in the other room.

Question is, will the Rega drive the XT8F and output from its own pre at the same time? I am yet to buy a second amp to drive the M20.

This is what Rega has to say about its Pre out section:

Pre-Amp Output -The pre-amplifier can drive at least 5 power amplifiers, sub bass units etc. The pre-amplifier output uses RCA type (phono) connectors. The output level is 760mV with a line input level.

My budget permits a power amp like the Emotiva Basx 300, which I have heard with the M20 and quite pleased with.

I could get a NAD 356 bee for a throw away price, hope someone can chime in on the sound from the 356 and M20.

Main concern is the simultaneous output from the Rega into the power amp and its ability to drive the tannoys without any problems. Will the volume levels be higher on the power amp or would they react equally according to the Rega volume levels?

I love the sound from the Rega Elicit and M20 and can also consider the cheaper Rega Brio Integrated, if that would be a better match electrically.

To get different volume controls, can we take the preout from the Rega and feed it into another Integrated line input like CD/Aux?

Cheers.

Click to expand...

The following is intended to allow both speaker systems to be used at the same time. It assumes that I've understood the manuals correctly so you should double check the content.

The Tannoy XT-8F has a rated voltage sensitivity of 91 dB (assume 2.83V into 8 ohms) and rated impedance of 8 ohms.

The Dynaudio Emit M20 has a rated voltage sensitivity of 86 dB (assume 2.83V into 8 ohms) and rated impedance of 4 ohms.

The difference in voltage sensitivity is 91 - 86 = 5 dB SPL, which is significant. Grossly 10 dB SPL is often taken as subjectively twice as loud. With the same voltage input the Tannoy speakers will play a lot louder.

The Rega Elicit R amp has a rated gain of 31.6 dB.

The Emotiva A-300 has a rated gain of 29 dB.

The gain of the Rega is 31.6 - 29 dB = 2.6 dB higher.

The difference in gain between the Rega/Tannoy and Dynaudio/Emotiva systems is is 5 + 2.6 = 7.6 dB. This means that with the same preamp output into the two power amplifiers the output from Tannoy speakers will be 7.6 dB higher than from the Dynaudio speakers. This is a significant difference.

In addition it appears that .760V is the maximum output preamp output from the Rega since this voltage will drive the Rega power amplifier section to maximum output. This preamp voltage will only drive the Emotiva amplifier to about 50 watts into an 8-ohm load vs. it rated maximum output of 150 watts per channel.

o A volume control ahead of each of the power amplifiers would be recommended.


o The most straightforward way to to add a volume control using your stated options is to purchase the NAD 356. The record output or record output link (they are in parallel) of the Rega unit would be connected to one of the line level inputs of the NAD unit. The record output links of the Rega do not go through the volume control of the Rega. For example, a 2V output from a CD player would still be 2V at the record outputs. This setup would allow separate volume control and power amplification for each system, with all of the sources connected to the Rega (see next paragraph).

It isn't quite clear, at least to me, how the phono input is handled in the Rega. If the output of the internal phono preamp in the Rega, before the internal main preamp, will pass to the record output then the above solution works. If phono preamp output isn't available then you might consider a separate phono preamp that has a line level output.