Hi Gang:

My Cambridge 851A Stereo Amp has "A" and "B" speaker taps and can be run as "A" only, "B" only or "AB" together. The amp's instructions state that the amp expects a nominal 8-ohm load at all times. I understand that my Triton Ones and Sevens are both nominal 8-ohm speakers - which means that, if I connect both One and the Sevens to the Cambridge and drive them together in the "AB" configuration, I am presenting a nominal 4-ohm load to the amp.

The Cambridge manual specifically states that, if "A" and "B" are driven together, each pair should be nominal 16 ohm speakers so that the resultant load remains at 8 ohms for the amp.

Any recommendations for adding something to the speaker connection arrangement to bring the nominal load to 8 ohms without adding distortion or other unwanted effects?

Thanks,

Art

Hi, Art

I'll bow to any clever suggestions that prevent amp overload and clipping, but here's my input:

When I was adding speakers and changing configurations years ago and in effect adding two channels more than the receiver at the time could support, I called GoldenEar tech support to ask if I could safely connect two pairs of Invisa's to two channels in the NAD receiver's amp in the interim, and other questions about using Tritons for surrounds, Sandy (THE Sandy) came to the phone to answer all. Re the part about connecting two speakers to one amp output, he didn't like it, suggested not doing it because of the impedance drop. And awhile ago on another thread, I had talked about Triton towers responding well for dynamics to amps with plenty of 4 ohm power available, Moderator had said the mid/bass drivers in Tritons occasionally like and need 4 ohm draws for the dynamics. So, with both pairs of Tritons drawing from the same amp's two channels, and maybe therefore dipping, with 4 speakers drawing power, to maybe 2 ohm loads for a short bit, I wonder how your Cambridge would handle that...

I know you play at reasonably low sound levels and hence power draws, but, I'd be some concerned about damaging the Cambridge, or clipping damage to the Tritons if sound levels get pushed a bit.

Just my thoughts, others may have very clever solutions to avoid that.

Rick

Hi Rick,

You are correct in your observations and concerns. I have not been able to get any further information from Cambridge with regard to the risks, the relationship between lower net impedances and sound levels, etc. I know there is risk in running the amplifier with both sets of speakers active - although the risk might be reduced at lower volume levels (the question then becomes, "at what lower volume levels?").

Do you have any thoughts related to adding a device to my system to alter the net impedance levels? There are a number of devices on the market which claim to balance the impedance levels for multiple speaker connections.

I have an alternative approach - using a second amplifier to drive the second speaker set, but I would like to avoid the extra hassle if possible.

Best,

Art

Hi, Art

As I understand it, impedance balancing devices prevent power over draw, which may protect your Cambridge amp. But the downside is that when you WANT the power and dynamics for peaks, it won't be there. That would be a non starter for me.

A second amp would be my choice. Just curious, I thought you were driving the T7's with a different receiver, is that not giving you what you want?

Rick

Hi Rick,

Your memory is on target. I do have a second amp readily available and, in fact, I have been driving the Sevens with the second amp. I would prefer to drive both the Ones and the Sevens with the Cambridge, just to simplify things. My current speaker configuration has my Ones further apart than they should be, due to room configuration limitations. I am using the Sevens as a second set of Fronts, more closely spaced than the Ones, to provide a more balanced stereo sound, particularly for classical music "sound staging".

The Sevens and the Ones play well together when driven by my Cambridge 851A. When I drive the Sevens separately with another amplifier, I have to re-balance the volume level for the Sevens each time I change the volume level for the Ones. With both speaker sets connected to the 851A, the volume levels match very well.

Best,

Art

Art

Maybe another tack: are your Cambridge and also the amp/receiver for driving the T7's IR remote control capable? If so, I'd invest in a programmable remote that would control sound levels etc. on both simultaneously and avoid the damage risks or possible performance drop-off of trying to power both sets of Tritons from the Cambridge.

Rick