Confused about Bi amping

[RickH]

I'm a little confused as to how to Bi amp my speakers...I have two Onkyo M504 power amplifiers. one Nakamichi CA5-A2 preamp which has two sets of pre outs...
and a pair of phase tech PC 8.5's which are set up with 4 binding posts with shorting straps. Lastly I have a large velodyne sub... can't remember the model, with RCA in and outs. Can someone please help and explain to me how this all gets hooked up to bi amp my phase techs and still run my sub?? Also,am I better off to run each speaker with one amp or would there be a sonic advantage to use one amp for the low frequencies of both speakers and the other amp for the high frerquencies of each speaker??? Thanks in advance to anyone who is willing to help!!!! Rick.

 

[TLS Guy]

I'm a little confused as to how to Bi amp my speakers...I have two Onkyo M504 power amplifiers. one Nakamichi CA5-A2 preamp which has two sets of pre outs...
and a pair of phase tech PC 8.5's which are set up with 4 binding posts with shorting straps. Lastly I have a large velodyne sub... can't remember the model, with RCA in and outs. Can someone please help and explain to me how this all gets hooked up to bi amp my phase techs and still run my sub?? Also,am I better off to run each speaker with one amp or would there be a sonic advantage to use one amp for the low frequencies of both speakers and the other amp for the high frerquencies of each speaker??? Thanks in advance to anyone who is willing to help!!!! Rick.

I can't find any details of those speakers. If the top terminals are connected to the band pass and high pass crossovers, (mid and tweeter), there may be minimal merit to passive biampng. If they are just connected to the high pass filter, (tweeter only), biamping is a waste of time.

To biamp remove the jumpers. Connect one set of pre outs to both amps with Y connector.

Now if your sub has right and left line inputs (LFE) then connect the second preouts to the sub. If there is only one input, then see what happens when you common one set of preouts. Quite likely everything will go to mono. If it does not, connect both right and left preouts to the sub with a Y.

If it goes to mono, then you will need buffer amps between a set of pre outs and your sub, or you will have to run just one channel to the sub.

 

[zumbo]

If the amps spec to be stable bridged with your current speakers, I would say one amp bridged per speaker would yield the best results.

 

[TLS Guy]

I the amps spec to be stable bridged with your current speakers, I would say one amp bridged per speaker would yield the best results.

The only problem I see, is that speakers have two bass drivers, and no matter what the manufacturer says about "nominal impedance", You have to regard those speakers as four ohms. If he bridges his amp he will need an 8 ohm load, or he might be out his amps. I would not recommend that course of action without knowing the impedance curve of the speakers, and how the amps will behave bridged into the load those speakers will present.

There are many amp disasters with bridging. However if the amp will tolerate the load presented by those speakers in bridged mode, I agree with your advice.

 

[zumbo]

As I stated, if the amps spec to be stable bridged with the OP's speakers.

 

[TLS Guy]

As I stated, if the amps spec to be stable bridged with the OP's speakers.

I know you did, and I should have phrased the post a little differently. The thing I was worried about was that the speaker specs might say 8 ohm nominal. I was only able to find a picture of those speakers, but absent a reliable impedance curve, you have to regard them as four ohm. I would hate the OP to trash his amps, and this is a good way to do it, even if you think you have covered the bases.

You really do need to know the impedance curve of your speakers before bridging.