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Arcam Alpha 7R with Arcam Alpha 9P?

Apr 17, 2016
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I've recently fixed up my old Arcam Alpha 7R, but I've read that the way to get a really decent sound from it is with some bi-amping.

The best option would be the Arcam Alpha 8 P, but they're quite hard to get hold of these days. I have found an Arcam Alpha 9P available to buy, but the 9P has 70W per channel, while the 7R is 40W.

I've read that it can be preferable to have more watts per channel for the low end when bi-amping, but wanted to check on here whether this was right. What do people think? Any advice would be much appreciated.

Thanks.
 

davedotco

New member
Apr 24, 2013
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Geoff Wright said:
I've recently fixed up my old Arcam Alpha 7R, but I've read that the way to get a really decent sound from it is with some bi-amping.

The best option would be the Arcam Alpha 8P, but they're quite hard to get hold of these days. I have found an Arcam Alpha 9P available to buy, but the 9P has 70W per channel, while the 7R is 40W.

I've read that it can be preferable to have more watts per channel for the low end when bi-amping, but wanted to check on here whether this was right. What do people think? Any advice would be much appreciated.

Thanks.
When passive bi-amping is used, the output of the setup is, effectively, the power of the least powerful amplifier, in this case 40 watts. Ie adding the 70 watt power amp does not increase the power at all, the 40 watt amp still sets the limits as both amplifiers are being fed the same full range signal.

It is arguable whether passive bi-amping has any benefits at all, in this case you might do better running as a simple pre-power single wired setup, at least you get the benefit of the extra power, modest though the increase is.

I'm guessing that the power amp is available quite cheaply, if this is so then I would recomend trying the different setups for yourself. Nothing in hi-fi will tell you more than listening and trying things for yourself, highly recommended
 
Apr 17, 2016
2
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davedotco said:
When passive bi-amping is used, the output of the setup is, effectively, the power of the least powerful amplifier, in this case 40 watts. Ie adding the 70 watt power amp does not increase the power at all, the 40 watt amp still sets the limits as both amplifiers are being fed the same full range signal.

It is arguable whether passive bi-amping has any benefits at all, in this case you might do better running as a simple pre-power single wired setup, at least you get the benefit of the extra power, modest though the increase is.
Cheers Dave.

Can you describe in a little more detail how a 'pre-power single wired setup' would work?
 

davedotco

New member
Apr 24, 2013
20
0
0
Geoff Wright said:
davedotco said:
When passive bi-amping is used, the output of the setup is, effectively, the power of the least powerful amplifier, in this case 40 watts. Ie adding the 70 watt power amp does not increase the power at all, the 40 watt amp still sets the limits as both amplifiers are being fed the same full range signal.

It is arguable whether passive bi-amping has any benefits at all, in this case you might do better running as a simple pre-power single wired setup, at least you get the benefit of the extra power, modest though the increase is.
Cheers Dave.

Can you describe in a little more detail how a 'pre-power single wired setup' would work?
If I recall correctly the 7R has a pre-out which is always active. Simply connect this to the input on the power amplifier with a pair of regular phono cables and then connect the speakers to the power amp using your normal cables in your normal way.

You do not connect the speaker outputs on the 7R at all. In this case the 7R is acting as a pre-amp only and the power amp supplies the power, all 70 watts.

As I said above, using both amplifiers hi-amped will limit the power to that of the 40 watt 7R since both amplifiers are driven with the full range music signal and the smaller amp will run out of power first. Even though the smaller amp is only connected to the hf (tweeter) terminals which require little power, the amp is actually delivering a full range signal most of which is 'dumped' by the crossover. (not technically correct but it gives a good idea of what is happening)
 
Apr 17, 2016
2
0
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davedotco said:
If I recall correctly the 7R has a pre-out which is always active. Simply connect this to the input on the power amplifier with a pair of regular phono cables and then connect the speakers to the power amp using your normal cables in your normal way.

You do not connect the speaker outputs on the 7R at all. In this case the 7R is acting as a pre-amp only and the power amp supplies the power, all 70 watts.

As I said above, using both amplifiers hi-amped will limit the power to that of the 40 watt 7R since both amplifiers are driven with the full range music signal and the smaller amp will run out of power first. Even though the smaller amp is only connected to the hf (tweeter) terminals which require little power, the amp is actually delivering a full range signal most of which is 'dumped' by the crossover. (not technically correct but it gives a good idea of what is happening)
Cheers for this, really helpful.

One last question: If I were to connect the two in the manner you describe (which sounds like the best option), how would the power amp be able to supply its full 70W of power, if it was only getting a maximum signal of 40W from the pre amp?
 

davedotco

New member
Apr 24, 2013
20
0
0
Geoff Wright said:
davedotco said:
If I recall correctly the 7R has a pre-out which is always active. Simply connect this to the input on the power amplifier with a pair of regular phono cables and then connect the speakers to the power amp using your normal cables in your normal way.

You do not connect the speaker outputs on the 7R at all. In this case the 7R is acting as a pre-amp only and the power amp supplies the power, all 70 watts.

As I said above, using both amplifiers hi-amped will limit the power to that of the 40 watt 7R since both amplifiers are driven with the full range music signal and the smaller amp will run out of power first. Even though the smaller amp is only connected to the hf (tweeter) terminals which require little power, the amp is actually delivering a full range signal most of which is 'dumped' by the crossover. (not technically correct but it gives a good idea of what is happening)
Cheers for this, really helpful.

One last question: If I were to connect the two in the manner you describe (which sounds like the best option), how would the power amp be able to supply its full 70W of power, if it was only getting a maximum signal of 40W from the pre amp?
It doesn't quite work like that.

Very briefly. All amplifiers have at least 2 separate stages or sections.

Firstly the pre-amp stage that takes the signal from the sources, allows you to select between them and adjust volume, bass, treble etc. The signal is amplified to around a couple of volts (typically, there is no real standard) and then passed on.

To the power amplifier which is simply that, it takes the 2 volts in and produces the power to drive your speakers.

They can be separate, ie a pre-amp and a power amp, or combined together to make an integrated amplifier. Your 7R is an integrated that, with the addition of the pre out sockets, can be used as a pre-amp with the onboard power amp not being used. Given that the 9P is a better power amplifier than the power amplifier section in your 7R, you are probably making an upgrade.
 
Apr 17, 2016
2
0
0
davedotco said:
It doesn't quite work like that.

Very briefly. All amplifiers have at least 2 separate stages or sections.

Firstly the pre-amp stage that takes the signal from the sources, allows you to select between them and adjust volume, bass, treble etc. The signal is amplified to around a couple of volts (typically, there is no real standard) and then passed on.

To the power amplifier which is simply that, it takes the 2 volts in and produces the power to drive your speakers.

They can be separate, ie a pre-amp and a power amp, or combined together to make an integrated amplifier. Your 7R is an integrated that, with the addition of the pre out sockets, can be used as a pre-amp with the onboard power amp not being used. Given that the 9P is a better power amplifier than the power amplifier section in your 7R, you are probably making an upgrade.
Thanks Dave, that's a big help. Very much appreciated, cheers for taking the time.
 

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