Bi amping

[ardtullaich]

was looking for a while to buy alpha 10p to biamping with my alpha 10a. I had no luck and missed out on a few on ebay.
So I decided to buy a arcam fmj a22 and run the alpha 10a as a power amp only. Using the a22 to run the mid and tweeters and the alpha 10a running the bass drivers. One thing I have noticed is that it dosn't seem to sound as loud as it did while just using my alpha 10a as a full integrated biwiring the speakers with the 2 speaker outputs of the alpha 10a before I got the fmj a22.
As anyone else come across this?

 

[davedotco]

The two amplifiers have the same nominal input sensitivity, so unless the spec is wildly out this should not be the reason.

Arcam amplifiers are generally gain matched, but you have models from two different series, so this might be the issue. Ie your FMJ might not be driving the 10 as hard as it is driving it's own power amp. Try switching the FMJ to the bass drivers and the 10 to the tweeters if that is possible, see what happens.

Also, you need to remember that in a (passive) bi-amp system, the effective power output is that of the smallest of the two amplifiers. Although nominally the same output, there might be a difference in the 'real' world power, and the amp with the lowest output will be the limiting factor.

 

[hybridauth_Facebook_100004211376004]

Ime bi amping arcam gear has little effect and your better putting the extra cash to either new speakers or a new amp all together.Maybe try using one as a pre and the other as power and see if that makes much difference...that is a combo I didn't try with my a85/p85 and might be better suited to your amps as they are both from a different series and generation of arcam amplifiers.

 

[eggontoast]

was looking for a while to buy alpha 10p to biamping with my alpha 10a. I had no luck and missed out on a few on ebay. So I decided to buy a arcam fmj a22 and run the alpha 10a as a power amp only. Using the a22 to run the mid and tweeters and the alpha 10a running the bass drivers. One thing I have noticed is that it dosn't seem to sound as loud as it did while just using my alpha 10a as a full integrated biwiring the speakers with the 2 speaker outputs of the alpha 10a before I got the fmj a22. As anyone else come across this?

The FMJ-A22 is exactly the same amplifier as the Alpha 10, it's just emperors new clothes but is the same under the skin. There shouldn't be a shortage of power either as they easily kick out 100watts per channel.

Both amplifiers should sound the same, have you checked you don't have the gain switch set to the low position on the rear of either of the amplifiers?

Also have you flicked the internal switch on the Alpha 10 to convert to power amp only and finally, how have you wired it all up ?

 

[davedotco]

was looking for a while to buy alpha 10p to biamping with my alpha 10a. I had no luck and missed out on a few on ebay. So I decided to buy a arcam fmj a22 and run the alpha 10a as a power amp only. Using the a22 to run the mid and tweeters and the alpha 10a running the bass drivers. One thing I have noticed is that it dosn't seem to sound as loud as it did while just using my alpha 10a as a full integrated biwiring the speakers with the 2 speaker outputs of the alpha 10a before I got the fmj a22. As anyone else come across this?

The FMJ-A22 is exactly the same amplifier as the Alpha 10, it's just emperors new clothes but is the same under the skin. There shouldn't be a shortage of power either as they easily kick out 100watts per channel.

Both amplifiers should sound the same, have you checked you don't have the gain switch set to the low position on the rear of either of the amplifiers?

Also have you flicked the internal switch on the Alpha 10 to convert to power amp only and finally, how have you wired it all up ?

That is good and looks like it should work fine.

Check out the details suggested by eggs and let us know what you find..*good*

 

[ardtullaich]

Thanks for all your replies

Yes the are exactly the same inside, i moved my phono board from the 10a to the a22. Though there are some slight mods to the pre amp i seem to remember in one review of the a22.

Both the gain switches are the set the same to normal and i have switched the 10a to power amp only internally.

This was the reason i settled on the a22 as the power amp stages are both the same.

I have the a22 as the main feeding pre to the 10a.

The a22 runs the mid and tweeters and the 10a runs the woofers.

The speakers are B&W 604mk3.

I have access to a db meter so i will measure the output .

then i might try running the 10a as main and a22 as power amp see if i get a different measurement then .

I have modded the amps slightly by adding 2 120mm pc case fans on top of each of the amps above the heat sinks

drawing air out throught the top of the case. this is run of a walmart 12v 5 amp power supply.

And what a difference it makes never had one trip on the 10a or the a22 since doing this. and it does draw the heat away you can feel the warm air coming off the fans.

 

[nopiano]

I'd be worried something else was amiss if I needed to pump air into my amp.

 

[eggontoast]

The Alpha 10's do run quite warm and require good ventilation, they definately shouldn't be stacked on top of each other. These Arcams do have the provision for fans to be added just underneath the heatsinks, all the circuitry is there, they are controlled by temperature sensors on the base of the heatsinks.

 

[ardtullaich]

yes the fans are installed on the a22 but they only come i am told when it actually trips.

When the amps were reviewed they always comment how the amps would trip out on them both the 10a and a22.

Even at quite light loads.

And extra cooling can only help the longevity of the components.