Arcam A75 as a power amplifier for bi-amping?

Johnny123456

Novice Member
Hi there
I have an Arcam a75 diva powering my Monitor Audio Silver 6 front speakers. I would like to bi-amp these and wonder could I use another p75 as a power amplifier rather than specifically an Arcam p75? Reason I ask us that there is one at a good price on eBay and matching p75 power amps don’t cone round that often. I assume This is not possible - but then I thought Perhaps it could if I use the AV input and set the amp volume to be controlled by the processor (as I have done with my current p75). Just a thought - welcome any advice - thanks!
 

Jamie

Distinguished Member
You can certainly use a second A75 as a power amp. It's exactly what a mate used to do.

The only bit I'm not sure about is if the first A75 bring used as a power amp for your AV receiver will still also send a signal via it's preouts to the second one. My mates system was purely stereo.
 

rccarguy2

Distinguished Member
Don't mix and match amp brands when biamping as each amp has its own gain and sound.

It's fine using one stereo amp for sides then another for rears. But not when biamping
 

Timmy C

Distinguished Member
I would like to bi-amp these and wonder could I use another p75 as a power amplifier rather than specifically an Arcam p75?

I'm a bit confused by this bit. Did you mean use a second A75 rather than a P75? If so then it should work fine. The A75 has processor mode which, for the purposes of what you want to do, turns it into a power amp. Set it up being fed from the pre out on the first A75 and leave the second one in processor mode permanently. I've done the same thing with a few old Arcam integrated amps in the past.
 

Mark.Yudkin

Distinguished Member
I'm a bit confused by this bit. Did you mean use a second A75 rather than a P75? If so then it should work fine. The A75 has processor mode which, for the purposes of what you want to do, turns it into a power amp. Set it up being fed from the pre out on the first A75 and leave the second one in processor mode permanently. I've done the same thing with a few old Arcam integrated amps in the past.
The Arcam A75 and Arcam P75 can be mixed - they are specifically designed for just that.

Rccarguy2 was probably confused by your statement "could I use another p75 as a power amplifier rather than specifically an Arcam p75?", which he understood to mean another amplifier brand, I think you meant to write another A75.
 
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Johnny123456

Novice Member
Thanks for all the advice and sorry I got my A's and P's mixed up and the title of the thread wrong - should have said bi-amping! Anyhow - you guys managed to give me useful advice despite all that so thank you again!
 

Johnny123456

Novice Member
Thanks for all the advice and sorry I got my A's and P's mixed up and the title of the thread wrong - should have said bi-amping! Anyhow - you guys managed to give me useful advice despite all that so thank you again!
 

Johnny123456

Novice Member
I'm a bit confused by this bit. Did you mean use a second A75 rather than a P75? If so then it should work fine. The A75 has processor mode which, for the purposes of what you want to do, turns it into a power amp. Set it up being fed from the pre out on the first A75 and leave the second one in processor mode permanently. I've done the same thing with a few old Arcam integrated amps in the past.
Hi there
I've just wired up my second A75 with a pre-amp feed from my first A75. The feed to the second A75 is going into the AV input and the amp is set to processor mode picture to follow. But it's not working which makes me think that Jamie was correct in that there's no signal coming from the first A75. In which case - what's the point of having a pre-amp output? Any advice on testing?! Starting to wish I'd just bought a P75 now!!! Thanks all
 

Johnny123456

Novice Member
2nd A75 on left set to processor mode accepting preamp output from main A75 - which I'm playing a CD into. I've not tried using this set up from my actual AV yet - I just wanted to see if I could bi-amp my speakers this way first. It appears not (?) so I guess there must be something about the signal that means the A75 preamp output must be fed into a dedicated P75 or other power amplifier as opposed an integrated amp.
 

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Timmy C

Distinguished Member
Hi there
I've just wired up my second A75 with a pre-amp feed from my first A75. The feed to the second A75 is going into the AV input and the amp is set to processor mode picture to follow. But it's not working which makes me think that Jamie was correct in that there's no signal coming from the first A75. In which case - what's the point of having a pre-amp output? Any advice on testing?! Starting to wish I'd just bought a P75 now!!! Thanks all


When you say it's not working, do you mean no sound at all? If the pre outs aren't working then a P75 wouldn't be getting a signal either if you had bought one. The manual says something about holding the processor mode button for 5 seconds for it to change to fixed input. I take it you have tried that? It seems some sort of light should come on to show it's in processor mode.
 
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Johnny123456

Novice Member
Hi there - yes no sound. I have set the processor to AV fixed gain (you can see the light on the silver P75). I know both amps work fine independently. I’m a a bit of a loss to be honest
 

Timmy C

Distinguished Member
OK so just to rule out a problem, have you tried using the new A75 alone but in processor mode and in conjunction with your av amp? I believe that's what you were doing originally with the first A75 is that right? At least that way, if it works then we know there's not a fault with the processor mode function on the new amp.

I've used Arcam integrated amps as power amps myself, as have friends of mine and never had a problem so I'm sure we can get this working, assuming there's no fault with the amp.

I assume you have removed the links connecting the binding posts on your speakers? Which amp is connected to which set of posts?
 

Johnny123456

Novice Member
OK thanks so much for your advice. I will try using the new A75 (silver one in photo) tomorrow in AV mode with my AV and get back to you.
Yes I removed the links. The black P75 is amplifying the mid/bass on both MA Silver 6s and the silver the tweeters.
From your comment on which amp is connected to which set of posts - I am now wondering if I’ve made a fundamental numpty error! Should the A75s be powering one speaker each rather than eitherthe low/highs? I’d made the assumption that one amp deals with the low/mid for each speaker and one does the top. I’m going to Google some set up drawings again in case I looked but didn’t see!
 

rccarguy2

Distinguished Member
OK thanks so much for your advice. I will try using the new A75 (silver one in photo) tomorrow in AV mode with my AV and get back to you.
Yes I removed the links. The black P75 is amplifying the mid/bass on both MA Silver 6s and the silver the tweeters.
From your comment on which amp is connected to which set of posts - I am now wondering if I’ve made a fundamental numpty error! Should the A75s be powering one speaker each rather than eitherthe low/highs? I’d made the assumption that one amp deals with the low/mid for each speaker and one does the top. I’m going to Google some set up drawings again in case I looked but didn’t see!

You can do vertical or horizontal bi amping. I'm doing vertical with my kefs.

Vertical is when one power amp drives one speaker and the other power amp drives the other.
 

Timmy C

Distinguished Member
OK thanks so much for your advice. I will try using the new A75 (silver one in photo) tomorrow in AV mode with my AV and get back to you.
Yes I removed the links. The black P75 is amplifying the mid/bass on both MA Silver 6s and the silver the tweeters.
From your comment on which amp is connected to which set of posts - I am now wondering if I’ve made a fundamental numpty error! Should the A75s be powering one speaker each rather than eitherthe low/highs? I’d made the assumption that one amp deals with the low/mid for each speaker and one does the top. I’m going to Google some set up drawings again in case I looked but didn’t see!

Either way is fine with matching amps although I would go with the way you have done it rather than one amp per speaker.

So are you getting no sound at all or just no sound from the tweeters connected to the new amp? Even if there was an issue with the old amps pre outs you should still be getting the low end if that's the amp connected to the LF terminals.
 

Johnny123456

Novice Member
Yes I’m getting low end sound from the original A75 as expected but nothing from the high end from the new A75. I’ve tested the new A75 powering the high end with a direct feed and it works fine. I tried all configurations feeding the preamp output into different inputs on the new A75 but nothing. I even tried making the phono input a line input by pressing the little blue button, but no joy. I might try reversing the whole thing and using the new A75 as the master and use it’s preamp output. Eventually I’ll have tried everything and have an answer!
 

Timmy C

Distinguished Member
Well that's odd. Is it muted or is it some sort of protection kicking in? I would double check that all four post couplers were removed at the speaker end and no stray wires are causing it to go into protection mode. That is assuming you haven't just muted it by accident somehow.
 

Johnny123456

Novice Member
I've powered up the 'new' A75 with no speaker connections or input RCA cables connected - and the LED remains orange. I guess I should deduce it's only doing this because there's an issue with the amp - I assume it wouldn't default to mute on powering up? Looks like I must have been sold a dud I guess. I thought yesterday when I was testing it I'd got it to work - but having done so many configuration tests and being excited about setting it up, I may have been mistaken. Looking back on the photo I took the LED seems to have always been orange
 

Johnny123456

Novice Member
I’ve found an article here about dry joints which i suspect might be the cause of the problem

 

Timmy C

Distinguished Member
I was just reading the same thing and was going to share the link. Yeah if it's powering up and staying orange with nothing connected at all then it's definitely faulty. I wouldn't let it put you off trying another Arcam integrated though as with a non faulty amp, you shouldn't have any issue doing what you have tried to do.

It's also worth noting that you don't have to use the same model. You could for example use an A85 for LF and your existing A75 for HF.
 

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