Monoblock's or Two Channel Power Amps for front 3 Channels?

hugemagicwand

Novice Member
So in another thread it was suggested that, in a 5.1 setup, I might be underpowering my front Celestion A3 speakers having them bi-amped from an Arcam AVR-350. So I went off hunting for cost effective power amp solutions and scored a deal on a job lot of little used Emotiva power amps.
Specifically, I managed to obtain, 3 * UPA-1 Monoblock's and 3 * BasX A-300 two channel power amps (and a PT-100 preamp).
What I would like to do is connect the power amps to the pre-out's of the AVR-350 such that I can use the system for movies and music roughly 50/50.
What I know so far is that the bi-amping feature of using the surround channels on the AVR-350 to be able to bi-amp the front main speakers works with two external power amps because having configured channels 6 and 7 for bi-amping I tested and found that this signal is routed to the pre-out's for those channels. Therefore I'd like to setup as follows:

A3 Main Front > bi-amped with 2 * power amps.
A4C Centre > 1 * power amp.
A5r Rears > 1 * power amp.

Which brings me to my question, in your view, which of the amps would be better for the main stereo pair and centre? the UPA-1 Monoblock's or the the A-300's and why?

The reason for asking is because both from listening test and specs perspective both approaches seem to have their pro's and cons so I was wondering what other folks with more experience than me would go with?
 

rccarguy2

Distinguished Member
Celestion don't need lots of watts as pretty efficient but being 4 ohm decent power supply. The 50W difference between the two amps isn't that much. Biamping may help for music also.

Try both layouts monoblocs or biamping.

I'd look at changing the A5R, they're dipoles and may prefer slightly more direct speakers

If you ever sell off A3 may be in them
 

hugemagicwand

Novice Member
Hi rccarguy2, I could swap the A5R's for A1's or A1 Compact's I suspect the Compacts would be the more "family friendly" option ;-)
Regarding the 50 watts difference, I was thinking that the A-300 put's out 300 watts into 4ohms per channel so doesn't that mean they are each putting out approx 600 watts into each of the front speakers as opposed to the UPA-1 which would be 350 watts into 4 ohms but only the single channel so just the 350, or did I misunderstand completely (which is more than possible)?
 

rccarguy2

Distinguished Member
A-300 is 300w but with laxer testing specifications 1khz, higher thd

Bi amping does not increase power, that's bridging. If you biamp with two a-300 you'll get four channels X 300w (but I'd knock a few watts off each amp to get FTC spec)

Under normal use you're probably using only a few watts into the Celestion A3. Your anps won't be outputting 150-300w.

I tested power usage on my whole system that's big TV, subwoofer, two amps on, and still under 500w.

If you have a smart meter or plug in meter you'll be able to see how many watts your amp is using.
 

Mark.Yudkin

Distinguished Member
Bi-amping won't increase the power, of which you already have more than enough to fill a disco with your reasonably efficient Celestions.

I'd suggest one monobloc per front channel (i.e. not biamped), a stereo for the surrounds, keep a stereo for the rear speakers you obviously need to get for 7.1 and either keep the third stereo speaker for Atmos heights or sell it on.

If you must biamp, you'd be better off with more monoblocs than using a pair of stereo amplifiers / both channels of a single stereo power amplifier. OTOH, you obviously bought 9 channels of amplification with another setup in mind.
 
Last edited:

NewAcousticDimension

Active Member
It's not clear what your set of kit is or your room layout etc. but just saying that if you still are just using the one old REL subwoofer in that room, then I would suggest selling some of those power amps, relying on your Arcam AVR for some of the channels and getting the money together to upgrade the subwoofer.
Just my view. As @Mark.Yudkin suggests you have more than enough power unless you are using seriously inefficient speakers all round.
 

hugemagicwand

Novice Member
Hi Mark.Yudkin, thanks for your feedback, I'm thinking to go monoblocks on the front three channels a stereo for the rear pair and sell on the rest of the kit which would be 2*A-300 and a PT-100 preamp. The feedback from everyone has been really useful and opened my eyes to a few things I'd gotten wrong :)
 

hugemagicwand

Novice Member
Hi NewAcousticDimension, well recalled, yes currently I have a REL Stentor in that room with the possibility to add another identical one. I also came across a BK Electronics XLS200 which I really like so I was thinking to maybe spend the money from selling on some of the power amps and the preamp to maybe replace the REL(s) with a pair of as yet unchosen BK Subs. Would you have any suggestions on which way to go with a pair of subs if I didn't go with the BK option?
 

rccarguy2

Distinguished Member
Hi NewAcousticDimension, well recalled, yes currently I have a REL Stentor in that room with the possibility to add another identical one. I also came across a BK Electronics XLS200 which I really like so I was thinking to maybe spend the money from selling on some of the power amps and the preamp to maybe replace the REL(s) with a pair of as yet unchosen BK Subs. Would you have any suggestions on which way to go with a pair of subs if I didn't go with the BK option?

Sell the subs off and buy new modern sub or two


Something like 12" mono price monolith. Don't mix and match subs
 

NewAcousticDimension

Active Member
Would you have any suggestions on which way to go with a pair of subs if I didn't go with the BK option?

The suggestion above from RCcarguy is a good one but if that is out of budget, then you should have a look at the ready reckoner here:


From memory, you have a large room (was it 5x6m?), as usual it depends on budget. I would expect that the cheapest option would be two Mono THX 10" that could achieve reference level. But, especially if you do not have separate EQ, I would suggest two SVS PB1000 Pro or 2000/3000 Pro if the budget allows as these SVS models have some built in EQ.

Whilst your REL Stentor is an amazing hefty piece of kit, it can't compete with the modern driver designs/construction, the electronic controls and importantly the (what can only be described as) immense amplification of modern subwoofers. A Mono 10" THX would, in my opinion, out perform that REL in every way.
 

hugemagicwand

Novice Member
Hello NewAcousticDimension, on the money my living room is 5x6m :) I'm very tempted to go with a BK Monolith Plus sub or pair of subs because the price is nice, they built the REL's they'd be replacing and they seem to have good reviews.
Also, I was thinking to swap out the AVR350 for an AV9 but I'm using the two "spare" channels on the AVR350 to bi-amp the front stereo pair (I know it just sounded "better" to my ears) can this be done on the AV9 as well because I quickly read the manual on the Arcam website and I could not find a single mention of the word bi-amp?
 

The latest video from AVForums

Samsung QN95B 4K QLED TV Review
Subscribe to our YouTube channel

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom