Introduction:

I have been using a Yamaha RX-V2700B for the last 2 years, but recently decided to go with a separate processer/power amp combo.

I'm budget limited, so the Yamaha RX-V663 and Rotel RMB-1085 combination seemed like a good solution.

I wasn't able to demo the RMB-1085, but I had previously demoed a setup with the same speakers as mine through a RMB-1075 and was blown away by the difference. Online reviews tended to indicate that the 1085 was at least as good as the 1075.

The rest of my setup is:

Krix Lyrix Gold mains
Krix KDX-C Center
Krix Equinox Rears
Krix Seismix 3 sub
HD-XE1 HD DVD/DVD player
PS3 BD Player

No fancy wiring, just 12AWG bulk speaker wire from selby's with banana plug termination.

First thoughts:

I sold my 2700B to a forum member, and had the RX-V663 in place straight away.

I immediately noticed a drop in sound quality, the bass was muddier and the sound was more "compressed" (damn I hate using audiophile terms, but these are the best I can come up with to describe the differences). This was not surprising nor unexpected considering I was going from a $3000 avr to a $1000 avr.

My RMB-1085 finally arrived on Monday, and it was with a mixture of trepidation and joy that I unpacked it, stuck it on my equipment shelf and connected it all up. I even lashed out on some audio interconnects from selbys to go between the avr and the amp (nothing special, cost me $70 for the 5 channels).

I was previously bi-amping the front speakers using the 6th and 7th amp channel of the avr, so I decided to use the 5 amp channels of the avr to drive the front speakers bi-amped and the center. The rear surrounds were left driven by the avr.

I ran the auto calibration and then did a final adjustment with my SPL.

The first thing I noticed was that the front and center channel needed a +5 dB adjustment to bring them into line, which I thought was quite strange.

Anyhow, how did it sound?

Well I chucked in my HD DVD copy of transformers, probably the most watched HD DVD that I own.

It sounded great, but I can't say that I was blown away.

Second thoughts:

Unfortunately I haven't really had a chance to play with the amp again until tonight.

I pulled everything apart again, and turned the amp and avr around so that I could easily get to all the connections.

I was limited in the testing that I could do, as my kids were sleeping, but I settled on the following 3 tests:

1. Eagles HD DVD

Track 2 (New Kid in Town) - I chose this track as it is a slower song, without overpowering vocals.

I listened to the entire song 4 times, twice each through the yamaha, and through the rotel.

It was very quickly noticable that the rotel gave a much clearer, more distinct sound.

There are a couple of guitar sequences where you can almost hear the pick on the string, and the reverb as the note dies out could be heard for a lot longer when running through the rotel.

I also immediately noticed that the rotel gave a "warmer" sound, smoothing out some of the harshness evident in the yamaha sound.

The best way I could describe it was that listening through the yamaha sounded like I was listening to an electronic recreation of a performance, whereas listening through the rotel made me feel like I was actually there.

At this point I was feeling less like I had wasted my money on the Rotel

2. Flags of Our Fathers HD DVD

Track 5 - Naval Bombardment

Anyone with this HD DVD will know the scene I am talking about. It starts with some dialog in near silence, followed by a range of gunfire, from fast ack-ack to big, boomy naval guns.

To be honest, I did not notice a massive difference in sound between the two setups.

I would say that the rotel had definitely removed the muddiness from the bass, but it didn't really give me the extra bass that I was expecting based on my experience with the 1075 in the demo room.

3. Top Gun HD DVD

Track 1 - The first 5 minutes

One of my favourite movies of all times, and what a way for it to start.

As the first lot of music rises to a crescendo, the jets kick in, along with all sorts of mechanical noises and the tempo raises again as we burst into "the danger zone"

Once again, the rotel sounded "clearer", but I actually felt that I was getting slightly less bass

I couldn't really push this up to the volume that I would have liked with the kids asleep, but I would have liked to have know what the difference would have been at -10dB rather than -25dB.

Class-D amps and heat:

Being one of the new Rotel class-D amps, some of you are probably wondering how the amps goes as far as heat.

After giving it a good running, there was far more heat coming out the vents at the top than I have ever felt from either of my Yamaha avrs, so I don't think I'd be sitting anything directly on top of it ...

Conclusions:

Was it worth the money? ... yes I think it was.

It hasn't given me as much of a "night and day" improvement as I was expecting, but then maybe I was expecting too much.

I definitely think I need to spend some time with the SPL and the Yamahas calibration options on the weekend to see if I can work out my perceived bass issue.

Hi Andrew,

Thanks for the review, it's good to see a honest opinion on a product .

No worries mate.

Nice choice of speakers there <wipes drool from chin>

"I have been using a Yamaha RX-V2700B for the last 2 years, but recently decided to go with a separate processer/power amp combo."

good choice mate, separates are definately the way to go.
not to say there arent some extremely nice receivers out there ...

Just a quick update.

I got up early this morning and spent the last hour playing around with the calibration.

I noticed that the 663 had set all 5 of my speakers to large so after setting these back to small I noticed a definite improvement in sound.

I know it sounds counter-intuitive, but Mark Techers's advice from the Audio Calibration Thread and my own experience bears out the fact that setting the mains to small reduces the load by removing the LFE frequencies, letting the speakers/amp work more efficiently. It actually seems to have fixed my "missing bass" issue

I'm even happier now than I was last night

The quest continues to make the system sound even better ...

Good review mate and I imagine with a tad more tweaking you will find out more along the way

Have you given the auto calibration a go?

oops

any better/worse than direct?

Sorry to go off-topic, but Hallzy, your set-up is so similar to mine! Eerily so, too! I used to have a Samsung 40-inch HD LCD TV, too! Hee hee.

Which power amplifier is soon to come? NAD M25? Hee hee.

Good to hear you like it Andrew. Think this could be a popular way to go for many on here in future. Better power than your average AVR, and makes updating to latest technology all that much cheaper.

Would love to know how the 663 stacks up against something like the 1800/3800 via the Rotel though...

Do you mean the Rotel is running the front 3 and the AVR the surrounds?

Have you tried just using the Rotels 5 channel to run your 5 speakers and leaving the AVR amps out of the equation altogether? ie not biamping.

Yes that's exactly what I mean.



No I haven't. It would be an interesting exercise, but a complete pain in the butt to redo all the connections.

thanks AndrewW, always good to read "honest" reviews and great to hear that its made a worthwhile improvement. no doubt it will sound even better once run-in.

I'd also suggest trying the rotel driving all 5 channels and leaving the 663 amps out of it.

are you using this set-up for music as well? if so, how does it compare to the 2700?

I picked up a Rotel RMB-1085 yesterday to compliment my existing equipment consisiting of Pioneer VSX-LX60 AVR and Ascension Speakers and unfortunately ended up returning the Amp to the shop today.......

I was already extremely happy with the sound for both music and movies so the addition of the power amp was an effort to get that last bit of detail and perhaps better sound stage than what I already had.
I went for the Class D Rotel as the equipment is in an enclosed cabinet (with venting at the rear) so heat and size was a consideration, so too was the cost, not wanting to spend thousands etc.
Picked up the Rotel for just under $900.

In summary, the Rotel did add a little in the mid to upper end of the spectrum, probably added a couple of percent in detail etc (which I can notice now without it), however as AndrewW noted at the top of this thread, I would estimate it robbed me of 30% bottom end bass. No amount of fiddling around with speaker size, sub and crossover settngs could get me back to where I was so in the end I pulled the pin and am 100% happier.

I tried really really hard to love this amp, at times I thought I had found a fix as some music sounded better, but in the end it wasnt enough. The guys at the shop suggested that I try the 1075 class A/B amp, which I was very tempted to do, but there was no guarantee this would overcome the problem and it cost more, was bigger, heavier etc etc which is not what I was wanting, so I settled for what I had.

The guys at the shop were great in refundung my money, so I thank them for that. They also said after, that of all the Class D amps that they had through the place, they had always been left somewhat underwhelmed which I would agree with so they didnt put up too much of a fight with me returning it.

It's possible that with a different processor or even speakers the result may have been more pleasing, but in my setup, it wasnt a good match.

cheers
TB

sad to hear TB. the 1075 worth considering perhaps. its actually a very balsy amp have done some demoing wiht it. I would never say it was lean in the bottom end either infact quite the opposite wiht in typical rotel fashion I'd say a bit full in the bottom end and rolled off at the top end. could have always asked the shop guys if they would let you try a demo model of it if they had one.

another thing with all this with an amp if straight otu of a box some can take a bit of time to fully run in, depending particualrly on the capacitors they use.

if you have a totally enclosed setup and looking for an amp that runs cool not sure what the options are. I'd suggest perhaps fitting some forced convection at the rear of the cabinet with some silent pcs fans perhaps. as even digital class D amps can run warm some even like the crown's and the hk ice powered ones can run quite hot.

in the end a good thing your going by your ears and lettign them decide. amp - speaker matching is pretty important some combinations working better than others. . in this price range either sticking wiht an avr perhaps a more (grunty one) or getting a different amp really not too many options can only think of the nad multichannel as an option. either way good luck in your search.

Thanks al,
I thought about trying out the 1075, however they dont allow in home demo without purchase first. I felt like I got out of jail a little already (as they would prefer to swap for something in shop rather than give a refund) with taking back the 1085 so didnt want to pay to upgrade to the 1075 and still be disappointed and get stuck with it. It was only $350 more, but in the end I chickened out.
edit1: just worked out you said borrow a demo model, unfortunately they didnt have any tho at the time.

Unfortunately now sitting here knowing there is at least something to be gained, it's eating away at me, especially with the price rises coming.

edit2: actually, just managed to track down a demo 1075 from them that I can have tomorrow night, so will see how it goes, fingers crossed!

TB

Hi TB _ if you don't mind PMing me i would love to know who lent you the demo 1075 as thismay be an amp i am interested in down the road...

Cheers

Same here...

Sorry the Rotel 1085 diddn't work out for you.
One of the things I noticed was a clean more restrained and tighter bottom end (in no way less bass but more in tune with music and was far deeper when called for).
Perhaps the 1075 will do it for you?

yes, it most certainly did!

This one's a keeper....

And....

And...... it's great. It gives the added detail that the 1085 gave me, but still the bottom end grunt that went missing.

I dont know if it went missing because of the components in my system or if its a trait of this amp, or all class D amps for that matter, but AndrewW had a similar issue with Yamaha / Krix gear. I know he had some success by using the sub woofer to suplement the missing bass, but I cant help but see that as a bandaid solution for an "issue" with the amp.

AndrewW, I would be interested to know the outcome of you experiment to sell the higher level Yammy and use two "cheaper" seperates. At first you mentioned the sound was more muddy with the cheaper Yammy which got better with the addition of the 1085.
In the end, was the sound the same or better than what you started with? Was it a worth while change?

TB

I have so far had a few days to play with this unit, a Rotel RMB-1085 5 x 100-watt Class D Power Amplifier. I believe that RRP is $1,200.00 (don't know if it has gone up in RRP, but I am pretty sure it used to retail for about $1,200.00).

My equipment list is as per my signature below.

I have never listened to a Class D amplifier before, and must admit that I have always wondered how a Class D amplifier would sound. I have heard people bad-mouth Class D amplifiers, but I have always believed never to judge before one actually listens to an amplifier.

So, a 5-channel Power Amplifier for a very reasonable RRP. How does this unit perform?

Powering my full set of 4ohm-rated Krix loudspeakers, I can say that I was exceptionally surprised at how well this Power Amplifier performed. In terms of sheer power out-put, it seems to have so much of it! This unit stands under 3-inches tall and weighs under 6kg.

Just by looking at it, one wouldn't think that it would be able to power multi-driver large loudspeakers to such aplomb. The clarity of dialogue and bass tightness was in abundance. The sheer scale that this thing manages is awe-inspiring.

I would say that it doesn't quite plumb the bass depths that my more powerful, Class A/B NAD M25 can, but it is not far off, and when you consider how much cheaper per channel it is, it is amazing how good this little Power Amplifier is.

For me, this unit doesn't lack in bass out-put; it is just that it is ultra-tight. It exhibits very good control of my Krix loudspeakers.

This Rotel RMB-1085 will have no problems powering most moderately-priced loudspeakers to a high level and will provide a good platform for someone looking to improve on the sound quality from their low-to-mid level A/V Receivers.

Dan.

I love the weight and was really seriously considering getting the 1077 from overseas... IIRC with class D they have to add a low pass filter to filter away the high freqs... Not an issue at all?

Sonically, no issues at all. In fact, if someone was listening to it, they wouldn't really know what amplification topology it contained. It sounds like it really should.

I had put a deposit on the '1077, but due to slight unavailability at that point in time, I ended up spending a lot more and purchasing the NAD M25 that I had been eyeing for quite a while.

I am sort of glad now, because the '1077 has since reduced in pricing by about $1,000.00.

The small size and lack of weight makes good sense to import from overseas!

I think that the pricing of some Rotel gear is extremely well-priced here. I think RRP of the '1077 is now only $2,200.00, which is superb value-for-money.

Even though on paper, the '1085 appears to be just a 5-channel version of the '1077, it actually is not.

The '1077 has got ICEPower modules that Rotel co-developed for about 18 months with Bang & Olufsen. Rotel worked with Bang & Olufsen to tune those Class D modules, to ensure that they met Rotel's high standards.

The '1085 has Rotel's own Class D implementations, thanks to their experience learned from the '1077.

Dan.

All is not lost yet, still hoping that somehow AUD will miraculously increase in value ... One can only hope...

I am sure that Sound Advice will do you a good deal, if you speak with them.

I purchase all my gear from Mark Hyland there, except for gear that they do not stock and sell.

Dan.