Rotel Pre/Pro & Amps - Purchase help

[RgrRW]

I’m a “Junior Member’ so I’m probably violating some protocol on thread selection but I hope you’ll indulge me.

I’m in the market to purchase a Rotel Pre/Pro and one or more amps. I have the old Matrix 803 (fronts), 805s (rear), CWM Cinema in the sidewalls and my room is about 20ft long x 16ft wide.
My research on this site has shown two recurring themes: 1) My speakers need a lot of power and 2) the RSP1098 is probably not worth the additional $1300 to me as I may have a good ear but I’m no audiophile. So I’ll likely get the RSP1068 and I’m looking for comments on amplified combinations.

First I’m interested in your thinking on whether 7.1 is worth the additional $$$ in terms of amps and speakers as I can use the 805s in another room.

Second my amplifier considerations would be:

1) For a 5.1 system - Would there be a distinct advantage on using the 1095 over the 1075?

2) For a 7.1 system I’m interested in comments on using an RMB1075 w/ a RM1080 for the fronts or an RMB1095 with a RB1070 for the side surrounds.

I have only auditioned the 1098 w/ N803s and it’s a beauty but I’m thinking my money is better spent on amplifiers.

Any and all comments are welcome and my thanks for your help.

[Azeke]

Welcome RgrRW to the forum.

My personal choice would be option 2 allow me to explain. I own the RSP-1098, RMB-1095, and the RB-1080. I have updated to DoProIIx (firmware version 2.1.2) and I am running a 7.1 channel system. It's a beautiful thing :T , but from what I have heard DoProIIx only benefits people with a 7.1 system.

The RB-1080 will drive your fronts beautifully and the RMB-1075 should be sufficient to drive your rears, I believe option 2 provides more bang for the buck.

Two key components I should mentioned, one ensure you calibrate your speakers. Secondly, your delays must be properly set.

Keep us posted on your decision.

Hope this helps,

Azeke

[Aussie Geoff]

RgrRW,

To help us with our advice:
1) What is / will be your centre (e.g. HTM1)?
2) What is your requirement (% or focus) on music vs. Home Theatre?
3) How loud do you play?
4) What Subwoofer (if any) do you have)?

For me all this effects the choice of RB-1080 and RMB-1075 (great for music but will struggle with the HTM1 centre) vs the RMB-1095 (great for home theatre and excellent with the HTM1 Centre and a little less great for music - but still good)

Geoff

[aud19]

I'd say it depends on your music to movie ratio but as Azeke pointed out the 1080/1075 is your best bang for buck even if you only do 5.1 and use the extra channels for second zone or bi-amping etc and would be especially benneficial for 2-channel music.

Jason

[Andrew Pratt]

If you have the room for 6.1 or 7.1 I highly recomend it given your room size. For me it adds a degree of depth to the surround sound stage that you just can't get with 5.1. i'd also recomend the 1075/1080 combo as the happy medium for power and cost...the 1095/1080 combo is awesome as well but likely over kill for the vast majority of people.

[Azeke]

There's that word again, overkill :rofl:

Azeke

[RgrRW]

Answers

Thanks for the welcome and responses.

My Center is the Matrix HTM (basically an 805 on its side)and I'm using a Velodyne FSR12 sub. I listen to mostly movies 80% and music 20%.

I have noticed that the 1075/1080 is the most common application (and least expensive :T ) but I would be interested in why the 1095 for the fronts/ctr & rears and the 1070 for the surrounds isn't used.

I also note that I got no argument about the 1068 vs 1098 so I can put that to bed (it was a beautiful machine).

Thanks again for the help (and no scolding).

[aud19]

There's that word again, overkill :rofl:

Azeke

None of you have told me what that means yet? :huh: :B

..but I would be interested in why the 1095 for the fronts/ctr & rears and the 1070 for the surrounds isn't used.

I think that for most people if you're going to buy a dedicated two channel amp, you want to get one for your mains to maximize stereo performance. That's likely why you see more 1075/1080 and 1095/1080 combo's. Why buy a nice 2-channel amp and use it for your...gulp... surrounds :E :B

And if you don't need the screen and the extra couple %'s sound quality of the 1098, the 1068 makes a fine unit at a good chunk less $$

Jason

[DrJRapp]

Let me give you another option altogether that may give you more bang for the buck. I'm not familiar with your mains and center but for the moment I will assume they are biampable. If they are then I would buy two 1075s which will give you 10 possible channels. If you were to biamp your mains and center that would use 6 of the ten leaving 4 left for 2 side surrounds and two rear surrounds.

This combination offers several advantages over a 1075/1080 or a 1095/1070 combination. First it will only cost about what one 1095 will cost and deliver essentially the same performance as a 1095/1070 will. Secondly, the two 1075s can be plugged into two different 15 amp power circuits. The 1095 cannot live up to it's potential unless fed from a 20 amp circuit. Third the 1075s are not plagued with the potential of ground loop hum that the 1095 and the 1080 are. Forth the center channel will not be the weak sister in the chain as it would with a 1075 with 1080 mains. Fifth, you could start with one 1075 and have 5.1, then graduate to 7.1 at a later date.

I could probably think of five or six other reasons, but it's dinner time and the bell is ringing! :lol:

[aud19]

Another good option and possibly a good solution considering your preference for movies :T

Jason

[RgrRW]

Bi amped 1075s - Hmmmmm

[QUOTE=DrJRapp]I will assume they are biampable. If they are then I would buy two 1075s which will give you 10 possible channels. If you were to biamp your mains and center that would use 6 of the ten leaving 4 left for 2 side surrounds and two rear surrounds.

That sounds like a good idea. I was leaning heavily toward the 1075/1080 option but am pretty spooked by the 1080 fuse issue so bi-amped 1075s sounds ike a good idea.

But nothing is clear. It would seem that the extra set of interconnects plus the 3 decent 'Y" connectors would put me well down the road to a 1095. Any recommendations
on approproiate quality interconnects that wouldn't break the bank?

Thanks again.

[aud19]

Cat Cables, click the link at the bottom of the page

Doug makes awesome quality stuff at reasonable prices and helps you to pick cables that suit your gear, budget and your tastes specifically. Not to mention it's a forum sponsor, so you'd be giving back to the forum to boot :T

Jason

[will1066]

I have had ZERO issues with my RB-1080 for stereo. It has performed rock-solidly. I also have a RMB-1075 with three channels active. (My room is small, so there is not enough space to support 7.1). With three channels running, the 1075 opened up, and I don't have any "weak sister" effect.

[Wolfenstein 2k2]

@ RgrRW

Also keep in mind that in most home theatre systems the center speaker is in principle a (completely) different speaker in comparison to the mains, although it might belong so the same series / brand. If so, using a 1075 + a 1080 for the mains should not lead to a strong "weak sister" effect. Unless you use 5 or even 7 identical speakers - then, using different amps for your mains / the rest could possibly cause inhomogeneous sound characteristics.

By the way: Has there also been this fuse issue with regard to the 1090 or is only the 1080 affected so often?

[DrJRapp]

It would seem that the extra set of interconnects plus the 3 decent 'Y" connectors would put me well down the road to a 1095. Any recommendations
on approproiate quality interconnects that wouldn't break the bank?

Thanks again.

Try www.knukonceptz.com. They have some wonderful 12 gage 4 conductor speaker cable called Karma Biwire cable that I use for bi-wire that can work just as well for biamping. It costs only about $1.40 a foot. They also have reasonably priced high quality bannana plugs. I use their Krystal Konnect copper interconnects which I have tested against some very high priced cables from Straitwire and Cat Cables with some rather surprising results.

[Nick T]

Hi all,

I was wondering if someone could explain something to me, and please excuse my gross ignorance in regard to this matter. Jerry suggested, in an earlier reply, bi-amping the front mains and centre speakers using 2x RMB1075s, leaving 4 spare channels for surround duties. If you were to do this running a 1068 processor (which i am looking to purchase soon), how would you actually hook it all up? From memory (and correct me if im wrong), the 1068 has 7.1 preout connection (actually, 2 centre preouts and 2 sub preouts), so how do you hook up 10 channels to a 7.1 processor (do you just use an RCA splitter connection for the front mains and centre preout on the processor, and run the signal to each amp input?) I hope this post has made sense

Thanks

Nick

[Aussie Geoff]

RgrRW,

I was leaning heavily toward the 1075/1080 option but am pretty spooked by the 1080 fuse issue

I have both the RB-1080 and RMB-1075. I had several blown fuses on the RB-1080 until I learnt what controlled it for me (no trigger and different speaker cables) Since then no problems at all. Talking to the Ausie Rotel distributors this is a 1 in a 100 issue - IE most people have no blown fuse ever.

There is no doubt that the RB-1080 sounds quite a bit nicer in stereo that the RMB-1075 (remember I have both). So I'd still keep it in mind...

Also there are a number of Club Rotel members or Club B&W Members svery happy with their RMB-1095 driving B&Ws up to 803 level... so I'd still consider it. You really need to let your ears decide...

Geoff

[Wolfenstein 2k2]

@ Nick T

This is the 1068´s back as an example - have a look at the preouts:



Provided that I want to use two 1075 power amps with altogether 10 channels available:

1.) Bi-amping the mains: I would use RCA splitter connections (Y-cables) for each of the two main speakers and connect them to the FRONT L / FRONT R preout jacks => 4 channels of the 1075´s in use

2.) Bi-amping the center: For a single center speaker, connect two mono RCA cables or 1 stereo RCA cable to the CENTER1 / CENTER2 preout jacks => 2 channels of the 1075´s in use

2a.) Bi-amping the center: Alternatively, use one RCA splitter cable and connect it either to CENTER 1 or CENTER 2 (both jacks are equal). If you choose this way, one could add another front center because one CENTER preout jack would still be free :B

3.) Single amping the rears: For the two rear speakers again use 2 mono RCA cables or 1 stereo RCA cable and connect them to the REAR L / REAR R jacks => 2 channels of the 1075´s needed

4.) Single amping the back surrounds: For the two back surround speakers also use 2 mono RCA cables or 1 stereo RCA cable and connect them to the CB1 / CB2 jacks => 2 channels of the 1075´s needed

Summary: Now, the two main channels and the center is bi-amped (as we have 3 speakers, 6 channels are needed), the remaining 4 channels of the two 1075 amps will be used for the two rear and the two back surround speakers (single amping). If you do not use back surround speakers, then of course 2 channels are still free for other purposes (e.g. zone 2).

The crazy people among us could do the following: Use RCA splitter cables for all 10 preouts jacks and connect up to 4 subwoofers and 16 speakers in single-amped mode or 8 speakers in bi-amped mode, respectively. Yes, that´s what I ever wanted to do: Having 4 main speakers, 4 centers, 4 rears and 4 back surrounds + 4 subwoofers. :rofl: :twisted: :W I must be complete nut having this idea in mind. But I have to admit, since I got the 1098 I want more and more - I was also thinking about upgrading my 1075 / 1080 to a 1095 / 1090 combo...

[RgrRW]

Will1066

Do you use the 1080 triggered off some other component or left on all the time?

It appears that triggering the 1080 is related to the problem. I'd rather use the trigger and if you are successful with it and Geoff is correct that it is a 1% problem, I'd be willing to take my chances.

Tough choices. Bi-amped 1075s or 1075/1080. Life is hard.

[Wolfenstein 2k2]

To my mind, bi-amping / bi-wiring will only lead to a very small sound improvement if at all in comparison to single amping. Maybe this depends on the speaker / amp combination, however I made the experience with my B&W speakers that bi-amping them does not lead to an audible change. If there had been a difference in sound, this change would have been too small to hear it immediately in my case. That is why I chose the 1075/1080 combo as the 1080 definitely sounds better in stereo than the 1075. Even after having exchanged the B&W´s with Dynaudio speakers (which do not allow bi-amping anyway), I do not have the impression of having a "weak sister" in my system concerning surround mode(s). As I prefer listening to pure stereo, the 1075 / 1080 was the better choice for me in the end.

PS: I do not trigger any component.

[Bing Fung]

Bi-Amping would yeild the best gains if the signal fed to the amp was sent through an active Crossover network first. That way the amplifier only has to amplify the frequencies that are intended for the particular speaker cone. The way it is generally done now at the speaker level, each amplifier has to amplify the full range 20hz-20khz for the tweeter, the mids, bass..etc, so gains are marginal.

Before my Rotel equipment, I had my B&W Mains bi-amped with the Tweeters receiving power from my Denon receiver (105w), and the mid/Bass powered from my Bryston 3B (120W). The improvment was audibly significant, but only at the upper volume levels. Was it worth it?? :scratchhead: Only if you have the spare amps lying around, however to go out and buy amplifiers expressly for bi-amping, with out the use of an actively adjustable cross over would be a waste I think. I would rather spend the money for a more powerful amp/watts per ch in the first place and run single amp per channel... ie 1 x 200wpc is better than 2 x 100wpc bi-amped, I think

[aud19]

I'd tend to agree with that Bing... You're smarter than your wife gives you credit for :

:rofl:

Jason

[will1066]

Do you use the 1080 triggered off some other component or left on all the time?

It appears that triggering the 1080 is related to the problem. I'd rather use the trigger and if you are successful with it and Geoff is correct that it is a 1% problem, I'd be willing to take my chances.

Tough choices. Bi-amped 1075s or 1075/1080. Life is hard.

I don't use the trigger. I still ogle and grope my gear on and off. :twisted: :B

[DrJRapp]

1 x 200wpc is better than 2 x 100wpc bi-amped, I think

According to all the material I have read on the subject, including an excellent article by Rod Elliott titled Benifits of Bi-Amping (Not Quite Magic, But Close) which can be viewed at http:/sound.westhost.com/bi-amp.htm ... properly done biamping with two 100 watt amps gives you the equivalent of 400wpc. There is a lot of engineering gobbeldi-gook in Rod's article to explain why that I won't repeat here for fear of boring everyone to tears! :T

[RgrRW]

Active Crossovers

Bing:

I agree that there is no point in sending low frequency signals to the high frequency speaker but the crossovers I found was $800 or $900. So I might as well get the bigger amp.

I assume good crossovers don't come from a Radio Shack punchboard project. Any suggestions on sources?

Thanks,
Rgrrw

[Andrew Pratt]

The only way to do a crossover before the amps is to use a digital crossover like a Marchland and even in kit form they're expensive and you have to know what you're doing with regard to the crossover points and slope etc.

[Nick T]

@ Wolfenstein 2k2,

Thanks for the easy-to-understand explanation on bi-amping. Much appreciated

[Bing Fung]

properly done biamping with two 100 watt amps gives you the equivalent of 400wpc. There is a lot of engineering gobbeldi-gook in Rod's article to explain why that I won't repeat here for fear of boring everyone to tears! :T

I'm not saying bi-amping is bad, on the contrary, I would prefer to biamp, if I had the means to use an active crossover before amplification.

However I still feel a lot of amplifier energy is wasted by amplifiying the entire frequency range just so a speakers crossover can strip out what it wants for the tweeter in example. Thats what I fundimentally was doing when I biamped at the speaker leads of my B&Ws.

Again, I was sending 105 watts to my tweeter and 120 watts to my Woofer, so thats like 225watts? There was a difference over when my speakers were single amped with my 120 watts Bryston, however I have noticed a much bigger gain of the 200 Watt pch Rotel (single amped) over my Biamped 225w system.

Biamp is a great way to amplify, no argument there, however to yeild it's full benifits, it has to be done properly where each frequency has it's discrete amplification range. That can only be achieved with active crossovers before the amplifiers.

So if you have the amps kicking around, sure may as well do it, but to go purchase equipment just for that purpose with out using a cross over before amplification has a lower Bang for buck ratio I think...

[Bing Fung]

I just read the top portion of Rod Elliot's Article, and I think basically he concurs with what I was saying.

http://sound.westhost.com/bi-amp.htm

This is a proper bi-amp circuit were the signal is sent through high and low pass filters before amplification. This means the amplifier does not have to amplify the full range signal, rather only the specific band for the intended speaker.

This is Rod Elliot's comment

"Do I need to disconnect the passive crossover in my speakers?"
The answer is ... YES, otherwise you are not really biamping at all.

[snip]

Passive biamping (where two amplifiers are used in a bi-wiring connection) is, IMHO, a waste of money. Although there may be some moderate sonic benefits, they are not worth the expense of the extra amplifier.

That was basically how my set up was when I was just using the speakers Bi-wire terminals. It did have some benefits, however it was not worth the expense of the amps if I didn't already have them. I just happened to have them lying around.

Jerry, if you meant bi-amping as in the top picture, then I agree with you. It is a nice way to amplify

[DrJRapp]

Jerry, if you meant bi-amping as in the top picture, then I agree with you. It is a nice way to amplify

Of course I meant biamping as done in the picture. If you remember, in my prior post I said .... properly done biamping.....

OBTW I have been told that Nady audio makes a 2 way stereo crossover (CX-22sw) which I understand is audiphile grade and can be had for less than $200. A 7.1 system as I described above will require two of the beasts.

[RgrRW]

NADY Crossovers

OBTW I have been told that Nady audio makes a 2 way stereo crossover (CX-22sw) which I understand is audiphile grade and can be had for less than $200. A 7.1 system as I described above will require two of the beasts.

I'm seeing them everywhere for $90.00. Anyone know if they're any good?

RgrRW

[Bing Fung]

Of course I meant biamping as done in the picture. If you remember, in my prior post I said .... properly done biamping.....

Then you should have understood when I initially said bi-amping where you amplify the full range frequency, with out a cross over before amplification was a waste... :W

So for RgrRW to properly bi-amp, he will have to make modifications to the B&W's cross over network and get adjustable crossovers before the speakers... This was not stated originally, as it seemed more a "If your speakers are bi-wireable, then you should bi-amp by using 2 separate amps" The addition and cost of the cross overs were not listed in your comparison. I just wanted RgrRW to be totally clear on that senario...

Bing:

I agree that there is no point in sending low frequency signals to the high frequency speaker but the crossovers I found was $800 or $900. So I might as well get the bigger amp.

I assume good crossovers don't come from a Radio Shack punchboard project. Any suggestions on sources?

Thanks,
Rgrrw

I think you have it right, in that situation you may be better off with the bigger amp in the first place. My vote would be for the 1095/1070 combo, then the 1080/1075 combo, both for simplicity. Your 803's should sing with just the 1080 or 1095 driving them :T



Carry on... 8)

[Wolfenstein 2k2]

Hi!

@ Those people who have made use of bi-amping so far: Do your prefer horizontal or vertical bi-amping? If nobody knows what I´am talking about:

Horizontal bi-amping means that one stereo amp amplifies e.g. the highs and mids of both the left and right speaker while the other stereo amp amplifies the bass of both the left and right speaker.

In contrast to that, vertical bi-amping means that one stereo amp amplifies the highs/mids + bass of only one speaker (i.e. either left or right speaker).

[Bing Fung]

I suppose that would be more dictated by the amplifier design or Speakers requirements...

If the Stereo amp is more of a mono block design where it has 2 separate power transformers, then vertical or horizontial may not really matter as the amp could keep up with the demands of 2 channels of low frequency/high power requirements.

If the amp is less powerful or designed to draw off one transformer, then there could be an advantage to bi-amp vertically, allowing one channel (bass) to take the reserves of power if needed, with out affecting the other channel (mid+highs) due to it's lower power requirements.

Good Question that could only be truely answered by trying with specific equipment.

[RgrRW]

Ordered my system today

After all that hemming and hawing, I put money down today on a 1068 with the 1095/1080 amplifiers. I sure hope I don't have the fuse problem.

In a week or so I'll be back with all the, "How do I..." and the "What's this for..." questions but in the meantime, my thanks to everyone who helped get me here.

RgrRW

[Bing Fung]

Congrats, great choices :T :T

The 1068/1080/1095 combo is going to be sweet 8)

Let us know when you get it with a report :B

[Wolfenstein 2k2]

@ RgrRW

Congratulations! :T

You won´t be disappointed! Hey, and please make some nice photos of your Rotel gear if possible and post it into Bing Fung´s thread: http://www.htguide.com/forum/showthread.php4?t=8229

[aud19]

Way to take the plunge! :T

Jason

[Aussie Geoff]

Great Choice - saves upgrading later

RgrRW,

After all that hemming and hawing, I put money down today on a 1068 with the 1095/1080 amplifiers. I sure hope I don't have the fuse problem.

Great choice - you won't regret it - saves 2 whole rounds of system upgrades and there are fe speakers you won't be able to make sing with those babies

Re the fuse problem - I think Rotels latest advice HERE to switch from 6.3 to 8 amp slow blow fuses is likely to put that one to bed for the few that have had it ...

Geoff