Rotel Amp Question

[StevieB]

Hey everyone, first time poster.

I have a whole bunch of older Rotel gear that I purchased in the late 80's and 90's.

Most of it is in use in a 5.i SS set-up in my media room.

I am looking to upgrade my audio/video for my large bedroom. Surround sound is not an option so I plan on just doing a two-channel scenario.

I plan on using my old (but still working great) Rotel RSP-960AX Surround Sound Processor and a pair of Vandersteen IC speakers. The power requirement for the !Cs is 20 - 100 watts.

I'd like to get a Rotel (probably) two channel amp for this application. Any suggestions. RB 1050? RB 1072? Something else?

[Legairre]

I use 2 RB-1050s for my side and rear surrounds. The RB-1050 is rated at 70wpc and according to the amplifier design section of the brochure it can produce a lot more power even at low ohms for short periods. If you only need up to 100wpc a RB-1050 should work fine.

Take the RB-1050 as an example. Modestly rated at 70W/8 ohm, it will actually deliver 125W under dynamic, music-like conditions, increasing to 225W, 375W and 470W into tougher 4, 2 and 1 ohm loads.

http://www.audioklan.com.pl/www-down...%20English.pdf

[wkhanna]

Some good deals are available on used 9 series amps like the RB-960BX or RB-970 @ 60-70 wpc x2, and the RB-980BX @ 120 watts x2. If you are not averse to buying used, check Audiogon.com.

IMO, the old 9 series are built like Sherman tanks, have good flat sonics from 20 to 20k, and provide a great value, especially for a 2nd system. My opinions are based on experience. I just sold my RB-980BX which I purchased new in '94 that runs as good as the day I bought it. I still have an RB-990 and it too is a great amp IMHO.

Otherwise, I too would recomend at least the 1050 (which I also own and love and have seen on the used market as low as $250) or better still for those wonderful Vandersteen's, the 1070.

As always, JMHO YMMV

[StevieB]

I use 2 RB-1050s for my side and rear surrounds. The RB-1050 is rated at 70wpc and according to the amplifier design section of the brochure it can produce a lot more power even at low ohms for short periods. If you only need up to 100wpc a RB-1050 should work fine.

Legairre . . . thanks for the input. I am definitely leaning towards getting the RB 1050.

Some good deals are available on used 9 series amps like the RB-960BX or RB-970 @ 60-70 wpc x2, and the RB-980BX @ 120 watts x2. If you are not averse to buying used, check Audiogon.com.

IHO, the old 9 seris are built like Sherman tanks, have good flat sonics from 20 to 20k, and provide a great value, especially for a 2nd system. My opinions are based on experience. I just sold my RB-980BX which I purchased new in '94 that runs as good as the day I bought it. I still have an RB-990 and it too is a great amp IMHO.

As always, JMHO YMMV

wkhanna . . . I hear you. I still have and use my RB 985 in my 5.1 set-up. I've probably left it "on" for 13 years and it has never caused any problems and is completely silent.

I think I'm headed for a new RB 1050 though for the 2 channel set-up.

Thanks!

[Legairre]

Anytime Steve, there's one on ebay in new condition. Not one of mine though, I'm keeping mine.

[wkhanna]

Me too, Legairre!

[StevieB]

RB-1050 or RB-1072

I've narrowed my amp choice down to either a Rotel RB-1050 (70 WPC)
or a Rotel RB-1072 (100 WPC).

I know that the RB-1072 is a Class D amp but I am not certain what that means in practical terms.

Again my setup will be for a large bedroom with very high ceilings and my ears as much as 17' away from the speakers.

I will be using Vandersteen 1C speakers and initially a very old (but still working great) Rotel Pre-amp (Surround Sound Processor) RSP-960AX.

The last factor is that the amp will be housed in a closed cabinet with some, but not very good ventilation.

What do you think?

[wkhanna]

From the Vandersteen website:

IMPEDANCE:
6.8 ohms 2 ohms

EFFICIENCY:
90dB with 2.83 volts of pink noise input at 1 meter on axis.

RECOMMENDED AMPLIFICATION:20 to 100 watts per channel

FREQUENCY RESPONSE:
38Hz to 22,500Hz +or- 3dB

DISPERSION:
38Hz to 15,800Hz 3dB
at 30 degrees off axis

CROSSOVER FREQUENCY:
2800Hz, 6dB per octave



In a large room, you will have some loss of LF weight.
Combined with an efficiency of 90 dB and dips in the 2 ohm range under high dynamic/bass signals, I would recommend the 1070 or 1072 at a minimum, or better yet, the 1080

One advantage of the 'digital' amps' is they run cooler, and might be less effected by the restricted ventilation.

These are good sounding speakers, but you may be disappointed in their performance when asked to fill a large room. More power will help

As always, JMHO, YMMV

[StevieB]

One advantage of the 'digital' amps' is they run cooler, and might be less effected by the restricted ventilation.

So the RB-1050 and the RB-1070 are ANALOG amps?

[wkhanna]

The other amps are class AB.
The 'digital' amps are not digital, it's a misnomer.
They are class D switching.
I believe they use what is called ICE topology, but don't rely on me, I don't know that much about them other than what I have read.

Do a search here, you will find a ton of info on them.

[StevieB]

The other amps are class AB.
The 'digital' amps are not digital, it's a misnomer.
They are class D switching.
I believe they use what is called ICE topology, but don't rely on me, I don't know that much about them other than what I have read.

Do a search here, you will find a ton of info on them.
__________________

Thanks wkhanna . . . I appreciate your help.

[peepaj]

I know I’m new to the board also but I do run 3 rotel class d amps, (2)-RB1092 & a RB-1091. I use a 1092 for 2 channel with paradigm studio 100s v.3 and the sound is just incredible. These amps do run cool, after listening for 14 hours you can lay your hand on top, very little heat. I also run a 1050 for zone 2, great little amp. I just think you might need a little more power. IMO give the 1072 a test drive if you can.

[wkhanna]

You are V welcome, Steve.

And BTW, welcome to the Forum!
It's great to have a another '9 Series' guy around!

[StevieB]

I know I’m new to the board also but I do run 3 rotel class d amps, (2)-RB1092 & a RB-1091. I use a 1092 for 2 channel with paradigm studio 100s v.3 and the sound is just incredible. These amps do run cool, after listening for 14 hours you can lay your hand on top, very little heat. I also run a 1050 for zone 2, great little amp. I just think you might need a little more power. IMO give the 1072 a test drive if you can.

I'm sure that the 1072 is a great amp, but I've been told by Richard Vandersteen himself, that he does not favor Class D amps (for whatever reason).

Relative to power . . . I believe the 70 watt RB-1050 is probably the best choice as it is a great match for the 90dB Efficiency rating of the Vandersteen ICs. Also, my room isn't that large and I don't listen to any speed metal any more!

[gianni]

Have you seen this article by HiFiCritic? http://www.hificritic.com/downloads/Class-D.pdf

This may explain some of the reservations Mr. Vandersteen has.

I'm not taking sides as I have not spent enough time listening to the class D amps yet.