Separate amps for my RF-7 speakers

[plissken99]

I've finally got the money to go with separates! I have the RF-7 main channels, RC-7 center and RS-7 surrounds. This is a 7.1 set up, but I'm just using my old Pinnacle AC-650's for the rears(can't justify another $500 for those channels).

I have the Denon 3805, which I'd like to use as the pre-amp to drive them all. What I want is stereo amps(or these 5 channel amps with a lot of power I hear about), with at least 200w going to each channel. I am trying not to spend more than $200-$300 per 2 channels. I don't care about getting amps for the rears, I figure the Denon can do those.

Can I get some product recommendations or advice?

Thanks

[scriven]

I don't know about power amps but if you want to run 200 watts into RF-7s you should definitely invest in some very good hearing protection!

[plissken99]

Will 200w be to much? It would be nice not to have to cut the volume up so high, so if it would sound better at a lower level... For those who know the Denon, I watch DVDs between -20 to 10.

I was told on AVS, the more wattage the better, but if 200 will be too much...

[knorman]

do not worry about too much with 200 watts. i run 200 mcintosh watts and it only makes the 7's better. you can throw anything you want at them and they will respond. the more clean power you have the better they sound. enjoy them.

[scriven]

I run my Khorns with a MC2505 - 50wpc. I have plenty of headroom and the RF-7s are only 2 db less sensitive than the Khorns. Knorman is correct that too much power will not cause harm under normal circumstances.

BTW: I would like to welcome to both of you to the forum!

[plissken99]

Ah, so you meant get hearing protection because I'll want to crank them. They already have that effect, I call them dangerous because the louder they get, the better they sound.

So can I get some recommendations for 200w amps in my price range? Mcintosh would be nice, but they are lightyears out of my range.

[Speedball]

For that budget and you don't mind used, Audiogon would be a good place to start. I have bought from them a couple times and am now saving pennies for the next amp upgrade.

[scriven]

For $.50 a watt you might be able to get some used Carver equipment.

[Mighty Favog]

I use a Rotel RB1080 (200 wpc) and they run about $900 (MSRP is $1k). It doesn't sound all that bad but it has to be turned up (beyond 1/4 watt?) to get all the dynamics, staging, bass clarity etc.

Here's a review:

Rotel RB 1080 power amplifier

Kalman Rubinson, March, 2002

What could be easier to review than a power amplifier? No features or functions aside from inputs, outputs, and a power switch. So when Jonathan Scull asked if I could help out by taking on the Rotel RB 1080, which another reviewer hadn't been able to get to, I accepted the assignment. Before I could click my heels and say "FedEx!" twice, Rotel's 200Wpc RB 1080 had appeared

I'm old enough to remember the Dyna Mk.II, which for the first time allowed impecunious audiophiles who had ogled Marantz and McIntosh equipment to acquire a power amp capable of driving nearly any speaker on the market. Later, in the 1980s, the Adcom GFA-555 rewrote that declaration of independence for Krell cravers, its 200Wpc capable of driving nearly any contemporary speaker.

Today, 200Wpc is still a lot of power, and is not commonly available for $1000. So despite the changing times, the Rotel RB 1080 offers a a lot of watts per buck. Moreover, the 1080 is far from a stripped-down device. Its sculpted front panel is decidedly more stylish than those of its utilitarian ancestors. It offers selectable balanced (XLR) and unbalanced (RCA) inputs, and has an input for low-voltage, remote power control. In fact, the made-in-China Rotel RB 1080 looks like a high-end amp, with specs to match.

The accompanying CD-ROM and DVD-ROM (edit from Tom- Mine didn't come with one) take the new owner on a simulated 3D fly-by tour of the 1080's innards, the pilot's voice describing points of interest along the way. Once past the Rotel-manufactured 1.2kVA toroidal power transformer, we fly over Vishay and Roederstein metal-film resistors, fancy slit-foil film capacitors designed by DNM's Dennis Morecroft, multiple power-output devices, and steep, cliff-like heatsinks that run from front to back on each side of the chassis. These inboard heatsinks do their work well; the sculpted front-panel extrusions, which look like heatsinks, are just pretty.

Playing in the Big Leagues

I briefly skimmed the Rotel's instruction manual (more warnings against stupid misuse than anything else), unpacked the amp, and plugged it into my main system. I used my usual balanced interconnect (AudioQuest Python) and speaker (AudioQuest Granite) cables to patch the RB 1080 in between the Sonic Frontiers Line-3 preamplifier and the Revel Studio speakers, pushed the button on the Rotel's front, and off we went.

The 1080 was virtually noiseless (except for the music), and my first impression was of a somewhat soft, dry sound lacking in dynamics. Balance across the audible spectrum was smooth, with tight, impressive bass, but there seemed to be a lack of presence. The treble was clean and detailed. Such hastily formed opinions are as often wrong as they are right; in the case of the 1080, they were mostly right but definitely incomplete.

With the unlikely load of the Revel Studios, the $1000 Rotel had two discrete personalities. At low levels, such as one might use for casual listening, the characteristics were as described above. I was persistently bothered by a microdynamic compression that sucked life out of the music, even though the really big moments did not lack for impact. I was also disturbed by a reticence in the treble that, by contrast, made the extreme treble transients of cymbals and triangles seem a bit over the top (!).

But when I turned up the volume, the 1080 came to life. The glossing-over of small dynamic changes was replaced by a clarity of inner detail that can happen only if subtle dynamics are not lost. Even allowing for the presence-region shifts that are the concomitant solely of playing louder, the Rotel-Revel combo became a bit more forward at high levels as the treble smoothed out. And, except for the sacrifice of domestic tranquility, nothing was lost in macrodynamic potential as the RB 1080 drove the Studios to quite impressive levels, and on down into the nether reaches of the lowest bass. Whether it was the dynamic and emotional extremes of Mahler's Symphony 5 (Zander/Philharmonia, Telarc 2SACD-60569) or the deep, detailed sonorities of Sera Una Noche (MA Recordings M052A), the Rotel was capable of truly impressive performancebut only when played at substantial levels. When I turned down the gain, the sound faded into pale miniatures.

After the Rotel had spent a few weeks with the Studios and a weekend in the country with the Paradigms, the even more wildly inappropriate B&W Signature 800s arrived. The RB 1080, which was still cooking in the system, was given the job of driving this "statement" loudspeaker. Mirabile dictu, it turned out that the 1080 was a better match for the S800s than for the Revels. This could have been because the S800s are more forward-sounding than the Studios, or are an easier load to drive. (Dunno about the latterthat's John Atkinson's job to determine).

Nonetheless, the RB 1080 displayed fewer symptoms of its bipolar personality with the S800sits behavior was exemplary. David Johansen and the Harry Smiths (Chesky SACD225) was vivid, with tremendous kick. Even with only two channels, I found the Rotel-B&W combo to be very convincing, despite my having just attended a recording session with the same group in the same recording venue. In fact, I used the 1080 for about two weeks with the S800s, and never felt the need to switch to one of the other amps on handI was curious to do so, but felt no urgency. The S800 made it clear how good an amplifier the Rotel was; only those intimately familiar with the S800's performance with other amps would notice any lapse from the speaker's optimum performance.

But I'd be misleading you if I gave the impression that one would ultimately want to get by by using the Rotel RB 1080 to drive the Revels, or even the B&Ws. The 1080 was not the last word in soundstage openness or grain-free treble, and always retained a slightly withdrawn mid- to upper treble. Switching swiftly between power amps in less than a minute, it became apparent that amps such as the Simaudio W-5, the Bel Canto eVo, and the Sonic Frontiers Power-3 did not suffer from the 1080's minor foibles in low-level microdynamics and treble reserve. Furthermore, those other amps ably demonstrated that the Revel and the B&W are capable of truly transparent treble, detailed and finely drawn, which the RB 1080 merely outlined. On Cyndee Peters' "House of the Rising Sun" (Test CD 4, Opus3 CD 19420), the ultimate delicacy of the triangle and brushed cymbals eluded the Rotel but not the other three amps.

But the votes did not go all one way. Sheer power was not a limitation for any of the amps, the 1080 included. Moreover, at the bass end of Béla Fleck's infamous "Cosmic Hippo" (Flight of the Cosmic Hippo, Warner Bros. 26562-2), the Rotel was simply world-class, nearly approaching the Simaudio, and making the otherwise super Bel Canto sound just a bit overripe and less controlled in comparison. (Could this be related to the RB 1080's damping factor of 1000 vs the eVo's 100?) And while I can't seriously suggest the permanent use of the $1k Rotel with the B&Ws, I know I can sucker-bet discerning listeners with this combination...because I have.

Pick on someone your own size...

When I ran the RB 1080 via its unbalanced inputs with more compatibly priced speakers, such as the Paradigm Reference Studio/20 or Studio/60, I had no complaint. The Rotel provided all the power the Paradigms could handle, and I heard no low-level limpness. The Paradigms' tweeters are a bit bright; the slightly reserved Rotel 1080 complemented them very well, and greatly tamed the Studio/20's slightly emphasized bass. That this was increased control and not premature rolloff was confirmed by the RB 1080's extended bass performance with the Studio/60, not to mention with the Revel Studio and the B&W 800. The Rotel 1080 and the Studio/60 made for the most complementary combination: the Rotel soothed the slightly extraverted Studio/60 at both ends of the spectrum, produced extended and convincing bass, and seemed to have infinite reserves of power for micro- and macrodynamics.

I ran through the varied and fascinating selections on Opus3's Test CD 4 and found the distinctions between the CD and SACD layers as readily apparent through this modestly priced combo as through the big system. If I had room for a two-channel amp in this usually multichannel system, the Rotel RB 1080 would be a permanent fixture.

Conclusion

In pure engineering terms, it would seem that it should be easy to make a good power amp at nearly any price. With the big budget of a high-priced amp, the designer-manufacturer can attend to all the fine details and still provide substantial output power. As the budget decreases, compromises must be made, and the usual one is in power output. Unfortunately, compromises in tonal balance and subtlety are sometimes encumbered as well, and the resulting tonal inaccuracies are often flaunted as a distinctive "character." Even some pricey power amps are guilty of this.

No such compromise was evident in the Rotel RB 1080. Sure, it was less than an ideal match for speakers costing 10 times its price, but it did better than I would have guessed. With everything I matched it withwhether fairly or unfairlythe Rotel did adequately to superbly.

The Rotel RB 1080 is as powerful an amp as almost anyone needs, and did not suffer from significant coloration or tonal imbalance. Only the nth degrees of treble grain and reticence separate it from the very best power amplifiers. I can't think of an amp for even twice its price that I'd prefer.

Sidebar 1: Specifications

Description: Solid-state stereo power amplifier: Line-level inputs: 1 pair RCA, 1 pair XLR. Outputs: 1 pair of multiway speaker binding posts per channel. 12V signal switching input and output for remote power control. Output power (continuous): 200Wpc into 8 ohms (23dBW), 20Hz-20kHz at 0.03% THD max, both channels driven. Input sensitivity for full output: 1.5V RMS. Input overload level: 5V. Input impedance: 32k ohms. Distortion at 1W: 0.02% max at full power, 0.01% max at half power. Frequency response: 15Hz-100kHz, +0.5dB/-3dB. S/N ratio: 116dB, A-weighted. Damping factor at 8 ohms: 1000. Power consumption: 550W.

Dimensions: 17 15/16" W by 5½" H by 15¾" D. Weight: 37 lbs.

Serial number of unit reviewed: 72563 05311.

Price: $999. Approximate number of dealers: 140.

Manufacturer: Rotel of America, 54 Concord Street, North Reading, MA 01864. Tel: (978) 664-3820. Fax: (978) 664-4109. Web: www.rotel.com.

[plissken99]

That Rotel is way to much, I was thinking 1k for 5 channels. Not seeing anything on Audiogon. Looks like my best bet is to save more and buy a Sunfire 5x. I'll bet I could nab one off Ebay for around $1,200.

[Big Ears]

Hey Tom, about how much does the Rotel 1095 cost?

[scriven]

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On 7/3/2005 5:33:03 PM plissken99 wrote:

... Looks like my best bet is to save more and buy a Sunfire 5x...

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That's pretty close to used Carver!

[Mighty Favog]

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On 7/3/2005 7:03:13 PM Big Ears wrote:

Hey Tom, about how much does the Rotel 1095 cost?

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Well, the RB1090 runs about $2k and it's 380wpc (2 ch.). I'd have a good guess of saying the 1095 runs about the same (@ 200wpc X5).

[Big Ears]

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On 7/3/2005 7:22:08 PM Tom Blasing wrote:

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On 7/3/2005 7:03:13 PM Big Ears wrote:

Hey Tom, about how much does the Rotel 1095 cost?

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Well, the RB1090 runs about $2k and it's 380wpc (2 ch.). I'd have a good guess of saying the 1095 runs about the same (@ 200wpc X5).

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I see quite a few people putting down the multi channel amps, from what I rhave read the Rotel seems to hold its own pretty well and looks like a bargin compared to others. What is your opinion?

[Mighty Favog]

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On 7/3/2005 7:33:01 PM Big Ears wrote:

I see quite a few people putting down the multi channel amps, from what I rhave read the Rotel seems to hold its own pretty well and looks like a bargin compared to others. What is your opinion?

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The Rotel is a very quick amp but not sharp and edgy (make any sence?). Meaning the slew rate is fast compared to most. I am also in the camp that multi-channel amps lose some of their dynamics and realism. There are things I've heard on my Rotel that I have never heard on my 150wpc Carver. Granted my Carver is a MXR150 Receiver but the topography of the amp section is very similar. When I switch it to A&B spkrs it loses volume level (understandably) but it also loses a lot of palatability of being lifelike.

[plissken99]

I was under the impression Carver and Sunfire were one in the same, more or less. So the general feeling is that the big 5 and 7 channel amps aren't as good as 2 channel separates?

Looking around, I MAY(as in I could get one now used, and wait for 2 others to pop up) be able to get a hold of enough Carver M500 amps(250wpc) for around $200-$300. Are these good amps? Also, how are Yamaha amps? They are pretty reasonable price wise on Ebay.

[plissken99]

If 5ch amps are ok, the Parasound HCA-2205a sounds really good, at 220wpc(5x), it's got nothing but great reviews at audioreview.com. And it looks like I can get it for $1,200 or less used. I'd have to save a bit more, but not much. If I do a 5ch amp, it would be between that Parasound, and the Sunfire, as both are about the same price.

[KathyMason]

Go with Rotel, you won't be sorry! Rotel goes excellent with Klipsch, better than the Carver/Sunfire will. The Rotel is worth it and gives one of the best quailty sound you will be very addicted to.

[getech]

Sunfire Cinema Grand amplifiers are the way to go. The 200x5 amp can produce 200 watts rms per channel into 8 ohms, and 400 watts rms into 4 ohms. The big breakthrough feature of the Cinema Grand is its tracking downconverter which uses 18 Herculean Mosfets in the Signature 400x5 and 12 in th 200x5.

These amps creat a multilayered soundstage that is deep, wide, three dimenisional and utterly unbelievable! Perfect with the RF-7's!

[plissken99]

I am definitly leaning towards a Sunfire 5ch. I've heard one of their recievers with some lower end Klipsch speakers, and the sound was amazing. Plus, I've heard they run very cool, which will be a big bonus, as heat tends to be a problem in my equipment closet.