SQ Opinions on Rotel RB-980 versus the RB-981

[gp4Jesus]

I've read a TON of posts on different forums. Unfortunately, some "other" forums struggle w/unbiased opinions.

Simple rules: prefer Rotel, particularly the 980/981 amps and to what speakers you connected. Tap dance lightly but please avoid gross comparisons w/other brand amps

A thousand thnx. Tony

[wkhanna]

my system in '94 was the rb-980bx 100 watt, Advent 300 pre, Advent 201A cassette deck, a Sony Discman and Signet speakers.







the Signets now serve serve rear surround duty, but the 980 did well at powering my Natalie Portman's for years after.
loved that amp, it was bullet-proof & sounded good.

the 981 is slightly different topography, however i can not offer opinions on the sound signature compared to the the 980 as i have never heard one.
i still have a 990, a 1050, & my main amp is a modified 1090.

my gut feeling based on my experience with these & many other Rotel amps tells me the 981 is likely just ever so slightly better than the 980.

but, imho, condition will have the greatest influence on amps as old as these models are.

[gp4Jesus]

Over Christmas my family allowed me 2+ hours to play with & evaluate my system. I focused my attention on my 900 series amps' bass response. In a nutshell, the 980BX has "it" over the 981. Read on.

Test subjects in 2ch mode were my Polk Audio RTi A7s. I completed tri-amp mods over Thanksgiving making woofers-only listening easy. My son handled switching chores eliminating bias. Both speakers sitting side by side ensuring the only variable was the amps.

Conducted testing in two phases. Phase one: low pass XO set just above 100hz. Phase two: XO ~70hz. Used Sheffield's track record for source material.

Conclusions: Better extension, better thump, seemingly more musical. Noticed greater differences during phase 2.

Next go around I'll compare the mids, highs, & imaging. Happy New Year. Tony

[wkhanna]

V interesting!
do keep up posted on further results, please.

have any components, like capacitors, been replaced on either of the amps?

[gp4Jesus]

All in good time. After I complete testing*, bi-amping my surrounds, and settle upon various amp choices, etc... Check my sig for details.
* 980 versus 981 to drive woofers, mids, etc.
Interesting Side note: both amps run cooler driving 4 ohm woofers than 8 ohm HP'd @ 100 driving a mid & tweeter through original XO regardless of volume.

[gp4Jesus]

Since my last post (from 5 years ago!) I upgraded to:
DSP driven EXOs for all* channels*.
Rotel 981 amps for mids & highs for same* - amps key to SQ more fluid; speakers seem to disappear.
Sunfire True Signature sub for LFE duties & Center channel heavy lifting
Audio Pro Evidence subs at each corner.

A while back I enjoyed several episodes of the house free of “distractions*.” This allowed me to spend sufficient quality and quantity of time to “sound shape” (SS) my LRs and their subs making use of my EXOs’ DSP w/an RTA and calibration mic. Very little “touching up” needed in the form of a slight cut here and there. Along the way I discovered flipped polarity of my LRs’ tweeters’ to the mids. In a later session for my Surrounds*, SSing to integrate their subs to the same*
*wife and kids.

For a few $s a Polk Audio forum member, made CNCd diffraction pads for my LCR - worth it!
Currently overwhelmed w/non sound system related “honey doo” projects preventing any intense work such as amplifier cap refreshing and other component swapping for either SQ restoration, improvement, or both.

Correction on Post dtd 1/7/2017 discovered early 2018…
“Interesting side note: amps feeding 8 ohm bass drivers directly*, run cooler than through the stock16 ohm load thru the 120hz passive LP filtering regardless of volume or program material.”
*system tri-amped