Review: Resolution Audio Opus 21 Great Northern Sound Mod CD Player

Category: Digital

I would like to start my review right off the bat by disclosing my past reviews and my current dealer status. I was responsible for the previous Resolution Audio Opus 21 review back in May 2003 under the moniker “Platsolos,” and now I am writing a follow-up to a modified unit. I do have the unit on display for audition.

I must admit I have been enamored with digital sound reproduction over the years for whatever reason and have continually been amazed by the sound differences that can come from differing transports, D/A converters and parts quality and construction. With that, I had reviewed numerous digital front ends from one box solutions to separate DACs and transports.

With the recent craze in ultra expensive digital sources, I started to question what can be done to, in my opinion, the best CD player under $10k? Can a modification of the Opus compete with the likes of the EMM Labs, Esoteric, Zanden, MBL, Reimyo and others? Well I can tell you right now I will never know, as I have not had the luxury of affording or being in the same environment as all these outstanding players to A/B them against each other. But I welcome any owner of these units to drop me a line, bring your unit over and A/B it. The GNSC modified RA Opus 21 is THAT good.

Choosing Great Northern Sound:
When I considered modifying the RA Opus 21 I wanted to work with a reputable company, one that is here to stay and one that backs the work through real warranties. After talking with Steve Huntley, I learned that every Opus 21 modified by GNSC comes with a backed up warranty, equal to the original RA factory’s warranty, and that Resolution Audio actually provides parts and support as needed to GNSC should a modified unit fail. Rest assured, this is not a fly-by-night modifier who is here today modifying mass market units, and then gone tomorrow.

Steve has two upgrade paths: Standard at $750 and Reference at $1500. There are differences in the extent of the modifications between the two, I chose the Reference modifications.

Sound right out of the box:
It is immediate that the change Steve makes to the Opus is apparent without any break-in. Deep 3-dimensional layering, black backgrounds with stunning resolution and detail typify the sound right out of the box. By far and away the biggest improvement is that CDs now approach the sound of vinyl to me. Previously the most analog-like digital source I heard was through a CEC belt driven transport, but this came with many and obvious faults. The GNSC Opus 21 is able to build upon what I considered the best balanced CD source I have ever heard (maintains liquidity of a CEC with the detail, snap and resolution of the finest) and adds detail, layering and amazing transparency.

Physical changes to the unit:
The modifications consist of extensive use of black gate capacitors, power filtering, power supply improvements, analog output stage modifications and extensive and strategic dampening of the chassis and mechanism. The unit is clearly heavier and has a more inert feel (mostly due to the damping of the chassis and mechanism).

Comparisons to other units:
I have yet to hear an SACD, DVD-A or CD player that can even match the modified Opus 21. The GNSC is clearly superior, even comparing CD vs. SACD. See my review on the base Opus 21 for what it already has beaten out, un-modified. I welcome anyone with any priced digital to A/B it against the GNSC Opus 21.

The changes can be summed up in the following points:
1) This is the closest to vinyl I have experienced
2) An improvement in the depth of soundstage
3) Each instrument continues to carry its own space, with even more body and fleshy tones to the instruments and voices. Acoustic guitars possess that intangible woody character; snare drums seem to resonate in air directly in front of you. Vocals are deep, breathy and
4) Black as night background, the music emanates from a 3 dimensional space
5) Increased dynamic attack and bass output
6) Staggering resolution and detail beyond reproach
7) Air
8) Air
9) Air

Final Thoughts:
The thoughts and opinions in this review are just that, my opinions and experiences. I urge anyone interested in hearing the unit to do so if you can. This is truly a player that has changed my view of what redbook can accomplish.

Associated gear
AAD Sound 7001 Monitors - $9000/pair
Audience AU24 XLR
Audience AU24 Speaker Cables
Pass Labs X250.5
Virtual Dynamics Power 3 Power Cables
Audio Magic Power Conditioner
I've got you beat, as I just found the closest digital sound to approch vinyl!!! While in my Grandmothers closet looking for a step ladder, I saw a sealed new in the box Magnavox top loading laservision laserdisc/cd player with a corded-remote circa 1983. Something she won during her Mary Kay/Avon sales days. Right out of the box, & without break-in, it was immediate that due to it's weight I needed Air, Air, Air! Let me know if you want to have a digital source shoot-out? ;0)~

Seriously, Nice Review! It's good to see Steve H at GNSC is offering affordable mod's on the Opus 21. Make sure to follow-up once you get about 500 hours of break-in on your newly modded player as things should improve... good things come to those who wait!
Thank You very much for this review.I am now seriously planning on having my unit modded.How long does it take for the full mod???
Allow 3-4 weeks for the mods.......
Great review Fat Cat! Are there others who own the GNS Opus? Mrcyn, did you have your Opus modified?
Hello Sammie - No I did not yet have my unit modified.I will eventually have it done.....
After using the GNSC Opus for about a week following a break-in period, I have to say I whole heartedly agree with Fat Cat's detailed review. Especially since I have lived a stock RA Opus 21 and, recently, an Ayre CX-7e. The GNSC Opus is simply in another league altogether. It's amazing! (IMHO)
Are there any plans for anyone to offer the GNSC mods in the UK? I've an Opus 21 which I think is absolutely great, but maybe it can be better still with this mod? However, I won't send my unit overseas (cost and risk reasons).
Very accurate review FATCAT....I agree the GNC OPUS 21 siginificantly narrows the gap between CD and Vinyl.... which is as high a compliment as one can give to CD !!

Following a telecon with FATCAT some months ago, I had my unit modified and I can say it has moved up several notches from the already stellar base OPUS21 unit.

I previously owned the Full Meitner CDSD / DCC2 and can say the OPUS 21 betters it on CD...much closer to the live event... ( I attend a lot of LIVE Classical Concerts).

I also recently compared the GNC OPUS 21 to several other highly regarded players mentioned in FATCATS review including the ca. $16 - 13 k Reimyo & Esoteric UX01...the GNC OPUS handily bettered these also.

I also compared the CD & vinyl versions of a well recorded Dave Brubeck recording and concur with FATCAT that the GNC OPUS21 significantly narrows the gap between Vinyl and CD... an outstanding achievement.

My mod took 3 weeks and Steve at GNC was a pleasure to deal with....the unit also comes with a very professional certificate ....

Unlike many mods, I beleive the GNC mod will significantly enhance the value of your OPUS investment.

I have owned the OPUS 21 and its matching DNM inspired 30 watt amplifier for over three years as my bedroom system and absolutly love it...

The OPUS 21 also fronts my main system which includes a Placette Passive, Dartzeel NHB 108 and the outstanding Gamut L3 Monitors.... interconnects are Placette RCAs.

HIGHLY RECOMMENDED and a Great value.... Ceol
Opus 21 Owners,

How long doss it take for the Opus 21 (stock) to break-in? What kind of improvements can be expected?

I just received one of these today, purchased on the Gon used. I am just amazed at the sound!!..Granted, I have been using an older model EAD Ultradisc, but the difference is astounding!! I'm in heaven, and it gets better as it goes.
Fatparrot, I do believe you have captured the essence of this CD player, and having never listened to the stock unit, I can't say how much the mod has improved the base unit. But, Lordy, is this a huge step up from what I had!

I must thank Steve H. for the suggestion of upgrading my source, and was contemplating buying new when this unit popped up. Now back to the music.....
Hi Ceol

nice to see you demonstrating the Opus stack (with GNC mod) at Cloney's today. I've got to hear it at home: it sounded great under less than ideal conditions in the shop!
Could you share your experience with ADD 7001 monitor?
I've recently replaced my Linn Ikemi with a Great Northern Sound's Reference-level modified Opus 21.

Right out of the box (wooden crate), it was very obvious that the Linn was beaten hands down. It was as close to an A/B comparison as possible, having listened to the same song several times on the Linn....then changing to the Opus.

It's true what's been said about similarity to vinyl sound.
I ran Stevie Wonder's CD and LP at the same time in the Opus and on my high-end turntable and flipped the switch on the pre-amp between the two. I attribute the very slight difference to the Manley Steelhead tubed pre-amp in line before the C-500 preamp adding a slightly warmer sound...but not much.

Definitely worth the money! My Ikemi is for sale!
The Opus 21 has been out for about 5 years now. How does the GNSC modded RA Opus 21 stack up against some newer CD players that get rave reviews (e.g. the Ayon and/or Raysonic)? Also, Resolution Audio and GNSC are small operations. Are they able and willing to service these units, especially if they are purchased used. Buying a used unit seems appealing to me, although I don't want to buy a unit that will become a doorstop if/when it breaks.
I AM FROM INDIA and have been very satisfied with the sound of stock opus and after reading this review i have been interested in getting this player modified can anybody recommend somebody send your recommendations regarding having these mods here in india or singapore or hong kong