Rotel Diamond Series Overview

History & Product Overview

It’s hard to believe that over 40 years ago when Audio Advice first became a Rotel dealer, Rotel had already been in business for twenty years making high-value stereo gear. This means it's now been 60 years since the founding of Rotel and to celebrate that milestone, Rotel is introducing a new series called Diamond. 

If you are a fan of excellent HiFi gear, you have likely seen all of the great reviews on Rotel gear over the decades. They have made a business of producing no-frills audio gear that sounds pretty incredible for the cost. 

Rotel spent several years developing their Michi series of products, which were in an entirely new price category for them. They were not typical Rotel, with a totally different design and much higher price point, but they have received very positive critical acclaim from around the world. After Michi came out, Rotel took some of the learnings they gained from its development and updated their main products to MKII versions, using Michi tech with a few other tricks they came up with during the design. 

The Rotel Diamond products come in between the more affordable Rotel gear and Michi. We were very lucky to get the first two products in before their release and even better got to spend some time with one of the people deeply involved in their development and get all the interesting stories of how they came about. 

The first two Diamond products are a CD player with a built-in DAC and a very powerful integrated amplifier.

Rotel Diamond Series Design & Build Quality

The Diamond series is pretty similar in design to the Rotel appearance we know and love. They have added some heat sink-looking fins on either side of the front panel which gives it a beefier look. Both models are available in black or silver like the classic Rotel pieces. Small round buttons for many of the functions are laid out symmetrically on the front panels with both having a nice LCD display in the center. 

Build quality to our touch and feel seems to be the same as the other Rotel pieces, which is quite high. The buttons all feel solid, the rear panel connectors are all well put together, and the physical fit and finish are nicely done. With Michi, Rotel went for a much more expensive outer chassis and front panel, but Diamond is all about putting as much of Michi tech into the parts we do not see from the outside and keeping the cost closer to typical Rotel gear by sticking with their clean and simple design.

When we had our first listening session with these and met with one of the key product designers, we learned some really fun stuff about how these pieces evolved. 

The Rotel engineers in Japan wanted to produce a far better CD player than they had ever made. If you know much about audio, you probably know the DAC’s (digital to analog converters) inside a CD player, or really anything digital for that matter, play one of the critical roles in the ultimate performance you get. There are several companies that specialize in high-performance audio DACs. The Rotel team went so far as to test DAC’s from all over the world to try and get the best performance they could. They had tried a few and were still not 100% pleased with the outcome and decided to work with ESS and test one of their high-end multi-channel DAC’s you would typically see in an expensive home theater receiver. Since they had never used something like this in a stereo application, they worked with the ESS engineers to develop the best type of circuit for stereo use. The end result allowed them to use 4 DAC’s per channel and have a completely balanced audio path from beginning to end which greatly reduced the noise floor. They paired this up with a great power supply system and some Michi parts and were just bowled over at how much better this design sounded than anything they had tried.

Then, this is the really interesting part. They had something on their hands that sounded so good, but it was just a CD player. With so many music streamers on the market and the popularity of music streaming, they actually went back to the drawing board and redesigned the entire unit to be not only a CD player, but a DAC with multiple inputs. This delayed the whole project for almost a year, but we are happy they went in this direction as it makes the Rotel DT-6000 DAC Transport & CD Player a great value.

In their quest for the best audio performance, this delay allowed their team to dive even deeper into trying different component parts inside the RA-6000 integrated amplifier to improve its audio quality. Hundreds of comparisons were made with various parts and signal paths using learnings from Michi and the MKII Rotel models. So while the CD player was transforming into a DAC, Rotel took that time to make the RA-6000 sound even better. That is pretty fanatical and that passion is one reason Rotel is able to celebrate 60 years in business!

Rotel Diamond Series Features & Technology

Rotel DT-6000 DAC Transport & CD Player

The DT-6000 as we said, along with being an awesome CD player has several digital inputs. You get Toslink, Coax, and PC inputs. The PC input supports high-resolution PCM audio (32-bit/384kHz) streams, unfolds and renders MQA and MQA Studio, and can also do DSD 1X, 2X, and 4X audio files. That is pretty darn flexible. We asked Rotel why they did not include a streaming platform and they gave us a very reasonable and interesting answer. They wanted this unit to be something that would stay current for many years and felt including a streamer, with the way that tech is changing, might not enable it to be current for a decade or more. With almost all streaming units having a digital output you can easily send their digital stream into the DT-6000 for much improved audio quality. And if you are into Roon, the DT-6000 is fully Roon tested and will show up in your list of audio sources inside Roon.

The transport on the DT-6000 worked flawlessly for us, loading and playing a physical disc very fast. Since this started out as what was supposed to be their best CD player ever, Rotel put a lot of effort into the CD transport. The CD mechanism is spring-loaded with damping materials designed to reduce any vibration during playback. They use a precision motor-driven optical laser system made to pick up every detail from your CDs. 

The rear panel includes IR jacks and an RS232 connection for control systems, but the part we really like is the addition of the balanced audio connectors. With the entire audio path being fully balanced, it's great they offered balanced outputs to complement it. 

We love it when manufacturers tell us which DAC they are using and the DT-6000 uses an ESS Sabre ES9028PRO 8-Channel DAC. As we said earlier, this was then custom configured with 4 dedicated, redundant channels to the left and right outputs. The entire signal path from the DAC to the analog outputs is a fully balanced differential circuit design using some of the very expensive capacitors they had specially designed for the Michi series of gear.

If you know about audio design, you are fully aware that the best circuit and DACs in the world will not perform to their best if the power supply is not up to the job. Rotel has always been known for their robust power supplies and as you might expect, developed a custom one for the DT-6000. It uses a low noise toroidal transformer they even custom-make at Rotel. This feeds independent analog and digital voltage regulators. 

Even the internal circuit boards have isolation and electronic decoupling designs that are filtered down from the top-end Michi products. These reduced noise and distortion in both the analog and digital sections. 

There is a lot to like about the features and technology inside the DT-6000. It seemed like a really great value to us even before we got to hear it. There is really nothing else we wish it had.

Rotel RA-6000 Integrated Amplifier

When we first saw the price of the RA-6000 integrated amp, we thought it might be a bit pricey, but that was before we saw its power ratings and how it was put together. This is one stout and very powerful integrated amplifier.

The class AB amp section is rated at 200 watts per channel into an 8-ohm load. This is not a fictional power rating as it's across the whole audio band at low distortion. But better yet, it comes very close to doubling down into a 4-ohm load producing 350 watts per channel into 4 ohms. That is pretty darn good!

Input wise the RA-6000 has just about everything the modern music lover would need. There is a moving magnet phono input, a balanced analog connection with three more RCA inputs, 3 Toslink, 3 Coax digital inputs, and Bluetooth aptX HD. In addition, there is a USB connection on the front for Apple products and the rear has a USB input for computer audio. 

We do wish they would have included an HDMI ARC connector as this would have made operation with a TV simpler, but it does have plenty of Toslink inputs to accept a feed from most TVs.

All of the digital sources use a high-end Texas Instruments 32-bit/384kHz DAC. The Coax and Toslink inputs support 24-bit/192kHz PCM audio. The PC-USB input renders up to 32-bit/384kHz high-resolution music files, and unfolds and renders MQA and MQA Studio. The RA-6000 is fully Roon tested which means you will be able to see it and control its volume from inside Roon. 

This is a very good DAC, but as we said earlier, the DT-6000 is really something special from a technical digital standpoint

For those of you considering pairing the RA-6000 with the DT-6000 transport, we recommend you connect the DT-6000 via the balanced analog outs as the DAC and the rest of the digital circuit is superior to that in the RA-6000. 

You can configure any of the analog inputs on the RA-6000 for home theater bypass mode which makes adding it to a home theater system a piece of cake. All of the inputs let you set a different turn-on level, which is pretty neat too. Bass and treble controls are also on board and can be fully bypassed for the purest path, but we have to say, these controls come in really handy for some older recordings where the music is great but the recording is not.

There are two sets of speaker connections for A/B speakers or you could just use both for easy bi-wiring. You also get a preamp output connection, although we can not imagine why someone would want to add a bigger amp to this guy!

Finally, there are a pair of mono subwoofer outputs. We wish Rotel would have allowed you to cross over your main speakers when you activated these, but that is not the case, these just each send a full-range mono signal you’ll connect up to the input on your subs that then crossover the signal. 

The big thing that struck us about the RA-6000 was its heft which obviously is due to the massive power supply. This guy weighs a shade over 41 pounds! 

Like the DT-6000, it uses a Rotel custom-designed and made toroidal power transformer which accounts for a lot of the weight of this unit. It also gets the same type of Michi custom-made caps. 

After reviewing all of these great features and specs, we expected the RA-6000 to be able to drive just about any pair of speakers with ease, so we decided to really put it to the test in our listening session.

Rotel Diamond Series Performance Review

We set up the RA-6000 and DT-6000 with a pair of Sonus Faber Amati speakers. While being almost a $40K speaker that is way out of the range one would ever use with the RA-6000, we wanted to use something very revealing to see just how good this stack might be. The source was a MacBook using Roon via the USB input on the DT-6000. Unfortunately, we only had these two units for a limited amount of time as they were the only two in the US and Rotel brought them to us to play with, so we were only able to test using the USB connection and DAC in the DT-6000.

The very first thing we noticed was how precise the soundstage was. Everything was just placed with pinpoint accuracy in a huge three-dimensional sound stage. We played a few tracks we knew could image outside the speakers with a great system and heard that huge soundfield beautifully on this combo.

As we moved on to some challenging bass cuts, it became obvious the RA-6000 was up to the task. It had almost as much slam as we were used to with the McIntosh MC611 mono amps this system normally runs on. This amp will be great for speakers that really need some guts to bring out the best bass like Magnepans or others that come to life when you give them plenty of high-quality power. 

When we played our tracks we used to listen for subtle nuances in voices and instruments, we heard everything we were used to hearing on the reference level gear normally connected up to the Amati speakers. We could tell the DAC in the DT-6000 is pretty darn amazing for its price point as we were able to hear all of the tiny little subtle emotional cues in both instruments and voices.

Our favorite tracks for rhythm and pacing toe-tapping also had us tapping our toes to the music, although not quite to the level we get with the reference McIntosh stack the Amati speakers are usually driven by in this room. 

One thing that stood out compared to the all-tube McIntosh preamp and mono power amps was the fact this system did not sound as rich harmonically as what we were used to with the McIntosh stack. Obviously, we are not making a fair comparison as the reference stack would sell for almost 6 times the cost of the two Rotel pieces. The Rotel stack sounded like we would expect from Rotel, great solid-state sound that ever so slightly leans to the analytical side with fantastic bass control and stupendous imaging.

Overall Recommendation

Rotel has done everything they set out to do with the Diamond series as these two new pieces are a great way to celebrate their 60th anniversary in the audio business. We feel like the DT-6000 is going to find its way into a lot of systems as it is just one heck of a stellar performer irrespective of price and when you look at everything you get for its price point, it offers a ton of value to someone looking to upgrade the digital side of their system.

The RA-6000 is at an interesting price, as it is almost where you could buy a separate amp and preamp, but we highly doubt you could find a combo with this many features and this much great Class AB power for the price of the RA-6000. It will be a fantastic way to wake up harder-to-drive speakers with its abundance of onboard power. The fact you get all of this in what is a fairly compact, although very heavy package, is also a bonus. 

Rotel sure has come a long way since we first heard one of their little integrated amps back in 1981. We look forward to more new products like the Diamond series in the future. 

If you have any questions, call 888.899.8776, chat with us, or stop by our award-winning showrooms. At Audio Advice, we've been designing and installing high-performance home theaters, two-channel setups, & smart home systems for our customers in North Carolina and the surrounding areas for decades. If you are interested in a custom home theater or listening room or upgrading your current system, give us a call at 888.899.8776, chat with us, or stop by our award-winning showrooms.