RDA-7.1 Overview and Build Quality
I have always been a fan of products that boast certain
specifications on paper that when benched, comfortably outperform those numbers.
It's a rarity to
say the least, and even more so when the product actually exceeds its specifications by a wide
margin.
When this occurs, a total solar eclipse is usually not far behind.
Fortunately we
can bask in the awe of the beautiful sight of just such an occurrence without fear or losing or
damaging our eyesight.
Our hearing on the other hand is another story and, while we don't condone
the adrenalin rush of sustained loud listening levels, it's nice to know a company provides this
capability for the hearing impaired.
Not surprisingly, this company is no other than Integra
Research, the upscale division of Onkyo electronics.
Build Quality
When amplifiers approach
the price class of the Integra Research RDA-7.1, I expect nothing short of superb build quality both
mechanically and electrically, as well as good ergonomics and a pleasing fit and finish.
The
RDA-7.1 had no problems delivering in this respect.
This amp is solidly constructed and has a
commanding appearance.
I could only find one minor nitpick,
85 degree C capacitors were
used throughout the design.
This is common in consumer audio, but I prefer to see 105 degree C
rated capacitors as they typically have longer lifespans since they can better cope with the heat, and
have lower ESR (effective series resistance) ratings.
As you will later see in this review, this
amp ran cool even under demanding loads, thus my concerns about the capacitor temperature ratings are
mostly academic.
Notice the ground strapping on
each individual power amp module.
The transformers are fully isolated away from the amp
modules.
There is plenty of good old fashion heatsinking to keep each module running cool, even
during demanding power loads.
Editorial Note: Notables on the RDA-7.1 Amplifier Design
- Eight high current complementary output power BJTs per channel - paralleling multiple BJTs is a good method of ensuring amplifier output impedance is low enough to deliver high current while driving low impedance loads. It's also an effective way of minimizing frequency response variations which can occur when driving highly reactive speaker loads and exotic cabling.
- Multiple high voltage (80V) capacitors (2 x 20,000uF = 40,000uF per channel). In order to do 150wpc a minimum recommended cap voltage of sqrt(2)*34.64 + 5 = 54V should be used. Using 80V gives them plenty of design margin and added headroom since the rails can swing much higher.
- Dual massive torodial transformers ensures this amp can utilize the full rated power from the wall outlet (120V,15A) if called upon.
Connections
The back panel of the Integra Research RDA-7.1 is pretty standard of multi-channel amplifiers in this price class. The WBT 5-way binding posts invoke the high end appeal audiophiles love and make me happy too since I have always found them to mate better with various types of banana plugs. Should you choose to utilize bare speaker wire, the holes in each of the speaker connector shafts can be situated so that all cables will be vertically-oriented - a nice touch, resulting in a cleaner cable assembly.
The RDA-7.1 allows for both balanced XLR and unbalanced RCA input signals, so if you have a high-end processor with balanced XLR outputs you can maximize your potential. Please note the proper switch setting of each amplifier module (up for balanced, down for unbalanced). A 12V trigger connection for the amplifier is provided via single 1/8" mini plug. I would have preferred the inclusion of a Music trigger (triggers on line level input) typically found on other amplifiers for those who simply can't get a trigger line to the amplifier. The power cord is a 3-way detachable allowing audiophiles to install their aftermarket exotic cables, though I recommend putting your money to better use such as room acoustics or adding another subwoofer.
