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Tweakers' Asylum: REVIEW: Dakiom A-203 and R-203 Accessory by machani

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REVIEW: Dakiom A-203 and R-203 Accessory

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Model: A-203 and R-203
Category: Accessory
Suggested Retail Price: $109 and $99
Description: Audio Feedback Stabilizers
Manufacturer URL: Dakiom
Model Picture: View

Review by machani ( A ) on February 21, 2006 at 13:49:19
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for the A-203 and R-203

I was intrigued by the buzz in Audiogon about the Dakiom feedback stabilizers, paying special attention to the suggestions by some reviewers that certain mid-fi components could be brought to hi-fi levels. Initially I dismissed what looked like tall claims in the Dakiom website, which suggests, for instance, that a $200 amplifier could be brought to sound like a $2000 amplifier. My curiosity was piqued nonetheless, enough for me to do some reading up on the technology behind these black boxes.

According to the Dakiom website, negative feedback circuits are prone to oscillation and instability, and "DakiOm Feedback Stabilizer Technology provides variable impedance elements into the circuit’s open-loop gain to detect and steer away from positive feedback conditions allowing true, high quality sound to emerge." I found that there are at least two patents for the device by Dakiom's founder, Dr. Kim Dao, a PhD from University of Wisconsin, Madison.

Curious about the science behind the concept, I Googled "negative feeback amplifier" and found a number of articles of interest. The consensus among the experts seemed to be that negative feedback is a necessary evil, but one that can result in fluctuations, instability and signal artefacts. This is perhaps the reason why some of the best designed components in the marketplace today, including high end SET amps and Class D amps, employ no negative feedback.

Dakiom has a 30 day money back guarantee that seemed pretty iron clad, so I decided to give them a try, initially ordering one R203 stabilizer to try with my Marantz CC4300 CD changer.

R203 on Marantz CDP
My R203 arrived a few days after I placed the order, neatly packaged with simple installation instructions. I applied ProGold before installing an R203 on the analog out of my Marantz CC4300 CD changer.

As a general rule of thumb I do not like having to strain to hear differences when evaluating new audio components - to avoid succombing to the "psycho-acoustic" effect. I have to be absolutely convinced that the new device makes a noticeable difference to the sound, and that the sound with the device is better than without. That said, I remember that it took me about half an hour to figure out what the Dakiom R203 was doing to the sound from my Marantz. I listened to a number of tracks and began to realize that the sound of instruments and voices had became more real, almost visceral and exciting. The sound of piano, in particular, became more natural and true to timbre. The sustain sounded more melodious.

I paid special attention to the top end and dynamics. There was a clear improvement in top end detail and "bell shape" smoothness without any added harshness. The shimmer from cymbals became more apparent. There was absolutely no drop in dynamics, although there was a slight removal of grunge from the bass and glare from the treble. The R203 did not seem to increase the bass weight but it did improve the timbre and texture, making the bass sound more natural and less boomy.

I did not perceive any particular opening of the soundstage with the R203, but there was slightly more precise rendition of the location of sound objects. There was slightly more clarity at the rear areas of the soundstage. Instruments and singers took on a more solid presence and there was better separation between them. Busy music with a lots of percussion, cymbals, brushes and maraccas that used to sound blurry sounded more focused and separate. The Dakiom darkens the background and removes white noise from the foreground. At the expense of sounding clichéd, the veil was being lifted and I was hearing details I never heard before.

Interestingly, I observed that the R203 made some music tracks sound forward, while in others it made them slightly recessed. All the same, my system sounds closer to the truth with the Dakiom.

Not to be left out is the Dakiom's ability to removes listener fatigue. I could relax and listen to mustic for long periods of time without being fatigued. Now, going back to my point that a component must make a noticeable difference to the sound, I decided to follow the Dakiom website's suggested test - to remove the device and listen to my system for half an hour without it. With the R203 removed, the realism and excitement diminished and white background noise became more noticeable. Just a few minutes of playing my system without the Dakiom was enough to convince me about the effectiveness of the product. I found myself straining to hear the details I had heared. With the Dakiom reinstalled the notes began to just flow, with no straining to hear them.

R203 on Tube Audio Design TAD-150 Preamp
When I tried the R203 on my TAD-150 preamp outputs, at ideal listening volumes it seemed to reduce background noise and add a touch more focus, but did not much else. However, it did require me to put some effort a to hear differences - contravening my general principle not to have to do so. So in the end I removed the R203 from the preamp and reinstalled it on my Marantz CDP, where it had the biggest positive impact.

A203 on Cayin TA-30 amp
With my positive impression of the R203 on my Marantz, I decided to give the A203 a try. I sent Dakiom a message asking whether this device would work on my Cayin TA-30 tube amp, which is a Class AB push-pull tube amp. I received a prompt reply from Dakiom saying it would, including a confident assertion that after installing it I would not be able to take it out of my Cayin amp for even 5 minutes. Boy were they proven absolutely right!!

After installing the A203 on the outputs of my Cayin amp using banana plugs (the speaker cables are connected with spades), I pretty much heared all the improvements noted above with the R203, but the improvements were further magnified. But this time around, the A203 opened up the soundstage by a wide margin! The images took on a solid, tightly focused form and any remaining white noise was mostly wiped clean. Besides soundstage, the A203 made a palpable improvement in bass weight, dug deeper and produced bass notes which I never heard before.

In terms of incremental improvement, the A203 made a much more dramatic improvement than the R203, and it required no special effort to feel the change. In short, the A203 added a new level dimensionality and realism to my Cayin amp! There was a break in time 10 - 15 hours after which the soundstage opened up further and top end become even more clear and "bell shaped" smooth.

Then for the acid test, I took out device from my amp and listened. There was an immediate constriction of the soundstage and drop in realism! It took me no more than three minutes to decide that the A203 needed to be back on my amp!!

I am absolutely convinced of the value of the Dakiom on my setup. The Dakiom devices took my system to new level in enjoyment and emotional connection to the music. The impact is exciting and visceral and got me closer to the truth. They allow you to hear the essence of the music and do not add artefacts.

The extent of improvement with A203 was almost amazing. I definitely cannot remove the Dakioms. They are like missing pieces of a puzzle in my system.

The Obligatory YMMV
The device is designed to work on negative feedback and do not work on amps that don't use negative feedback. So they apparently may not work on high end SET amps and Class D Digital amps.

Dakiom's website lists over three hundred components on which the device has be used succesfully. If your component is not listed, just send them a message describing your component and you should receive a promt reply.

Product Weakness: Not suitable for all components.
Product Strengths: Remove white noise and darken background. Improves clarity and transparency and removes fatigue. A203 opens the soundstage and enables deep bass notes to emerge. Improves focus, adds dimensionality and realism.

Associated Equipment for this Review:
Amplifier: Cayin TA-30 (without Bizzy Bee feedback control mod)
Preamplifier (or None if Integrated): Tube Audio Design TAD-150
Sources (CDP/Turntable): Marantz CC4300
Speakers: Quad 22L
Cables/Interconnects: Acoustic Research MS230 ICs, DHLabs Q10 speaker cables
Music Used (Genre/Selections): Many genres, mainly jazz, blues and acoustic rock.
Room Size (LxWxH): 14 x 12 x 9
Room Comments/Treatments: Speaker positioning, carpet
Time Period/Length of Audition: 2 months
Other (Power Conditioner etc.): Panamax
Type of Audition/Review: Home Audition

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Topic - REVIEW: Dakiom A-203 and R-203 Accessory - machani 13:49:19 02/21/06 ( 1)