DM-100D Power Amplifier

Totally dual-mono performance in single chassis! Latest Elite model available!

Introducing the Musical Design DM-100D, an exquisite audiophile power amplifier.

DM-100D design: Our original DM-100 amplifier used three circuit boards - power supply and channel driver boards. This has been integrated into a single board with reductions of wiring lengths and mechanical/wire connections by comparison. The circuitry has changed too with front-end circuitry distilled down to a simple but very effective design using a unique Class-A Ultra-Linear Cascode driver stage.

The Sound: Yes, there are some moderate powered amplifiers that have superb sound quality, but they are mostly tube-type and always expensive. And yes, there are low priced, modest powered amps from some of the mainstream companies, but they sound modest. You know the sort. The DM-100D is a new generation of amplifier with sound quality comparable to the finest products on the market, yet affordable.

It is an amplifier with wide-open soundstaging and unhesitating naturalness. It has superb inner detailing, yet without edge or bite. Oh yes, sometimes live music can have an edge and bite, then those dynamic shadings are captured in a way that just has to be heard. There is a glorious ability to render the subtlest of shadings, micro-contrasts if you will, while cruising through complex passages. The sense of naturalness with human voice is stunning. Subtle clues are revealed, that tell you something about the vocalists and the emotion they felt during the performance. In fact, there is always an exhilarating sense of emotional impact whenever the software can deliver it. You move it into a system up to the high standards and the DM-100D provides years of thrilling, satisfying musical enjoyment. Come to think of it, the sound is hard to describe. You know, like the sound of live music.

Elite Sound: The Elite gets it name from the Elite parts which make it so special. Firstly, we have a quiet pair of toroid transformers. We employ great sounding Mundorf Black Titanium power supply caps even better than a certain “black cap” from the recent past. We use high performance, quiet resistors. We have found the Nichicon Muse capacitor superb in it's natural octave to octave balance and it's open, dynamic freedom and frequency extension. They allow the music to achieve its full natural color shading. The results are that the Elite is utterly natural, clear, dynamic and 100% foot tapping great.

Elite Ultra Technology: The Elite Ultra is, well, ultra. It uses a costly CRC power supply for the output stage which is then cascaded into a further CRC power supply for the front-end stages.

What is “CRC”? The power supply rectifiers convert the AC voltage supplied by the power transformer into a pulsating DC which refreshes the voltage to the power supply caps 60 times per second. Over that short period of time, 1/60th of a second, representing the charge-discharge cycle the capacitor will discharge somewhat because it is supplying the current to bias the power amplifier into a rich Class-AB operation while the diodes are ‘switched off’. That produces what looks like a ‘saw-tooth’ wave if you view it on an oscilloscope. The vertical dimension on the ‘scope’ represents the amplitude of a wave and the horizontal dimension represents the passage of time. Now here’s the technical trick. A second power supply cap is added but you don’t put it in parallel to the first one, rather you separate them with a resistor. That is the CRC, capacitor-resistor-capacitor connection. It is also known as a pi-filter. Now you see something more like a greatly diminished trace of a sine wave on the second cap. It is a far smoother and far more pure voltage in terms of switching noise, high frequency content if you wish. Yes, we use eight(8) power supply caps to accomplish this for the two channels of the MOSFET output stage quite unlike most solid-state amps typically using two or four power supply caps dedicated to the output stage. We use eight superb Mundorf Black Titanium electrolytic caps for the output stage. Expensive? Yes! Worth it? Yes!

So we know it sounds great, but what does CRC look like. Here is a sample of a MOSFET amplifier pulling 300ma bias with a single 10,000uF power supply capacitor. Ouch, look at that voltage peak. The top two pictures are shown at the same scale. The final picture is to show a sense of comparison. Vertical is voltage and horizontal is time.

Now lets double the capacitors and have a look see. That looks better, yes? More capacitance equals smoother output. It doesn’t guarantee better sound since all capacitors are not equal in other respects. With the same quality of caps this is good.

Lets have a look at the Musical Design CRC. The input cap is in red showing a sort of similar result to those above. The output cap is the one on the bottom in green. Wow, the sharp peak current is gone and we have a nearly sine wave look. This looks and sounds a lot different, a lot smoother and silkier, plain better in every way.

These illustrations were generated by PSU Designer II from Duncan’s Amps, but actual measurements are very close to these results..

The great sounding Nichicon Muse KZ caps are employed in the additional CRC front-end circuit producing smooth, highly filtered DC voltage for the input stages with purely passive techniques. It gives you more true, vivid ‘tonal colors’ than a certain silk capacitor. The voltage here has no trace of the peaky saw-tooth noise you see in many front-end supplies. High purity, passively filtered DC means high-purity sound.

Takman CF resistors are used. They have a great purity and naturalness. The 3D soundstage and pinpoint imaging quality is a treat too.

Elite Ultra sound: The CRC technical details aside you get an even greater benefit than you might expect. The sound is much in the same family that you get from our Elite version, but with an added smoothness, silkiness, dimensionality and a striking purity. The soundstage is even more solid and ‘locked in’. It produces wide dynamics without hesitation or soft peaks.

DM-100D model is well equipped with superb sounding resistors, carefully selected capacitors and a few hidden tweaks
Single-Ended, Class-A front-end with Current Source
Single-Ended, Class-A Ultra-Linear Cascode, LED-Biased driver stage operates in high quiescent current mode - extremely wideband and linear design.
Power MOSFET output stage is rugged and reliable, yet delicate sounding. There is no need for sonically compromised VI limiting, like that used in bipolar output stages.
Large Power Supply - Each channel has separate power rectification and capacitor bank
Twin Toroid power transformers for totally Dual-Mono performance, double contact power switch
Gold-Plated, Teflon® RCA jacks, Gold-plated, hi-current 5-way binding posts even on standard version
IEC Power cord socket for alternative power cords
Elite version adds Mundorf Black Titanium capacitors, Rhodium-plated RCA jacks, Binding Post and IEC power socket
Elite Ultra Version adds CRC power supplies with Mundorf Black Titanium capacitors, Takman resistors