Hardware Reviews

McIntosh D100 digital preamp


Every once and a while someone is kind enough to loan me a McIntosh product, this time it was the Dutch distributor New Transtec that brought a D100 digital preamplifier to play with. I have been in love with McIntosh since the 70’s although I’ve never bought a single piece because it might finish my hobby (there’s no danger of that, Ed.). I consider a McIntosh component or system as my own ultimate dream. Would the D100 fit into that dream? I was going to find out in my living room with my own system.

D100 digital preamp
The D100 can be used in its simplest form as a digital to analogue converter, the second option is to use its variable outputs and connect it to a power amplifier. However, using the second option you must realize that the D100 has no analogue inputs, only digital. It has two optical and two coaxial inputs plus USB. Each accepts 24-bit resolution PCM data with sample rates up to 192 kHz (but not DSD). Except for the USB, that accepts 32-bit information. For Windows you need a driver for higher speeds, this being available from the McIntosh website. Unfortunately no balanced digital input is available, but I guess most people don’t need one.

As I mentioned all outputs are available in RCA and XLR with the addition of a jack on the front for 20 to 600 Ohm impedance headphones. Remember to use the ‘mute’ knob if you only want to listen to your headphones, otherwise your loudspeakers will still produce sound. On the back some triggers are available to switch the unit on and off with other equipment next to a mains input. On the front panel there are source and mute switches, a large display, IR sensor for the remote control, set-up knob, volume control and power on/off. The easy to read display is very bright, even when it’s dimmed it’s still bright. It shows the input choice, sample rate and the bit depth. When you change the volume this shows up for a number of seconds. The set-up is quite simple. It turns off if there’s no signal for 30 minutes, the display brightness is adjustable in two steps and the firmware version is all you can alter or read. Look at the D100 and you find a typical McIntosh glass front panel, black case and the standard McIntosh width of 17.5inches.


McIntosh D100Back


McIntosh uses an ESS Sabre converter, which is actually eight converters on a single chip. These converters are configured in Quad Balanced Mode. It’s not very hard to figure out that both channels use two converters in parallel for both the plus and minus signal. So, Quad Balanced Mode sounds impressive, but from a technical point of view it isn’t all that radical. Inside the box we find nicely arranged printed circuit boards. On the input board a clock sits beside the USB receiver chip to make asynchronous re-clocking possible. The system clock is positioned next to the ESS Sabre converter. A power supply with C-core transformer feeds buffer and smoothing capacitors from Rubycon. That the  circuits are fully balanced is easy to recognize. Each output has its own circuit, even the headphone output. That means that every output, RCA or XLR, variable or fixed, is independent from the others. Mostly the output mode is chosen with the use of DIP-switches or through software. Volume control takes place in the analogue domain within a special chip driven by impulses from the front panel rotary knob.

McIntosh does not tell us whether they use any form of upsampling or possibly conversion of the PCM signal into DSD before the ESS Sabre converter starts delivering analogue output. But conversion from PCM to DSD might secretly take place inside the box, you will read later why I suspect as much. McIntosh is not very open with its specifications, all we know is that the output level is 2 Volts on RCA and 4 on XLR, or 0-8 and 0-16 Volt for the variable outputs. Plus some details are given on frequency response, distortion etc. We better start listening to the D100, after all this is far more important than tech talk.

In my system the D100 replaces my Esoteric converter between a NAD M50/M52 combination and my Audia Flight amplifiers. Loudspeakers are mostly PMC fact.8 but I do swap them for a pair of Harbeth P3ESR on heavy Target stands. The D100 uses a Supra power cord, Stereovox digital cable and Van den Hul balanced interlinks. While my own DAC uses a balanced Apogee digital cable, Crystal Cable power cord and Yter balanced interconnects. Both DACs get clean power from Kemp Elektroniks mains conditioners. On the M50/M52 files are stored in FLAC, WAV and ALAC, at various sample rates. Later I connect the D100 directly to my Audia Flight power amplifier. The shortest route, but is it the best? We will find out later. USB is used in conjunction with a Vortexbox media player and AudioQuest Cinnamon cable. No additional driver is needed, the Linux software recognised the DAC immediately.



I can hear you
Form the first note till the last I loved the D100, because it sounded almost identical to my own converter on the fact.8 speakers. Only the Harbeth P3ESR showed a little more difference in the midrange and stereo image, still not enough to recognise each converter in a blind test. No matter the sample rate, bit depth or file type. Extraordinary since the two converters use different power cords, different interlinks and one uses RCA and one an XLR digital input. Even the converter IC’s differ from AKM in my Esoteric to ESS Sabre inside the D100. My Esoteric up-samples and changes the PCM signal into DSD before conversion and that is why I suspect that the D100 does the same thing. But I cannot prove it and I might be totally wrong on this point. Sceptics may find these results prove that all digital systems and all cables sound the same, but that is definitely not true. I have had many cables and DACs at home and they all differ from my reference. Sometimes better, sometimes worse, but they do differ. Except the D100, how strange is that.

For now I will only describe the performance of the D100 and forget the far more expensive Esoteric DAC. I enjoy the female singer Stacey Kent who has recently released a new album called The Changing Lights, covering a mix of easy listening, light jazz and South American tunes. She has an appealing voice, is always surrounded with fine musicians and the recordings are natural with a lot of detail, fine stereo image and good sound balance. Exactly the elements that make a D100 sing. This is my favourite sound, all these tiny graduations, the natural accents and pure output. The D100 has a very analogue voicing, very different from technical and digital sounding DACs. Listeners who are only used to digital music might consider the D100 too soft and slow, vinyl lovers will embrace the performance. Music flows, warms your heart and surrounds you and not your speakers or system. On the other hand you simply cannot reject the D100 for being uninspiring, on the contrary music comes alive, swings, demands the attention and captivates you. Not for short moments, I would say for hours if you have the time to play music that long. Renée Fleming caught my full attention this morning with her Guilty Pleasures and now the classical CD Il Progetto Vivaldi 3 by Sol Gabetta does it again. I love to listen to the D100, it feels like coming home. It’s proof that McIntosh is alive and kicking, despite the several owners it has had in the past. McIntosh has been and still is allowed to cherish their own interpretation of high fidelity. I’m thankful for that because the D100 brings back memories and I promise myself that one day I will own at least one McIntosh device.

I have to mention the magic word: USB. A D/A converter without a USB input is hard to sell these days, although I prefer to use a network player or standalone music player like my NAD M50. My own Esoteric has a simple USB input, adaptive without re-clocking, that won’t help either to take that route. With the D100 connected to my Vortexbox (ripper/server) I start with the same Stacey Kent CD as before. We are talking about the FLAC file ripped from the CD of course. To tell the truth, the USB port has the same quality level as the RCA input, no better, no worse. The true digital audio adventurer might reach a higher level using kernel streaming, JRiver and JPlay, I like to keep it simple and good (enough). Same goes for a high resolution file of the Alan Parsons Project (24/192) and some studio masters I recently received from STS Digital in 24/176 format. I want to compliment the D100 for its results with RCA versus USB, I have come across DACs that sounded only good enough over USB or only over RCA, and that does limit your choice of front ends.



McIntosh D100FrontTop 1


The final possibility is to use the D100 not merely as a D/A converter, but to connect it directly to the power amplifier and use the built-in volume control. My Strumento is set aside and some Yter interconnects plug into the D100 variable outputs. Since I have to switch off some components to change the connections, this is the right time to upgrade the D100 to a better power cord from Crystal Cable. Well, that change of cords is not a success, in comparison a very cheap Supra power cord is a better combination with the D100. Lesson to be learned: Be careful what cable you use if you buy the McIntosh. Again the same music is played, Stacey Kent, Renée Fleming, but also work from Agnes Obel, Janine Jansen, Ray Brown, The Nits (Dutch) and Tic Tac Toe (German). Broadly speaking the sound does not change much, however without my beloved Audia Flight preamp some magic disappears. This must be due to the volume control in the D100, which is far more simple than the one in the very expensive Strumento. But I am sure that in a complete McIntosh chain, for instance the D100 in combination with the tube MC275 monoblocks or a MC302 stereo power amplifier with Autoformers, you will be very happy with the results. If funding allows, the ultimate goal will be a system that includes a high quality preamp from McIntosh or another manufacturer. For that matter, remember the look of a stack of McIntosh components, the visual impact is part of the fun.

I have a dream
This was a new chance for me to feed my greed and renew my relationship with the McIntosh brand. Greed to own only a single component or maybe a complete system. The D100 revealed to me over and over the high level of craftsmanship from the people in Binghamton USA. The new owners have not compromised on quality. The D100 plays all your music with great joy, in a way that resembles the analogue reproduction of vinyl a lot. But be aware that the D100 has some shortcomings like the absence of an analogue input, which will limit you to digital sources if you use it as a preamp. But it sounds even better via its fixed outputs. And last but not least, the D100 is among the best converters for music, if not in terms of resolution, finesse and accuracy. But I like music and the D100 will bring you lots. Within a McIntosh system or used in combination with other brands I can recommend the D100 unreservedly even with its limitations. Why? Because with an appropriate CD drive or streaming device it will let your music collection glow.


Headphone Output: 1/4", High Drive
Variable Outputs Unbalanced
Variable Outputs Balanced
Digital USB Input: 2.0, 32/192 Asynchronous
Digital Coaxial Input: 2
Digital Optical Input: 2
Power Control Output: 1
Rear Panel Data Ports: 1 in
Rear Panel IR Sensor Input
Dimensions (W x H x D): 17.5" (44.45cm) x 3-7/8" (9.8cm) x 16" (40.64cm)
Weight: 13.5 lbs (6.1kg)

Price when tested:
Manufacturer Details:

McIntosh Laboratory


Digital preamplifier


René van Es

Distributor Details:

New Transtec
Tel. +31 (0) 180 590184

Jordan Acoustics

Tel: 01202 911886


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