The MHDT Stockholm V2 is the second revision of Stockholm DAC, which was conceived as a successor to the Havana non-oversampling DAC, with additional capabilities for high resolution playback, up to 24bit – 192kHz.
This is allowed by the usage of different USB receiver and digital filter (CS85416), while preserving the same 16 bit R2R, non oversampling PCM56P-J DAC chip, already found in the Havana model.
With such a peculiar combination of digital filter and DAC chip, the Stockholm places itself as a NOS device that’s performs at its best with redbook audio (16bit – 44.1kHz), but distinguishes itself over its NOS siblings by extending its compatibility to high resolution material by truncating some of the available resolution before decoding it.
The MHDT website doesn’t show much information regarding difference between Stockholm V1 and V2. Apparently, the main difference is in output voltage, as the first Stockholm revision (V1) was criticized by some because of its low output voltage (1.1v), and the V2 has been brought to 3v, matching the volume requirements of a broader range of amplifiers.
The Stockholm is a beautiful looking piece of hardware: it’s elegant, stylish, and has a touch of vintage feel. Such attributes are emphasized by the glass on the front panel, and, in my unit, the black paint.
Connectivity and test system
The Stockholm has the following digital inputs: SPDIF (with both coax and BNC connectors), Toslink and USB. It offers playback up to 24/192 with SPDIF and USB, while it only goes up to 24/96 music playback through Toslink. For the purpose of this review I have used Audiophilleo 2 connected to the RCA and BNC inputs, and I have compared it to the native USB input.
I have used Headamp AE-2 with Etymotic ER4P and AD2000, and also the “Babystax” portable electrostatic headphone system (custom upgraded Stax SRS-001 Mk2 portable amplifier/earspeakers).
The Stockholm approaches the music with a combination of relaxed midrange, powerful bass (albeit lacking ultimate depth), clear, but not piercing treble, wide soundstage.
The resulting sound is full bodied, dynamic, full of charge, and very detailed at the same time. It is helpful especially with older type of recordings, which become slightly more rounded and lose harshness compared to other upfront sources. There is a slight sense of glossiness.
The Stockholm is a very good pairing with Audio Technica AD2000 out the AE2 amplifier: the gentle midrange and slightly U-shaped signature make for an easy listening, with wide and deep soundstage, and focus on microdetails without any sibilance.
The constant feeling, when wanting to listen to music, is to choose the Stockholm in order to have and easy, immersive and pleasant listen.
The Stockholm V2 scales well with Audiophilleo 2, compared to the integrated USB input. The Audiophilleo makes spatial positioning and the soundstage much clearer: spatial details (the “sparks”), with their own path of drifting, are more easily spotted instead of just disappearing. This clarity of perception adds up to the sensation of delicacy and sense of ‘control’ over the music.
There are several sources on internet as to how to improve the Stockholm using different parts.
Among tubes, the most loved choices seem to be Bendix / Tung-Sol 2c51 and Bendix 6385. The former is considered better for tonal richness, while the latter has a little better definition.
The PCM56 chip can also be upgraded with a PCM56-K (K-grade), or with an AD1865. The latter chip is a bit more detailed and less rounded than the PCM56 family, and might be better matched with the 2c51 tube.
Signal capacitors can also be upgraded to Blackgates, Vcap or other high end ones.
On Head-Fi.org there is a big thread where to find lots of suggestions.
Conclusion and pairings
The Stockholm 2 offers a sweet, effortless and energic presentation, which makes for an unfatiguing listening flow. The DAC tonality is in the middle between neutral sounding gear (like the Audio-gd NFB9.2 or the Antelope), and the more analogue sounding gear (such as Audio Note DAC2).
I see it as an especially good match for Audio Technica headphones (like the AD2000), Grado’s, several orthodynamics, the Stax Lambda series.
The thickest headphones, like Sennheiser HD650, might not enjoy the most out of the Stockholm full bodied tonality.
Given its particular signature, it can pair equally well with tube and solid state amplifiers if carefully matched.