Mhdt Labs Stockholm V2 Balanced User manual

Instructions and Manual Rev 1.0
Stockholm 2Balanced
Realistic yet Natural Sounding DAC
Mhdt Labs
Audio Products

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
1
Thank you for purchasing the Mhdt Labs’ Stockholm 2Balanced DAC.
Please take a few moments to read over this instruction manual to get the most
out of your unit. The manual describes how to operate the Mhdt Labs’
Stockholm 2Balanced DAC and provides some technical background information.
Should you have any further questions or suggestions on how to improve this
manual, please feel welcome to get in touch with us.
We hope this investment will bring you many years of outstanding listening
enjoyment.
Important Safety Instructions
Please follow these precautions when using this product:
zRead and keep these instructions.
zHeed all warnings.
zDangerous voltage is inside this apparatus. Opening is only allowed by
qualified service personnel.
zVerify line voltage before use.
zProtect the power cord from being walked on or pinched, particularly at
plugs, convenience receptables, and the point where they exit from the
apparatus.
zDo not use this apparatus near water.
zDo not use this apparatus outside.
zDo not expose the apparatus to dripping or splashing. Do not place objects

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
2
filled with liquids (flower vases, drink cans, coffee cups, etc) on the
apparatus.
zUnplug the unit from the mains supply before cleaning. The case should
normally only be cleaned with a dry, soft, non-fluffy cloth. Do not spray any
liquid cleaner onto the cabinet, as this may lead to dangerous shocks.
zDo not install near any heat sources such as radiators, heat registers,
stoves, or other apparatus (including amplifiers) that produce heat. Avoid
exposure to direct sunlight.
zThis unit runs slightly warm when operated normally. Operate in a normal
ventilated area. If this product will be installed in a rack, make certain there
is sufficient air movement within the rack.
zRefer all servicing to qualified service personnel. Servicing is required when
the apparatus has been damaged in any way, such as when the
power-supply cord or plug is damaged, liquid has been spilled or objects
have fallen into the apparatus, the apparatus has been exposed to rain or
moisture, does not operate normally, or has been dropped.
zTo reduce the risk of fire or electric shock, do not expose this apparatus to
rain or moisture.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
3
1. Introduction
Stockholm 2Balanced DAC is capable of up to 24bits/192kHz digital signal
inputs yet remains driving legendary PCM56 R-2R digital to analog output.
Stockholm 2Balanced DAC is a non over-sampling, no digital filter, no op-amp,
no feedback structured DAC. This tends to produce most realistic and natural
sound.
The USB input section can handle 16-24bits at 44.1, 48, 88.2, 96, 176.4 and
192kHz digital signals. This makes Stockholm 2Balanced DAC a powerful
digital music station.
2. Connections and Operation
2.1 Front Panel
1 Main power push on/off switch
2 Indication Led, Green lights on when signal is locked
3 Digital input select switch – A, AES/EBU input, SPDIF format 110Ω

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
4
4 Digital input select switch – U, USB input, SPDIF format
5 Digital input select switch – B, BNC input, SPDIF format
6 Digital input select switch – R, RCA input, SPDIF format
7 Digital input select switch – T, Toslink input, SPDIF format
When any of digital inputs is selected, this input is stored after selection, and will
remain the last selection after disconnection from mains power.
2.2 Rear Panel Connections
1 Right Channel Analog Output – Connect to Pre-Amplifier or Receiver’s line
input
2 Right Channel Analog Balanced Output – Connect to Pre-Amplifier or
Receiver’s line input
3 Left Channel Analog Output – Connect to Pre-Amplifier or Receiver’s line
input
4 Left Channel Analog Balanced Output – Connect to Pre-Amplifier or
Receiver’s line input
5 Fiber Optical Digital input – Connect to CD Transport, CDP, DVD or PC’s
Digital Optic output. Capable of 16-24bits, 32-192kHz SPDIF digital
signals.
6 Coaxial Digital Input / RCA - Connect to CD Transport, CDP, DVD or PC’s
Digital output. Capable of 16-24bits, 32-192kHz SPDIF digital signals.
7 Coaxial Digital Input / BNC - Connect to CD Transport, CDP or DVD Digital
output. Capable of 16-24bits, 32-192kHz SPDIF digital signals.
8 USB Digital Input - Connect to PC’s USB Port, please do not connect to
USB port on external hub to achieve better sound quality. Capable of
16-24bits at 44.1, 48, 88.2, 96, 176.4 and 192kHz digital signals.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
5
9 AES/EBU Professional Digital Input / 110Ω- Connect to CD Transport, CDP
or DVD Digital output. Capable of 16-24bits, 32-192kHz SPDIF digital
signals.
10 Main Powercord Inlet – Check the preset voltage indicated below this slot,
this can be either 220-240VAC or 100-120 VAC (50/60Hz).
The 4 analog outputs, i.e., 1 , 2 , 3 , 4 are output simultaneously., ie, 1 output +
and gnd and 2 output + and – simultaneously, and so as 3 , 4 in left channel.
The 5 digital inputs, i.e., 5 , 6 , 7 , 8 , 9 are independent to each other, only one
among them will be active and is controlled by the tact switches located in front
panel.
2.3 Powering up
Before applying power to the Stockholm 2Balanced DAC, ensure that the
correct mains voltage is used. This can be either 220-240VAC or 100-120 VAC
(50/60Hz). The factory preset voltage is indicated on the rear panel.
After applying mains voltage, a blue led on all inputs will sequentially light up
and stay on the last input when powered off.
The filaments of vacuum tube located in the right side of the DAC will also slowly
lighting up, it is visible through the transparent acrylic front panel. A slightly
click sound of relay can be heard in about 15 seconds after power on and it
represents that the DAC is in stand-by mode.
3. Technical specifications
Digital Receiver CS8416
D/A converter PCM56 (J-Grade)
Frequency response: 20 Hz to 20 kHz (± 2dB)
Output impedance: 32 ohms

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
6
Output level: 3.0 Vrms
USB input 16, 24 bits 44.1 kHz or 48 kHz, 88.2kHz, 96kHz, 176.4kHz and 192
kHz; drivers required
USB inputs are all in asynchronous operation.
All other inputs (SPDIF) 16, 24 bits 32 kHz up to 192 kHz, please check section
5 of this manual for detail.
Dimensions (W x D X H) 346 x 200 x 75 mm
Weight 2.7 kg
4. Warranty
Warranty of this product is one year after original purchase. During the period of
warranty, all repair needed parts, labor and shipment is free. Moreover, we
usually replace with a new unit within this warranty period.
This warranty is enforceable only by the original retail purchaser and cannot be
transferred or assigned.
This warranty does not cover claims for damage due to abuse, neglect,
alteration or attempted repair by unauthorized personnel, and is limited to
failures arising during normal use that are due to defects in material or
workmanship in the product.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
7
5. USB input driver installation
No driver installation is needed if using w/ Mac and Linux OS,
Android (Mi TV box / cell phone) just plug and play
USB2.0 driver installation on Windows OS
To support 176.4kHz and 192 kHz formats, the Stockholm 2Balanced DAC is
operated in USB2.0 full speed condition. Thus, you have to install USB2.0
driver before use USB input.
The use and setup of USB2.0 can be referred to our USBridge user manual
located in: http://www.mhdtlab.com/Usbdriver.htm,
Let’s take W7 (32/64) as example:
Installed driver version: CM6631_6631A-1.03(CR)
After drivers installed, please check control panel to see if the drivers is properly
installed.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
8
Test if the supported formats sounded normally.,

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
9
Note:
If you want to install different version of drivers, please uninstall previous drivers
before install new driver.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
10
The uninstall is operated in control panel like following:
After driver is installed properly, you may try to run media agent to play the
USB2.0 audio.
The Stockholm USB2.0 input supports: 16, 24 bits 44.1 kHz, 48 kHz, 88.2kHz,
96kHz, 176.4kHz and 192 kHz formats and can handle Direct Sound (DS),
Kernel Streaming (KS)(will support in newer version of driver ) and WASAPI and
ASIO with specific player such as FooBar or Winamp etc.
Take foobar as example.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
11
ASIO driver. You can download these drivers from
CM6631_6631A-1.03(CR)\W7\SoftwareDriver\DLL
W7 is just a demonstration; it can be XP, W8, VISTA
CMUACWOASIO64.dll
CMUACWOASIO.dll
Copy these ASIO drivers to the Components folder of Foobar2000 if you are
using Foobar and restart Foobar. Then, you are ready to use ASIO.
6. Tube, Fuse Replacement
The vacuum tube installed in Stockholm 2Balanced DAC is GE JAN 5670W.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
12
The reason we choose 5670W is that this tube is very reliable, durable, good
sounding and easy to find in nowadays’ market,
The typical life of GE JAN 5670W is about 6000-8000 hours. If you listen to
music by two hours every day, you don’t have to care about tube’s life for almost
10 years.
The burn in time will takes about 1 day for components and about one month for
tube.
Tubes can be used: 5670, 2C51, 396A, 6385, 6386, 6CC42, 6854, 6N3,
CV2575, CV4013, CV5894, CV8247, CV2381
Changing tube is by your own risk. You have to remove the top cover plate to
remove and insert a new tube. The hex/torx screwdriver needed is hex/2mm
or torx/T8x50.
Please consult to experienced person if you are first time to do this.
Fuse spec: 5x20mm 1.0A slow blow
7. Selection of input AC Voltage
The input AC Voltage is presented according to your country and is marked in
the rear panel.
In case of traveling to different voltage area:
Find JP2 (Voltage selection jumper) on the PCB beside IEC AC socket.

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
13
The DAC is designed to be fully regulated in circuit. So, select 110-120V case
can also works well in Japan’s 100V.
8. Troubleshooting
In case there is no audio coming out of your system, there are a few things to
check:
zStockholm 2Balanced DAC accepts USB audio signal via USB port. Be
sure the input is USB audio signal.
zStockholm 2Balanced DAC accepts only SPDIF (PCM) format digital signal
for the rest of inputs; BNC, RCA and Toslink. Other formats like dts, ac3…
are not accepted.
zAre both sides of filaments of the vacuum lighting? If not, try to firm the
tube or the tube is dead. Changing a new tube to check the problem
remains.
zIn case of no sound from USB port, please check if there is any device
conflict by device management under control panel.
zAvoid using USB hub in connecting Stockholm 2Balanced DAC. Signal
through USB hub may not work properly and also decrease the sound

Stockholm 2 Balanced
Realistic yet Natural Sounding DAC
Mhdt Laboratory
Taipei, Taiwan
http://www.mhdtlab.com/
Rev 1 Mar., 2015
14
performance.
If none of these suggestions cure the problem, please do not hesitate to contact
us.
Latest version of firmware/driver can be downloaded from our website:
http://www.mhdtlab.com/