Mhdt Labs Stockholm User manual

Instructions and Manual
Rev 1.0
Stockholm
Asynchronous DAC
Mhdt Labs
Audio Products

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
1
Thank you for purchasing the Mhdt Labs’ Stockholm 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 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
filled with liquids (flower vases, drink cans, coffee cups, etc) on the
apparatus.

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
2
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
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
3
1. Introduction
Stockholm DAC is a successor model of our successful Havana series DAC. It
is capable of up to 24bits/192kHz digital signal inputs yet remains driving
legendary PCM56P R-2R digital to analog output.
Stockholm DAC is a non over-sampling and no digital filter DAC.
To maximize the performance of PCM56P R-2R dac chip, the Stockholm is
designed to be an asynchronous operation between digital receiver and
PCM56P chip.
The USB input section can be configured to be synchronous or asynchronous
operation by firmware.
2. Connections and Operation
2.1 Front Panel
1 Main power toggle switch
2 Indication Led, lights on when signal is locked
3 Digital input select switch – B, BNC input, SPDIF format

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
4
4 Digital input select switch – U, USB input, SPDIF format
5 Digital input select switch – R, RCA input, SPDIF format
6 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 Left Channel Analog Output – Connect to Pre-Amplifier or Receiver’s line
input
3 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.
4 Coaxial Digital Input / RCA - Connect to CD Transport, CDP, DVD or PC’s
Digital output. Capable of 16-24bits, 32-192kHz SPDIF digital signals.
5 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, 96 kHz digital signals. No driver is needed. Support
Linux, Windows XP, SP2, SP3, Windows Vista, Windows 7 and Apple Mac.
6 Coaxial Digital Input / BNC - Connect to CD Transport, CDP or DVD Digital
output. Capable of 16-24bits, 32-192kHz SPDIF digital signals.
7 Main Powercord Inlet – Check the preset voltage indicated below this slot,
this can be either 220-240VAC or 100-120 VAC (50/60Hz).

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
5
The 4 digital inputs, i.e., 3 , 4 , 5 , 6 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 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 will light up in one of the tact switch on
the front panel.
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 10-15 seconds after power on and it
represents that the DAC is in stand-by mode.
3. Technical specifications
Digital Receiver CS8416
D/A converter PCM56P-J
Oscillator used to asynchronous operation: 11.2896 kHz, 0.3ppm, low jitter
Frequency response: 20 Hz to 18 kHz (± 2dB)
Output impedance: 32 ohms
Output level: 1.1 Vrms
USB input 16, 24 bits 44.1 kHz or 48 kHz, 88.2kHz, 96kHz no drivers required
USB input can be synchronous or asynchronous depends on firmware installed
All other inputs (SPDIF) 16, 24 bits 32 kHz up to 192 kHz

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
6
Dimensions clear (W x D X H) 276 x 150 x 60 mm
Dimensions w/ socket (W x D X H) 295 x 170 x 60 mm
Weight 2 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.
5. USB input firmware
The USB input of Stockholm DAC can be in either synchronous or
asynchronous operation.
6631-2315-MHDT-ALL.hex is the firmware for asynchronous operation
6631-2316-MHDT-ALL.hex is the firmware for synchronous operation
Asynchronous operation works well in Linux, Mac, Windows W7, Vista
Some Windows XP may not smoothly works in asynchronous operation.
The preset USB input is in synchronous operation (2316 firmware).
FWUdate.exe (version 1,0,1,0) is the tool to change USB firmware of Stockholm

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
7
DAC.
Please be noted that power must be remains on during updating firmware.
To achieve better audio performance in Microsoft Windows O.S., we suggest to
use Windows 7 instead of XP,
If you are using Windows XP, use ASIO to get better sonic performance.
6. Tube, Fuse Replacement
The vacuum tube installed in Stockholm DAC is GE JAN 5670W.
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

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
8
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 JP3 (Voltage selection jumper) on the PCB beside IEC AC socket.
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 DAC accepts USB audio signal via USB port. Be sure the input
is USB audio signal.
zStockholm DAC accepts only SPDIF (PCM) format digital signal for the rest
of inputs; BNC, RCAand Toslink. Other format like dts, ac3… is not
accepted.

Stockholm
Asynchronous DAC
Mhdt Laboratory
Taipei, Taiwan
http://dhost.info/mhdtlab/
Rev 1 .0 Sep, 2011
9
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.
zStockholm DAC doest not need to install additional USB driver. However,
in 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 DAC. Signal through USB
hub may not work properly and also decrease the sound 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://dhost.info/mhdtlab/