[ Audiocavi.com – webzine different from any others ; ]
January 24, 2013[ Albedo Flat One interconnect got an excellent review on Audiocavi ]
January 28, 2013
The DAC with Volume Control makes preamp redundant. The DAC has a great preamp already built in. This way we achieve clarity unheard before. Without doubling spending for separate power supply, enclosure etc. We reached the target and got a non compromise unit boarded. Additionally consumer not only is simplifying his system for best, but he also saving rack space , money for power cord and interconnects. Some of those cost very often much more than a good preamp or DAC itself. Bingo.
From all existing volume solutions (pots, stepped pots, stepped ladders, auto-formers, digital chip volume controllers, ) this one is by far the most convenient, transparent and long term reliable (unlike noisy pots and switches).
TAIV kit is made in USA and designed by the aerospace engineer. The resistors were selected from many others as having least sonic signature, even if honestly those are ridiculously expensive resistors (SMD type).
The principle of operation is BINARY: the resistors are selected by microprocessor ans switched by gold contact relays in a binary fashion: 1,2,4,8,16 etc. This way we have 64 steps in 6-bit arrangement and using only 7 relays. This is the most logical and elegant way of doing this. At any given time there is only a pair of resistors in the signal.
– 5 individually switched analog inputs (stereo)
– Remote control IR unit , and the receiving module can be user-programmed to understand also other remotes from all major brands and coding groups (not Samsung) for example Apple Remote which is so handy. This is soooo coool !!! Isn’t it ?
– hand operated infinitely rotating “pseudo pot” to operate the volume by the knob
– 2 Open Collector outputs for controlling your other devices
– 1 freely programmable Relay output for controlling your other devices via remote
– user programmable dimmer function (in 9 discrete steps)
– possibility to upgrade to BALANCED later
– nice 2×16 alphanumeric LCD display with analog as well as text visualizations of volume level
– module for controlling the mains power to the amp or preamp in which the volume resides so you can switch the amp on and off via remote or by button.
-Power-ON indicator LED output
– It is compatible ONLY with the momentary, non-latching button switches.
Attention: There is no volume balance function.
It’s provided wit a generic simple knob, encouraging you to find elsewhere the knob that suits the system you have and match rest of your equipment visually up to your preference
TAIV VC-02 Technical Specifications:
Number of Inputs4 Standard, up to 5 (option)
Effective Volume attenuation range0 to -63dB
Mute attenuation-130dB or better
Input Impedance, Ohm 25k
Display LCD with back- light, 2×16 characters, fast recovery
IR remote compatibility: NEC, Sony, RC5 and RC6 protocols currently supported
Additional digital outputs for external control: 3X TTL level (4,9 VDC) un-buffered/buffered ports, IR remote controlled.
Buffered ports – not to exceed 500mA total for 3 ports.
AC power consumption, Max. 6W
AC Load, Max.30A, 250VAC (power on/off controller for external devices)
DIY Sound Lab VC – 03 – product description and specification.
During development and building of high quality DAC and amplifiers, this project surfaced as most logical next step. After using variety of volume controls I experienced lack of features and flexibility, low value/price ratio, low end bulky design and poor performance – those are just some of the factors that created lots of setbacks. Volume control is not even a primary part of audio equipment, but slowly surfaced as a foundation on which state-of-the-art build can happen. Flexibility and functionality, top quality audio and seamless performance. And as much as I like mechanical resistor ladder switch with 64 or more steps – I didn’t want to jump to adjust volume on the amp every time. IR remote control was a “must have”.
Please welcome 3rd generation of universal volume control with input selector and IR remote capabilities – VC-03.
Philosophy behind VC-03 design:
1. Top audio performance as result of extensive component research and careful design and testing.
2. No sliding mechanical parts, like motorized volume pots. They age and are unstable under changing temperature conditions inside amplifier, DAC etc.
3. No digital volume regulating ICs like CS3310, PGA4311 and others. Not that they are evil, but take a look at datasheet and you will realize they need buffer stages to work with low input impedance amplifier schematics and need some buffer on input as well. Extra TWO stages to get best out of IC and no guarantied results because volume is regulated by semiconductor, non-linear element.
4. Minimalistic approach to volume attenuation – simple and reliable schematic, no audio signal distortions.
5. Flexible input selector (1 to 5 inputs).
6. Seamless controller performance with instant reaction, without delays or funny behavior.
7. Memory stored values for many parameters, like last input selected and its volume level etc.
8. Ultra-quiet power supply and maximum isolation of digital signals from audio circuitry.
9. Only Highest Grade electronic components, especially in audio path.
10. Possibility to use extended controller capabilities beyond volume control.
After 3 years of research, prototyping and 2 earlier versions, volume control VC-03 revision took shape. Firmware testing and debugging was taken very seriously to allow best possible user experience and flawless operation. VC-03 extends functionality of previous revisions, allowing it to use as control module for electronic equipment. Extended control ports, I2C architecture and flexible design can make it part of amplifier, pre-amp, receiver, DAC, control center and other designs.
VC-03 Distinct Features:
– Hand made in US by Aerospace engineer and audio fanatic.
– US-manufactured PCB, hand assembly and quality control of each board.
– Aerospace standards PCB design with via stitching and RF noise suppression. In our tests relay boards were put next to AC power supply in tight design and no noise/leaking detected.
– PCB routing with minimized parasitic capacitance and inductance of signal traces and ground plane.
– State of the art carefully designed precision “constant input impedance” R-2R ladder attenuator based on binary code. Combination of 7 different attenuation levels provides 0 dB to -63 dB and over -130dB in mute passive level regulation. Ultra-Precision low noise resistor attenuator is based on latest technology Japanese resistors, designed for noise-sensitive and medical equipment. Chosen after months of research, those low inductance surface mount resistors provide better performance in high-end audio than military grade resistors.
– Gold-on-Silver contacts sealed fast acting signal relays.
– Up to 5 selectable inputs with individually memory stored volume level.
– Easy direct control and setup with precision optical encoder.
– Learning IR remote control system. Use your own remote or supplied generic remote control. There will be option to choose fine design remote control with VC-03 kit in near future.
– Grounding flexibility – separate ground for each channel allows you to connect ground the way that works best for your design.
– Modular construction that allows flexible arrangement and connections (all inter-modular cables are included). Easy choice of Stereo Single End (SE) or Balanced versions. SE easy upgradable to Balanced version upon request for a fee (See price list).
– High power relay allows to use VC-03 as main AC power entry to turn on/off your device (remotely controlled).
– Extra low noise ground separation between digital and analog circuitry.
– Surface mounted components to minimize parasitic effects in a signal path.
VC-03 Functional Specifications:
– 3-modules design: Powers Supply (PS), Control and Display Unit (CDU), Relay Module (RM) in SE or Balanced modification.
– Volume attenuation and input selection by rotating optical encoder or from IR remote control
– Main AC power on/off control
– Display auto dimming with adjustable brightness level
– IR remote functions:
- Power On/Off
- Volume +/-
- Mute
- Input Next/Previous
- Input select individual: 1,2,3,4,5
- External ports trigger on/off (user design) – memory stored state, IR remote controlled.
- All ports have TTL level output, 0 – off, 1 – on (pull-up resistors optional). In addition, three of the ports have duplicated high current buffered outputs. Buffered outputs have high impedance off state and grounded in on state. Maximum current when using VC-03 power supply – 300mA, not to exceed 300mA total for all three ports. When using external supply for buffered port outputs, absolute maximum levels are 500mA at 30V for each port with external power supply.
- Custom firmware is possible for OEM customers, as well as design alterations.
– Intuitive Setup Menu to set:
- Speed of volume regulation for encoder
- Dimmed Display brightness level
- IR remote learning menu – easy point-to-point setup
- Individual Input naming – assign and store in memory new name for each input to be displayed on LCD and other functions as described in VC-03 Manual.
VC-03 Technical Specifications:
| Number of Inputs | 4 Standard, up to 5 (option), actual number of used inputs is adjustable from setup menu |
| Effective Volume attenuation range | 0 to -63dB |
| Mute attenuation | -130dB or better |
| Input Impedance, Ohm | 32k, different values possible upon request |
| Display | LCD with backlight, 2×16 characters, fast recoveryOrange (default), Red, Blue, White transmissive |
| IR remote compatibility | IR remotes with NEC, Sony, RC5 and RC6 protocols |
| Additional digital outputs for external control | 3X TTL level (4.9VDC) nu-buffered/buffered ports, IR remote controlled.Buffered ports – not to exceed 500mA total for 3 ports. |
| AC power consumption, Max. | 6W |
| AC Load, Max. | 30A, 250VAC |
| Current Software Version | VC-03 v3.01 |
Here is a manual linked as well to download. It explains all features perfectly with all details.
Link to VC-03 Manual: VC03-DIYSoundLab_Manual.pdf
As it is clearly explained VC gen.3 is simply better product in every field. Those who are using previous generation will find the same comfort which they are already used to in the current version. Among features which had been most welcomed by customers those two simply won buyers attention and had been voted as most welcomed and appreciate are :
1. Ability to change colour of the display from ORANGE to Red, Blue, White . 2. Ability to chose remotely digital input in the DAC ( up to 3 inputs) including USB and possibility to name them as you wish and have it all displayed ; ]
