TentLabs Volume control
"Clean and transparent sound, easy application, incredible specs "
" My point is, this is a very good stepped attenuator indeed, it beats the DACT CT2 by quite some margin, which I've been using for some time (2 years). And its fully remote with 64 steps on the gain and 4 inputs all via little relays which are quite audible. (but its no problem, a faint click is all that one hears) "
" Staging improved, the ambiance is much clearer, voices can be heard much better, I am enjoying my system much more now. PS: If you know someone interested in a second hand DACT CT2, let me know "
DIYThe module consists of 2 PCBs, and comes fully stuffed and tested. It is intended for either upgrade of existing equipment, or building new. OEM customers, please apply for more info.
General DescriptionDesigner Jos van Eijndhoven set the concept for this DIY module. It fills a gap by combining high end sound quality with ease of use: Volume can be set in 64 steps of exactly 1.0dB by rotating the encoder. Additionally, 4 inputs can be chosen by pushing the encoder. Philips / Marantz and Sony remote controls will be able to fully control the unit as well. The attenuator is a passive design, hence long cables and low impedance power amplifiers cannot be driven. To solve that, a high performance, discrete design line amp / buffer will be introduced soon. This module is a stereo unit that can be cascaded for multi-channel / mono use.
Technical description64 steps of attenuation are achieved with 6 Omron G6K relays, controlling 12 Dale RN6 resistors in parallel configuration. This is a fundamental difference compared to other attenuators, which usually have more contacts or resistors in their signal way. The relays are controlled by a micro controller. A second micro controller on board of the display section takes care of remote control decoding and controls the other micro to achieve correct volume and input settings. It also displays these settings. Power supply consists of a low drop 5V regulator. On board rectifiers and decoupling capacitors assure proper functioning of the whole unit, being powered by either AC or DC. An additional power on/off signal is present to directly drive an external relay which in turn can switch a power amplifier, or fulfill other functions. In power off mode, the controller of the volume control remains active, with a very low standby power. The volume control is supplied as tested module and comes with interface wiring and mounting accesoires.
For balanced use, order 2 pieces. Both relay boards can be controlled by one encoder / display board by cascading the controls. See the application note for more information.
Input impedance: > 40 k-ohm (actual value depends on volume setting)
Output impedance: < 8 k-ohm (actual value depends on volume setting)
Power: AC or DC, 6 to 10V max, current max 150mA DC, 225mA AC (power connector supplied with module)
Volume setting: 64 steps of 1.0 dB
Channel imbalance: < 0.15 dB
Input / Output connectors: Cinch / RCA (can be supplied without connectors on special order)
Remote control: Not included, can be programmed by Philips / Marantz models and most Sony types
Power on/off output: Open collector
Main PCB size: 120*58*28 mm (W*L*H)(excludes connectors)
Hole pitch: 111*49 mm (symmetrical)
Display PCB size: 120*20*8 mm (W*L*H) (excludes control shaft)
Hole pitch: 111*11 mm (symmetrical)
Display PCB size can be reduced to : 80*20*8 mm (W*L*H) (excludes control shaft)
Hole pitch: 71*11 mm (symmetrical)
All hole diamters 3.2 mm