I have recently completed a DIY build of an LDR attenuator using the Tortuga LDR3x.V2.1 preamp controller, PS12.5 power supply and Tortuga Encoder module. These were fitted into a case from landfall systems, www.landfallsystems.com. I have attached some photos of the results.
I've had an interest in LDR attenuators since long ago when I came across The Lightspeed, and have followed the various diy versions and threads here on the forum. My interest in the Tortuga products is quite recent and after lots of reading I decided to give things a go, in a simplified diy version.
I have single source systems so do not need the relay board and three inputs. I also do not particularly care for remote control or displays. However, because of the additional capabilities with the remote, this may be added in the future.
In reading and researching LDR attenuators I noticed lots of attention to the essentially direct signal path circuit with no resistor(s), switch contacts, or long runs of wire as in a transformer volume control, and the supposedly resultant improvement in sound quality. There is mention of LDR's being essentially crappy linear devices and needing lots of corrective circuitry, or matching to make a usable product. The circuitry required to keep the LDR's properly operating can be quite complex, as here, or much simpler, as in the diy versions. Thus you get a passive controller with power and a power supply.
As for the sound, well you have to listen. I found the sound of the LDR attenuator compared with my stepped attenuator, with Goldpoint switches fitted with PRP and Holco resistors, to have a slightly lower noise floor with resultant more musical detail, and lots more dynamics. What I noticed the most was the additional dynamic range of the sound.
I listen mostly to big orchestra classical music which has lots of musical details and dynamic range. The lower noise floor and additional music details were kind of a subtle change, but the dynamic improvement was not subtle at all. This is the result of swapping a resistor chain and switch contact for essentially a pass through.
Time will tell if the circuitry will properly work and keep the LDR's functioning as they now do. Hopefully this will be so.
I've had an interest in LDR attenuators since long ago when I came across The Lightspeed, and have followed the various diy versions and threads here on the forum. My interest in the Tortuga products is quite recent and after lots of reading I decided to give things a go, in a simplified diy version.
I have single source systems so do not need the relay board and three inputs. I also do not particularly care for remote control or displays. However, because of the additional capabilities with the remote, this may be added in the future.
In reading and researching LDR attenuators I noticed lots of attention to the essentially direct signal path circuit with no resistor(s), switch contacts, or long runs of wire as in a transformer volume control, and the supposedly resultant improvement in sound quality. There is mention of LDR's being essentially crappy linear devices and needing lots of corrective circuitry, or matching to make a usable product. The circuitry required to keep the LDR's properly operating can be quite complex, as here, or much simpler, as in the diy versions. Thus you get a passive controller with power and a power supply.
As for the sound, well you have to listen. I found the sound of the LDR attenuator compared with my stepped attenuator, with Goldpoint switches fitted with PRP and Holco resistors, to have a slightly lower noise floor with resultant more musical detail, and lots more dynamics. What I noticed the most was the additional dynamic range of the sound.
I listen mostly to big orchestra classical music which has lots of musical details and dynamic range. The lower noise floor and additional music details were kind of a subtle change, but the dynamic improvement was not subtle at all. This is the result of swapping a resistor chain and switch contact for essentially a pass through.
Time will tell if the circuitry will properly work and keep the LDR's functioning as they now do. Hopefully this will be so.
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Very nicely made, and a similarly well done write up about your impression.
Well done!
I've been wanting to try ldr volume controls in my preamp. Your post pushes me closer to the edge....
Well done!
I've been wanting to try ldr volume controls in my preamp. Your post pushes me closer to the edge....
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