This is part 1 of a review of the Tortuga Audio LDR1 passive volume control, or passive preamp, as some like to call it.http://www.tortugaaudio.com/
There was a delay in getting a newly implemented control software chip due to refinements that were required after beta testing. Part 2 will consist of a comparison between the original chip and the new chip. I felt compelled to post my thoughts while they were fresh in, what little is left of, my mind.
My system consists of a Sony BDP S580 BluRay player hooked up via a 15ft length of DH Labs SilverSonic D75 coax BNC/RCA adapter->BNC to a Bryston BDA-1 DAC(Mojo Audio PC). The single ended out then goes to Creek OBH-12 passive pre via a 26" pair of Sweet Spot Reveal "Silver" interconnects then from the Creek to a pair of W4S SX500 mono amps(W4S P-1 PCs) via a 3ft pair of Grover Huffman ICs. A 3ft pair of Anti-Cables go from the amps to Aether Audio Black Boxes, Aether Audio Timepiece Minis and VMPS Super tweeters(facing backwards). The amps are plugged into the wall, and eveything else in plugged into an APC S15 power conditioner and Belkin PureAV PF60.The LDR1 replaces the Creek.
I have not used an active pre in almost 20 years. My system is optimized for use with a passive pre. The Bryston DAC was selected because of its 2.3V, 50ohm, discrete analog output, and reliability. The W4S amps were chosen for their high gain, low noise and distortion, and relatively high, for ICE power type amps, input impedance of 60k ohms. ICs are short and low capacitance. No accommodations were made to substitute the Creek with the Tortuga.
I've been on the hunt for a replacement for the Creek for some time. To be sure, the Creek is an entry level passive but offers 3 input switching and remote so it met my needs. The replacements that I have considered over the years all have some perceived weakness. Mostly they offered no, to me, significant increase in sound quality commensurate with their price. AFAIK, there are only 3 methods of implementing passive pres; resisters, transformers, and light dependent resisters. Each method has its assets and liabilities. It wasn't until the Tortuga came along that I felt there was something that minimized the minuses and maximized the pluses and justified the asking price. I jumped at the opportunity to secure a spot on the audition tour that was offered.
I received the unit on Halloween. Trick or treat? It is housed in a nondescript black case with a window for the infrared remote receiver, blue lettering, a black knurled knob, and an on/off blue LED that some might find too bright. After substituting the LDR1 for the Creek I got no sound. I called Morten to see what could possibly be wrong. He indicated that there was not much that could go wrong. When installing the unit I had double checked that I had made the correct input/output connections, as I have made that mistake in the past. While on the phone it occurred to me that maybe I had forgotten to turn my amps back on. That, indeed, was the case. How embarrassing. I had a nice chat with Morten, indicated all was well, and he could not have been more cordial. I had tricked myself and now for the treat.
It became immediately apparent that the LDR1 was a more transparent component than the Creek. At 3 times the price, one should expect that. What they had in common was the black background, low/no distortion, and wide sound stage. The LDR1 improves on the Creek in a number of different areas.
Leading edge attack transients are more delineated throughout the frequency range. This was most noticeable with all types of percussion. Snare, cymbals, toms, and kick had much more snap and precision.
The mid-bass on down seemed to gain a few extra db of authority. Not lumpy mind you, but a smooth fullness contributing a sense of realism to whatever instrument was in that range. The extra degree of sub 40hz info gave an increased sense of acoustic space.
Low level detail increased to a great degree. Previously obscured detail was laid bare. Each instrument and voice gained, not only an extra dimension in space but, resolution giving a sense of the artists emotional intent.
It seemed like the LDR1 was letting more signal through. I was listening at levels above my usual, 85db-95db, to levels of 100bd+ as everything just sounded so good. Some discs which I had been able to turn up all the way with the Creek, and in theory should be the same as a bypass, were needed to be restrained a bit as not to push the amps, and/or speakers, past their limits.
There was a greater sense of dynamics, compered to the Creek, at all volume levels. Greatly anticipating the new chip to see if this is expanded.
If I were to change anything I would give some sense of the volume going up and down other than just the aural evidence. As it is the blue LED flashes slowly when either the volume is all the way up, or all the way down. There is an enter button on the remote which causes the LED to flash rapidly and I would prefer this sense of feedback when raising and lowering the volume. This is the way the Creek works but this is by no means a deal breaker for me. I would also like a less bright LED, but, again, not a deal breaker.
I listen to a wide variety of music. I pulled out discs that I had not listened to in years and probably listened to more music, since receiving the LDR1, than I had listened to in the past 6 months. I was given a renewed sense of excitement that I had been missing for a long time. I can't think of higher praise. As a casualty of the part-time economy I shall have to find a way to acquire one of these.