DACT Stepped Attenuator - A Revelation
Some time ago my aging ARC SP9 Mk II developed a noise in one channel when the gain control was rotated. After a couple of attempts at cleaning it, I replaced the ALPS potentiometer with another ALPS pot, and all was well.
Then a month ago on audioasylum.com I read about the superiority of the TKD pot from Japan, and the supposedly even better stepped attenuator from DACT, a Danish company. I located both at partsonnexion.com. The DACT was way too expensive at $190, so I bought the TKD for $68. There is a warning on PC's site that pots should be tested with test clips prior to being soldered in circuit as once they are soldered they cannot be taken back if found defective. I tested the pot with a meter and it was fine. I soldered it into the cicuit and immediately got a noise on one channel. PC refused to take it back, saying that TKD would not take it back as the pots are sensitive to overheating, hence the warning on their site. PC did offer me a discount on another. I asked about the DACT, and they did offer me a discount on it as well, so I bought it.
I soldered in the DACT today. It is not a one-for-one replacement physically for the ALPS/TKD, so I had to do some minor surgery (of the non-revertive kind) on the mounting plate of the ARC. I was immediately stunned by the difference ! The treble is a lot more clear, and the bass was more solid. Listening to the Proprius "Cantate Domino" on LP was absolutely astounding ! On that LP and on others I heard stuff I had never heard before; There were instrumental lines that I had never heard before. And this was without the pot even broken in; I expect that it will improve dramatically after 500 hours (you listening Dave ?? ).
The ALPS pot is standard on a lot of even high end preamps. I very highly recommend that anyone with the itch to upgrade should first look at the preamp pot.
Bernard ...., i personal know the owner of the firm which produces the DACT Att. among other products (NLE Electronics), i can asure you that the DACT Att. is treated with a burn in session, so i doubt there will be any difference of the performance over time, other than if the contacts gets dirty you will get more and more second order distortion which of some people like that sound since its like getting a valve in the chain.
Mod. is fun! Sony CDP-X505ES (6xLME49860, 2xAD812), Sony ST-S730ES (1xLM4562) -> Dynaco PAS2 (ELMA Att., Philips "SQ" E80CC , Clearity Caps) -> DIY Hybrid EC 24dB 150Hz -> Nakamichi PA-5EII (PSU mod.) + Martin Logan CLS (Jensen/Duelund Flat Sq. Alu. Capacitors, Coils 2.65mm tread, costum stands) ->> Luxman Advance Z501 + 2x Peerless SLS 10" in 150L Bassreflex Cabs. Audioquest: Quartz interconnects, Forest speaker cables
About ten years ago I was trying out a few different surround monitor controllers for my mastering lab, as we were starting to get into surround work. There were several candidates that had useful capabilities, but I couldn't shake the feeling that they were losing a bit in sound quality. So I picked up a DACT six channel attenuator and had my tech build a simple box: input and output connectors, a selector switch and the attenuator. This was just intended as a baseline for comparison; I never thought of it as something I would put to use. However, when we put it in, the sound came back, and that simple box has been in place ever since.
I have evaluated a few monitor controllers since then, and many have features I really could use. But none has been able to displace it, because the DACT box is just so much more transparent.
It does need to be spritzed with contact cleaner every couple of years, but that's a small enough price to pay.