Review. The Danish Audio ConnecT (DACT) CT2-100k-2 Volume Control Pot
I would like to begin with a question ; how many ASoN members have had their current preamplifier (or integrated) for 10 years? I guess that I could count you on the fingers of one hand, maybe two. Yes you can count me, but it is not quite the same preamp.
(Disclaimer : This article is not an advertisement for, nor an endorsement for Vacuum State Electronics, Danish Audio Connect, nor Joe Rasmussen’s Custom Analogue Audio.)
I have had the Allen Wright Vacuum State Four Valve Preamp (FVP) in my system for almost 10 years, and Joe Rasmussen has performed upgrades for me along the way at reasonable charge. Some of the ideas have been his own, so it is a case of the technician becoming the designer!
I initially purchased the unit from Joe, when my NAD 3020, being used as a preamp, became too noisy, for my critical use, in 1991, when the listening room was Tweaker’s Cube. It was one of Joe’s demonstrators, having been built by McGrath Engineering in 1986. It was configured for Moving Magnet, with a 47kOhm input, with 12 AT7 for phono, and 12 AU7 in the line stage. Of course, it was a huge improvement on the NAD, which I had tried to modify further. It initially had a hum, which was overcome by connecting the ground from the NAD 2150 power amplifier, to the phono ground. The cartridge used was the Grado Signature 8 Revised. On changing to the AT OC-9, the gain was increased to 69dB, and input impedance reduced to 100 ohms, which opened and livened up the sound.
The first major upgrade was in 1995. It was the installation of the Super Linear Cathode Follower (SLCF), which a friend and I both had done at the same time. This modification increased the speed of the unit. Transients were sharpened, and detail improved. It was like that unit had gained some of the positive attributes of solid state, without losing the musicality of tubes. At no time did this preamp have the overly warm, mushy sound some accuse tubes of having.
The next mod was in 1997, when the FETs were removed from the line stage, and the 12AU7s replaced with 6922s. This increased the gain, as well as transparency. This occurred in 1997. In 1999, the original Allen-Bradley volume control pot was replaced by the Alps Black Beauty. It was microphonic initially, but quickly rectified by Joe. Last year, the phono EQ was changed from active to passive, and the tubes from 12AT7 to 6922. Again, an improvement in transparency and gain. All these were significant improvements, but nothing compared to what I am about to describe.
Along came DACT
DACT are a company from Western Denmark (Jutland) who make high quality audio parts; passive (volume and balance controls, speaker crossovers) and active (phono preamplifier). Manufacture occurs in both Denmark and Thailand. It is headed by Allan Isaksen, who is based in Bangkok, and can be contacted on firstname.lastname@example.org, and DACT have an excellent web site on www.dact.com.
Joe first brought DACT to my attention via e-mail. Fellow ASoN member and FVP owner Les Pieratos had upgraded the pots on his unit, with dual mono 100k DACT pots, which he had purchased from a friend. These were installed by Joe, and caused a not so subtle improvement. I shall invite Les to share his findings in these pages. So Joe e-mails those on his list about this pot. If we ordered it, he could fit it for us.
So I e-mailed Allen, and sent a telegraphic transfer from my bank, to the bank account given on the web site. It is more prudent to order in EUROs rather than US Dollars, given the weak state of our dollar. Three weeks later, a small brown parcel arrives in the post. I am naturally excited, but am disappointed when I open the small box, and find a 50k pot, instead of the 100k one I ordered. So I send a FAX to Isaksen, and he sent a replacement to Joe at no cost, in exchange for the 50k, which Joe will use in one of his RTPs. How is this for customer service? DACT is one company I will be dealing with again.
I was without my preamp for a week, but it was worth the wait. The Alps was traded in.
My initial impressions were of greater quietness. The microphonics associated with the Alps had disappeared, even at full gain, where tube rush and hiss were less pronounced. I initially set levels using the tuner, and found the setting similar to previously , with 4 to 5 clicks (around 9 o’clock, or -38dB). The increase transparency was more noticeable on the classical stations, but the pop stations sounded too bright. This could be a limitation of the roof cavity aerial, the FM stations, or the tuner itself. I will reassess this after my cousin Daniel returns the Magnum Dynalab aerial. The pop music stations were subsequently more listenable, after a warm up period.
As the bulk of my listening is done on vinyl, this was the real litmus test. Having replaced a 250k pot, with a 100k pot, I expected to use more of the pot’s range. This is precisely the case, as previously, the setting for phono was at 10 o’clock, whereas with the DACT, it was at nine clicks, or between 11 and 12 o’clock, for a comfortable listening level. I first played the famous third movement of Scheherazade (Beecham/RPO). The Australian pressing sounded natural, but the greater dynamic range and contrast on the Testament reissue were easily apparent (see more detailed review). The Munch/BSO Tchaikowsky "Romeo and Juliet" Overture, on a Classic Records reissue, was played in the evening, with the lights out, and the dynamic range was awesome. In the reproduction of dynamic contrasts, the DACT allowed them to emerge naturally, from a quieter noise floor, which made the Alps sound etched and forced, in comparison.
Going through my Top Ten Jazz recordings, from Sonny Rollins, Dave Brubeck, Miles Davis, Harry James, Ella Fitzgerald, Astrud Gilberto to Linda Rondstadt; the brushed cymbals were details, and appeared to extend upwards forever; string bass was deep and extended, with good wood sound. Instrumental timbres of sax, trumpet and piano were natural and realistic. Sometimes the voices would sound too forward; I suspect that it is the increased transparency of the DACT revealing what is on the recording.
Listening to a selection of Sheffield Lab Direct to Disc recordings reveals their immediacy of their sound, and the superiority of the D2Ds to the 2 track masters.
The superiority of the DACT is already clear, and I will write more, once I get a better handle on further improvement to my system, testing it with a wider range of music. (To be continued)