Moving back to a low output moving coil has been a real eye-opener. Yes I had experience with the venerable Denon DL-103R mounted on a rather sketchy VPI HW19 Mark III with a Rega RB300. But, at least with that system from long ago, I never quite cottoned to the sound I was getting. I wanted more. Luckily I found it (some time later!) with the Rega Planar 8 with a Rega Ania Pro MC cartridge. This combination has quickly become my favorite analog reproducer so far.
My MC step-up transformer is the popular Cinemag 1254 which did its job quite admirably. Nonetheless I had a nagging thought I could do better here. Would a passive device, especially something made of wound wire actually make a difference? I had to find out. So I read and read some more, trying to find an affordable venue to follow. I thought of buying some Lundahl transformers and DIYing my own case. Or I could have gotten anything else, including an active device to give me that additional gain needed for the low 350 micro volt output of the Ania Pro.
Several searches on Ebay and I saw a Denon AU-S1 unit for sale. It looked extremely well built, more so than my Cinemag "transformers on a box" look. But finding information on the Denon was, to be blunt, extremely difficult. It was designed for Denon's once top-of-the-line cartridge, the DL-S1 that cost a princely $1000 way back in 1996. The transformers themselves are mounted horizontally in the case with padding to reduce vibration. How much this would work in real life is questionable.
After several audio philosophical discussions a friend, I decided to take the risk on purchasing the AU-S1. It was the idea that something like this would be of the highest quality given the amount of time and research that a company like Denon can do. There was only way to find out. Thankfully the Japanese seller was very quick and I received the transformer(s) in only three days. The AU-S1 weighs _alot_ for such a small thing. Build quality was extremely good with gold-plated RCA jacks and (oddly enough) separate grounding lugs for each channel.
I took out the Cinemags and put the Denon in its place. Turning the volume up I was immediately taken aback by the amount of hum I was getting out of the speakers. Moving the AU-S1 around and I was able to get some reduction in noise but still I wasn't happy about it. It wasn't until I touched my fingers to the left RCA outside jack and then to the ground lug that the hum completely disappeared. It's the nature of the Rega turntable output connection which doesnt have a separate ground wire. To circumvent this grounding issue I took a length of solid-core bare wire and wrapped it several times around the left RCA outside lug with one end plugged into the ground lug of the AU-S1. After that I was hum free!
Well, dear readers, that was a lot of introduction for something that was ultimately bought as an experiment. How does it sound? Read on.
Initial impressions were good - solid bass, a "cleaner" view of the soundstage, and just better air. Several records later and a listening session with my audiophile friend and I can say the Denon AU-S1 was a worthwhile upgrade.
Does it surpass the Cinemags? Yes.
The Denon reproduces the space around instruments better - such as the horns on Lonnie Liston Smith's Visions of a New World. This gives the impression of more body and weight.
And speaking of body, the bass is terrific. It feels like an extra octave is being recovered - not bloated - but detailed with depth and slap. Something that was really apparent on Brian Bennet's Voyage album as the excellent bass player provides the space age groove.
Soundstaging is deeper and wider than before. An example of this is the beautiful Dead Can Dance album Into the Labyrinth. The second song, "The Ubiquitous Mr Lovegrove," has a moment where the drum shifts left and right, now well detailed beyond the edges of my KEF speakers. A true demo disc moment.
Overall there seems to be less grain than before. Why? I have no idea. The purity of the copper? The padding reducing microphonics? The quality of the transformer windings? Your guess is as good as mine but the clarity is higher than before and that's all that matters. Finesse would be a fine word to discuss these SUTs, and given their roughly $700USD price they are a good bang for the buck. Perhaps, when funds permit, I'll try something more expensive.
Denon AU-S1 Step-up Transformer Specifications
- Ratio: 1:13
- Frequency range: 10Hz-80kHz
- Size: W150 x H70 x D175mm
- Weight: 7.1 pounds
