HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

I am considering the possibilities of a DSD-capable DAC at the moment and one of the more affordable models appears to be this:

http://www.hegel.com/products/dac

The Hegel HD12. Designed and built in Norway.

Has anybody heard this or any other Hegel gear?

Never heard em Fret, but i like the minimalist look and battleship build.

The Hegel HD12 DSD DAC came in Friday, and has caused a major re-jig of my main system.



Due to the fact that the HD12 is not just a DAC but has its own variable output (with remote!) it doesn't need a pre-amp. So I have shifted the TT and pre-amps to the lounge system and now have the Hegel DI-ing into the NVA A40's.
An all-digital setup with the Arcam CD62T as transport (via toslink), The Pi on an NVA SSP digital coax and USB from a netbook. Close-up:



The HD12 also has a headphone socket on the front and switches over to run as a headphone amp when a pair of cans are plugged in. Volume and input selection are run from the remote control.

Soundwise: My Musical Fidelity M1DAC was crowned as the best under 1000-pound choice about 3 years ago. In comparison to the Hegel it sounds noisy and flat. The HD12 is quiet, really, really inky-blackness quiet. Sounds come out of nowhere.
The sound is also fuller and richer than the M1DAC.

I could go on but now I just want to go and listen to it. And it hasn't even been run-in yet.
DSD can only be done via USB and requires installation of specific drivers. I'll get around to that later this week.

If you're looking for a DAC and you've got the budget. Look VERY seriously at this one.

Anyone who says they cannot hear a difference between DACs has either got bad hearing, a crap installation or only listens to MP3's .

Further adventures in DAC land:

Having removed all of the analogue side from the system, leaving the DAC to directly run the A40's, I plugged in the headphones to the Hegel to see how it drives my AKG K601's . Immediately a quite loud earth hum issued from the speakers. Taking the 'phones plug out, everything went dead quiet again. A problem with the DAC? I turned it off - and the humming started again.

Flummoxed by this I thought that the DAC must be faulty. It had been fine plugged into the P50sa pre-amp. So I put that back in place - and the problem was gone, no hum. The Hegel back in DI to the monoblocks and again the humming - only when either the DAC was off, or that the headphones were plugged in (bypassing the line-out).

Thinking logically, I surmised that the hum was probably caused by magnetic fields around the SSP interconnects. So I tried shifting them up and way from the other cabling. This definitely reduced the noise and so it was an earthing effect which the P50 had cancelled out.

NVA SSP Mk1 is a wonderful connector if treated with loving care and very carefully handled. In my enthusiasm to get the RF noise reduced I suddenly got a very loud and unpleasant noise coming out of one speaker. Immediately I turned off the A40 on that side and inspected the phono plugs - yes I had broken a solder joint. It looked easy enough to repair so I got out an ancient and (very) seldom-used soldering iron and went carefully to work. Ten minutes later the cable was up and running again and I could continue with my tuning activities.

However I had not done as good a job as I thought and the same joint broke again. A second attempt at soldering didn't help this time, So I have removed the SSP for the time being and replaced the link with SSC from the phono pre-amp. The SSC also sounds magnificent - a bit leaner and meaner (more direct) than the SSP, but very enjoyable and clear. When funds allow I will probably get a pair of SSP Mk2's as the lack of flexibility of Mk1 is fine until you change something (i'm too ashamed to ask the Doc to fix my bodged repair attempt). With the SSC in place the earth hum is still there, but quieter.

All of this means that I still haven't begun to properly explore the audio qualities of the Hegel HD12 properly, but what I have heard is very impressive.

Next stop -DSD!

Humming and earthing needs to be done with care. In my workroom setup, the HH power amp has an earth-lift switch and it's either silent or humming like a swarm of bees through the speakers, depending on what it's connected to (big upgrade in 'emotional connection with the music' taking the AVI preamp out and using a passive, which stunned me somewhat, although the NVA amps still sound better here).

If you don't want to use the P50SA, then why not carefully attach a fly lead from the Hegel case to mains earth (check with the Doc first to make sure I'm not talking bollix here). The headphone sockets I'm most used to using have switching on them, which you can either use or not depending on need. I suspect the DAC switches the signal returns over as well as the 'hot' for each channel, leaving the A40's wide open via the SSP's.

If the Hegel has a fixed output, I'd probably use that into the P50SA myself. The addition of an extra gain control of the quality of the one in the P50SA should make no discernible difference at all.

Thanks for that Dave. I suppose I could leave the P50sa in place running the DAC through the 'Direct' input. Although the headphones will not really be used (for now) and I was just trying it out. The fact that it threw all the earthing into sharp relief is more important. Earthing the casework - doesn't the mains earth do that? (pardon my ignorance).

The HD12 has no fixed line outs - only RCA and XLR, both variable. Advice from the manufacturer is to just set the output level to max if you have volume control via an amplifier.

Does the DAC have a chassis earth?

Not that I'm aware of - does have a standard 3-pin mains socket.

This has got me wondering, in the philosophy of NVA do the pre-amp and interconnects act as a single electrical entity with regard to earthing and shielding? This would help me to understand what I am doing (wrong) here.

'Ask the designer' or trawl though that 'room' on here, as he's explained it enough.