Greetings all,
I am writing you to inquire about the USB Tube based DAC. From what I can tell, it looks like a great unit that is available in Kit form. For those of you who own and used to own the chime, what so you think of is sound quality? I would to know as much and I can from you!
Do you feel this is a quality unit that plays music, is quiet , noise? What is the musically like, build quality, reliability, etc?
Is this a tough unit to build?
There's no doubt in my mind that the Chime is a quality kit. The circuit board is top notch: HagTech
pays for quality boards. Nice and thick glass, thick copper, strong plate through, good masking,
thoughtful labelling backed up with legible silk screening, consistent tinning of the pads, etc. Mind
you, none of that is rocket science. It's just a matter of using a board fab which offers quality
manufacturing and then paying for it. Additionally, the board is well laid out with generous pads,
good spacing between components, thermals as needed, nice traces, and an eye towards being
friendly/welcoming to tinkering/modding. However, there are other, non-book-learned aspects to
making quality kits and that's where HagTech clearly stands heads above the rest. The design is
superb sonically as well as engineering wise (i.e., following safe design practices, taking failure
behaviors into account, keeping well, well within rated tolerances and limits, etc.). Additionally,
the realization of the design as a kit is fantastic as well: another case where you simply need
lots of experience and willingness to iterate over your design (and sometimes obliterate parts of it).
So yes, I find it to be a quality kit. Indeed, I think HagTech's kits are the best DIY electronic
kits I've built. (I've been soldering electronic kits since I was a kid in the 60's.)
As to reliability, my units have been running solid for 1 and 3/4 years now.
The Chime is definitely my favorite DAC, tubed or otherwise. It has just the right amount
of 2nd harmonic coloring, adding just enough warmth. When I want something a little
more sterile, I use my modified Transcendent Sound Grounded Grid pre-amp: modified
for 30dB gain and with an onboard HagTech HagDAC (the DAC daughterboard found within
a Chime). [For example, for harpsichord recordings I prefer less warmth from the electronics.]
At this point, I have two Chimes plus my GG pre-amp + HagDAC and I've kept with them for
nearly two years now: I'm blissfully content with them and have no interest in replacing them.
As to noise, they are for me dead quiet. And, for what it's worth, I use very sensitive speakers
(98 dB in my office, and 102 dB in the home). That is, if my equipment is noisy, I'll hear it.
I did have an issue a while back with a lousy power supply for a SqueezeBox 3 which was
causing the SB3 to put out a 46VAC signal on it's S/PDIF RCA jacks. That then carried through
into the Chime. However, Jim of HagTech quickly helped me resolve it by suggesting I use a
tiny 1:1 pulse transformer as an isolation transformer. (Digikey 470-1006-ND; approximately
the same size as the USB isolation transformer, T500, used in the Chime.) Mind you, the Chime
was NOT at fault here: the problem was first and foremost with the digital transport. HagTech
was just helping me to work around the problem within my system even though their part of
my system was not at fault.
Now for the tough question: is it a hard unit to build. Well, I found it them quite easy and enjoyable
to build. No problems: they fired up and ran wonderfully the first time. (Always leaves me worried
for a day or two.) However, I've built lots of kits over the years and have always been good with
my hands. Just take your time, double checking ALL parts: are they the correct part, have you installed
them in the correct location (which includes knowing which side of the board they go on), and are
they in the correct orientation (e.g., polarity)? Only install a few parts at a time and then, under GOOD
light, inspect the solder joins with a magnifying glass. Then trim the leads and again inspect the joins
under a magnifying glass. Since I'm not trying to assemble boards for a living, I often take the time
to reflow the solder and again inspect the joins. Oh, and remember to OFTEN wipe the tip of your
soldering iron on that sponge you moistened. It also helps to have a soldering iron whose temperature
you can adjust.
For me the most tedious part was the chasis. Not so much hard as just tedious. Not the part of
kit building that I enjoy overly much.
If you've never assembled an electronics kit -- one which requires soldering -- then I wouldn't
make this my first project. Instead get your feet wet with something very simple. (However,
be warned that there are some devilishly difficult "simple" kits out there. I cite some of the
cutesy Velleman LED Xmas kits my kids asked me to assemble about two years ago. Talk about
microscopic pads and oh-too-close spacing.) Most public libraries have a book or two which will
illustrate the fundamentals of soldering.
If, however, you are comfortable soldering electronics, there's another IMPORTANT consideration:
tube electronics often involves HIGH DC voltages. The Chime sports at least 305VDC. Now, don't
be telling yourself, "Oh, I've accidentally gotten 120V from my wall outlet and it was annoying but
bearable." Bzzzzzt! This is Direct Current (DC) voltage and not Alternating Current (AC) voltage.
I suspect that a nice solid 120V DC is pretty unpleasant. I can tell you for a fact that the ~200V DC
I one time got was significantly painful and burnt the tips of my fingers. You need to have some
electrical common sense and experience before attempting to work with such kits.
Anyhow, I've rambled on too long. Hope this helps.
Cheers,
Dan (author of the previously cited website in which I offer up
my experiences building two Chimes)
