RCA vs BNC for S/PDIF outputs/inputs
stevej
Audio Alchemy, Theta, and even Wadia (singular examples) equipment
with 50 ohm BNC's. Check:the female connector on a 75 ohm BNC has NO
insulator around the exposed center pin (on the male 75 ohm BNC there
is NO inner metal shield within the outer shell of the connector).This
advice goes double for BNC connector digital cables.I've seen
McCormack, Cardas, and Audio Alchemy's active cable with 50 ohm
connectors, in the past (I don't have experience with their current
products).Trust, but verify!
Next, find a good coaxial digital cable. I've had good luck with
Belden's #1694A. It's specifically designed serial digital
transmission and has a low SWR. It's a RG6 sized coax, so finding the
correct 75 ohm BNC on your own may be a little difficult. You might
give Belden a call at 1-800-Belden-4 and ask for recommended connector
P/N's. I got my BNC's through Newark (don't have the P/N's handy). All
in all, this cable/connector system makes for a DC - 2 Gigahertz
(their specs) digital cable with very low SWR. This cable/connector
was damn good in an all Levenson system, easily as good or better than
the Levenson MDL-1 AES/EBU connection (note: Levenson models 36 and 37
DO use true 75 ohm BNC's).
So, how's it work in my system? Good enough that my jitter paranoia
has pretty much subsided, and I can get back to just enjoying the
music. Recommended.
My system (seemingly obligatory)
Audio Alchemy DDE v1.0 (with mods per Arthur Loesch-THANKS)
'passive'preamp (series Vishay with ALPS pot to ground)
Moffat Modified Citation II (Mutation?) EL34 amp
Reference 3A speakers (Lowther PM7A's are in the works)
Transparent Ultra and Goertz wires
Hope this helps,
Steve Jones
Kevin Sutton
jacks on SPDIF outputs and inputs to 75ohm BNC connectors.
The good folk at The Parts Connection have recommended this as a "good
thing", recommending the Illuminati DV-30 cable with BNC connectors as
a good value digital cable ($70 terminated), and I trust them on this,
based on past experience with their advice regarding passive component
swaps.
I would like to hear from anyone who has performed an RCA/BNC
conversion and their opinions of its sonic worth (say, in comparison
to just changing digital cable types). E-mail replies will be okay.
[Moderator's Note: But posts to r.a.h-e are even better! RD]
BTW, I am using a Philips CD880 player as a transport and an Audio
Alchemy DDE1.1 as a converter.
Cheers
Kevin Sutton (SUT...@CROP.CRI.NZ)
Randall C. Couch
> conversion and their opinions of its sonic worth (say, in comparison
> to just changing digital cable types).
I'll relate my experience (although I stress that since several
variables were changed at one time, assigning relative correlations
between specific changes and perceived results would be unsound--so to
speak).
I bought a Stan Warren-modified Monarchy 22A DAC several years ago.
Though very good value for money at the time, there were aspects of
the sound I thought might be improved. I was using an early Mod Squad
Prism player as transport, with the Monarchy silver digital cable and
later the Canare HAVE digital cable.
I had some long conversations with Mark McCalmont at MACH I Acoustics,
who offered his own (actually a Bell Labs engineer friend of his) mods
to the Monarchy unit. I decided to have him make some changes and
additions, including a new current-to-voltage conversion stage and new
receiver section. He also recommended a digital interconnect he made
up from bulk semirigid high-bandwidth data cable (again a find from
the research engineer). Since my DAC was already so heavily modded, I
asked if it wouldn't be a good idea just to hard-wire the DAC side of
the cable directly in to the receiver section, and bypass one
potentially detrimental set of connector interfaces altogether. He
agreed. (BTW, I noticed awhile back a post from one of the PF
gang--was it Stu?-- on the new EVS DAC indicating he was using the
MACH I cable. Is it still competitive?)
At the same time, having had some conversations with the folks at G&D
Transforms about their isolated stable clock module and buffered
output stage, I decided to buy one of their Reference One transports.
Since that is another rebuilt unit I asked if they could put a 75-Ohm
BNC on the output, which they were happy to do. I had Mark terminate
the loose end of the cable with the female BNC.
So I have BNC-to-hardwired now.
The resulting system (new transport, cable, heaviy modded DAC) sounded
better by an order of magnitude (figuratively speaking!). It was
clearer, with better low-level detail and more natural timbre, than
anything I heard in the shops at up to twice the total cost, and maybe
more. In addition, I noticed that all the resonance damping/tuning
efforts (footers, cones, books on top, etc.) that had made quite
audible changes on the old transport had minimal if any effects on the
new one. It's my supposition that this configuration offered
extremely low-jitter SPDIF transmission, contributing to the great
improvement in sound.
Though I understand the two pairs of differential Burr-Brown PCM-63K
DAC chips are still very competitive, the rest of the DAC design is
probably pretty long in the tooth by now. I won't rush to replace the
homely-but- hardworking G&D Transport though. And maybe I can have
this cable hardwired into my next DAC...
By the way, I never asked them--does anybody know if G&D does OEM work
for any of the better-known brands? I wouldn't be surprised...
-RC
StuartMcc
>> conversion and their opinions of its sonic worth (say, in comparison
>> to just changing digital cable types).
>gang--was it Stu?-- on the new EVS DAC indicating he was using the
>MACH I cable. Is it still competitive?)
Hey, good memory there Randall -- it *was* me. To answer your
question, yes it still is very competitive - that is, if you are
referring to the flexible cable. I also have the Mach -1 semi-rigid,
but I find it to be a bit spitty on the top end compared to his
flexible cable. I must qualify this by saying that the semi-rigid is
only a 1 meter length, while the flexible cable is 1.5 meters. There
are some people that hold that cable reflections are minimized in
cables shorter than 8" or at least 1.5 meters long. I've tried lots
of digital cables lately (always BNC) and none yet have made me want
to toss the Mach -1 cables.
As for RCA vs. BNC, it's my experience that the BNC connections are
far better for fine resolution and information retrieval. I put a BNC
on my transport, DAC and also on the Audient Technologies Tactic and
Audit that I use in conjunction with a DTI Pro 32. I credit Marc
McAlmont of Mach-1 Acoustics for turning me on to this.
Stu McCreary
Contrib. Ed., Positive Feedback
Kevin Briddon
<Sut...@crop.cri.nz> writes
>I am looking for a bit of advice as to the merits of changing the RCA
>jacks on SPDIF outputs and inputs to 75ohm BNC connectors.
>
>The good folk at The Parts Connection have recommended this as a "good
>thing", recommending the Illuminati DV-30 cable with BNC connectors as
>a good value digital cable ($70 terminated), and I trust them on this,
>based on past experience with their advice regarding passive component
>swaps.
>
>I would like to hear from anyone who has performed an RCA/BNC
>conversion and their opinions of its sonic worth (say, in comparison
>to just changing digital cable types).
[ quoted text deleted -- jwd ]
Some years ago I had a Naim 32 preamp. Naim started to use BNC
connecters(instead of gold phono's) on their disk(i.e moving magnet
and coil) input stages, this being available as a retro fit so I did
it. The sonic improvements were in my opinion not particularly great
but never the less noticible. What is different though is that they
then maintain their quality. With phono's I used to have to push pull
them every month or so to self clean them, this doesn't seem to be
required with BNC's. So in summary I would say do it as it costs very
little and makes your system slightly better and much more consistent.
Kevin Briddon
* The views and comments contained herein are purely personal and in *
* no way represent the views and beliefs of the Signet Group plc. *