[HAL]

Any impressions?

I like the way it sounds with the RCA-RCA adaptor and 5VDC battery supply better than with the 75 ohm cable and pads. 

Very clean sound.  No sylibants on the Nat Cole piece.  Has more air around the instruments with the hard link and battery supply.

I like it alot! 

[oneinthepipe]

I have been listening to John Kenny's modified HiFace for approximately one week, although I haven't had enough time to be very critical.  Notwithstanding, there are two significant improvements over the stock HiFace, in my experience.  The background is noticeably quieter, and brushes and cymbals are much more distinct.  (On The Look of Love on Shelby Lynne's Just a Little Lovin', recorded in her studio on analog tape.) In my system, this is the first time that I have heard cymbals and brushes sound this good from a digital source.  Piano and acoustic guitar is also much cleaner and realistic sounding. (The difference on Be Be Your Love on Rachel Yamagata's Live at the Loft was significant.) This is getting much closer to analog.  I have a 6 dB attenuator on each end of the digital cable.  The HiFace and the cable have BNC connectors.

Nice job, John.   

[jkeny]

Thanks Henry,
What do you think of the device without attenuators Vs with attenuators?n

I was in a friend's house yesterday & we were listening to a number of different pieces of equipment, including Hugh dean's new Naksa amplifier ( a stunner). Anyway, one thing that we listened to was the modified Hiface into a Buffalo DAC & it immediately gave a crackling sound - not good at all - I checked all the connections but saw nothing wrong. We decided that the Hiface might be outputting too high a signal for the Sabre DAC input & it was causing over-driving of the DAC. We put an attenuator on the SPDIF cable & pure music flowed, no crackling. So in some cases this attenuation of the overall signal level is needed apart from the added benefit of the reduction in reflections!

[oneinthepipe]

Cleaner, quieter with the attenuators than without.  I haven't tried a 10 dB with a 6 dB yet.  Maybe tomorrow if the kids go out. Otherwise, too noisy.

[jkeny]

Great, let us know the results when you do this test.

[oneinthepipe]

Great, let us know the results when you do this test.

I couldn't get the kids to be quiet, but I had my eight-year-old daughter listen with me for a few minutes.  Her opinion is that the combination of the 10 dB and 6 dB attenuators had less "hissing" than with the two 6 dB attenuators.  She told me that she has good hearing.  I agree.  Less sibilant. 

[jkeny]

Very good Henry, my wife is the one with golden ears - she can hear HF way past my hearing but has no interest in this audio stuff. However when she says "turn that down" I know there is something wrong with the reproduction   

These attenuators are great, aren't they? I would love to hear a test of a so-so SPDIF cable with attenuators Vs a highly regarded (expensive usually  ) cable! I don't own such as I don't like giving money to snake-oil salesmen.

[PeteG]

I had time to sit down and give my attenuators a listen, I have two 6db BNC attenuators.
I tried different combinations and settled on both 6db connected to the HiFace and then to my Belden 16ft BNC/BNC cable and going into an EE Dac.

Using the attenuators the background is quieter and notes on say a piano recording are cleaner, I really didn’t have a problem with sibilants from the Nat King Cole song but it did help a little.
Overall I liked the blacker background, it was worth the cost of the attenuators.

Latter on I might try a USB hub w/external power supply.

[jkeny]

Great, Pete, a 10 & 6 might be even better? Both 6dB attenuators at the Hiface end sounded better than one at each end of the cable?  Your 16foot SPDIF cable is ala Jocko's recommendation of long SPDIF cables?

The sibilance I was hearing on the Nat track was probably because I was using a fairly crappy set-up - a BNC Hiface with a BNC/RCA adaptor & a RCA cable

[PeteG]

Both 6dB attenuators at the Hiface end sounded better than one at each end of the cable?

It seemed that way to me but very close someone else could hear it the other way.

  Your 16foot SPDIF cable is ala Jocko's recommendation of long SPDIF cables?

Yes, some believe the longer cable helps plus its nice when my listening chair is 15ft away .

[oneinthepipe]

The 10 dB and 6 dB attenuators, both connected to the HiFace side of the cable, and the 6 dB attenuator connected to the DAC side of the cable, sounds better, listening to Santana's Samba Pa Ti, than the 10 and 6 dB attenuators.  Guitar notes are more distinct.  Background is quieter. 

I am becoming an attenuation junkie.  Anyone know where I can score a 15 dB bag?   

[jkeny]

The 10 dB and 6 dB attenuators, both connected to the HiFace side of the cable, and the 6 dB attenuator connected to the DAC side of the cable, sounds better, listening to Santana's Samba Pa Ti, than the 10 and 6 dB attenuators.  Guitar notes are more distinct.  Background is quieter. 

I am becoming an attenuation junkie.  Anyone know where I can score a 15 dB bag?   

Minicircuits have 3,6,10,15,20dB attenuators - where did you get the ones you have?
You can use too much attenuation &  SPDIF lock will fail but just before that the sound will probably be worse dropping out randomly. This is also dependent on the DAC are you running into?

[Alexdad54]

My distinctly amateurish efforts didn't bear much fruit. I used a powered USB hub from Rosewill and an RCA to RCA adapter to connect the HiFace directly into my Havana DAC and the results were pretty bad. The highs were quite sharp and there was absolutely no soundstage at all. On switching back to my GH spdif coaxial cable and the HiFace plugged into my netbook, everything improved immensely with great separation and soundstaging and the edge on the highs disappeared. At least I can use the hub on my other PC so all was not lost.... .

[jkeny]

My distinctly amateurish efforts didn't bear much fruit. I used a powered USB hub from Rosewill and an RCA to RCA adapter to connect the HiFace directly into my Havana DAC and the results were pretty bad. The highs were quite sharp and there was absolutely no soundstage at all. On switching back to my GH spdif coaxial cable and the HiFace plugged into my netbook, everything improved immensely with great separation and soundstaging and the edge on the highs disappeared. At least I can use the hub on my other PC so all was not lost.... .

I believe what you are hearing in that HF sharpness & soundstage collapse is the sound of increased reflections (jitter) from impedance mismatches - maybe your RCA to RCA connector is introducing this. I've seen scope shots of a Hiface plugged directly into a scope & badly terminated - it showed horrible reflections. Try the attenuators for an even more improvement in sound!

[oneinthepipe]

Minicircuits have 3,6,10,15,20dB attenuators - where did you get the ones you have?
You can use too much attenuation &  SPDIF lock will fail but just before that the sound will probably be worse dropping out randomly. This is also dependent on the DAC are you running into?

I received the attenuators from minicircuits.  I might order a few more.  I haven't had any dropouts with the 22 dB combination.  I am using an AVA Vision DAC.

[jkeny]

I received the attenuators from minicircuits.  I might order a few more.  I haven't had any dropouts with the 22 dB combination.  I am using an AVA Vision DAC.

With 22dB, you are now mainlining ( ) did it sound any better/worse? I don't think you will get any more out of it - that is a significant attenuation.

What these attenuators do is give you the equivalent of a very good i.e. expensive cable (in fact I would say it betters a very good cable) for a pittance!!

[HAL]

My distinctly amateurish efforts didn't bear much fruit. I used a powered USB hub from Rosewill and an RCA to RCA adapter to connect the HiFace directly into my Havana DAC and the results were pretty bad. The highs were quite sharp and there was absolutely no soundstage at all. On switching back to my GH spdif coaxial cable and the HiFace plugged into my netbook, everything improved immensely with great separation and soundstaging and the edge on the highs disappeared. At least I can use the hub on my other PC so all was not lost.... .

Interesting.  This seems to be S/PDIF receiver dependent.   The Havana has a Crystal Semi (Cirrus Logic) CS8414 receiver from what I could find and my DAC has a Wolfson Micro WM8804 receiver.   With the Wolfson receiver the direct feed with the RCA to RCA adaptor sounds really good.  I checked and the board RCA jack has a 75ohm resistor at the board across the RCA connections, so it is terminated at the output of the connection.

The other variable seems to be the power feeding the USB hub.  I am using a regulated battery supply to feed the Hub.

[oneinthepipe]

With 22dB, you are now mainlining ( ) did it sound any better/worse? I don't think you will get any more out of it - that is a significant attenuation.

What these attenuators do is give you the equivalent of a very good i.e. expensive cable (in fact I would say it betters a very good cable) for a pittance!!

The sound is not as lively.  I haven't noticed any missing of low volume sounds.  I think that everything is better defined.  I haven't noticed a downside, but if there were, the improvements seem to make up for it.

[Alexdad54]

I believe what you are hearing in that HF sharpness & soundstage collapse is the sound of increased reflections (jitter) from impedance mismatches - maybe your RCA to RCA connector is introducing this. I've seen scope shots of a Hiface plugged directly into a scope & badly terminated - it showed horrible reflections. Try the attenuators for an even more improvement in sound!

It's possible although I purchased a supposedly 75 ohm RCA-RCA adaptor off the web. I know they are not true 75 ohm connections but I figured it might be a better quality. What I got looked like a pretty bog-standard one, no gold finish, nothing.
How would I determine if it is an impedance mismatch?
Also how to I attach the attenuators? I thought they were only BNC-ended.

I'm also not sure if I hooked everything up correctly. I had originally trouble finding a decent A to A USB cable and the instructions said to connect the hub to the netbook using the small USB A to mini-B supplied cable. After that I then connected the HiFace directly to the hub and the Havana via the RCA-RCA adaptor. Did I do something wrong here?

[jkeny]

It's possible although I purchased a supposedly 75 ohm RCA-RCA adaptor off the web. I know they are not true 75 ohm connections but I figured it might be a better quality. What I got looked like a pretty bog-standard one, no gold finish, nothing.
How would I determine if it is an impedance mismatch?
Also how to I attach the attenuators? I thought they were only BNC-ended.

I'm also not sure if I hooked everything up correctly. I had originally trouble finding a decent A to A USB cable and the instructions said to connect the hub to the netbook using the small USB A to mini-B supplied cable. After that I then connected the HiFace directly to the hub and the Havana via the RCA-RCA adaptor. Did I do something wrong here?

Do you know if the Hub is actually providing external power to the USB - what is the quality of this power? You really need to answer these questions before you can evaluate.

RCA connectors are NOT 75 ohm & can never be!

To use an attenuator buy a RCA to BNC adaptor!