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Firestone BRAVO 24/96 USB transport w/o drivers + reclocker? - Page 34

post #496 of 542
Thread Starter 

I did try a very short belden/canare cable...and I really hated the sound. That's the day I lost faith in DIY digital cables biggrin.gif

 

Toslink is a deal breaker due to the two light conversions(using low grade LED's at that)....even 50 strands glass toslink can't compete w/ a short coax IME. WM8804 doesn't accept mediocrity for an answer.

 

AFAIK, the computer uses the USB cable ground for hot-plug detection, and the Bravo itself uses the +5V to detect the computer. The Tenor chip feeds 3.3V, and Firestone told me that they were feeding it from its own PSU anyway.

 

Yes, Firestone are always very helpful when it comes to technical questions. They're an head-fi sponsor too happy_face1.gif

post #497 of 542

The lifatec toslink is actually 470 strands, which given their smaller cores each cuts down on path delay variations of the light going thru the fiber vs standard single core toslink cables.  If that even matters.  The lifatec toslink has very sturdy connectors that fit VERY snugly into the toslink ports on the back of my receiver and Bravo.  This should help to make a good solid connection which is supposed to also help cut down on jitter/errors from the connectors of a standard lower cost TOSLINK connection that may fit too loosely.

 

I have started testing the lifatec toslink vs my digital coax.  With my 48 year old ears with reduced high freq hearing I am having trouble telling the difference between the two.  I will try some headphones next for listening tests between the two cables.

 

I am still awaiting delivery of a USB adapter plug so I have not been able to fully test the olimex yet.

 

Either way, the Bravo is very nice and I am happy with my purchase. 

post #498 of 542
Thread Starter 

Well, I tried this cable: http://cgi.ebay.com/6-6-ft-GLASS-TOSLINK-DIGITAL-OPTICAL-CABLE-Premium-/380335397999

 

and this one: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-954

 

They both come from the same chinese factory(same logo on the plugs), but I don't have their url handy.

 

It's been thoroughly discussed on several forums that the less strands, the less optical distortion...and tbh, the second cable sounded better than the first one IME. I also lent them to a friend of mine who confirmed it.

 

I'd advise getting a RCA male/male adapter, as this is a good real world application of the "the best signal path is the shortest" rule to my ears.

 

You could also input toslink and output coax, to hear what WM8804 can do for you. It does the exact same processing to the USB Tenor chip output via I2S.

post #499 of 542

Just a quick update on my experiments with the Bravo.  I have tried a few different configurations as follows:

 

1.  HTPC Windows 7/ Jriver MC16/ WASAPI / USB Wireworld Ultraviolet / Bravo / Belden 1695 coax to AV Receiver

2.  HTPC Windows 7/ Jriver MC16/ WASAPI / USB Wireworld Ultraviolet / Bravo / lifatec toslink to AV Receiver

3.  HTPC Windows 7/ Jriver MC16/ WASAPI / USB Wireworld Ultraviolet / Olimex USB isolation dongle / Bravo / Belden 1694 coax to AV Receiver

4.  HTPC Windows 7/ Jriver MC16/ WASAPI / USB Wireworld Ultraviolet /Olimex USB isolation dongle with external DC linear regulated powersupply/ Bravo / Belden 1694 coax to AV Receiver

5.  HTPC Windows 7/ Jriver MC16/ WASAPI / onboard ALC888 digital audio output / lifatec toslink / Bravo / Belden 1694 coax to AV Receiver
6.  HTPC Windows 7/ Jriver MC16/ WASAPI / onboard ALC888 digital audio output / Belden 1694 coax / Bravo / Belden 1694 coax to AV Receiver

 

For me configurations 1-4 all sounded very similar, good but not one better then the other.  I could just barely hear the differences if I put headphones on.   I am guessing that once the Bravo does it's reclocking magic, the input feed's impact is greatly reduced as long as it is of a sufficient high quality to pass the data.

 

However, surprisingly, configuration 5 and 6 was the best for me.  Feeding the bravo from it's SPDIF input instead of USB was noticeably better, clearer, lighter, more detail.  With headphones on the configuration 5 with the TOSLINK was better.   Again I am using a HTPC as a source, the TOSLINK RFI blocking type connection seems to be the best for me.

 

Configuration 5 is the one I am going with for now.

post #500 of 542
Thread Starter 

indeed reclocking toslink to coax is fun, and does achieve galvanic isolation on the go too.

post #501 of 542

Toslink is galvanically isolated by design anyways, but re-clocking it is a definite bonus.

post #502 of 542
Quote:
Originally Posted by leeperry View Post

Well, I tried this cable: http://cgi.ebay.com/6-6-ft-GLASS-TOSLINK-DIGITAL-OPTICAL-CABLE-Premium-/380335397999

 

and this one: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-954

 

They both come from the same chinese factory(same logo on the plugs), but I don't have their url handy.

I'm pretty happy with my Valab toslink cable.

 

1.  Japan SUMITOMO ELECTRIC optic fiber; 2G bits data rate per second in one meter, near 50 times higher than spdif signal transmission.

2. Thick soft damping surround and doule insulation for optic fiber protection.

3. fulfill EIJA (Electronic Industries Association of Japan) RC-5730A standard.

4. Top grade optic fiber connector, comfirm to Japan JIS F05 standard.

 

post #503 of 542
Thread Starter 

personally, I don't believe a single word of what those Valab "NOS" ppl say...and I also don't trust DIY toslink cables as cutting plastic wires requires very strict rules otherwise you'll do more harm than good and end up w/ major light distortion issues. Glass is the way to go because plastic is terrible when it comes to OTF/MTF optical distortion, and the less strands the merrier(due to optical distortion as well) IME.

post #504 of 542
Quote:
Originally Posted by leeperry View Post

personally, I don't believe a single word of what those Valab "NOS" ppl say...



Why not?

 

What was your bad experience...??

 

 

post #505 of 542

Although it did not appear to help much for my setup.  I am posting this info as a possible aid to others wishing to try upgraded power with thier OLIMEX USB isolator dongle.

 

I used a Partsexpress Regulated Linear Power supply (3-12v DC selectable).

 

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-536

 

I also used the partsexpress power plug adapter set:

 

http://www.parts-express.com/pe/showdetl.cfm?PartNumber=120-537

 

The BLUE barrel connector adapter worked with the OLIMEX dongle.

 

Also shown in the picture is my Wireworld Ultraviolet USB cable.

 

There is no indicator on the OLIMEX on if it is using external or USB cable supplied power.  However when I power cycled the partsexpress powersupply the audio from the bravo momentarly reset.  So I believe that the OLIMEX was taking power from the external plug.

 

IMG_2618.jpg

post #506 of 542

That pretty much the exact same set-up I had going into my Audiogd DI....then I stepped back a looked at the cost of everything.  DI+USB cable+Adum+Powersupply etc. and figured I was adding a good 400+ to the price of the Dac.  Might as well get a better dac that does not need all the extra gear vs. having so many other pieces of gear in the audio chain.  Each connection and piece of equipment degrades the signal....while the perfect piece of gear does nothing.

post #507 of 542
Thread Starter 

.

post #508 of 542
Thread Starter 

Originally Posted by dumpingground View Post

Although it did not appear to help much for my setup.  I am posting this info as a possible aid to others wishing to try upgraded power with thier OLIMEX USB isolator dongle.

 

It prolly didn't help because those cheapo linear regulated PSU's often output +100mV ripple(check the datasheet, you'll see)...so it's actually worse than an ATX PSU. Also, the DC input on the Olimex dongle goes through a BD9001F switched regulator. I was advised to tap the external PSU directly onto the USB power pins, but the Tenor chip feeds 3.3V and the Bravo takes care of it anyway.


Edited by leeperry - 8/14/11 at 2:03pm
post #509 of 542
Quote:
Originally Posted by leeperry View Post

 

It prolly didn't help because those cheapo linear regulated PSU's often output +100mV ripple(check the datasheet, you'll see)...so it's actually worse than an ATX PSU. Also, the DC input on the Olimex dongle goes through a BD9001F switched regulator. I was advised to tap the external PSU directly onto the USB power pins, but the Tenor chip feeds 3.3V and the Bravo takes care of it anyway.



Yes, but at least you get a separate ground from the PC.  Also, I don't know the ripple specs of the partsexpress PSU since they are not published by partsexpress.  But it is a linear regulated PS.  At any rate, at least for my setup, the extra PSU did not provide a noticeable improvement in the sound.

post #510 of 542
Thread Starter 

Your money would have been far better invested in a Supplier PSU IMHO. And let's not mention the WW USB cable, and yes I did try it...I even tried their Starlight devil_face.gif

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