New PCM1794A Kit – Balanced Mode Update – Good to Fantastic Sound! - Page 11 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 31st August 2011, 03:01 PM   #101
diyAudio Member
 
Join Date: Jul 2009
Hello,

I am bringing back this thread up after a tweak I operated on my FDA-1 that turns then into an Airplay DAC.
It works now wirelessly with devices like MAC, PC, iPad, iPhone, Apple TV, ... but also with original coaxial, optical and balanced inputs and best of all the sound quality is improved

I hacked an airport express N by bonding out the I2S bus and directly connecting it to the two PCM1974A from the FDA-1.
In the end the Marvell main controller is driving directly the Burr Brown DACs, the system becoming fully sunchronous and the CS8416 is completely bypassed removing in the same time the possible jitter problems due to I2S signal extraction from AES/EBU frames.

I posted photos of Airport hacked + installation in the FDA-1 here:

Modification Airport Express (Zardoz, Rosita, Airstream...) - Page 25 - Sources
DAC FDA-1 (PCM1794A Spencer) - Page 11 - TDG

I can comment / give additional details if some of you are interested.

Again audio quality is getting a step further, mainly precision & details are even better, instruments sounds so real, bass are a bit improved as well.

It is a good and not too difficult upgrade if you have a good soldering iron and good eyes

Alex.
  Reply With Quote
Old 31st August 2011, 04:29 PM   #102
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
thanks for the pics, i hve been thinking about the airport i2s mod. i do think that you could improve performance by making a couple of changes. firstly, thats a massively long, unshielded and not even twisted pair cable for the i2s connection, plus several connectors that are not at all suited to high speed signals. i fear your jitter will be very bad. so if you must have it this long, you should use belden shielded low capacitance networking cable or similar and pair each signal with a ground wire, delete the connectors if possible. but you really should try to make it shorter. you could also use a quality ribbon cable with every second wire as ground if you arent already doing that

Last edited by qusp; 31st August 2011 at 04:34 PM.
  Reply With Quote
Old 2nd September 2011, 08:36 AM   #103
diyAudio Member
 
Join Date: Aug 2011
hi All,

Have been following this thread with great interest.

Ordered the balanced kit from Spencer today. He has been very helpful in answering some of my initial questions. Looking forward to receiving the kit from him.

Embarrassed to say, especially in DIY forum, but I ordered the kit assembled (parts mounted on board), because of personal situation I just don't have the time to work on DIY project such as this. Hoping to be very satisfied with it (sonically), but if not then will look into tweaking.

Will update you all once I get my unit. Will hook up to a Marantz CM1040 (slim-line series) CD/mini-disc player.

Charles
  Reply With Quote
Old 4th December 2011, 08:20 PM   #104
ENSen is offline ENSen  Sweden
diyAudio Member
 
Join Date: Dec 2010
I bought the balanced kit from spencer a while ago. This weekend I finally had time to finish it. Have listened to it for a couple of hours today and I am very impressed. The sound is clean and dynamic with very good resolution. Instruments sounds like real instrument and not synthetic ones which is the case with many DACs

When I have time I will compare it to my commercial DAC that uses the PCM1792 chip which is almost the same as PCM1794.

The support from Spencer is superb and the kit is very nice with all components sorted in plastic bags that are clearly marked. I highly recommend this kit.
  Reply With Quote
Old 12th December 2011, 09:28 AM   #105
spencer is offline spencer  Hong Kong
diyAudio Member
 
Join Date: Jun 2004
Location: Hong Kong
Send a message via MSN to spencer Send a message via Skype™ to spencer
Reversion 6 Manual updated in my website:

FDA-1 PCM1794A DAC Kit Revision 6 Manual

Thank you for all the support.
  Reply With Quote
Old 16th January 2012, 06:06 PM   #106
arupg is offline arupg  Latvia
diyAudio Member
 
Join Date: Dec 2005
Location: Riga
Hello Gentlemen :

I've read each one of your posts all the way to #105 and must say that I've so far YET to see & go thru a "Thread" on this Forum with so much enthusiasm bubbling all over ... Its Just awesome !! (reminds me of the CarlosFM days ...) haha !!

Indeed - Spencer has pulled a BIG one here ...

TC's inputs were most illuminating & must say I'm kinda itching to get my hands on a dual-set board and get going ...

However, I am mainly a classical music buff (though I do jazz & some rock / pop once in a while), I wish to ask what's your opinion of this FDA for classical ? I like my bass stretching low with articulation (as I listen to a lot of Organ material) and am kinda fussy on the top end too - as l like it mellow yet open to the sky ... Mids - as usual clean, clear & spacious ...

Inputs will be most appreciated.

And ahh, well done Spencer! You've got a real winner here ...

Cheers!

Arup

Last edited by arupg; 16th January 2012 at 06:12 PM. Reason: typos
  Reply With Quote
Old 17th January 2012, 08:39 AM   #107
Nomdi is offline Nomdi  France
diyAudio Member
 
Join Date: Sep 2011
sorry that's not the good thread ..

Last edited by Nomdi; 17th January 2012 at 08:53 AM. Reason: thread error
  Reply With Quote
Old 17th January 2012, 08:49 AM   #108
TC Goh is offline TC Goh  Hong Kong
diyAudio Member
 
Join Date: Jan 2010
Location: Hong Kong
Hi Arup

Welcome to the band wagon! I was one of the early adopters and have been impressed with the DAC ever since. With the new lower pricing (…. grrrrrr…..), it is even more tempting. With this, I would go for the full balanced version. You will find that the improvements from SE will be well worth the $$$ and effort. You will be able to cut the assembly time by doing both boards at one go – saves you from having to locate component positions twice! Also, you get twice the fun at once … now how can you resist that? Ha ha.

I would suggest you listen to the vanilla version (Silmic BP and all) and then progress from there. After that, the fun continues …. You can consider upgrading the 7805 regulators to the L4941BV. This increases the punch of the music, which is a good thing in my all tube system.

Next … the really fun part … output coupling caps and bypass caps!! I tried various output caps and bypass but the best combination, in my opinion, is still ‘bare’!! OCL! The sound is more dynamic, musical and lifelike, all with a wider and deeper soundstage. I think this set up has the least amount of colouration. However, word of caution …. READ THE MANUAL!!!

Of course, whatever set up you end up with needs to match your system so I guess there is no one formula that works.

Oh, do get a good and sturdy case too. Just the eye candy would be well worth it.

The latest ‘upgrade’ I did was to shield the TXs with a grounded aluminum plate. I can’t tell if this improves the fidelity but I am sure it prevented those EMF gremlins from attacking the DAC.

Do please keep us updated as to your progress/decisions.

Oh.. Welcome to the world of flux smoke, sleep deprivation and blurry vision...

Have fun….

Best wishes

TC
  Reply With Quote
Old 17th January 2012, 08:52 AM   #109
TC Goh is offline TC Goh  Hong Kong
diyAudio Member
 
Join Date: Jan 2010
Location: Hong Kong
Hi Nomdi

I think everything you need can be found here ...

http://www.fetaudio.com/wp-content/u...-Manual_r6.pdf

Best wishes

TC
  Reply With Quote
Old 23rd January 2012, 08:57 PM   #110
diyAudio Member
 
Join Date: Nov 2011
Anyone of you tried other regulators than those 2 mentioned at documentation? Im thinking of replacing it by some kind of discrete regulator like supertedddyreg, DEXA etc.
Any hint? Im really curious for resyult and which one to choose? Also do you believe it will change sound for both Cirrus and PCM? Anyone tested it?...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hum in Balanced Mode in Balanzed Bride Of Zen Erlend Sæterdal Pass Labs 35 12th August 2010 08:17 PM
Help TDA 4X 1541 balanced Mode gil-garcia Digital Source 1 6th December 2007 04:12 PM
Anyone used a PCM1794A with balanced output? hifimaker Digital Source 11 18th March 2006 05:36 PM
PCM1798 mono mode with balanced output help mpopovics Digital Source 8 24th September 2005 10:00 PM


New To Site? Need Help?

All times are GMT. The time now is 12:26 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2