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.
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.
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
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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
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
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.
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.
Reversion 6 Manual updated in my website:
FDA-1 PCM1794A DAC Kit Revision 6 Manual
Thank you for all the support.
FDA-1 PCM1794A DAC Kit Revision 6 Manual
Thank you for all the support.
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
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
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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 $$$ and effort. You will be able to cut the assembly time by doing both boards at one go – saves you from having to locate component positions twice! Also, you get twice the fun at once … now how can you resist that? Ha ha.
I would suggest you listen to the vanilla version (Silmic BP and all) and then progress from there. After that, the fun continues …. You can consider upgrading the 7805 regulators to the L4941BV. This increases the punch of the music, which is a good thing in my all tube system.
Next … the really fun part … output coupling caps and bypass caps!! I tried various output caps and bypass but the best combination, in my opinion, is still ‘bare’!! OCL! The sound is more dynamic, musical and lifelike, all with a wider and deeper soundstage. I think this set up has the least amount of colouration. However, word of caution …. READ THE MANUAL!!!
Of course, whatever set up you end up with needs to match your system so I guess there is no one formula that works.
Oh, do get a good and sturdy case too. Just the eye candy would be well worth it.
The latest ‘upgrade’ I did was to shield the TXs with a grounded aluminum plate. I can’t tell if this improves the fidelity but I am sure it prevented those EMF gremlins from attacking the DAC.
Do please keep us updated as to your progress/decisions.
Oh.. Welcome to the world of flux smoke, sleep deprivation and blurry vision...
Have fun….
Best wishes
TC
Welcome to the band wagon! I was one of the early adopters and have been impressed with the DAC ever since. With the new lower pricing (…. grrrrrr…..), it is even more tempting. With this, I would go for the full balanced version. You will find that the improvements from SE will be well worth the $$$ 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
Hi Nomdi
I think everything you need can be found here ...
http://www.fetaudio.com/wp-content/uploads/2011/12/PCM1794A-DAC-Manual_r6.pdf
Best wishes
TC
I think everything you need can be found here ...
http://www.fetaudio.com/wp-content/uploads/2011/12/PCM1794A-DAC-Manual_r6.pdf
Best wishes
TC
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?...
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?...
Hi Zibra
I haven't personally but I do share your view that the choice of regulators do affect sound. Perhaps you can try using a LM317T regulator too. I know these do sound a little faster and with more punch. Also, they are cheaper too
It should be interesting... Keep us posted as to whay you decide to do...
Best wishes
TC
I haven't personally but I do share your view that the choice of regulators do affect sound. Perhaps you can try using a LM317T regulator too. I know these do sound a little faster and with more punch. Also, they are cheaper too
It should be interesting... Keep us posted as to whay you decide to do...
Best wishes
TC
Hi Spencer
Of course you are right. Sorry for not being clearer but I think Zibra may be aware of this.
Best wishes
TC
Of course you are right. Sorry for not being clearer but I think Zibra may be aware of this.
Best wishes
TC
Yeah, I will post my observation. Actually friend of mine is preparing DIY regulator for me. Something like Teddyreg without any resistors. Ill try to make as clean power as possible
Already tried Rubycon ZA instead of Silmic for PCM power supply and found it better without somewhat bloated bass in comparision.
I will be also experiencing with another filter capacitors instead of Russian ( ordered silver mica, amtrans and polystyrene) and conversion resistors (Caddocks).
Spencer made great dac. No doubt about it. You can just buy it, plug it and forget it However for hardcore and curious modders its great field for experiencing and achieve even more nirvana)
Strong recommendation for that dac!
Already tried Rubycon ZA instead of Silmic for PCM power supply and found it better without somewhat bloated bass in comparision.
I will be also experiencing with another filter capacitors instead of Russian ( ordered silver mica, amtrans and polystyrene) and conversion resistors (Caddocks).
Spencer made great dac. No doubt about it. You can just buy it, plug it and forget it
However for hardcore and curious modders its great field for experiencing and achieve even more nirvana)Strong recommendation for that dac!
I would be very keen to compare the full-scale FDA with my reference setup, i.e. [metronome kalista ref + accuphase dc-801] vs. FDA (yeah! its totally unfair from the monetary point-of-view) but nevertheless I just wanna see where things stand ...
And as Zibra correctly points out, Spencer's FDA is excellent as standalone but there's room for lots of experimentation to change & suit the flavor for an individual's system, music & taste ... which is by itself a superb feat !!
Voila ! ...
And as Zibra correctly points out, Spencer's FDA is excellent as standalone but there's room for lots of experimentation to change & suit the flavor for an individual's system, music & taste ... which is by itself a superb feat !!
Voila ! ...
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I guess the next mod, if the results of the digital side are +ve, will be the I/V ones... Whoa ….. That will get very interesting.
I googled Teddyreg and I think they are using the standard LM317 too. This should be a very interesting experiment.
The Silmics are a very interesting e-cap. Apparently, it uses natural fibers (Silk?) in its construction. In my system (all tubes), the Silmics actually improves the bass volume, albeit, with a little less control, as you have observed. Maybe I should try some OSCons.
I do second you in saying that Spencer made a great DAC. This DAC is already capable right out of the gate (Silmic, Dale, Russian PIO and all) but can be 'customized' to a degree to match the rest of the system to arrive closer to the individual’s musical taste. I guess this is what drives passionate (aka crazy!!!) Diyers.
Keep us posted, please ...
TC
I googled Teddyreg and I think they are using the standard LM317 too. This should be a very interesting experiment.
The Silmics are a very interesting e-cap. Apparently, it uses natural fibers (Silk?) in its construction. In my system (all tubes), the Silmics actually improves the bass volume, albeit, with a little less control, as you have observed. Maybe I should try some OSCons.
I do second you in saying that Spencer made a great DAC. This DAC is already capable right out of the gate (Silmic, Dale, Russian PIO and all) but can be 'customized' to a degree to match the rest of the system to arrive closer to the individual’s musical taste. I guess this is what drives passionate (aka crazy!!!) Diyers.
Keep us posted, please ...
TC
Yeah, I will post my observation. Actually friend of mine is preparing DIY regulator for me. Something like Teddyreg without any resistors. Ill try to make as clean power as possible
Already tried Rubycon ZA instead of Silmic for PCM power supply and found it better without somewhat bloated bass in comparision.
I will be also experiencing with another filter capacitors instead of Russian ( ordered silver mica, amtrans and polystyrene) and conversion resistors (Caddocks).
Spencer made great dac. No doubt about it. You can just buy it, plug it and forget it
Strong recommendation for that dac!
Wow!!!
A 59 kg transport (that looks like moon base alpha) with its isolated 5 battery pack and 8 regulators PS feeding the FDA-1!!!! Talk about Goliath and David!!!
I am speechless ....
Anyway, it will be an interesting, albeit and unfair one, comparison between the DC-801 and the FDA.
TC
A 59 kg transport (that looks like moon base alpha) with its isolated 5 battery pack and 8 regulators PS feeding the FDA-1!!!! Talk about Goliath and David!!!
I am speechless ....
Anyway, it will be an interesting, albeit and unfair one, comparison between the DC-801 and the FDA.
TC
I would be very keen to compare the full-scale FDA with my reference setup, i.e. [metronome kalista ref + accuphase dc-801] vs. FDA (yeah! its totally unfair from the monetary point-of-view) but nevertheless I just wanna see where things stand ...
And as Zibra correctly points out, Spencer's FDA is excellent as standalone but there's room for lots of experimentation to change & suit the flavor for an individual's system, music & taste ... which is by itself a superb feat !!
Voila ! ...
I believe Spencer uses Dales for most resistors in the signal path and he once told me that the critical I/V resistors are the 475ohms at locations R1, R2, R18, R19.
On a different set up, I compared the Dales to Welwyn's Metal film precision 0.25W,0.1% resistors. They sound clearer (more analytical) but not as warm.
Trade offs, I guess...
Best wishes
TC
On a different set up, I compared the Dales to Welwyn's Metal film precision 0.25W,0.1% resistors. They sound clearer (more analytical) but not as warm.
Trade offs, I guess...
Best wishes
TC
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