New PCM1794A Kit – Balanced Mode Update – Good to Fantastic Sound! - Page 21

spencer · 20th August 2012, 11:53 AM

Short pin 1 and pin 2 of J1 to pin 3 (ground) to have default = (0,0) or I2S as input from J5. Short R171 to un-mute the I2S input or use the pin 9 of J5 to control the mute from external source. Mute is active High.

AudioSan · 20th August 2012, 03:13 PM

exelent

maybe i have to get this dac then

and use a 3U chassis.

apoo · 25th August 2012, 05:31 PM

Quote:

Originally Posted by florentino

hello FDA-1 user!
I am looking for the best combi of cap´s in the output
the input-impendance of the most pre´s is 10-100K!?
What do you think about one silmic 100uf +10uf pio+0,01uf pio? It’s a compromise ?

I've seen some have used jensencaps?
pleace helb me to find a combination
pio´s in 10 uF i have here!
thanks for helbing
regards
florentino

The best caps are NO caps :-)

I´m listening to FDA-1B OCL! After one week of burn in, just shorted the output caps an set DC offset to 0mV (+-1mV). Sounds great, more focus and more 3D!

apoo

recorder · 2nd October 2012, 09:00 AM

No caps and the daughterboard with the TI chip. That's what I am using for critical listening. Worth every penny!!!

cheers rec.

apoo · 25th October 2012, 09:01 AM

Hi folks,

i was very impressed of the dynamics of this DAC from very beginning, but the sound was after a short time of listening fatiguating. I´ve changed the i/v resistors with dale resistors and PIO capacitors K40Y-9. This was better but not enough. I decided to try batteries.

These are the changes:
- OCL! all output caps shorted, DC offset adjusted to 0mV
- analog supply PCM1794A - two separate belleson +5v reg with LiFePO 2x3,3v
- digital supply PCM1794A - two separate LiFePO @3,3v
- a huge improvement in sound was the battery supply for the discrete IV! 4x24v lead-acid batteries
- 12v lead-acid for the receiver

The WaveIO USB receiver (XMOS) i´m using is also fed with 6v lead-acid and a 2A-5V belleson reg. The onboard isolator with 3,3v LiFePO

The change is huge! It´s another DAC! It´s not fatiguating at all, it has tremendous dynamic and the treble is not so "hi-fi" like. Bass is very, very controlled and deep. It´s maybe the best DAC i´ve heard for a long time!

Give it a try!

spencer · 2nd November 2012, 11:33 AM

Add a RX-V8 interface board for Amanero Combo384 to FDA-1B and FDA-2A. Details can be found in below link:
RX-V8 Interface Board from “Amanero USB-I2S module” to FDA-1B or FDA-2A DAC

AudioSan · 2nd January 2013, 07:21 PM

Quote:

Originally Posted by spencer

Short pin 1 and pin 2 of J1 to pin 3 (ground) to have default = (0,0) or I2S as input from J5. Short R171 to un-mute the I2S input or use the pin 9 of J5 to control the mute from external source. Mute is active High.

hey. i've got the FDA-2 from you, and soldered it an tested it now. i guess this is the same for FDA-2 as for FDA-1?

spencer · 2nd January 2013, 11:59 PM

See J5 table:

AudioSan · 3rd January 2013, 12:10 AM

J5 is all good. i was thinking of J1. just short pin 1 and 2 to pin 3?

spencer · 3rd January 2013, 12:41 AM

Pin 3 is also an input pin for FDA-2. Pin 3 can be short to ground using R97 (default become 0 = ground).
When R97 is shorted, then short R107 and open R106 to have same function as FDA-1B.

FDA-2 is more flexible to have 5 input or 4 input and thus jumper(or resistors) need to be set properly. Of course a new control board is required.

20th August 2012, 03:13 PM	#202
AudioSan diyAudio Member Join Date: Feb 2009 Location: Trondheim	exelent maybe i have to get this dac then and use a 3U chassis. __________________ aleph P1.7 pre. F5 power amp. CDpro2(need DAC). Vivaldi8 speakers

3rd January 2013, 12:10 AM	#209
AudioSan diyAudio Member Join Date: Feb 2009 Location: Trondheim	J5 is all good. i was thinking of J1. just short pin 1 and 2 to pin 3? __________________ aleph P1.7 pre. F5 power amp. CDpro2(need DAC). Vivaldi8 speakers

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2nd October 2012, 09:00 AM	#204
recorder diyAudio Member Join Date: Jan 2011 Location: Where you live	No caps and the daughterboard with the TI chip. That's what I am using for critical listening. Worth every penny!!! cheers rec.

3rd January 2013, 12:41 AM	#210
spencer diyAudio Member Join Date: Jun 2004 Location: Hong Kong	Pin 3 is also an input pin for FDA-2. Pin 3 can be short to ground using R97 (default become 0 = ground). When R97 is shorted, then short R107 and open R106 to have same function as FDA-1B. FDA-2 is more flexible to have 5 input or 4 input and thus jumper(or resistors) need to be set properly. Of course a new control board is required.