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
No caps and the daughterboard with the TI chip. That's what I am using for critical listening. Worth every penny!!! 😎
cheers rec.
cheers rec.
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!
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!
Attachments
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
RX-V8 Interface Board from “Amanero USB-I2S module” to FDA-1B or FDA-2A DAC
Attachments
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?
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.
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.
aha. i'm not going to use a control board. it will be internal DAC for my CDpro2 player.
so what i need to do is short pin 1 and 2 to ground?
right now it's playing with my squeezbox, and its sound wonderfull🙂
so what i need to do is short pin 1 and 2 to ground?
right now it's playing with my squeezbox, and its sound wonderfull🙂
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Hi,
I just have a fda 1B ( buy to a forumer for christmas) and i would like to know :
1) what is the function of the resistors 4R99 ( like R130) behind the analog out of the dac pcm1794 ?
2) I have a clock 11,286Mhz /5V from tentlabs. Can i use it with his own power supply and few modifications of the asrc card ? I want use the dac in a first time only with a cdpro at 44.1 khz.
3)Is that possible to have the schematics of the asrc board ?
bruno
I just have a fda 1B ( buy to a forumer for christmas) and i would like to know :
1) what is the function of the resistors 4R99 ( like R130) behind the analog out of the dac pcm1794 ?
2) I have a clock 11,286Mhz /5V from tentlabs. Can i use it with his own power supply and few modifications of the asrc card ? I want use the dac in a first time only with a cdpro at 44.1 khz.
3)Is that possible to have the schematics of the asrc board ?
bruno
The circuit of the ASRC BD is here:
http://www.fetaudio.com/wp-content/uploads/2012/05/FP7-ASRC-Ckt.pdf
Regarding clock to the ASRC, it is a 24.576Mhz XO. Not sure if you can use 11.286Mhz or not.
http://www.fetaudio.com/wp-content/uploads/2012/05/FP7-ASRC-Ckt.pdf
Regarding clock to the ASRC, it is a 24.576Mhz XO. Not sure if you can use 11.286Mhz or not.
thanks for your answer.
Could you confirm to me i can sold ad1896 or src4192 on the pcb ? Or you have a pcb for each ?
( I have a pcb with ad1896 write on.)
bruno
Could you confirm to me i can sold ad1896 or src4192 on the pcb ? Or you have a pcb for each ?
( I have a pcb with ad1896 write on.)
bruno
The pcb is designed for AD1896. For SRC4192, there is no MCK out and thus the clock will be using the XO frequency. Thus the soldering is different.
I'll try to sold together pin 2 and 3 of the src4192 and so, Mck Out will be the same of XO frequency and that would be working with your pcb.( I have one src4192 in my stock of parts but no ad1896)
and about the function of the resistor 4r99 at the entry of the I/V stage it's a secret ?
In a first time I have think this resistor is using for decrease the entry impedance of the stage i/v but on the MicroCap8 simulation, it's not the case.So I don't understand what is this function.
and about the function of the resistor 4r99 at the entry of the I/V stage it's a secret ?
In a first time I have think this resistor is using for decrease the entry impedance of the stage i/v but on the MicroCap8 simulation, it's not the case.So I don't understand what is this function.
Regarding the output resistors to the IV, there is someone take some measurement and analysis on that in this forum. The findings is that driving a resistor IV up to 50 ohm to ground will not increase the distortion level much.
In my case, I find that putting the resistor in will ensure the distortion will be minimum at all situations. As you can see my design is not driving the output to a virtual ground but rather a positive reference set by the diodes. After doing that, the distortion is more consistent and low. Thus the resistor effect is minimized and become just a crossover of signal. I think if you are interested, you can change the value to see if you can hear any sound difference. I did not tried all possibility as it is a very time consuming process.
In my case, I find that putting the resistor in will ensure the distortion will be minimum at all situations. As you can see my design is not driving the output to a virtual ground but rather a positive reference set by the diodes. After doing that, the distortion is more consistent and low. Thus the resistor effect is minimized and become just a crossover of signal. I think if you are interested, you can change the value to see if you can hear any sound difference. I did not tried all possibility as it is a very time consuming process.
Has somebody interest for buying my full assembled and working FDA-1B with both ASRC boards? External i2s prepared for WaveIO, Dale i/v resistors and russian PIO capacitors. No output capacitors. Eventually a Schuro encapsulated and ground-shielded toroidal transformer 230v-2x18v 65VA. Delivery from Germany. I´ve payed for all parts, inkl. transformer 560$ / 430€. Please PM me for offers!
apoo
apoo
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