This must be one of the easiest amplifier to setup, one trimmer for bias and that's it!
Set it at 20mV which is 50mA. Since they're not like Mosfets which love heat, I decided to keep them biased like this. I think this will a good start point and will test different set points to hear any differences if any. I know that VZaudio keeps their amps biased around 20mA and they sound amazing.
Do
Set it at 20mV which is 50mA. Since they're not like Mosfets which love heat, I decided to keep them biased like this. I think this will a good start point and will test different set points to hear any differences if any. I know that VZaudio keeps their amps biased around 20mA and they sound amazing.
Do
So this was all setup properly after I read the second section of the manual.. 
Still have these questions though..
- What is the optimal input cap value 2.2uF / 3.3uF? Can we omit input cap?
- If using the XLR input board, the 3 pin input connector is not labelled with +/-/gnd, I found out that center pin is gnd by probing and looking at Vitalie's pictures (which was hard to see the connection), if looking at the PCB from the input side, from left to right, left being pin 1 for this scenario:
1 = (-) or cold
2 = (gnd)
3 = (+) or hot
Is that correct? There's no documentation for the XLR input PCB...
Thanks
Do
Still have these questions though..
- What is the optimal input cap value 2.2uF / 3.3uF? Can we omit input cap?
- If using the XLR input board, the 3 pin input connector is not labelled with +/-/gnd, I found out that center pin is gnd by probing and looking at Vitalie's pictures (which was hard to see the connection), if looking at the PCB from the input side, from left to right, left being pin 1 for this scenario:
1 = (-) or cold
2 = (gnd)
3 = (+) or hot
Is that correct? There's no documentation for the XLR input PCB...
Thanks
Do
Hi, what should I say. Or how should I begin.
I have awaken from the dead. I have not heard hifi for many many month. For a long time I could not concentrate on making PCB nor software.
In June it started to get better. But I had to learn every thing I have made from the beginning.... I could not remember it. In July and August I was more or less forced to work with software again for another project. It helped me a lot.
So the last two month I have been working extensively with USB software and display firmware. I have made new USB firmware that works better for the ak4490/4493.
Yesterday and today I was so far that I could finish of some old projects and ship them on Monday. I did not want to be active again before I had it in control.
- Sonny
I have awaken from the dead. I have not heard hifi for many many month. For a long time I could not concentrate on making PCB nor software.
In June it started to get better. But I had to learn every thing I have made from the beginning.... I could not remember it. In July and August I was more or less forced to work with software again for another project. It helped me a lot.
So the last two month I have been working extensively with USB software and display firmware. I have made new USB firmware that works better for the ak4490/4493.
Yesterday and today I was so far that I could finish of some old projects and ship them on Monday. I did not want to be active again before I had it in control.
- Sonny
Thanks pinnocchio, factory2nd and Joseph K.
Dominic: Did you get it fired up? It is best to run it with XLR frontend. It is setup as differential with output sense point attached to amp. it has a huge poisitive impact on the current loops. If you use it without the frontend you could use 3.3uF in series giving it a highpass frequency of around 4,8Hz
BR
Sonny
Dominic: Did you get it fired up? It is best to run it with XLR frontend. It is setup as differential with output sense point attached to amp. it has a huge poisitive impact on the current loops. If you use it without the frontend you could use 3.3uF in series giving it a highpass frequency of around 4,8Hz
BR
Sonny
I hope it looks good now
We would like to see more of that gorgeous amp picture.
BR
Sonny
Hi Sonny,
I will use the XLR board and use pseudo differential cables if I need to run a unbalance source on it. I got the first board fired-up last week and adjustments was quite easy. I was just missing some standoffs for adding the second board, I received them this Tuesday and will play with the amp this weekend if time allows it. Can't wait to listen to it!
Ciao!
Do
I think it is as good as it gets now. I do not produce hormones except cortisol. So the rest I get as gel and injection in my stomach / legs. They have also lowered my Blood pressure medicine and they say I have recovered better than they actually had expected.
I do not sleep that much anymore.
But I have a lot to catch up on.
I am waiting with eager to hear what you think Dominic
I do not sleep that much anymore.
But I have a lot to catch up on.
I am waiting with eager to hear what you think Dominic
I have 10 of those es9038q2m . I am thinking of build 10 USB dac with those and keeping 2 of them. Should be very simple. Board will be identical to the AK4493 with 4 extra pins for reference voltage to run them in current mode. That would require a new shield board. But it will also work very well with the present output shields.
Crystal should be good so I will add a cchd-575 100Mhz. Reference voltage will be made with lt3042.
I have tested on the es9038q2m and es9038pro and they can replace src4392. So even if es9038q2m and cchd-575 is more expensive then I think the price will be the same.
Crystal should be good so I will add a cchd-575 100Mhz. Reference voltage will be made with lt3042.
I have tested on the es9038q2m and es9038pro and they can replace src4392. So even if es9038q2m and cchd-575 is more expensive then I think the price will be the same.
No it is not that tough any more. It is down to just medicine and check every 3 month and Mr scan every 6 month. There is a small amount of tumor that they cannot remove, but until now it is not growing and it is not influencing me in a bad way.
The growth hormone gave me a boost in energy. So I am really happy. Expensive stuff. I am glad the government pays for it through our medical ensurance.
- Sonny
USB DAC V1.0:
I have just sold one DAC of them. I also have a few more asking for it, but i have to make changes to it because one of the items are no longer available.
It will be a little bit more expensive, but DAC is mounted on a shield. So it will be easy to switch to a new DAC.
Planned DAC's will be AK4490,AK4493 and ES9038Q2M for a start.
BR
Sonny
I have just sold one DAC of them. I also have a few more asking for it, but i have to make changes to it because one of the items are no longer available.
It will be a little bit more expensive, but DAC is mounted on a shield. So it will be easy to switch to a new DAC.
Planned DAC's will be AK4490,AK4493 and ES9038Q2M for a start.
BR
Sonny