• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

dam1941 - Next Gen Discrete R-2R Sign Magnitude 24 bit 384 Khz DAC module

Jump to Latest
Terry Demol

Terry Demol

Member
Joined 2002
TNT

TNT

Member
Joined 2003
Paid Member
Digital gain is about math. -2 or +2 dB is "the same thing". In the case of minus you are throwing away LSB "bits" and on plus, your have to suck in (LSB) bits - 1 bit for every 6 dB.

You do the math :)

I would say like this - even if you put it at 0 and think you have a bit clean conversion - think again as the filters are also math so everything is recalculated anyways before conversion compared to the CD record. If you like the sound then you are OK - no?

So + is no info loss but minus (attenuation) really is. Then you have the rounding errors for both directions in the math...

//
 
Last edited:
B

Blitz

Member
Joined 2002
Well, I looked at it with an Oscilloscope while playing a sinus 1000hz 0db...full signal. With 0db you have a clean sinus, the more you add like +4 the more it does not look like a sinus anymore, becomes more a non symetrical triangle.

Different question:
I am reading always about transients in a music signal like the strike of a drummer etc can create impulses which are like 16db bigger than the musical signal...well what does mean in terms of Vpp-Envelope really ? What I mean: When I play a sinus digital 0db, so full digital signal: And I measure this with an osci: Is this the biggested technical possible analog signal the DAC can send to whatever comes next ? Or can those transients become even bigger than that ?
 
hirscwi

hirscwi

Member
Joined 2014
Paid Member
I apologize in advance for the dumb question.

I have a dam1941 that is built up with the Soekris power supply, user display and output buffer. It is working fine.

I want to add a headphone amp. I have the headphone amp but am not sure where to connect it so that it is controlled by the output switch on the user display board (S4) and the volume is controlled by the rotary encoder. I have looked through the manual and this thread but can't seem to find the answer.

Thanks for assisting me.
 
S

soekris

Member
Joined 2009
soekris.dk
Paid Member
hirscwi said:
I apologize in advance for the dumb question.

I have a dam1941 that is built up with the Soekris power supply, user display and output buffer. It is working fine.

I want to add a headphone amp. I have the headphone amp but am not sure where to connect it so that it is controlled by the output switch on the user display board (S4) and the volume is controlled by the rotary encoder. I have looked through the manual and this thread but can't seem to find the answer.

Thanks for assisting me.
Click to expand...

First you need an amplifier to drive the headphones.
Phones are then active when EN_PHO, J13 pin 4 is active high, Line then active when EN_LIN, J13 pin 3 is active high. It's designed to use CMOS relays for switching, just like a dac1541/dac2541, but you can also use mechanical relays with a relay driver.
J13 pin 1 & 2 is then used to control the amplifier gain, to optimize S/N.
 
hirscwi

hirscwi

Member
Joined 2014
Paid Member
soekris said:
First you need an amplifier to drive the headphones.
Phones are then active when EN_PHO, J13 pin 4 is active high, Line then active when EN_LIN, J13 pin 3 is active high. It's designed to use CMOS relays for switching, just like a dac1541/dac2541, but you can also use mechanical relays with a relay driver.
J13 pin 1 & 2 is then used to control the amplifier gain, to optimize S/N.
Click to expand...

Thanks, that's helpful. I understand about using J13 pin 4 to control the headphone amp but don't quite follow the use of J13 1 & 2 to control amp gain. Some experimentation required...
 
W

w3rn3r

Member
Joined 2020
connection display board via cable

pecci said:
And this is my just finished dam1941, with Salas triplet too and display board (short version, w/o headphone and volume section).
Click to expand...
Hello pecci,
thanks for showing your project, very nice build!
may I ask you regarding your realisation of the connection between DSP- and display board? which cable did you use ? do you have a parts number?
I have also the plan to connect the display board via a cable but was not able to find it at mouser, digi etc.
Many thanks and Regards
Werner
 
P

pecci

Member
Joined 2004
Hi,
That cable and connectors are ok, but in that case you must first solder 2x10 male pins header (straight but better angled) on DSP board.
Actually on that side I use connector from attached photo, mount flat ribbon cable by press fit and solder them from underside (watch out for correct pinout)
I find them at local store and sorry haven’t any Mouser or DigiKey ref no.
Br
 

Attachments

  • AD48502E-1E69-4AB6-8F23-F398F90E7201.jpeg
    AD48502E-1E69-4AB6-8F23-F398F90E7201.jpeg
    58 KB · Views: 300
B

BarG01

Member
Joined 2013
Be extremely cautious with the resistance of the strip cable! I also tried with a piece of cable from the drawer. It did not work, the display was half bright and all segment lit. I thougth I burnt the ICs when soldered but after many attempts of resoldering, troubleshooting I was unsuccesful. But i connected the control panel to the main board and then everything was OK. Then I decided to prepare a strip cable from individual wires with appr. 0,8mm diameter and voila it started to work properly. My distance is appr 20cm between the 2 panels.
 
You must log in or register to reply here.
Top Bottom