Messages

1

DACs / Re: I am making a correction amp and have a question :)

« on: June 09, 2016, 02:48:40 am »

Yes and no.


I agree that the first unity gain buffer is redundant and this could be done with only 2 opamps, but i wanted to make it differential so i needed 3. As there is no TL073 i just figured why not use the 4th as a buffer on the input. 


Also opamps are much cheaper than trimpots so the total cost of material is cheaper.

2

DACs / Re: I am making a correction amp and have a question :)

« on: June 08, 2016, 05:43:42 pm »

Thanks!


This is what i came up with. Haven't tested it yet, so i'm not sure how well it performs. The reference is just a 7905 with a voltage divider which is referenced on all channels.


Any thoughts?

3

DACs / I am making a correction amp and have a question :)

« on: May 23, 2016, 03:04:09 pm »

Hello all. 


I just started building my own projector and want to make a soundcard DAC to control it. While i'm waiting for the soundcard to arrive i am making the correction amp for it. I have been looking at schematics and pictures of this and afaik they all seem to have individual offsets for each channel. I think this is due to the offset being affected by the gain.


My idea is to put a unity gain opamp in front of the amplifier and reference that to a single trimpot controlling the offset reference. This means less trimpots and should make it easier to adjust. Do you think this will work or am i missing something?


When i get this up and running and tested i will put up the schematics and PCB design for download. Maybe i will have some spare PCB's as well if anybody wants.


Thanks and keep it real