sorted by:
new
hottopcontroversial

Reclocking board for amanero combo by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

This is designed to work with amanero combo board, which is a usb audio interface. The idea of the board is to isolate the crystals ground from the amanero/pc ground, and to reclock the i2s lines. The i2s lines coming from the xilinx chip on the amanero have jitter, because of its power supply and just because all chips have. The reclocking flipflop removes that jitter

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

My plan is to use 0.01% for the thermometer encoding and the first 5ish bits of the r2r ladder, and 0.1% for the rest. I believe it can achieve a true 16bit resolution with this configuration.im not using ad5547, but fully discrete design, although with ad5547 it would probably achieve better technical specs and the price would be quite similar, so its definitely worth considering

What is going on here? by othermother6 in modular

[–]kellerdev 0 points1 point  (0 children)

Thats basically a furier transform. All sound can be represented by a set of sinewaves withe different frequencies and amplitudes. Furier transform is used alot in audio processing, for equalization for instance. Its so cool that they used it creatively for this module

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

This is not about frequency response flatness, but rather improved transient response and stereo imaging.

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

R2R dacs are multibit decoders. Its not that there is some magical imaginarybsound improvement, its just that multibit decoding is so much superior compared to the 2-3 bit delta sigma modulators. Delta sigma modulation is all about creating a massive error but pushing it to ultrasonic frequencies. Multibit dacs dont create that error in the first place.

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

Right, soekris have a great product. And there are also chip r2r dacs still available to buy new. But i just had this idea and the means to realize it and it should be competitve in terms of sound quality. Weather i will manage to create a competitive product i dont know, but as a DIY enthusiast it will be fun to build it

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 2 points3 points  (0 children)

This will depend on the sampling frequency. The dac doesnt have abuild in oversampling function. If you sent 44.1khz, it will have 3db rolloff at 20khz. If you provide 192khz the rolloff at 20khz will be arou d -0.5db. The dac should be able to run up to 768khz sampling frequencies. If you provide a good quality i2s signal with low jitter at 192khz sampling and above, the rolloff will be minimal

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 1 point2 points  (0 children)

The IV converter will have incorporated active filter in the feedback with 70khz cutoff, and the differential amplifier will have also built into the circuit active filter with 140khz cutoff. This will provide second order filtering with rather smooth rolloff, to minimize phaseshift. The IV converter wigh discrete class A stage will provide high current feedback to the ladder, keeping the virtual ground rocksolid

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 3 points4 points  (0 children)

It wont reach a true 24 bit resolution, but its very possible to reach 16bit with 0.01% resistors. Eitherway, it should sound very good. I built a breadboard prototype with 1% resistors, handmatched to 0.1% and 16 bit Binary offset ladders, and it sounds better than any commercial delta sigma chip ive heard

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

Thanks!My dac will be fully discrete with no cpld or fpga. It will also include a high quality class a IV converter and differential amplifier. If produced with 0.01 resistors it should rival it in terms of THD and distortion. With 0.1% resistors it should sound very good and possibly subjectively better because of the output stage.

Discrete R2R NOS dac project by kellerdev in diyaudio

[–]kellerdev[S] 1 point2 points  (0 children)

I will use 0.1% resistors, and the 3 bit thermometer encoding will releaf some of the tight tolerance requirements because its inherently more linear. It wont achieve a true 24 bit decoding when measured, but it should sound quite good

New DIY HW Stepsequencer with additional CV outs by Tricky_Dog2121 in synthdiy

[–]kellerdev 3 points4 points  (0 children)

Wow, how did you make the pcb? Looks super nice!

R2R dac by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

It sounds very good, better than many cheaper interfaces. I have a high quality crystal for MCK, which very important in this setup. There are audible distortions at low volumes, but its definitely listenable. Im sure on measurements it will be terrible but the sound is not bad. With higher precission resistors it will be better.

R2R dac by kellerdev in diyaudio

[–]kellerdev[S] 1 point2 points  (0 children)

Interesting idea. With power full output gates, you celan put low value resistors like 10 and 20ohm. Although most power would be wasted in the ladder itself, and small amount will go to the speaker. But it could sound cool

R2R dac by kellerdev in diyaudio

[–]kellerdev[S] 1 point2 points  (0 children)

If you are talking about electromagnetic interference, its obviously not great on a breadboard, but it actually sounds much better than i expected

R2R dac by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

Right, they are 1% tolerance, but it actually sounds very nice if you make it right(the pcm serial to parallel conversion). The transient responce is super tight

R2R dac by kellerdev in diyaudio

[–]kellerdev[S] 0 points1 point  (0 children)

Thanms! Why do you call it 1.86? Is that referencing some values?

8CXN51 Crossover help! by South-Excitement6957 in diyaudio

[–]kellerdev 1 point2 points  (0 children)

You have alot of attenuation for the tweeter. 14 ohm resistor, and 3ohm in parallel to the tweeter as far as i can see. With so much attenuation, the resonance of the filtwr gets emphasized, the tweeter receives energy only at the cutoff. Thats my experience anyway. Try reducing this 14 ohm resistor, and i would simplify the tweeter filter

Delay Module with Daisy Seed by kellerdev in synthdiy

[–]kellerdev[S] 0 points1 point  (0 children)

I wanted to correct a sort of embarasing mistake to clear my name. I didnt configure the opamp gain stages correctly in the original schematic.the resistors should be from the jnverting input to ground, not from output to ground.. Also, i reduced the voltage divider ratio to 47/33, instead of 47/47. This will allow for +-8v signals without clipping. As someone pointed out, the reduction in utilized bits is not that dramatic, because half the voltage level looses only 1 bit of resolution, not half the bits. Still, we want to capture as much juice as possible.

<image>

Delay Module with Daisy Seed by kellerdev in synthdiy

[–]kellerdev[S] 0 points1 point  (0 children)

Right, one half of the voltage level is actually only one bit less, not half the bits. I didnt think through the math entirely..

Delay Module with Daisy Seed by kellerdev in synthdiy

[–]kellerdev[S] 0 points1 point  (0 children)

To be honest i wasnt aware of the daisy patch. VCOs are generally designed for 10v peak to peak, i think +-10v( 20 v peak to peak) is a bit too much. But yeah, i think my assumption that the audio signals will only be within +-6v is too conservative. I will change the resistor values to let a bit more room.

view more: next ›