| ??? 04/20/08 11:07 Modified: 04/20/08 11:15 Read: times |
#153734 - Music Machine Responding to: ???'s previous message |
Hello Everybody,
Thanks Jim Deas,Richard Erlarcher and last but not the least, Kai Klass. Making Gif drawing in Mspaint is,I find,not trustworthy.However for the moment I have to continue and modify my drawing specially to show the output capacitor which is really 220µF.Kindly take note .http://www.8052.com/users/AsokRudra/DacSong1.gif Kai said Asok, it's impossible to say something useful as long as we do not know what the purpose of your circuit is! This is a music machine!Kai,there was an article "Metronome/Diapason" in Elektor long back.I am sure Google will remind you the date and all.The present purpose is some what similiar.Plus having spent lot of time fiddling with music I found I can write nice melodies for 8051 as I can do in Cakewalk.So a toy or morning alarm set to mood if not a calling bell hence the cheaper and louder,the better.Plus certain music has productive (agriculture,dairy, and in factories,I think Philips proved it) and healing effects. Although square wave tone from 8051 is nice enough,I am experimenting with PWM to produce triangular and pseudo sine wave etc. for different musical effects. Kai said the additional 68k resistor (behind the R-2R-ladder) should be omitted. There seems to be no reason for it anyway. The same is valid for the high pass filter formed by 22nF (22kpF = 22nF?) and 68k in series, in front of LM386. Such a load destroys the exact performance of R-2R-ladder DAC, by introducing uneven steps in the DAC stairway. In the lower scheme a FET-OPamp can be seen, which works as a high ohmic buffer, allowing the R-2R-ladder DAC to work properly.
.....But do you really want a corner frequency of 1 / 2 / pi / 33kOhm / 22nF = 220Hz? Kai,many thanks for clearing my doubts.I think those 68K-22nF in parallel are BLEEDING my crude DAC since precision is probably not important here but PWM shapes because after all we are going to amplify it in later stage/s. I do not like the sound of cellphone ring tones.Actually I was christened to audio by Mullard Valve Amplifiers and my ear prefers bassy music.Kindly suggest corner frequencies accordingly and suitable filters for musical notes.I would love to have roundish(smooth,spherical Fender type) tones and later attack,decay,and sustain. I am using 1.5",8 Ohms,0.4 Watt speakers and 300 mA transformers.With TL072P,how much output is expected?Are you suggesting a power amp later? With best regards, A.S.Rudra |
| Topic | Author | Date |
| 8051 LM386 | 01/01/70 00:00 | |
| You can use a different power supply | 01/01/70 00:00 | |
| What you have here ... | 01/01/70 00:00 | |
| What do you want to do at all? | 01/01/70 00:00 | |
| Music Machine | 01/01/70 00:00 | |
Ok, then 4 bit is enough | 01/01/70 00:00 | |
| Thanks Kai | 01/01/70 00:00 | |
| Link | 01/01/70 00:00 |