555 timer class D amplifier and tape recorder experiments

Well now I've sorted out the sound problems on my computer (it was a ground loop problem), I can get on and do stuff.

in this video I use my 555-based pulse generator as a class D amplifier, a schematic is included near the end of the video, the quality is surprisingly good and clean, but the chip becomes unstable if I connect a speaker directly to the chip's output.

I also experiment with attempting to record onto tape with it connected up to the head in an el-cheapo tape transport that came out of a toy. Again the quality is better than I thought it would be, a little distorted but much better than a recording with no bias.

Category:

Science & Technology

Tags:

• 555
• timer
• class
• amplifier
• transistor
• sound
• audio
• tape
• recording
• AC
• Bias
• PWM
• Pulse
• Width
• Modulation
• Frequency

[videolabguy]

Awesome. You ARE the coolest nerd I know of.

[CoolDudeClem]

@davesworld85100 And? You have a problem with that?

[TheJaHa5]

You should come out with your own line of Cassette tape recorders! This video is very interesting!!!

[raymond9987654321]

@CoolDudeClem

Oh. Hmm, have you tried recording videos by putting your mic, preamp'd into your line-in on your PC, recording it, then sync'ing your audio recording with your video, and removing the camera audio? Just wondering (note: a clap at the beginning of the vid may help with sync'ing the audio easily)

[CoolDudeClem]

@raymond9987654321 Yes because my camera's audio is even worse, just sounds muffled and noisy.

[Vintagesoundz14]

Hi Clem, i would like tomasic a basic amplifier for my old computer in the Loft, do you have the Scchematic for this or could you make one, i am not good at making things like this but have a box of components form an old hi-fi and wouldlike to make a basic amp, this looks like a goodstarting point.

[MrStemkilla]

@CoolDudeClem yes i am having problems with heat but then agen i was useing way too small transistors :) it was rated for .6 A i was pulling about 1 amp .. and when they are that small they do not have heat sink mounting holes.. ya i was just protoboarding and i need to order better

[CoolDudeClem]

@MrStemkilla When it come to efficiency,it's all mainly about heat loss, Class A amplifiers, although give the cleanest output, they loose a lot of energy as heat, class D barely looses any energy as heat, and AB is somewhere in the middle.

[MrStemkilla]

@CoolDudeClem i do not understand how the efficiency is lost on some amplifiers. when the efficiency is high then its giving out fractions what the full wave form of the signal coming in meaning its not giving off the same wave length as it is receiving. i can see where that may come in to be important in some devices but generally i find a class AB just as efficient as A since its not giving the full signal output if you get what im saying

[CoolDudeClem]

@MrStemkilla There are many types, class A, B, AB, C, D and even a class T, unfortunately there's too much here to explain in a comment, best to go and look it up on Wiki.