I was playing on my workbench this evening, with my inverting gainclone, a scope and a function generator.
This is well know, gainclones have a very bad behaviour when clipping. I can't post illustrations because I don't have the digital camera right now, and I don't know how to connect my Tek 2232 scope to my computer to acquire data (if you know, tell me!), but the curve is really ugly!
But I saw another phenomen, that I haven't read about here: the input signal is deteriorated when the gainclone clips!
At first, I thought that my source was clipping, and that I was seeing the amplified clipping input signal at the amp's output. But when I disconnected the signal generator from the amp, and looked at the signal, it was perfect!
Any other feedback (this is the more appropriate word I found 🙂) about this phenomen?
This is well know, gainclones have a very bad behaviour when clipping. I can't post illustrations because I don't have the digital camera right now, and I don't know how to connect my Tek 2232 scope to my computer to acquire data (if you know, tell me!), but the curve is really ugly!
But I saw another phenomen, that I haven't read about here: the input signal is deteriorated when the gainclone clips!
At first, I thought that my source was clipping, and that I was seeing the amplified clipping input signal at the amp's output. But when I disconnected the signal generator from the amp, and looked at the signal, it was perfect!
Any other feedback (this is the more appropriate word I found 🙂) about this phenomen?
That's an intrinsic problem of feedback amplifiers: Coupling stuff back to the input. If that's a clipped waveform, it'll show up as such at the input.
And the back coubling can be real bad!!!
I managed to do something stupid (not uncommon 🙄 ) and this caused the magic smoke to leave the output cap's on my sound card
(I was using it as source).
It was a lm3886 and I messed up by putting a 94uf cap in || with the resistor from - to mute, instead of from the mute leg and to ground.
I guess a non inverting opamp doesn't have this issue?
I managed to do something stupid (not uncommon 🙄 ) and this caused the magic smoke to leave the output cap's on my sound card
(I was using it as source). It was a lm3886 and I messed up by putting a 94uf cap in || with the resistor from - to mute, instead of from the mute leg and to ground.
I guess a non inverting opamp doesn't have this issue?
My quesion is why all of a sudden it started clipping when i didnt before?I had my home amp IGC (LM3875 300k/10 K loop, battery P/S +/- 24V) start clipping about 2 weeks ago and it is clipping at a lower power level than it did for about 6 months.Right now i am getting approx 4 watts before clipping.I really cant point out the actual point as my trusty old heathkit scope died.
ron
ron
How did you see it's clipping? Did you look at the output with a scope? If yes, what was the peak voltage?
Yes,i used my old Heathkit scope i built about 20 yrs ago.It died shortly thereafter.I believe its the CRT as i am gettig voltage to the crt.Happened last week.I Noticed the amp distorting so i hooked up the scope to the speaker leads and turned up the amp till i saw the signal start to flatten out slightly.Then i hooked up my heath signal generator to conferm.
I tested the voltage on each battery and all 4 measured within 12.4 to 12.72.
Sorry i am having a hard time typing as i had a cycle accident yesterday and my hand and sholder are messed up.
ron
I tested the voltage on each battery and all 4 measured within 12.4 to 12.72.
Sorry i am having a hard time typing as i had a cycle accident yesterday and my hand and sholder are messed up.
ron
- Status
- Not open for further replies.