Search found 31 matches

by lsburden
Fri Jul 15, 2022 11:19 am
Forum: Pro Audio Design
Topic: Discrete Op Amp clipping behavior
Replies: 6
Views: 12543

Re: Discrete Op Amp design

What you describe is phase reversal which occurs when the common mode voltage is exceeded. There are many newer enhanced versions of older opamps that the datasheet indicates as not having phase reversal. The TL072 datasheet is one example. You will definitely see this on a general purpose part suc...
by lsburden
Fri Jul 15, 2022 11:18 am
Forum: Pro Audio Design
Topic: Discrete Op Amp clipping behavior
Replies: 6
Views: 12543

Re: Discrete Op Amp clipping behavior

I had somebody point me to the OPA4197 datasheet because there was a description of this behavior that sounded similar. In the datasheet it is called Phase Reversal - "Many op amps exhibit a phase reversal when the input is driven beyond its linear common-mode range. This condition is most ofte...
by lsburden
Fri Jul 15, 2022 9:35 am
Forum: Pro Audio Design
Topic: Discrete Op Amp clipping behavior
Replies: 6
Views: 12543

Discrete Op Amp clipping behavior

I'm working on a simple discrete Class-A op amp. This isn't the first time I have worked on a discrete amplifier but there is a clipping behavior I would like to dig into this time. The amplifier design is simple - run of the mill input differential pair, single transistor VAS (active or bootstrap l...
by lsburden
Fri Oct 08, 2021 1:49 pm
Forum: Document
Topic: "Low Noise Electronic Design," Motchenbacher and Fitchen, 1973
Replies: 9
Views: 40311

Re: "Low Noise Electronic Design," Motchenbacher and Fitchen, 1973

I was also able to get something going by applying the positive DC voltage to transistor base...duh.
by lsburden
Fri Oct 08, 2021 1:47 pm
Forum: Document
Topic: "Low Noise Electronic Design," Motchenbacher and Fitchen, 1973
Replies: 9
Views: 40311

Re: "Low Noise Electronic Design," Motchenbacher and Fitchen, 1973

ok.
I'm aware of the positive DC potential at the non-inverting input of the amplifier in figure b.
I was able to get something going with a negative DC potential at the non-inverting input of the amplifier in figure a.
This looks like a fun circuit to play with...
by lsburden
Fri Oct 08, 2021 10:04 am
Forum: Document
Topic: "Low Noise Electronic Design," Motchenbacher and Fitchen, 1973
Replies: 9
Views: 40311

Re: "Low Noise Electronic Design," Motchenbacher and Fitchen, 1973

I tried simulating the inverting amplifier with no luck.
What am I missing?
by lsburden
Fri Nov 01, 2019 11:23 am
Forum: Test, Measurement and Repair
Topic: APx500 Flex Audio Analyzer
Replies: 7
Views: 46710

Re: APx500 Flex Audio Analyzer

I agree. Pricing for this does not make sense.
by lsburden
Thu Oct 31, 2019 10:55 am
Forum: Test, Measurement and Repair
Topic: APx500 Flex Audio Analyzer
Replies: 7
Views: 46710

Re: APx500 Flex Audio Analyzer

Doesn't really matter to me.
Both are out of reach for me.

Good deal or not - AP has some clout and name recognition throughout the audio industry (pro, consumer, hi-fi, etc.)