I built a small amp with an LM2877 and sounded pretty good. I added a custom 2 way filter/ crossover to make the stereo amp a mono High/Low. It was very quiet so I added a TL082 Op Amp and it is now very over driven or distorted. The crossover point and sepperation is ok. I have provided a drawing and I hope it is readable.
https://sites.google.com/site/kroekerta/opamp1
https://sites.google.com/site/kroekerta/opamp1
The LM2877 is intended on a single power supply but most opamps including the TL0 series are not. They CAN be used on a single supply but you have to add biasing and DC blocking capacitors to 'fool' it. It's not difficult at all but will need a few more resistors and caps.
Analog Devices: Analog Dialogue: Avoiding Op-Amp Instability Problems In Single-Supply Applications
Refer to figure 3 in this link. That will fix your problem. One bias network will be OK for both channels meaning you only need one RA and one RB. If you want to use a separate bias for each channel that's OK too, it's just a few more parts.
Since the gain of the first stage is less than unity and the impedance is so low, why do you even need an opamp here? A simple resistive attenuator would do fine.
G²
Last edited:
Your opamp 'gain' is 274/665 or 41.2 % So you need a pair of resistors such that r1 plus r2 = 665 AND r2 = 41.2% of 665. Get your calculator because you don't learn when I do the work. (It's really easy)
G²
Not according to the application notes.. The schematic shown is from the application notes, but there is also a schematic using a symmetrical power supply.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.