Well here I am travelling again, and this time stuck for an extra week away from home. The design bug has bit, and this time I tried keeping things small rather than crazy.
I have built a number of discrete operational amplifiers in the past. Usually integrating everything onto the board so that they wind up being preamplifiers rather than operational amplifiers.
If that confuses you - the difference is that an operational amplifier needs to be plugged into a circuit to be useful, a preamp is a standalone PCB.
The inspiration was seeing a burson amp on ebay. I looked and thought to myself "I keep starting that, and keep ending up with a preamp". Then I thought "Do it right for once".
The resultant goals:
- Dual channel op amp
- DIP8 pinout
- Good perfromance
- Class A (vs class AB which many are)
- Minimum size, whilst
- Sticking to 0805 SMD resistors caps, and...