I just bought a kit to build a little stereo pre-amp based around the LM833 op amp chip. I’m going to use it for a phono signal. The circuit has RIAA equalisation for that purpose.
The kit says that it needs a 15VDC power supply. For various reasons it would be much much more convenient if I could run it off a 12VDC power supply. I have checked the data sheet for the LM833 and it says that the minimum supply is 10VDC. But of course the rest of the circuit may be built around the assumption that it will be getting 15VDC, and it may not work (or may not work as well) if it only gets 12VDC
Can anyone shed any light on this? If you would have to see the circuit diagram to be able to comment let me know and maybe I could work something out.
Desmostylus, it’s a DSE K-5402, which you can read a brief description of on their webpage (www.dse.com.au). It is actually based on an April 1994 Silicon Chip article. It is exactly the same as what Jaycar call their “Universal Pre-Amp”. You can see a brief description on Jaycar’s website too. But neither is much use in relation to the question I ask, I’m pretty sure.
I’ve been trying to find a circuit diagram on the web that was the same or close so I could direct you to it. this very rough hand drawn circuit is the closest I have found so far. The values of the various parts are different, obviously. Other differences, my kit:
[list] has an inductor immediately after the input.
has a resistor and cap. in parallel leading to another resistor and cap. in parallel where the above linked diagram has only R9
has no leds
has no cap. leading off from pin 7 of the op-amp./[list]
Apart from the above and the differences in values, the circuits are very close.
It’ll work with ±12V although it will clip sooner. ±15V will allow you to realize a (theoretical) maximum possible output of 30Vpp. Since I doubt you are trying to get more than 5-6Vpp out of this, it shouldn’t be a problem.
In fact, the performance characteristic trace on page 5 of the spec sheet shows the output with the chip powered by ±12V.
Actually this chip doesn’t have rail-to-rail output, so it’d be something like 28.8 Vpp. I think that’s a moot point though. Audio signals don’t go above 1V, I believe.