Am 12.10.2012 05:34, schrieb Richard Prosser: > Ciruit2 should be OK with a few tweaks. > > But some questions arise also. > 1. what is the frequency range of interest? 10 Hz to 20 kHz. > 2 The desired 3V output - is that pk-pk or rms? Vpp =3D 6V. This is the MAX! It shouldn't be reached when the input signal= =20 is at max, it should be around Vpp =3D 4V to 5V then. > 3. What are the actual input signal levels? Vpp before transformer should be 0.154V or 154mV max. > 4. What is the supply? If it is a 9V battery, then your 30ohm biasing > resistors are going to drain it fairly quickly. Yes I am. > Better to use higher > value resistors and bypass with 10uF or larger caps. > > Other Comments: > You have the transformer turns ratio set at 1. This isn't in > accordance with your 1.6:1 statement above. On my transformer there is "1:6, RPrim =3D 4.6 Ohms, RSek =3D 180 Ohms". Do you mind modifying my circuitry (=20 https://www.circuitlab.com/circuit/ru78q2/zusammenfugen/ ) using your=20 ideas and republishing it? Makes this conversation a lot easier. > Are you actually going to use a '741? If you are, then you will have > limited gain for any reasonable frequency range. And noise may be an > issue also. I have LM358 LM393 741CN LM2901N at my disposal. Which one would you recommend? Or would you rather=20 recommend building an amplifier the way I did in the first schematic ie=20 using transistors? Alex > > RP > > > > On 12 October 2012 16:06, Alexander Winnig > wrote: >> Both signal sources are being shown at max amplitude. My goal is to mix = them >> so each signal source has the same volume and the final result is not to >> exceed 3 volts. >> >> Here's the current schematic. >> >> https://www.circuitlab.com/circuit/x6hjxg/verst2/ >> >> Feel free to modify and repost the link. >> >> But I thought that maybe I can save a lot of components and do it like >> >> https://www.circuitlab.com/circuit/ru78q2/zusammenfugen/ >> >> Factor between source one and source two is about 100. Thus the resistor >> values R24 and R27 to make them even. But is is not quite satisfactory. = It >> seems that -(V(Transformer)/R27 - V3/R24) * R12 is not -3 Volts as you'd >> expect from an adding amplifier. Also there's something wrong with the >> transformer. It's an 1:6 transformer that should produce about 0.013V on= the >> output side. >> >> I am not sure but I guess it is a better approach to optimize circuit 2 >> rather than the old one. >> >> Alex >> >> >> Am 12.10.2012 04:05, schrieb Richard Prosser: >> >> Maybe you meant something more like this? (Minimal Changes and one >> input changed to 200Hz to separate the inputs). >> >> RP >> >> On 12 October 2012 14:16, Dave Tweed wrote: >> >> Alexander Winnig wrote: >> >> I created this https://www.circuitlab.com/circuit/r2kea4/verstarker/ >> circuit. You can open it and simulate it in your browser, no additional >> software needed btw. >> >> But simulating creates a weird pattern. Is this really the output or >> just some flaw in the simulator? >> >> What you see is an amplifier on the left side and a signal mixer on the >> right side. So the result of the first amplifier acts as second source. >> Measurement is taken at R15. >> >> What I see is what looks like the ground node of the mixer connected to = the >> output of the amplifier, and the upper input to the mixer connected to t= he >> amplifier's power supply. Surely this isn't what you intended. >> >> -- Dave Tweed >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> >> >> >> > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .