Well, just trying to make the point that it may not be as simple as the question seems. The original circuit is calibrated as a whole package. Component tuners and amps and preamps and decks etc are designed differently, expecting to be modular. In circuits expecting to feed multiple outputs, there are usually some isolating componentry as well as a buffer amp to ramp up and prevent loading down of the circuit. You simply can't draw a square around the existing preamp circuit and power amp circuit on the schematic and expect them to work in a modular way, especially if the orig amp and appurtenant circuitry is still connected. The preamp transistors are very sensitive to bias current changes and impedance mismatches have a way of causing the bias to drift off spec. Also, powerful amps usually requires an intermediate robust preamp that is capable of outputting more than these small preamps. Some preamps are more powerful than your boombox output amp. They are designed to ramp up the power to feed the hungry output devices. One method of perhaps making this work for you is to take signal from the line-out jacks. Those jacks are intended to feed another component. The only problems are that A: You won't be able to "shape" the audio tonal curve and B: you'll need to use an amp that has an integral volume control. Many amps, especially those T-amps and Digital amps already have their own. Give it a try. Might result in much more cleaner sound than sneaking some juice from the volume pot circuits.
The old "Cut First, Measure Later, PM Norm" thing seems to always apply with me!
:super:
