Aiwa TP-1011 preamp

Aiwa TP-1011 is the reel to reel tape machine that Ritchie Blackmore have used (and apparently is still using as he was using it with Deep Purple just weeks ago) to boost his amps to get a certain tonality and gain. People have been making different versions of the preamp part of the Aiwa for years. The original schematic is available on internet if you are interested to study it.

So I made my "Aiwa" also. I will put the schematic and the layout for vero board down below. I used the original transistors made by Toshiba but people have been using others as well. The vero board layout has only generic symbol for the transistors: Collector, Base and Emitter. When you assemble the board, you need to find the right orientation for the transistors that you use because different transistors have different pinouts. The correct pinout for the original Toshiba transistors is indicated on my schematic. The best way to determine the correct pinout for a transistor is to use the digital multimeter hFE measuring function (gain measurement). When you get a numeric reading, the orientation is correct.

I also found that the gain control is pretty essential (to turn the gain down) for the circuit because the original circuit that has the 56k resistor, gives a tremendous amount of gain. The circuit distorts on its own pretty heavily. That's why I replaced the 56k resistor with 1k resistor and B10k potentiometer in series. The 1k resistor on it's own (the B10k pot at minimum) gives a clean signal and anything more than that, the circuit will start to introduce distortion that actually sounds pretty cool but I just wanted to have some control over it. B50k pot would offer almost the original gain on tap if needed but I found the B10k pot to be more than enough for my needs. There is no 56k resistor anymore on my schematic. Replaced it with the aforementioned arrangement.

Other places to experiment are the input and output capacitors. I found 1uF for the input and 1nF at the output pretty good values. For example the 1nF output capacitor will cut a lot of  unnecessary low end. The smaller the F value, the more it cuts low end and focuses the tone towards higher frequencies. Same goes for the 4,7uF coupling caps but I kept the original values for now. I used bipolar coupling caps but I don't know if it makes any difference. Again you may want to adjust these to your liking. Everything else is according to the original circuit AFAIK. All capacitors are 25V or more.

The circuit needs +18 VDC and you can add a charge pump circuit to make it from +9 VDC or use external power supply that offers +18 VDC. I happened to have a small utility PCB (called Road Rage) made by Madbean Pedals that uses a charge pump chip to make +9 VDC to +18 VDC.