Re: Building the 'Minimod' AM modulator-questions!
Apart from the polystyrene caps, which were rather expensive as they were only in multiples of 10, I sourced all the caps for the project from RS. I am planning to build three of these units, so caps in multiples of 5 were fine for me.
All of the following were acceptable from a size, functionality and price point of view.
So, as requested, here is a list. I tend to use RS as they have no minimum order and the bits will be there next day. Anyone can set up an online account.
C1, C13 Polystyrene 270pf sourced from Ebay
C2 Polystyrene 100pf sourced from Ebay
C3 Ceramic 10nf /50V RS 5381196 qty 5
C4,C11 Electrolytic 330mfd /35V RS 2286789 qty 5
C5, C7, C10 Ceramic 47nf /100V RS 5381348 qty 5
C6 Ceramic 4.7nf / 100V RS 5381304 qty 5
C8, C9 Electrolytic 10mfd / 35V RS 2286717 qty 5
C12 Ceramic 680nf / 50V RS 5381607 qty 5
LM386N IC RS 5342911 qty 1
Hope that helps.
At the moment I haven't finalised the audio input circuitry. Mono audio, from the headphone jack of the computer, goes straight to the 0.68mfd capacitor, C12.
Having played with it, for my audio sources, some form of auto level control would be really useful to ensure the modulation depth stays at maximum without distortion.
I'm sure there must be a 8 pin DIL IC that is an auto level control? I've not investigated yet.
Cheers
Nick
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