EHX Freedom Preamp schematic?

52
the finger genius wrote:Thanks, I d missed this, also the single battery is making more sense, I ll see how it sounds since obviously a single 9v would be easier.I think I would get a 16-20 volt DC power supply and use that instead of batteries. that won't cost more than a couple of batteries and allows you to build the pedal in a small enclosure.also, not sure if that's been mentioned, I think you should bypass it directly from the input jack instead of the way it's bypassed in the schematic after the first input stage.

EHX Freedom Preamp schematic?

53
the finger genius wrote:Thanks - input jack is wired the same way - if I just get an a regular 18v power supply and treat positive and negative like the positive and negative of two batteries it should work? I did move the bypass point.yep, that should work. you could always just try this on the breadboard, just building the voltage divider (the upper left corner of the schematic) and measure the voltages. from the "center tab" (ground) to the positive and to the negative side of the supply and should read +9 / -9 volts.

EHX Freedom Preamp schematic?

56
the finger genius wrote:Tried this on a breadboard yesterday and again having issues where my pots aren't really doing anything, going to start fresh one more time today. One other question - is there a good reason why the 1uF caps should be 100V . I thought the maximum voltage here is 9 or 18, right?does the volume pot work? what do you use to test the circuit? a loop pedal or a test tone?try to replace the trimpot with resistors (1K, 3k3, 5k, 10k ......).as I understand it, the tone pot should work on both sides, from middle positon to one side cut some highs, to the other side cut some lows. the bite pot on my breadboard does cut some "bite" as in cutting some highs in the distortion. both these changes might be hard to hear if you only use a test tone to check it.

EHX Freedom Preamp schematic?

57
the finger genius wrote:Tried this on a breadboard yesterday and again having issues where my pots aren't really doing anything, going to start fresh one more time today. One other question - is there a good reason why the 1uF caps should be 100V . I thought the maximum voltage here is 9 or 18, right?100V is overkill for the electrolytic decoupling capacitors in a pedal. I'm guessing they used them because they bought them in bulk and used them in other circuits where they might have been exposed to higher voltages.If, for some strange reason, you were using 1 uF ceramics for decoupling, then you might want to use high-voltage rated caps to overcome the capacitance de-rating effects of DC bias.

EHX Freedom Preamp schematic?

59
I've been using both music from my phone and a guitar to check. Just finished again, and this time volume works, gain works but I feel like there should be more variance from it, tone doesn't seem to be much audible difference but if I sweep the pot quickly I feel like I barely hear something. I tried with 9V, 12V and 18V, and definitely hear a difference in headroom, so nice to have the options. For the tone circuit - I am feeding middle of tone pot from a 27k resistor (replacing the parallel 47k and 68k), 1 / CCW of tone pot is going to 10k (to ground) and 22n, 3 / CW of tone pot is going to 22n (to ground) and 10k. Am I misunderstanding the pot wiring, or should I not have replaced the parallel resistors?Also, does anyone have any suggestions on how to alter to give the bite / gain knob more variance?Thanks!

EHX Freedom Preamp schematic?

60
the finger genius wrote:I've been using both music from my phone and a guitar to check. Just finished again, and this time volume works, gain works but I feel like there should be more variance from it, tone doesn't seem to be much audible difference but if I sweep the pot quickly I feel like I barely hear something. I tried with 9V, 12V and 18V, and definitely hear a difference in headroom, so nice to have the options. For the tone circuit - I am feeding middle of tone pot from a 27k resistor (replacing the parallel 47k and 68k), 1 / CCW of tone pot is going to 10k (to ground) and 22n, 3 / CW of tone pot is going to 22n (to ground) and 10k. Am I misunderstanding the pot wiring, or should I not have replaced the parallel resistors?Also, does anyone have any suggestions on how to alter to give the bite / gain knob more variance?Thanks!sounds about right with the tone circuit , and then connected between the 1uF cap and the 4k7 resistor. the 27k resistor should work fine.to me the "bite" cuircuit looks like a bandpass filter, so it will not have much effect on the distortion. maybe Nate or Dr Balls could enlighten us?

Who is online

Users browsing this forum: No registered users and 0 guests