Building custom boost circuit from scratch

[Isg1315122]

Thats everything i plan on using in one pic sorry for my bad drawing skills. The buffer ( not as drawn ) I would think could be used to increase the output impedance. The problem lies In that I can't remember if you want high or low output impedance. The obsidian overdrive has high input impedance but I think lower output. The Apollo has low input impedance compared to the obsidian overdrive and like a 390k to ground on the output. I'm really not sure what to do. I want it to be able to use either effect and have a bypass for each much like the hot fuzz pedal by bae. I'm assuming this can be done with them in series. I also want to at least build it for testing purposes (before mounting to a stomp box) to be able to switch the effect chain using a 4tdp switch. Some of this seems like a tall order but this is my plan atm.

[GibsonGM]

Hi Isg, I haven't really followed this thread, so I'm not up on what you really want, however: you want low output impedance, and a buffer will give you that.   I wouldn't get too hung up on comparing input/output impedances of effects...it is like 'RELATIVELY high input impedance, RELATIVELY low output...".  "Good" input Z could be anything from 50k to Megs!!

[Isg1315122]

It's been a little bit since I have worked on it (life) and It makes sense to why I wanted the buffer then. Thank you GibsonGM.

[pinkjimiphoton]

So i built the apollo and tried the 2n5401 and i get nothing (no signal). Collector V is -1.8v
Base V is -2.3v
Emitter V is -1.7v

Again nothing gets through, and the pot does nothing to improve or change that. Collector V seems low if its supposed to sit around -4.5v.

So my build passes sound but its attenuated which maybe because thats natural when dealing with negative feedback on bjts. Is this correct?

you sure the pinout is right? seems like the base voltage is way off.

a lot of these old vintage style circuits are less than unity gain, before true bypass, no one really noticed it.

[Isg1315122]

So i rebuilt it with original values and it does pass sound but at less than bypassed volume. I biased the collector resistor to get -4.5 v on it. That definitely  works better and sounds more crisp than the build i figured out. 

Base: -2.5v @ .04mA
R1 150k
R2 82k
Collector: -4.3v @ 2mA
R3 4.2k
Emitter: -1.9v @ 2mA
R4 2k

Im think im gonna go with this. Now i want to mix the signal with an overdrive circuit (obsidian overdrive). Is it worth it to mix the signals with either active or passive mixing (i have opamps tl071 and 2s but  with two other circuits i really want to power everthing off of -9v the opamp would likley need more voltage)

Or should i just test one before and after the other with a bypass for each? Then is it good practice to buffer the output. I know running the effects in series is less parts, and i dont mind adding the buffer but dont know if its really needed.

This is the build as it currently stands. It works fine with the values given but I used standard value resistors.  And i biased the collector Resistor to get -4.5 volts.

[Isg1315122]

So I'm checking in here, I have built the box and circuits. Each circuit checked out individually when I tested them. Once I got them in the box and hooked up things went a little weird.

A little more info about final build:
Obsidian overdrive + Apollo booster into a buffer.

The obsidian and Apollo portions can be position switched (change circuit order) via a 4pdt toggle, it uses 3/4 of the poles to do this . The other pole is used for an led which indicates which is first in the order.

I used shielded wire from input stereo Jack to the 4pdt then it goes to the foot switches with norm solid wire. Each output from the foot switches uses shielded wire back to the 4pdt. The wire coming back from the gain knob also uses shielded wire.

The problem: when the booster is the first circuit I get quite a bit of squeal. When the guitar is unplugged I get some musical interference.  The squeal is there when the order is switched but only when the gain and volume on the overdrive are up high. I checked grounds best I could, the wiring is very tight in the box.

The wiring is probably a bit sloppy. I tried my best to keep things short but once the 4pdt was in there it got crowded really quick. The 3rd pic is the way the foot switches and the bulk of the 4pdt are wired, minus the leds.
The boost is the left switch in pic and admittedly do to my poor planning the foot switches are on the opposite sides of the logical placement on the circuit board so the wires cross in the middle.

[Isg1315122]

Any body around, im stuck here with little to no idea what to do. I have some pretty hardcore squeal going on. There is a power up noise when the booster is switched on. Its worse with a power supply (one spot) and i can get it (main squeal) to go away with a battery. That is a bit subjective because the interference is there if i wiggle the circuit board around.  But in the same vain it goes away when i wiggle it too.

Im thinking its a 2 stage problem, A. Something is loose/ faulty on the board and B. the power supply is really making it worse.

Please, im begging here, inneed some help.