Author Topic: Tried building this circuit, no sound ):  (Read 9627 times)

duck_arse

Re: Tried building this circuit, no sound ):
« Reply #20 on: October 13, 2016, 10:07:43 AM »
supply filtering: read this page.

http://www.muzique.com/lab/hum.htm

your 1k goes between "dot" and "effect 9V" on your dia. "effect 9V" now becomes the clean 9V/supply/Vcc**. the LED A also goes to "dot", which is the 'dirty DC'. the 220uF cap then goes to the far right, connect (+) to the clean 9V, and the (-) end of the cap to ground.

you need some way of breaking the plus end of the battery connection when the external DC is in-plugged, I'm assuming you know that.

the 47uF does the gain fooling. the 22uF cap does impedance things, bootstrapping the bias point to the emitter to increase the input impedance (I think, I'm always hazy on bootstraps).

AC gain is the diference between the input and the output voltages, yes (before the output begins to clip the signal). [dBV, also, hazy.]

ask your co-worker to find you a 10uF poly cap that he can afford, and that you can fit the build, and yes, fine then replace the electro. we use the electros because they are cheap/small/the correct capacity for the task at hand.

your choice of a high voltage power transistor (2sc3317) as replacement for a small signal audio amplifier is an interesting one. go for your life, mate, it won't break the circuit and it is not dangerous. not much is at 9V. can I ask why, though? can you hear differences?


** you need a new name for each different node, like DC in, supply, +9V. you can't have a point named "9V" this end of a resistor and that end of the same resistor.
can't be bothered

PointOfGravity

Re: Tried building this circuit, no sound ):
« Reply #21 on: October 13, 2016, 12:26:56 PM »
Thanks, I'm just sketching up a dia of what you mean. I also did a bit of browsing on reddit's diypedals sub and found out that I can't live without tone control, so I plan to put the the Big Muff Tone Control after the output cap. The only problem is, it's passive so it will take some signal away from my boosted signal, partly taking away the point of the circuit. I'm now deciding if I should replace the boost pot with a cap to hardwire the booster and then build another NPN booster circuit after the tone control, or if I should just put the tone control before the NPN booster circuit.

Quote from: duck_arse
you need some way of breaking the plus end of the battery connection when the external DC is in-plugged, I'm assuming you know that.

I have to admit I didn't know that.I figure I can do this with a SPDT Relay - do you have any recommendations?
Also, since the mains supply noise is coming from the mains supply, does this mean I don't need the resistor and cap when the relay is connecting the battery for power?

Quote from: duck_arse
your choice of a high voltage power transistor (2sc3317) as replacement for a small signal audio amplifier is an interesting one. go for your life, mate, it won't break the circuit and it is not dangerous. not much is at 9V. can I ask why, though? can you hear differences?


Slightly, but I think it might be a placebo. Before, I was using a 2N5551 transistor and noticed that I couldn't turn it up too much without getting distortion, and it was quite extreme, but I think with the 2SC3317, I could turn the pot a bit more before the signal started getting distortion. The tone also felt a bit warmer using the 2SC3317 and could still get a bit of bite when it was distorted, but I don't know if I was imagining that.  I will continue to keep sticking transistors and capacitors (I think they go in tandem with the transistors) until I find a combination I like.

Thank you for the amazing replies, A** 100/10 Distinction with bacon.

duck_arse

Re: Tried building this circuit, no sound ):
« Reply #22 on: October 14, 2016, 10:46:38 AM »
people say many things about the sound of different transistors. no reason you should be any different, if you hear it, you hear it. the lower/higher hFE of the individual transistors may well be coming into play*, as well as the internal capacitances with the power transistors. Gus has published a fuzz face derivative using power transistors, a few builds are floating around the forum currently.

as for the BMP, why not just copy the last transistor stage from a BMP, kill some birds with some stones, learn a bit more on transistors? or an LPB-1, or an electra.

your supply question. the DC jacks we mostly use have 3 connections, so that when you jamb in the plug from the wall wart, the connection to the batter opens. unfortunately, they are too simple a device to allow easy "decide between dirty DC and filter or clean battery and no filter", it's just battery or external supply. no relay needed.

* if your multimeter has a transitor tester, why not test the hFE of each before you try them in circuit. and when they are in circuit, do the static voltage measure again, keep notes of the E-B-C voltages for each transistor, maybe sound notes as well, you never know what you may find.
can't be bothered

PointOfGravity

Re: Tried building this circuit, no sound ):
« Reply #23 on: October 14, 2016, 01:32:48 PM »
....is that what that extra lug is for? damn, I've been sticking the side and middle ones together. Oops  :icon_redface: and I've already stuck a relay onto the perfboard....hmm  :-\ I'll look into the BMP transistor circuit though, thanks for the heads up.