My First Schematic

[M.Spencer]

I've been working on learning how to read and draw schematics, and since I have been playing around with a circuit that I like on my breadboard I thought I would try to draw it up.

This feels like me asking the MENSA club to check my algebra 1 homework, but would someone mind looking at this and telling me if A), it looks like I'm doing this right and it's a functioning circuit schematic; B) what could be done more efficiently (i.e., power filtering, redundant components); and C) what's the best way to go about learning how to translate this to a vero board layout?



It's a SHO pushing two Bazz Fusses with a switch that bypasses the second BF stage into a LPB as a basically a volume knob, with a BMP tone stack at the front end and what I thought was a voltage sag for the BFs (but might actually be a bias pot? I'm not sure, just know it sounds cool). I'm considering ditching the LPB because I don't need THAT much clean vol boost at the end of the signal...or maybe just attenuating the output volume somehow?

Let me know what you folks think, and thank you for your consideration!

[bool]

C 10uF and R 100K after the mosfet are redundant.

[merlinb]

The 1M resistor after the tone pot is also redundant.

[duck_arse]

Q3 has no collector load resistor.
anode of D1 goes to source of Q1, not ground (possibly a drawing overlap). the gain pot wiper needs a connection.
generally accepted practice is to boost some, then tone control, preventing the tonestack loading the signal source.
a voltage sag would usually be in series with, sagging, the collector supply.
the 43k should be base to ground on Q4, not before the cap.

[M.Spencer]

Thanks for your input folks, back to the drawing board!

[M.Spencer]

How's this? I ditched the LPB stage and a few extraneous components and moved the BMP TS after the SHO. I left the resistor off the collector of Q3 on purpose - the bias pot (originally intended as a voltage sag, but wired up incorrectly which yielded cool results) didn't sound as interesting with a resistor there. Does this open up the possibility of frying the circuit?  The first diode (zener) actually does go between Q1 base and ground as per the schematic I used.

Anything else you folks see?
@duck_arse could you explain what you mean by "loading the signal source"? Is that another way of saying 'reducing the signal below unity gain'? 



Thanks!!

[antonis]

You need a collector resistor (to "feed" Q3 with DC ) which have to be connected at C8/D4/D5 joint...

I can't clearly understand R8's purpose but if you want it for - selectable by SPST - feedback you have to connect it also at the above mentioned joint (and move the switch between C7 & Q3 base - omitting C6)..

Perhaps you have to increase C8's value to 100nF or higher (depends on what you want to drive next..)

[duck_arse]

I could try and explain it, but you'd be better searching the forum for "stage loading", and "input impedance", as they will turn up some well spoken experts, instead of my fevered dribble.

thats a good pedal name, by the way. are you drawing with eagle?

that bias pot will have Q2 wondering just what is going on, starving it current and pinching its C-E volts (maybe?), but Q3 still has no DC on the collector, so it will be even more confused as to what to do.

[M.Spencer]

thats a good pedal name, by the way. are you drawing with eagle?

I used EasyEDA for the schematic; it was a bit buggy but worked well enough. My girlfriend dreamed she was in a band called Stiff Sisters so I stole it from her subconscious.

So I did a little update on the circuit and schematic:



And last night I drew up my first veroboard layout of the project (using DIYLC).



It's as yet unverified. Hopefully I will have time to build it after rehearsal tonight. Still deciding whether it needs a pulldown resistor, and the ripple smoothing cap didn't seem to do much so I'm leaning towards emitting it. Either way I'd love the opinions from the more experienced builders/designers. Ideally I'd like to fit this in a 1590B (fingers crossed), with 4 knobs and one switch. Any place you can see to save space on the vero layout? Love to cut down a column or row if possible. Any tips on boxing with such a tight fit? Any other major flaws you notice in the design? Thanks folks!   

[antonis]

2 minor notes: There is no need for C7 and also no need for E24 resistor values...

and

1 major comment: If you want to bias (simultaneously or not) Q2 & Q4 you better move the 10k Pot(s) to their Emitters and wire it(them) as variable resistor(s)..
(you didn't take in mind duck_arse's notice about that..)

[duck_arse]

without ANY regard for the correctness of the layout OR the circuit ..... jump Q4 left to L (all top references). shift the P 100nF to N. move the Q3-B cut from P to O, under the 100uF. move the 430k at U to P. move 100nF at T top connection and Switch 1 down 1 hole. move the 2k2 at U bottom leg and Bias 1 up one hole, then left to T. cut off V.

if you use a flying link instead of board level tinned wire at H, flying from I/A to I/N, shift those top four cuts on H, top 2 1 right, next 2 1 left, you can then cut H. that's 2 coloumns gone. that should open so other avenues of reduction, like the 22k and the link at K. you also need to check the voltages on either end of yr electros, make sure they are pointing the right ways, and mark the circuit diagram accordingly.

a very minor point on yr circuit dia, "m" is the "milli" multiplier. we want whacking big "M" to indicate the mega-ness. (antonis, it's your language ....) a major point on yr dia, the vol pot is wired wrong. out almost always comes from the wiper, with the hot signal going to one end, most usually clockwise. that 100uF should probably go from bias wiper to ground, but that's a whole nuther kettle of fist.

if you've breadboarded this, and it sounds and works like 'something', go ahead and vero it. otherwise, a rethink, esp that bias pot.

[antonis]

we want whacking big "M" to indicate the mega-ness. (antonis, it's your language ....)

I can clearly state - with sole responsibility - that I have never intervened to metric prefix (from yotta to yocto)...

[M.Spencer]

There is no need for C7 and also no need for E24 resistor values...

Yeah, I took C7 out. Thanks for the tip. But I'm not sure what you mean by E24 values. Could you explain?

If you want to bias (simultaneously or not) Q2 & Q4 you better move the 10k Pot(s) to their Emitters and wire it(them) as variable resistor(s)..
(you didn't take in mind duck_arse's notice about that..)

I did see that issue mentioned earlier and I tried wiring it as a VR, but I to me it sounds more interesting this way (even if it does cut the volume the more CCW it gets). I like the gated/sputter sounds in addition to the full fuzz onslaught!

[M.Spencer]

Great suggestions on the vero reduction, thank you very much!

a major point on yr dia, the vol pot is wired wrong. out almost always comes from the wiper, with the hot signal going to one end, most usually clockwise.

I rewired it as you suggested, but I didn't notice any difference. Apart from Vol 3 out being "wrong" as per the norm, are there any disadvantages to doing it this way?

that 100uF should probably go from bias wiper to ground, but that's a whole nuther kettle of fist.

I tried this suggestion but I think I like how it sounds with that cap going to 9v instead of ground.

It's on the breadboard and does indeed sound like a fuzz pedal! But more so this is a big learning exercise for me.

[LightSoundGeometry]

I am new but it looks good to me lolol!! when I seen you put it to a vero layout I was thankful. I can understand vero somewhat but not yet good with schematics. I am looking for an easy fuzz on vero . I still dont understand positive ground so I wont try another fuzz unless it is wired normal.

[antonis]

But I'm not sure what you mean by E24 values. Could you explain?

Ε6, Ε12, Ε24, Ε48 & Ε96 are preferred value system with number indicating how many standard values are included per decade..
(this has to do with value tolerance..)
http://www.logwell.com/tech/components/resistor_values.html

When you use resistors (or caps) in a not accuracy depended circuit (such as voltage dividers, biasing items , passive filters etc.) it's more practical to choose commercial availiable values (like E12 series..)

[duck_arse]

antonis - it's all greek to me. is metric a greek word too? (and why did the lpb-1 use E24's?)

M.S - #1 rule is - don't let us tell you what you like. if it sounds like something, you have something. build that something if you like it. this goes for the funny bias and the 100uF cap to where.

the volume pot wired as per V3.2 will vary the load on the output stage as the volume setting is changed. again, you might like the tone to change with vol level, most people would be surprised by this action, and complain it don't work rite.

also, did you check your datasheets for the transistors you've specified, and make sure of their orientations? cause I didn't. rule #2.

with a name as good as stiff sisters, you gotta have something built to show by the end (even if it's something completely new/different). that's rule #3.

and LSG - have you thought of doing a bazz fuss, or variant, yet?

[antonis]

it's all greek to me. is metric a greek word too? (and why did the lpb-1 use E24's?)

To me too..  Yes..  (I haven't the slightest idea..)

[M.Spencer]

(and why did the lpb-1 use E24's?)

I had some initial muddyness/distortion trouble with my LPB1 stage with the Jack Orman values, and after reading this thread  [http://www.diystompboxes.com/smfforum/index.php?topic=104730.msg940320#msg940320]I changed the values to reflect Philip Bryant's schematic and it worked fine. (the E12 values you're talking about the emitter resistor, 360R vs 390R correct?)

M.S - #1 rule is - don't let us tell you what you like. if it sounds like something, you have something. build that something if you like it. this goes for the funny bias and the 100uF cap to where.

I appreciate that. The nice thing about not having electrical engineering background/experience is that I DON'T know the rules, you know? Some of my favorite musicians didn't know the rules either... I'm willing to suffer many electronic defeats as long as there's an occasional happy accident!

the volume pot wired as per V3.2 will vary the load on the output stage as the volume setting is changed. again, you might like the tone to change with vol level, most people would be surprised by this action, and complain it don't work rite.

I think I gotcha. The V3.2 version of my volume out would vary the load and therefore change the tone, and how it effects the next pedal in the chain.  

also, did you check your datasheets for the transistors you've specified, and make sure of their orientations? cause I didn't. rule #2.

with a name as good as stiff sisters, you gotta have something built to show by the end (even if it's something completely new/different). that's rule #3.

Check. I will double check with the breadboard circuit as well. And thanks again!

and LSG - have you thought of doing a bazz fuss, or variant, yet?

Yeah dude, if you're looking for an easy, decent-sounding fuzz, try the bazz fuss. The part count is criminally low and it will teach you a bunch about this hobby (that's where this thread started - me building two bazz fusses in series on a breadboard and extrapolating from there).

If you want something a little more toothy, check out one of these:

http://tagboardeffects.blogspot.com/2013/04/1-knob-fuzz-bonanza.html

The Meathead is wicked. I plan on building a few of these to see how the different component values alter the tone.  

[LightSoundGeometry]

I just got a notice in email

very cool..I really appreciate that, I tried a few fuzzes and wasted some parts lol!  I will put a list of BOM together and get working on one. I enjoy playing the bass as well as the guitar to !

also very cool name for your circuit.