Vref on tube booster (pedal i designed) is ~3.5v instead of 4.5v

[bartimaeus]

moving on, don't you agree that the position of the RelayB switch in snow123's schematic will likely cause pops?

Where do you locate the possible pop..??
(C2, C50 or somewhere else..??)

like i said, after Q1 and R3. the bias from R2 will result in a DC of 0.39V (Vr minus diode drop) at the emitter of Q1. that DC is present on a pin of the RelayB switch.

[duck_arse]

he's got you, Antonis. will it pop?

also - snow's relay contacts are drawn non-sensical. like mr black does.

another also - snow - you need to check your board and see if there is actual copper connecting C5 to R6. your schem does not show a junctioning dot at that node. you probably should run DRC or whatever that button is in Eagle.

[antonis]

he's got you, Antonis. will it pop?

Frankly, my friend, I don't give a damn..
As you've already pointed out, switch wiring is mildly unacceptable..

As long as lug B doesn't come to Q1 Emitter, with A connected to C2 & C to C50, popping should be the last issue of concern..

P.S.
My poor experience taught me that an IN-OUT switch grounding (with or without pull-down resistors) is more than enough for popping prevention..
(even with leaky big electro caps..)

[bartimaeus]

he's got you, Antonis. will it pop?

Frankly, my friend, I don't give a damn..
As you've already pointed out, switch wiring is mildly unacceptable..

As long as lug B doesn't come to Q1 Emitter, with A connected to C2 & C to C50, popping should be the last issue of concern..

P.S.
My poor experience taught me that an IN-OUT switch grounding (with or without pull-down resistors) is more than enough for popping prevention..
(even with leaky big electro caps..)

with the schematic wired as it is, won't the switch grounding make things worse? by bringing the left pin of C2 to ground, it will cause a greater voltage discontinuity when it connects to the bias voltage at the emitter of Q1

it's pretty simple to just place C50 and R50 between Q1+R3 and RelayB. that way the input buffer is correctly isolated from the rest of the circuit.

[antonis]

with the schematic wired as it is, won't the switch grounding make things worse? by bringing the left pin of C2 to ground, it will cause a greater voltage discontinuity when it connects to the bias voltage at the emitter of Q1
it's pretty simple to just place C50 and R50 between Q1+R3 and RelayB. that way the input buffer is correctly isolated from the rest of the circuit.

I think it should be more simple to wire the switch properly..

P.S.1
I don't get any reason for trying to heal a bad design than to just alter it..

P.S.2
P.S.1 also stands for that ridiculous bias configuration of Q1 & Q3 buffers, also..

[snow123]

another also - snow - you need to check your board and see if there is actual copper connecting C5 to R6. your schem does not show a junctioning dot at that node. you probably should run DRC or whatever that button is in Eagle.

there is a trace there.

[snow123]

also - snow's relay contacts are drawn non-sensical. like mr black does.

how so?

[snow123]

and FWIW, i did have some switch pop with my current board, but its pretty quiet and doesn't happen every time i hit the switch. but if i can reduce the pop even further, i would like to do that.

[antonis]

also - snow's relay contacts are drawn non-sensical. like mr black does.

how so?

Precisely so..

[snow123]

also - snow's relay contacts are drawn non-sensical. like mr black does.

how so?

Precisely so..

how is it "non-sensical" though?

[antonis]

@snow123: Shouldn't be more sensible to ask for possible issues the author/creator/designer of what you follow, should it..??

[snow123]

@snow123: Shouldn't be more sensible to ask for possible issues the author/creator/designer of what you follow, should it..??

well if you're saying that im following mr blacks diagram (which im not sure if you are), im not. the wiring that i currently have is just what made sense to me.
I really just took the switch wiring from this pedal: http://effectslayouts.com/wp-content/uploads/2021/05/tracksuit-build-doc.pdf and moved one of the relays towards the circuits input, because if i just directly copied the tracksuits switch wiring (without making any changes), i would get no sound with the effect on.

[snow123]

and honestly, im just lost on if the current relay switch placement is fine or not, or how to fix it if it is not fine.

[bartimaeus]

i was wrong about the order of components like C1 and R1, you can ignore what i said about those. unfortunately i think antonis's disagreement with mr black is preventing antonis from offering any real help after i said that.

overall, your circuit should be fine! really, you just need to move C50 to the be after Q1 and R3. see the image i attached. that will isolate the switch and anything else from the bias voltage present at the emitter of Q1.



at this point, i'd just do that and order a board.

[antonis]

unfortunately i think antonis's disagreement with mr black is preventing antonis from offering any real help after i said that.

(you've got me wrong but let it be..)

As I said before, it should be better for RELAY switch to be wired in a different way..
(at least, not with a permanent 100k load on Q1/Q3 Emitters, which load severy dominates any next effect high input impedance..)

But plz proceed with any anti-pop configuration you might think effective..

[duck_arse]

also - snow's relay contacts are drawn non-sensical. like mr black does.

how so?

Precisely so..

how is it "non-sensical" though?

switches have sense**. this includes relays, rotaries, momentaries, "stomps". the common part of a switch is connected to a something that then moves it, throws, from the 'normally closed' to the 'normally open' when you actuate the switch. normal means when-at-rest, unpowered, as drawn, how it is when you pick it up off the desk.

add a second pole. the now two commons are attached to a something that moves them to make/break contact, but both commons throw at the same time, and in the same direction, as they are on the same handle, actuator, armature, lever, toggle, whatever. so for a double pole switch drawn in circuit, both throws must be drawn in the same sense, that is in the snow123 drawing EITHER both up normally closed, or both down normally closed. one up and one down cannot make mechanical sense, so it doesn't make circuit drawing sense either.

there are ways around this, for the real schematic hardnuts. you can connect the two remote poles with a Z-shape dotted line, to indicate one up and one down, but the line can make an otherwise tidy diagram a mess. in mr black's case, he just says look away if you know this stuff, cause then he can put any old rubbish as fakt. or straight jive. someone new to the sport may well translate the electrical drawn wrong to the mechanical wired wrong, and wonder why their just completed pedal then doesn't work.

further to switch drawing etiquette, if you have multiple poles in a switch, identify them as such. include SW1A, SW1B, SW1C etc, at the very least. draw the switch right and convolute the wirings if you have to, but draw the switch right to start with.





** I dunno where I lernt this, might have been a C&K catalogue, or a technical drawing for electrical circuits textbook, or R.G., or Mark Hammer ......

[duck_arse]

i was wrong about the order of components like C1 and R1, you can ignore what i said about those. unfortunately i think antonis's disagreement with mr black is preventing antonis from offering any real help after i said that.

overall, your circuit should be fine! really, you just need to move C50 to the be after Q1 and R3. see the image i attached. that will isolate the switch and anything else from the bias voltage present at the emitter of Q1.



at this point, i'd just do that and order a board.

don't poke antonis unless you've brought beer.


you have left a C50 large electro hanging in your dia. it will pop for sure from leakage when that switch switches.

[antonis]

you have left a C50 large electro hanging in your dia. it will pop for sure from leakage when that switch switches.

I think C50 is grounded via a 100k resistor..
(not shown here but existing in complete schematic..)

[duck_arse]

but antonis, we can only comment on what we can see. we must not conject, surely, on incomplete dias?

[anotherjim]

Argghhh...
I see the correct relay contact arrangement. Contact "A" of both poles is the bypass position & contact "C" for active. Maybe my eyes are seeing it wrong?

Yes, Q1e has Vr-Vbe and the relay switches between that and 0v. C2 will pop.
C50's new position at Q1e makes me happy so long as the 100k R50 remains.
Perhaps R20 should be duplicated in the bypass output for perfection?