A few more beginner questions...

Started by deadlyshart, December 17, 2016, 01:16:23 PM

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deadlyshart

Hey guys, sorry to bother you again but I've come up with a few more questions since my last build, that I'm wondering about, and it would be great if anyone could help me understand.

1) What kind of wire should I be using inside my pedals, to connect the board to the jacks/etc? Solid or braided? I'm guessing I want it flexible, so braided? Then again, if it's solid, I can bend it to a shape I want inside, and it will stay in that shape. So what do most people use? And what thickness?

oops I hit enter. Here's the rest:

2) In a lot of photos of circuits I see with transistors, the transistors are in a socket. Is this because transistors are really sensitive to heat or something, and the heat of soldering could damage them? Should I always use sockets for transistors?

3) I'm also seeing a lot of these "boxy" components (I can't tell, but I think they're caps), like in the second photo of this guy's thread. Why use these instead of the more common types, is there some advantage?

4) I see audio/log taper pots a lot of the time. Is there any reason I can't replace one of them with a linear pot of the same value, aside from just how the resistance will grow as the pot is turned through its cycle (if they're both 100k, for example, the linear one will be 50k at the halfway point, but the log one will be 10k) ? Is there any other difference?

5) I really can't figure out how most people are anchoring their circuit boards inside the chassis. So far I've been able to attach the pots to the board, which has worked well enough, but it's definitely not going to work for larger ones. What do you guys do? Do you leave it "floating" in there, just connected by wires and smooshed down when the lid is closed? Do you use standoffs? Epoxy it to the chassis?

6) I'm worried that I'm using subpar jacks and pots. For example, I use these pots right now. They're not as hefty as these awful squat ones, but are there better, slimmer ones, or are those standard? Similarly, I currently use this type of jack, but it both takes a bunch of space and is fairly "exposed" inside. I've seen these enclosed ones, should I be using them? They seem to be harder to find and more expensive when I do.

Sorry for all the questions again, and any advice is appreciated.

EBK

Quote from: deadlyshart on December 17, 2016, 01:16:23 PM
Hey guys, sorry to bother you again but I've come up with a few more questions since my last build, that I'm wondering about, and it would be great if anyone could help me understand.
Fixed that for you. No need to apologize for being willing to learn.

Quote
1) What kind of wire should I be using inside my pedals, to connect the board to the jacks/etc? Solid or braided? I'm guessing I want it flexible, so braided? Then again, if it's solid, I can bend it to a shape I want inside, and it will stay in that shape. So what do most people use? And what thickness?
24 gauge stranded is pretty standard around here.  There are different levels of quality, however....

Quote

oops I hit enter. Here's the rest:

2) In a lot of photos of circuits I see with transistors, the transistors are in a socket. Is this because transistors are really sensitive to heat or something, and the heat of soldering could damage them? Should I always use sockets for transistors?
If possible, always socket transistors and ICs.  They can be more sensitive, and they often offer opportunities to tweak things.

I only have time to tackle those first two questions at the moment.  Someone else will happily chime in.

Quote
Sorry for all the questions again, and any advice is appreciated.

Again, fixed that for you.   :icon_wink:
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GGBB

1) Typically braided 24awg - but 22-26awg is fine. Thicker gauge is too bulky and doesn't fit in pcb holes. Thinner is too fragile. Solid core breaks more easily from repeated movement, especially if it is nicked (when stripped), but I like using it for pots with lugs when the pcb is supported by the pots (designed for pcb mount pots). I don't like using it for other connections because it breaks and because even though it stays in place it is a hassle get everything into place without ending up with misshapen wires.

2) Often in DIY the purpose is experimentation and ease of replacement, but yes they are more easily damaged by heat or static discharge than say resistors. Some component such as MOSFETs especially so.

3) Caps. Advantages are looks and standard pin spacing increments.

4) No other difference. Just remember that the resistance at position x difference translates into how the control feels or responds to the user, so the taper is chosen for a specific reason.

5) All of the above. There are probably many threads here addressing that topic.

6) Style is a different issue than quality. It doesn't pay in the long run to use low quality pots and jacks, but many diy pedals aren't intended for the long run - that's okay. Cheap jacks feel flimsy - like the contact isn't really solid and gets looser over time - I don't like using those. I have a hard time knowing a low quality pot from how it feels when its new, so I typically just buy what's tried and proven - Taiwan Alpha.
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GibsonGM

3) That looks like a green cap, yes...no matter, it's just a style...poly types, etc. are all good....the only ones to TRY to shy away from (IMO) would be ceramic and tantalum, but both are actually used quite a bit and are not "bad" or anything.  Long story, ha ha.   Small value caps (picofarads) tend to be ceramic, they are fine.

4)  Well, since you know about how the taper works, you can probably imagine that the control won't function *the same* as it was meant to.  You CAN replace each type with the other, but you may find it difficult (near impossible?) to make the control behave the way you want.  With log pots, part of the range happens very fast....and also, as the ear HEARS in a log manner, a volume control is much more intuitive if it too is a log taper.

5) many people use metal or plastic standoffs...I bet Smallbear has some.  They offer solid attachment.   I actually just use solid core wire for my builds, and 'fold' the PCB into the enclosure. I place non-conductive foam around, padding it, so it can never hit the back of the enclosure.   I'm a hack  ;)   I've never had a single issue this way.  The board is not actually "hanging" from the pots, or eventually the wire WOULD break, someday...

6)  Generally, if the pot/jack FEELS well-constructed, it is.  Sounds like you sorta know the pot there may not hold up over years and years ;)   I like Alpha pots, the small kind (6mm?), and Switchcraft jacks...open, as you showed, are what I use but some ppl also like the enclosed kind, which I find better for amps.    Input jacks are frequently (most always?) the stereo jack type, since we use them for power switching at the same time you plug your cord in...

Again, peruse Smallbear electronics, whose owner is on this forum....not affiliated, but I have never had a negative experience purchasing my parts there - he knows what we're looking for, and only provides quality stuff. 

Good questions! 
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MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

rutabaga bob

I think there's more than one thread on here about mounting circuit boards...I've probably started one myself somewhere!  Right now, I hot glue the circuit to a piece of cardboard, which in turn gets glued to the enclosure.  That said, I also have done some on standoffs, and some with pcb-mounted pots, which allow you to just insert the pots through the holes and tighten down the nuts.
Life is just a series of obstacles preventing you from taking a nap...

"I can't resist a filter" - Kipper

robthequiet

I like this style:

Standoffs

There are other types. If you visit a hardware store you can find items used for securing AV cables or antenna wire (is that still a thing?) that might work -- depends on your build. One idea is to do a general search for "Gutshot" to see how people do things.

stringsthings

My 2 cents on #4.

99% of the time, it's best to use the taper specified in the build.  The pots will have much better control in their various circuits
when the taper is correct.

bool

Sockets for transistors ....

They allow for swapping when you start chasing the "tone grail". Often, when the particular "holly transistors" are found, you can solder them permanently (into your sockets).

duck_arse

#8
sockets - can be a point of failure, we have had debuggs here that were IC pins not connecting with the socket they were fitted to. and things can fall out of sockets. although there are ways to hold them in, as well.

many methods of board mounting. use short lengths of 0.6mm tinned copper wire on your pot-to-board links, if the pots are in line and layed out right, and in many cases this will be support enough for a small board. there is millions of different types of standoffs, some self adhesive, some screw mount. looks around, try what you can find. some are just too big and difficult to fit in the cases.

pots - like they say, alpha taiwan. (you need to watch your shafts match your knobs, vicie-versie.) many pedals built/shown here are chock-full of tayda-quallity components, that a base-level to work from. and the taper doesn't really matter to test/prove a circuit, it is a user nicety once you know the circuit's a goer.

and box caps - because they fit the same size every time. greencaps would be different leg spacing for each value, each voltage rating, each bloody colour! the box caps are much more stable mounting, as well.

what was the question again?
" I will say no more "

Electron Tornado

Quote from: deadlyshart on December 17, 2016, 01:16:23 PM

2) In a lot of photos of circuits I see with transistors, the transistors are in a socket. Is this because transistors are really sensitive to heat or something, and the heat of soldering could damage them? Should I always use sockets for transistors?

Transistors and ICs are more sensitive to heat, but I've rarely had a problem soldering transistors. Several years ago, people were having trouble with socketed transistors falling out of their sockets, and I think most were using glue to keep them in place. I don't socket transistors.

Quote from: deadlyshart on December 17, 2016, 01:16:23 PM
4) I see audio/log taper pots a lot of the time. Is there any reason I can't replace one of them with a linear pot of the same value, aside from just how the resistance will grow as the pot is turned through its cycle (if they're both 100k, for example, the linear one will be 50k at the halfway point, but the log one will be 10k) ? Is there any other difference?

In a final build, it's best to use the taper that the schematic calls for. However - when you a breadboarding a circuit that calls for a 100k log pot, for example, and all you have on hand is a 100k linear pot, most of the time you can just go ahead and use the linear pot just to get the circuit going. That gives you a chance to fix mistakes and tweak things until you can obtain a pot with the correct taper.
I have used linear pots for volume controls where an audio pot was called for and they worked just fine, so I left them in my final build.


Keep the questions coming. If one person has a question, chances are ten others will learn something from it as well.
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amptramp

For best reliability, I tend to follow military standards and in military electronics, you do not use sockets for transistors or IC's.  The military considers contact corrosion and the possibility of a device falling out of a socket to be more important than any benefits gained from socketed devices.  In a lot of commercial equipment, you will see socketed IC's but soldered transistors.  It is a pain to unsolder IC's without specialized equipment whereas a transistor has three or at most four leads and can be unsoldered without too much trouble.  It is more likely for a transistor to fall out of a socket because the socket pins may not have the holding power of an IC socket.  If you subject a socketed board to shock and vibration, the transistors will fall out before the IC's.

Soldering temperature also has something to do with this choice - a device with three or four leads can be heat-sunk easily if necessary.  An IC is a different thing - there are shorter leads and more of them.  But people have learned to use a hot iron and make connections as quickly as possible before heat transfer takes place.  Heat sinking was more important with germanium than silicon devices.

If you consider a piece of equipment on tour, it gets placed in front of speakers where it is subject to vibration, dropped, kicked around, tossed in a van and subjected to high and low temperatures so this corresponds to some of the MIL-E-810 environmental tests for mobile equipment.  If you are building something for a studio environment, resistance to shock, vibration and temperature is not as essential.

EBK

Quote from: amptramp on December 18, 2016, 10:27:46 AM
For best reliability, I tend to follow military standards and in military electronics, you do not use sockets for transistors or IC's.  The military considers contact corrosion and the possibility of a device falling out of a socket to be more important than any benefits gained from socketed devices.  In a lot of commercial equipment, you will see socketed IC's but soldered transistors.  It is a pain to unsolder IC's without specialized equipment whereas a transistor has three or at most four leads and can be unsoldered without too much trouble.  It is more likely for a transistor to fall out of a socket because the socket pins may not have the holding power of an IC socket.  If you subject a socketed board to shock and vibration, the transistors will fall out before the IC's.

Soldering temperature also has something to do with this choice - a device with three or four leads can be heat-sunk easily if necessary.  An IC is a different thing - there are shorter leads and more of them.  But people have learned to use a hot iron and make connections as quickly as possible before heat transfer takes place.  Heat sinking was more important with germanium than silicon devices.

If you consider a piece of equipment on tour, it gets placed in front of speakers where it is subject to vibration, dropped, kicked around, tossed in a van and subjected to high and low temperatures so this corresponds to some of the MIL-E-810 environmental tests for mobile equipment.  If you are building something for a studio environment, resistance to shock, vibration and temperature is not as essential.
Or, assuming you have good sockets, you could throw a glob of hot glue at it to hold it in place.  (Full disclosure: I've advocated using a glue gun more than once on this forum, but I haven't actually owned one in years, so they may not be as useful as I remember....  :icon_rolleyes:)
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GibsonGM

I'm different in that the only thing I'll socket is IC's.  I get the transistor subbing out of the way on the bread board...for actual builds, no sockets.  I just don't trust that the transistor won't fall out at a gig...but that's just me.  YMMV, of course.
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MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

amptramp

Tubes are often used with spring-loaded tube shields that fit in the socket like a BNC cable and have a spring on the top pushing the tube down.  So far, I haven't seen anything similar for transistors or IC's although there are TO-3, TO-66 and TO-220 sockets that allow you to bolt power transistors down.

thermionix

I had a metal can CA3080 fall out of its socket in my DynaComp clone.  So I put it back in and added a blob of hot glue.  I realized later that I never had it pushed in all the way!  Now it's fully secure without glue and has no chance of falling out, even difficult to pull out intentionally.  Having 8 pins helps there.  Corrosion is still a potential threat, as is a meteorite strike.

deadlyshart

Quote from: EBK on December 17, 2016, 02:34:16 PM
Quote from: deadlyshart on December 17, 2016, 01:16:23 PM
Hey guys, sorry to bother you again but I've come up with a few more questions since my last build, that I'm wondering about, and it would be great if anyone could help me understand.
Fixed that for you. No need to apologize for being willing to learn.

Quote
1) What kind of wire should I be using inside my pedals, to connect the board to the jacks/etc? Solid or braided? I'm guessing I want it flexible, so braided? Then again, if it's solid, I can bend it to a shape I want inside, and it will stay in that shape. So what do most people use? And what thickness?
24 gauge stranded is pretty standard around here.  There are different levels of quality, however....

Quote

oops I hit enter. Here's the rest:

2) In a lot of photos of circuits I see with transistors, the transistors are in a socket. Is this because transistors are really sensitive to heat or something, and the heat of soldering could damage them? Should I always use sockets for transistors?
If possible, always socket transistors and ICs.  They can be more sensitive, and they often offer opportunities to tweak things.

I only have time to tackle those first two questions at the moment.  Someone else will happily chime in.

Quote
Sorry for all the questions again, and any advice is appreciated.

Again, fixed that for you.   :icon_wink:

Thanks for all the advice, as usual. You've helped me a ton here  :D

deadlyshart

Quote from: GibsonGM on December 17, 2016, 02:53:33 PM
3) That looks like a green cap, yes...no matter, it's just a style...poly types, etc. are all good....the only ones to TRY to shy away from (IMO) would be ceramic and tantalum, but both are actually used quite a bit and are not "bad" or anything.  Long story, ha ha.   Small value caps (picofarads) tend to be ceramic, they are fine.

4)  Well, since you know about how the taper works, you can probably imagine that the control won't function *the same* as it was meant to.  You CAN replace each type with the other, but you may find it difficult (near impossible?) to make the control behave the way you want.  With log pots, part of the range happens very fast....and also, as the ear HEARS in a log manner, a volume control is much more intuitive if it too is a log taper.

5) many people use metal or plastic standoffs...I bet Smallbear has some.  They offer solid attachment.   I actually just use solid core wire for my builds, and 'fold' the PCB into the enclosure. I place non-conductive foam around, padding it, so it can never hit the back of the enclosure.   I'm a hack  ;)   I've never had a single issue this way.  The board is not actually "hanging" from the pots, or eventually the wire WOULD break, someday...

6)  Generally, if the pot/jack FEELS well-constructed, it is.  Sounds like you sorta know the pot there may not hold up over years and years ;)   I like Alpha pots, the small kind (6mm?), and Switchcraft jacks...open, as you showed, are what I use but some ppl also like the enclosed kind, which I find better for amps.    Input jacks are frequently (most always?) the stereo jack type, since we use them for power switching at the same time you plug your cord in...

Again, peruse Smallbear electronics, whose owner is on this forum....not affiliated, but I have never had a negative experience purchasing my parts there - he knows what we're looking for, and only provides quality stuff. 

Good questions!

Yeah, I really like the idea of standoffs actually, and already have some -- but I've always been worried about how you attach the standoff base to the chassis. You can screw it through, which will be the most secure, but also the most ugly... you can epoxy it in, which might work fine depending on the epoxy and material... alternatively you could also have standoffs, but with them not attached to anything, so it's still technically "floating" but held pretty steady/electrically isolated by the standoffs. I'll check out smallbear, thanks.

deadlyshart

Quote from: robthequiet on December 17, 2016, 06:14:16 PM
I like this style:

Standoffs

There are other types. If you visit a hardware store you can find items used for securing AV cables or antenna wire (is that still a thing?) that might work -- depends on your build. One idea is to do a general search for "Gutshot" to see how people do things.

Cool, I like the idea of that too, but how do you usually secure the standoff base to the chassis, epoxy? I guess if it was secured by the back side I wouldn't mind countersinking a very small screw, so it doesn't stick out...

robthequiet

They usually have a sticky base, you peel off the plastic and they last a good while.

deadlyshart

Hey guys, one other more general question. I'm going to try and build a really nice version of my next pedal (a Small Clone... clone). I've already printed and etched a PCB for it, but I want to do this one as right as possible (hence all the questions).

How much do you guys layout the parts before you assemble it and stuff? So far most of my projects have pretty much involved me assembling the circuit board, and then drilling the chassis to fit it after the fact. It's worked alright, but always been a bit of a shitshow when I've tried to get things to fit. Do you guys used CAD software? Or at least draw it out, saying "here's where the PCB is gonna be, here's how it's gonna attach, etc?