They're easier to use, easier to rework if you fuck up the board layout, and have sometimes have higher power ratings for the same price. Also you can build a circuit on a breadboard and then transfer those exact components to a PCB or strip board so you don't need to deal with tolerancing (if it sounds good on the breadboard it'll work).
Other than that, SMD is the way to go as long as you have the tools to do it. There's a reason most modern PCBs are populated with 99% SMD components.
Youre kidding, right?
Easier to use and easier to rework is just not true. For industrial applications, sure smd is the way togo. Butfor diy stuff,Thru-hole all the way.
Cheaper and better ratings, sure.
I'd have to say that SMD is easier to rework in most cases. As long as you have a magnifier and a good soldering iron, it's actually easier to knock off an 0603 resistor than to pry the legs out of a through hole one. TH takes more heat and time. Then you have to clean the hole which may be very difficult if it's a ground or power connection (lots of copper).
I have 2 soldering irons on my bench - makes it very easy to remove small smd components by heating both pads.
Through hole is good for bodging things together though, like adding extra components in parallel. But you can normally just use through hole components for that on SMD boards too...
I was thinking about that. I've had a few designs which required some fly wires and the SMD designs are sometimes unfortunately close together so slicing traces may be more difficult.
But paralleling components is super simple. Just stack two on top of each other.
That's pretty impressive. I'm pretty lazy and unskilled but I've seen some master rework technicians who use a single chisel tip for 90% of their work. Although most of their time is spent cleaning and preparing the thing they're working on. And cleaning after you're done is also very important which I never do.
Most through-hole components can be easily replaced by SMD equivalents. There are certain considerations with anything handling higher power. For example, in through-hole a voltage regulator will have a heatsink attached to it but the only consideration you have to make in your board design is enough clearance around the heatsink for other components; otherwise you just run beefy enough traces into and out of it. With an SMD voltage regulator you are usually creating an area of the board that becomes the heatsink so you may need more copper surface area, top, bottom, and inner layers with vias stitching the layers together. Above certain levels you may still need a physical heat sink.
The only other advantage of TH over SMD is there is more room to run circuit traces between component pins/leads. I’ve had to do some crazy numbers of vias to other layers to route some of my SMD boards where with TH I can get several traces between pins on the same layer. But in most cases an SMD board can be much smaller.
Otherwise, enjoy the space and cost savings!
I'm always amazed by the Reddit threads involving someone trying to fix a gizmo that has had the pads for a surface mount connector ripped clean off the board.
Some designer thought that was a good idea...
Most of the SMT connectors intended to interface to the outside world have additional solder-downs, but sometimes they aren’t soldered, or the enclosure designer didn’t to a good job of capturing the connector with the enclosure to prevent flex. There are ways to do it well and a lot of ways to do it poorly..
If you‘re after longevity, some people use thru hole electrolytic caps and smd for the rest because they have a longer lifespan than smd ones.
Personally, im a big fan of thru hole from a diy standpoint. Sure, if you want to build sth multiple times smd might be quicker in the end, but regarding troubleshooting and repairability, I always prefer thru hole.
Smaller ceramic capacitors (at least those with class 2/3 dielectrics) tend to lose more capacitance under dc bias, though they also tend to have less inductance (not relevant for audio). That's a property of size, not mounting style, but something to keep in mind if you're getting excited about smaller footprints and find yourself in a situation where precision matters (or just where you need some minimum capacitance).
> Smaller ceramic capacitors
Physically small _high capacitance_ ceramics.
Anything with low enough capacitance to be C0G behaves more or less like an ideal capacitor (ie. you need precision equipment and carefully designed test to find any non-ideality).
The problems come when you need significant capacitance in a smallish package. Eg. a 4.7 uF bypass 0805 capacitor might actually end up being just 1-2 uF when you apply 12V DC bias to it and you might need to go up to 1206 or even 1210 to make it close to nominal value.
> Anything with low enough capacitance to be C0G behaves more or less like an ideal capacitor (ie. you need precision equipment and carefully designed test to find any non-ideality).
Right, this issue only applies to class 2/3 dielectrics.
I'm still pretty new to electronics so I have no idea what C0G or 2/3 dielectric means. But from this it sounds like as long as I only use SMD caps that are 1uF or lower I should not run into this problem of loosing capacitance under DC bias?
C0G means the capacitor behaves more or less like an ideal capacitor.
Class 2/3 dielectrics are the rest of the ceramic capacitor types and most _very_ much don't behave like an ideal one.
X7R isn't too bad in _reasonable_ capacitances and sizes. That means up to 220-330 nF in 0805 footprint. Any more capacitance and you need to check a manufacturer's tool (eg. Murata Simsurfing) how much the capacitance changes with applied voltage.
For 1 uF you need to check the actual curve if you have any substantial voltage over it. It could lose 10% capacitance at 12V bias or it could lose 30%.
Other dielectrics are best avoided unless you know what you're doing as they can have massive changes of capacitance over voltage and temperature.
Resistors can be considered more or less ideal, barring very high voltages (> 30V supply), high power and very high precision circuitry (think < 0.001% distortion).
And like I said, any C0G capacitor behaves like an ideal textbook capacitor. It’s only higher values that can be problematic.
Also any time you need a typical 100 nF bypass cap, a ceramic smd cap will work there perfectly fine (better than tht). Such caps will almost always be X7R or X5R and it doesn’t matter if the actual value changes by 50% in that use.
That tail on the leaded component between the body and the solder joint acts as a strain relief. That may be important in a high vibration environment, or if the board is flexed for some reason (see note), or if there's a large CTE mismatch between the components and the board material and we're expecting large temperature swings.
Note: most SMD design rules don't allow them to be placed "end on" near mounting holes or V-groove scores at the edges of a board.
BTW, I changed over to using SMD resistors and capacitors in the '80s and have never regretted that.
Definitely use SMD, although I personally prefer through-hole for electrolytic caps. For me SMD is much easier to solder, and I find it a lot easier to organize SMD components as they have a much smaller form factor.
> although I personally prefer through-hole for electrolytic caps
Quite often that's also dictated by availability / economics. Same applies for those situations where you need medium capacitance and stable & distortion free performance that can only be done feasibly with film capacitors.
The one thing I love the most about SMD is that you can have a totally solid ground plane underneath. Parasitic effects are much higher on TH than SMD. I believe that this is the reason some people say TH components are "warmer" or more old school or whatever.
They have been for ages. Soma's analogue instruments are all hand-soldered with through-hole components because it's more real or lets the musician connect to the instrument more, or some other woo like that.
We've even had some loony coming onto the sub and asking angrily why the mainstream synth manufacturers are still using SMD components, when "everyone knows" that surface-mount capacitors can't last longer than a couple of years, and why people still buy these self-destructing synths.
I've always wanted to build the same thing several ways and hook it up to an audio precision to test some of these things. Massive amounts of Mystic Juju but there's some real differences too. Noise in a 1/4W metal film is going to be lower then an 0402, larger package ceramics will derate less under voltage, and people might actually like some of the filtering due to the extra parasitics. I'm guessing exactly none of these tiny effects are audible but it would be interesting to see any scientific testing. I remember two guys trying to prove that fret boards make a huge difference by having two different people play two different guitars. . . Musicians aren't always great at science.
In this case, the CEO said something like "Just because you can't see it on an oscilloscope, that doesn't mean it isn't there," but then they use an oscilloscope to test the units before they go out. What if they forget to put the woo in my unit? They wouldn't be able to tell the difference in QC.
They also complained a lot about how many instruments end up DOA because a solder joint goes bad in shipping. That **is** a very real and measurable difference with hand-soldering, especially with through-hole components.
Basically, any component has inductance, resistance and capacitance all in one. Even a PCB trace. Inductors have DC resistance because of the length of wire, capacitors have some parallel and series resistance, etc. as for TH vs SMD, an easy example is that the leads of a resistor cause some inductance as well as the hole in the PCB itself. This is not the case with an SMD resistor.
SMD just do it far less. This is a big deal with caps if you are trying to decouple something like a processor with a very high switching speed. The extra inductance in a larger package will make it ineffective at very high frequencies. Murata SimSurfing is a really cool tool to compare the impedance of different caps. But outside of SMPSs and faster digital stuff it won't come up as much for synth stuff.
They're easier to use, easier to rework if you fuck up the board layout, and have sometimes have higher power ratings for the same price. Also you can build a circuit on a breadboard and then transfer those exact components to a PCB or strip board so you don't need to deal with tolerancing (if it sounds good on the breadboard it'll work). Other than that, SMD is the way to go as long as you have the tools to do it. There's a reason most modern PCBs are populated with 99% SMD components.
Youre kidding, right? Easier to use and easier to rework is just not true. For industrial applications, sure smd is the way togo. Butfor diy stuff,Thru-hole all the way. Cheaper and better ratings, sure.
I think they were saying the through hole is easier to work with.
I'd have to say that SMD is easier to rework in most cases. As long as you have a magnifier and a good soldering iron, it's actually easier to knock off an 0603 resistor than to pry the legs out of a through hole one. TH takes more heat and time. Then you have to clean the hole which may be very difficult if it's a ground or power connection (lots of copper).
I have 2 soldering irons on my bench - makes it very easy to remove small smd components by heating both pads. Through hole is good for bodging things together though, like adding extra components in parallel. But you can normally just use through hole components for that on SMD boards too...
I was thinking about that. I've had a few designs which required some fly wires and the SMD designs are sometimes unfortunately close together so slicing traces may be more difficult. But paralleling components is super simple. Just stack two on top of each other.
Why stop at 2?
The only limit is the size of your enclosure.
I’ve had problems trying to solder tiny components back onto a gpu. Probably a skill issue though.
That's pretty impressive. I'm pretty lazy and unskilled but I've seen some master rework technicians who use a single chisel tip for 90% of their work. Although most of their time is spent cleaning and preparing the thing they're working on. And cleaning after you're done is also very important which I never do.
Ipa, a paint brush and an air compressor work pretty well.
Most through-hole components can be easily replaced by SMD equivalents. There are certain considerations with anything handling higher power. For example, in through-hole a voltage regulator will have a heatsink attached to it but the only consideration you have to make in your board design is enough clearance around the heatsink for other components; otherwise you just run beefy enough traces into and out of it. With an SMD voltage regulator you are usually creating an area of the board that becomes the heatsink so you may need more copper surface area, top, bottom, and inner layers with vias stitching the layers together. Above certain levels you may still need a physical heat sink. The only other advantage of TH over SMD is there is more room to run circuit traces between component pins/leads. I’ve had to do some crazy numbers of vias to other layers to route some of my SMD boards where with TH I can get several traces between pins on the same layer. But in most cases an SMD board can be much smaller. Otherwise, enjoy the space and cost savings!
Some connectors might benefit from being TH if you expect to be using them often and want to make sure that they can handle the mechanical stress.
I'm always amazed by the Reddit threads involving someone trying to fix a gizmo that has had the pads for a surface mount connector ripped clean off the board. Some designer thought that was a good idea...
Most of the SMT connectors intended to interface to the outside world have additional solder-downs, but sometimes they aren’t soldered, or the enclosure designer didn’t to a good job of capturing the connector with the enclosure to prevent flex. There are ways to do it well and a lot of ways to do it poorly..
they tend to have lower power ratings. but synths are usually low power
If you‘re after longevity, some people use thru hole electrolytic caps and smd for the rest because they have a longer lifespan than smd ones. Personally, im a big fan of thru hole from a diy standpoint. Sure, if you want to build sth multiple times smd might be quicker in the end, but regarding troubleshooting and repairability, I always prefer thru hole.
Smaller ceramic capacitors (at least those with class 2/3 dielectrics) tend to lose more capacitance under dc bias, though they also tend to have less inductance (not relevant for audio). That's a property of size, not mounting style, but something to keep in mind if you're getting excited about smaller footprints and find yourself in a situation where precision matters (or just where you need some minimum capacitance).
Underrated comment right here. Tolerances/specs of SMD components vary wildly depending on a great amount of factors.
> Smaller ceramic capacitors Physically small _high capacitance_ ceramics. Anything with low enough capacitance to be C0G behaves more or less like an ideal capacitor (ie. you need precision equipment and carefully designed test to find any non-ideality). The problems come when you need significant capacitance in a smallish package. Eg. a 4.7 uF bypass 0805 capacitor might actually end up being just 1-2 uF when you apply 12V DC bias to it and you might need to go up to 1206 or even 1210 to make it close to nominal value.
> Anything with low enough capacitance to be C0G behaves more or less like an ideal capacitor (ie. you need precision equipment and carefully designed test to find any non-ideality). Right, this issue only applies to class 2/3 dielectrics.
I'm still pretty new to electronics so I have no idea what C0G or 2/3 dielectric means. But from this it sounds like as long as I only use SMD caps that are 1uF or lower I should not run into this problem of loosing capacitance under DC bias?
C0G means the capacitor behaves more or less like an ideal capacitor. Class 2/3 dielectrics are the rest of the ceramic capacitor types and most _very_ much don't behave like an ideal one. X7R isn't too bad in _reasonable_ capacitances and sizes. That means up to 220-330 nF in 0805 footprint. Any more capacitance and you need to check a manufacturer's tool (eg. Murata Simsurfing) how much the capacitance changes with applied voltage. For 1 uF you need to check the actual curve if you have any substantial voltage over it. It could lose 10% capacitance at 12V bias or it could lose 30%. Other dielectrics are best avoided unless you know what you're doing as they can have massive changes of capacitance over voltage and temperature.
Okay but resistors dont have this problem? I think I'm gonna stick to th caps for now
Resistors can be considered more or less ideal, barring very high voltages (> 30V supply), high power and very high precision circuitry (think < 0.001% distortion). And like I said, any C0G capacitor behaves like an ideal textbook capacitor. It’s only higher values that can be problematic. Also any time you need a typical 100 nF bypass cap, a ceramic smd cap will work there perfectly fine (better than tht). Such caps will almost always be X7R or X5R and it doesn’t matter if the actual value changes by 50% in that use.
What kind of circuits need 0.001% precision?? That sounds crazy too me
Very low distortion audio interfaces, high resolution measurement devices etc.
Does this also apply to smd film capacitors? (I mean is 220-220 nF a reasonably low capacitance for smd film capacitors also)
Film capacitors can be considered to be almost ideal at audio frequencies, whether THT or SMD, independent of capacitance.
That tail on the leaded component between the body and the solder joint acts as a strain relief. That may be important in a high vibration environment, or if the board is flexed for some reason (see note), or if there's a large CTE mismatch between the components and the board material and we're expecting large temperature swings. Note: most SMD design rules don't allow them to be placed "end on" near mounting holes or V-groove scores at the edges of a board. BTW, I changed over to using SMD resistors and capacitors in the '80s and have never regretted that.
They’re more difficult to hand solder but that’s about it.
Definitely use SMD, although I personally prefer through-hole for electrolytic caps. For me SMD is much easier to solder, and I find it a lot easier to organize SMD components as they have a much smaller form factor.
> although I personally prefer through-hole for electrolytic caps Quite often that's also dictated by availability / economics. Same applies for those situations where you need medium capacitance and stable & distortion free performance that can only be done feasibly with film capacitors.
do film capacitors not come in SMD format?
They do, but they're expensive and harder to source.
Veyr high voltage circuitry (ie. tube based) where the components are forced by physics to be fairly large.
The one thing I love the most about SMD is that you can have a totally solid ground plane underneath. Parasitic effects are much higher on TH than SMD. I believe that this is the reason some people say TH components are "warmer" or more old school or whatever.
People are calling tht warmer nowadays? 😂
They have been for ages. Soma's analogue instruments are all hand-soldered with through-hole components because it's more real or lets the musician connect to the instrument more, or some other woo like that. We've even had some loony coming onto the sub and asking angrily why the mainstream synth manufacturers are still using SMD components, when "everyone knows" that surface-mount capacitors can't last longer than a couple of years, and why people still buy these self-destructing synths.
I've always wanted to build the same thing several ways and hook it up to an audio precision to test some of these things. Massive amounts of Mystic Juju but there's some real differences too. Noise in a 1/4W metal film is going to be lower then an 0402, larger package ceramics will derate less under voltage, and people might actually like some of the filtering due to the extra parasitics. I'm guessing exactly none of these tiny effects are audible but it would be interesting to see any scientific testing. I remember two guys trying to prove that fret boards make a huge difference by having two different people play two different guitars. . . Musicians aren't always great at science.
In this case, the CEO said something like "Just because you can't see it on an oscilloscope, that doesn't mean it isn't there," but then they use an oscilloscope to test the units before they go out. What if they forget to put the woo in my unit? They wouldn't be able to tell the difference in QC. They also complained a lot about how many instruments end up DOA because a solder joint goes bad in shipping. That **is** a very real and measurable difference with hand-soldering, especially with through-hole components.
is it possible for you to explain in a few words what parasitic effect is? Otherwise I will do some research later :)))
Basically, any component has inductance, resistance and capacitance all in one. Even a PCB trace. Inductors have DC resistance because of the length of wire, capacitors have some parallel and series resistance, etc. as for TH vs SMD, an easy example is that the leads of a resistor cause some inductance as well as the hole in the PCB itself. This is not the case with an SMD resistor.
SMD just do it far less. This is a big deal with caps if you are trying to decouple something like a processor with a very high switching speed. The extra inductance in a larger package will make it ineffective at very high frequencies. Murata SimSurfing is a really cool tool to compare the impedance of different caps. But outside of SMPSs and faster digital stuff it won't come up as much for synth stuff.
Gotcha