Question re. Ceramic Caps

[gkterry]

the cap in a guitar is just dumping signal to ground, the signal path to the amp doesn't go through it in series.

PERFECT! A fancy tone cap in a guitar tone circuit is like using gold sewer pipes in your house–total unnecessary extravagance–solely for bragging rights

 

[David Barnett]

For a time Fender used a ceramic for the coupling cap into the front end of their Long Tail Pair phase inverters. And if you look inside a '60s Marshall 18-watt or other small Marshall practice amps like the Popular or Mercury, you'll see ceramic coupling caps. You'll find them in '50s and '60s record players, radios, consoles, and hifi gear too. They were widespread until polyester film caps became more common and more affordable.

 

[redhouse_ca]

For a time Fender used a ceramic for the coupling cap into the front end of their Long Tail Pair phase inverters. And if you look inside a '60s Marshall 18-watt or other small Marshall practice amps like the Popular or Mercury, you'll see ceramic coupling caps. You'll find them in '50s and '60s record players, radios, consoles, and hifi gear too. They were widespread until polyester film caps became more common and more affordable.

I didn't know that. I assumed electrolytic for the older stuff and when ceramic came along, I assumed just to block at ground. Thinking about it, it makes sense, tho. New stuff tends To get fast and loose in the beginning.

 

[redhouse_ca]

@redhouse_ca - I think we have to bear in mind that 92% of the time we are dealing with pedals, and amps, and other devices that want to distort (in the general sense) and color the sound. We're rarely looking for pure signals. In fact, we detest them. No one wants to play through a hi-fi amp - at least not unless we've been able to, in an audiophile sense, butcher our signal before it gets there. So when that cheap ceramic DC filter cap in line with the input jack in our pedal pulls off "unintended" high frequencies, we smile and say "I love how it fattens up my sound!".

My take.

Thanks. I love the "92% of the time" part (I say that genuinely with no sarcasm). I rarely use peddles but I know wait you mean. It's like around 91.6% of the time I screw up, it's because I haven't learned from previous screwups, which happen with a with a frequency of roughly 81.4% when I say something on-line

 

[Swirling Snow]

Archetype_tone_circuit_sm

www.tdpri.com

If you really want "simple", take the amplifier out. Then erase the ground symbols, and simply connect the capacitor to the coil.

Now, remembering that a guitar pickup produces alternating current, are you still sure the signal never "goes through" the cap?

 

[redhouse_ca]

If you really want "simple", take the amplifier out. Then erase the ground symbols, and simply connect the capacitor to the coil.

Now, remembering that a guitar pickup produces alternating current, are you still sure the signal never "goes through" the cap?

Sorry, misread the diagram (interpreted the pickup symbol as a transformer - I never drew a pickup on a schematic and it looks a lot closer to a transformer from what I know.

So EDIT: even as a pickup, I consider it signal path. It's clearly not direct on the path out, like a film coupling cap in audio, but (why am I doing this, I gotta stop), IMHO, the component that filters frequencies to ground is signal path, as what remains (ie continues down the signal path) is signal.

Anyhow, I'm pretty sure that we both mean kinda the same thing in terms of what is happening electronically, and o respect your view of this. Is just a semantic thing. Hard lines with invisible forces are sometimes arbitrary.

 

[dsutton24]

...In audio circuit design, no circuits tha o have ever seen (not even the cheap consumer gadget stuff) would ever use a ceramic cap in the signal path, even as a filter to ground...

Then you haven't seen a lot of consumer electronics. If you get away from the SMD stuff, consumer electronics are loaded with ceramic caps.

 

[Swirling Snow]

IMHO, the component that filters frequencies to ground is signal path, as what remains (ie continues down the signal path) is signal.

This obvious bit of arithmetic is apparently difficult for most people to grasp. I want to smother you with kisses. You've made my day.

Now, when trying to understand AC generators you can't use DC circuit analysis and treat everything as passive components. Realize that the coil can only let current flow when there's something for it to flow through, but if that something is a straight wire, there can be no voltage differential. In other words, the coil needs a load to do "work".

If we put a pot across the coil ends we can dial in a load or a dead short. With a dead short, no signal is produced. According to the signal tracers, the voltage is produced and then "goes to ground" but with a more global view we can see that never had a chance to happen. Especially if we haven't plugged our guitar in.

As far as caps go... when I walk up... let me make this a sporting analogy for you guys. When I walk up to the starting line, what's on my feet matters a lot. If I'm going to get to the finish line as fast as possible, I need all the psych I can get and believing in my gear is a big part of that, whether it's shoes, skis, or a bike. So, when I walked up on stage I had $40 worth of caps in my guitar, and they paid for themselves when I was invited back.

 

[redhouse_ca]

Then you haven't seen a lot of consumer electronics. If you get away from the SMD stuff, consumer electronics are loaded with ceramic caps.

I'm going to leave this alone, but thanks for the reply and I respect your perspective on this.

 

[redhouse_ca]

Then you haven't seen a lot of consumer electronics. If you get away from the SMD stuff, consumer electronics are loaded with ceramic caps.

EDiT: I try really hard not to make assumptions about people, even people I know, but for sure with people I don't know. Maybe read my comments on SMD again. Or don't. Either way, I respect your opinion. As a closing comment, tho, let me leave you with a quick pic of my workspace. I guess you could look at that and think I got cap religion (I don't) but the Wima and other films are as various filters for audio preamp or test ccts, and unfortunately, I had to buy those. But if you look closely, and pay attention to the details, you'll see a bunch of salvaged and reused parts of all shapes and sizes and ceramics, which I am still grappling to see how anything I've said implies a dislike of them or some skepticism of their utility and merit. It's just strange to me to follow but I guess I should have just ejected early (before posting what I thought was a reasonable request to learn more). Anyhow, I have to get back to work on doing all the smd and other things...

 

[dsutton24]

EDiT: I try really hard not to make assumptions about people, even people I know, but for sure with people I don't know. Maybe read my comments on SMD again. Or don't. Either way, I respect your opinion. As a closing comment, tho, let me leave you with a quick pic of my workspace. I guess you could look at that and think I got cap religion (I don't) but the Wima and other films are as various filters for audio preamp or test ccts, and unfortunately, I had to buy those. But if you look closely, and pay attention to the details, you'll see a bunch of salvaged and reused parts of all shapes and sizes and ceramics, which I am still grappling to see how anything I've said implies a dislike of them or some skepticism of their utility and merit. It's just strange to me to follow but I guess I should have just ejected early (before posting what I thought was a reasonable request to learn more). Anyhow, I have to get back to work on doing all the smd and other things...

Nobody ever made any kind of value judgement on you, your abilities, sensitivities or junk collection. You said, "In audio circuit design, no circuits tha o have ever seen (not even the cheap consumer gadget stuff) would ever use a ceramic cap in the signal path, even as a filter to ground."

That's what I quoted, that's what I responded to.

You are either wrong or have a very limited experience in component level electronics. Anyone who has ever seen consumer electronics of years past has seen countless thousands of disc ceramics. Modern electronics is full of ceramic caps, they just take the form of SMD devices that are hard for many people to identify.

Heck, all you have to do is look at gutshots of any tube amp. I'd bet that your average Silverface Twin has thirty or more of the things.

That is all. No judgement, no hidden meanings, no slight to you or SMDs.

 

[David Barnett]

Then you haven't seen a lot of consumer electronics. If you get away from the SMD stuff, consumer electronics are loaded with ceramic caps.

A lot of SMD stuff is ceramic too, they just don't look like brown discs anymore.

 

[redhouse_ca]

A lot of SMD stuff is ceramic too, they just don't look like brown discs anymore.

Ok, thank you.

 

[Peegoo]

Capacitors in passive guitar circuits are not used as voltage reservoirs to remove ripple or to block DC as they are in a guitar amplifier. Instead, they are used as a tuned audio frequency filter at a very low voltage and current.

This is why ceramics are ideal for guitar circuits: they are inexpensive, very small, and perform the job perfectly. A larger metallized poly film cap like an orange drop or green chicklet will not provide bigger or orangier or greener tone than the little ceramic will. It simply cannot do the job better or even last longer.

Two caps of the same spec will perform the same way, whether they're big or little, and whether they cost three for a penny or $28 apiece.

Plus shipping.

 

[Peegoo]

I think they all use electrolytics as the caps for filters for the audio band

Not all capacitors in guitar amps are electrolytic (polarized) type. Many use silver mica caps in the tone circuits because their construction provides exceptional stability and low loss at those very low capacitance values. Similarly, not all coupling caps between stages are electrolytic.

 

[redhouse_ca]

Nobody ever made any kind of value judgement on you, your abilities, sensitivities or junk collection. You said, "In audio circuit design, no circuits tha o have ever seen (not even the cheap consumer gadget stuff) would ever use a ceramic cap in the signal path, even as a filter to ground."

That's what I quoted, that's what I responded to.

You are either wrong or have a very limited experience in component level electronics. Anyone who has ever seen consumer electronics of years past has seen countless thousands of disc ceramics. Modern electronics is full of ceramic caps, they just take the form of SMD devices that are hard for many people to identify.

Heck, all you have to do is look at gutshots of any tube amp. I'd bet that your average Silverface Twin has thirty or more of the things.

That is all. No judgement, no hidden meanings, no slight to you or SMDs.

All is good with me. Im fine with personal judgement. It's just hard for me to follow some of this. I'm trying, but it feels a sincere discussion about, say "Keith". Are we taking about the same Keith? I dunno, but I dont want to judge, maybe it is. I'm just going to give folks the benefit of the doubt. It's best that way for me.

one man's junk is another man's joy, I guess.

 

[Jasonpatrick]

This little guy is super important for that Fender sound… among other ceramic caps in older Fender amps….

 

[jvin248]

...yet some people still like to insist that they are special or have special powers, trained or not, despite evidence to the contrary.

This is always fun for 'Tone Wood' videos ... no player likes to admit they "can't hear a difference" so they will always report "I could hear a difference" -- even if the could not or that the difference never matters in practical situations like playing in a band at the corner bar or touring for months at stadium events. Ego.

...engineering in the beginning days of guitar production was resolved thusly:
Gibson chose the most expensive cap they could find.
Fender chose the least expensive cap he could find...

And the Telecaster forced Gibson to discontinue building the Les Paul... must have been the caps!

Guitar signal voltages and amperage are low so you don't need electrolytic caps nor their expense. Ceramic caps are super durable compared to other capacitor choices. What you hear is the value. Measure caps' actual uF and rank them so you can find your preferred size -- they typically have a wide tolerance range. I really like to use 0.033uF caps on humbucker equipped guitars instead of the most common 0.047uF as it lets more sparkle through. Single coils I tend to stay at 0.022uF.






.

 

[Greenmachine]

Boss pedals are loaded with ceramics.

 

[dsutton24]

All is good with me. Im fine with personal judgement. It's just hard for me to follow some of this. I'm trying, but it feels a sincere discussion about, say "Keith". Are we taking about the same Keith? I dunno, but I dont want to judge, maybe it is. I'm just going to give folks the benefit of the doubt. It's best that way for me.

one man's junk is another man's joy, I guess.

I have no idea what you're saying. Try this on for size: Ceramic capacitors have been in common use in electronics from the very start. Keith agrees with me.