To set this up.. I hate hiss. I hate pedals that produce hiss. The first pedal I ever modified was my Boss eq; it just couldn't be used in front of an amp, so I modded it with one of the kits and the thing is now dead quiet.
That kit replaced some caps and IC's, really simple but because of my experience with that mod I always have this needling worry that my choices of caps / resistors / ic's or what ever might be hiss/noise producing.
So, is there some general guidelines to keep in mind when ordering parts? Like this brand is better than that brand, use audio grade electrolyte caps, look at this value on IC's etc?
Things outside of tidy short wiring and shielded wire when possible....
This is one of those topics I thought would have become more apparent to me by this point but... is still a mystery.. like every time I read "this pedal uses boutique parts"??..?? what the heck is a boutique cap?
Thanks.
Koko
Eh, is there a question...or some guidance in there somewhere?
QuoteSo, is there some general guidelines to keep in mind when ordering parts? Like this brand is better than that brand, use audio grade electrolyte caps, look at this value on IC's etc?
It was a round-a-bout way to ask that question.
Quote from: angrykoko on July 10, 2012, 04:57:11 PM
So, is there some general guidelines to keep in mind when ordering parts? Like this brand is better than that brand, use audio grade electrolyte caps, look at this value on IC's etc?
I haven't seen a single, clear, definitive answer to your question thus far in my DIY experience. However, there are some basic rules that are sort of common knowledge:
1. Metal Film resistors give lower noise than other types. I use them almost exclusively. Some people find that other types work fine for them, and that's great, but it sounds like you would prefer metal film.
2. There is no 'rule' as to what brand, but rather different 'types' of capacitors make a difference. Film caps are often the first choice, and the types to choose from include polyester, polystyrene, and some others. Generally, Panasonic, Topmay and Wima caps are very common these days because our major suppliers supply them.
3. Electrolytics are known to be a noisy type of cap. I think that's partly why Tantalum caps are often recommended, but not the primary reason. I don't really know what the 'audio grade' types upgrade to make them better, but mostly I suspect it's marketing for extra money.
4. When it comes to ICs, generally it's not the brands but the type itself. For example, a TL071 is much, much quieter when compared to the classic 741 IC. Both are Single Op Amps, and are interchangeable, but it's obvious that the 071 is better for noise. The key with ICs and such is to experiment and switch out compatible ICs until you find one you like. They do sound different, and a lot of the difference has to do with noise.
5. On IC's again, because of the variety in their documentation, it's very difficult to point to one measurement value and say 'look at this' to find out their noise issues. Most of the time, they only give the data that sets them apart in a better way. The engineers in the crowd might give you an answer, but lets say that most of the DIY world has sussed out the good ones, and the lists are around. One rule of thumb might be that the more expensive an IC is, chances are high there's something that sets it apart.
Jacob
Thanks.
Yeah IC's, Caps and transistors are always the things that cause me the most pausing when ordering (especially if I'm on Mouser, some things can be worlds apart cost wise but look the same spec wise).
On the Caps, you say that Tantalum are less noisy...What about MLCC -vs- Ceramic disc? i've been wondering the same about them.
I only build pedals for myself so an extra $1-$2.00 to the total cost is worth it for less noise / better quality.
Thanks for the reply.
Koko
Quote from: angrykoko on July 10, 2012, 04:57:11 PM
The first pedal I ever modified was my Boss eq; it just couldn't be used in front of an amp, so I modded it with one of the kits and the thing is now dead quiet.
I think the important question is: Did the mod kit change just the part types or was it also the values?
A hissy pedal can often be cured by adding or augmenting some low-pass filtering.
Ceramic discs have a reputation for microphony. Don't know if that applies to MLCC.
Quote from: culturejam on July 10, 2012, 09:34:04 PM
Quote from: angrykoko on July 10, 2012, 04:57:11 PM
The first pedal I ever modified was my Boss eq; it just couldn't be used in front of an amp, so I modded it with one of the kits and the thing is now dead quiet.
I think the important question is: Did the mod kit change just the part types or was it also the values?
A hissy pedal can often be cured by adding or augmenting some low-pass filtering.
It was the Monte Allum mod kit. At the time I did it I was such a noob that I didn't even know I was replacing capacitors so no idea if values changed along with the type (a assumed only type before you asked that). It did swap out the ic's though. It really cleaned up that pedal though, I was amazed.
I believe in tantalums in all applicable places regardless of cost. lower noise, longer life, generally smaller size.
Awhile back on FSB, Joe Gore posted the results of some capacitor tests he did. (http://freestompboxes.org/viewtopic.php?f=6&t=12118) It's a worthwhile read, as is the ensuing discussion.
Quote from: calciferspit on July 11, 2012, 12:33:08 AM
I believe in tantalums in all applicable places regardless of cost. lower noise, longer life, generally smaller size.
Tantalums are known for shorter life and to be fragile. They can litteraly explode if you treat them badly...
I think metal film resistors (as CJ pointed out) are a good start for getting the noise floor down.
Making sure you have good PSU filtering is always a good idea as well.
Shielded In/Out signal wiring can also help.
Unfortunately, with all OD/Distortion pedals you are raising gain, so are always going to raise the noise floor no matter what you do.
Quote from: derevaun on July 11, 2012, 03:14:00 AM
Awhile back on FSB, Joe Gore posted the results of some capacitor tests he did. (http://freestompboxes.org/viewtopic.php?f=6&t=12118) It's a worthwhile read, as is the ensuing discussion.
That was a good read. thanks! I'll need to re-read it later but I liked this quote he made:
Quoteand in the future I'm going to worry more about decisions that actually, you know, matter. Like whether to trim my right-hand fingernails another sixteenth of an inch.
I agree with him but I think he was speaking more towards "mojo" components. I don't believe in mojo components for the most part because I have to a/b things to hear any (if any) difference and even then sometimes is so small that I wonder who would even know (or I wonder if I could just adjust my eq pedal and get the same and..who would know)? That was a good one thanks for posting that link.
So as far as my question regarding hiss and noise, I'm kind of getting this:
- Use metal film resistors (cool they are the cheep ones)
- Electrolyte caps are noisiest and still not sure if the "audio quality" ones do anything for the money. If possible sub in a film cap for Electrolyte??
- Use whatever cap fits and stop worrying so much.
- transistors, diodes, etc - buy a bunch and just try them.
- Short (distance wise) off board wire's
- Use shielded wire in audio path wiring when possible.
- Learn how to tweak the filtering as culturejam points out
Jacob you hinted at a list for subs? I've never stumbled on one.. do you know of a list you could send me?
Thanks everyone
Koko
Quote from: night-B on July 11, 2012, 04:37:11 AM
Quote from: calciferspit on July 11, 2012, 12:33:08 AM
I believe in tantalums in all applicable places regardless of cost. lower noise, longer life, generally smaller size.
Tantalums are known for shorter life and to be fragile. They can litteraly explode if you treat them badly...
The tantalum capacitor distinguishes itself from other capacitors in having high capacitance per volume and weight. Tantalum capacitors have lower equivalent series resistance (ESR), lower leakage, and higher operating temperature than other electrolytic capacitors. Tantalum capacitors are considerably more expensive than any other commonly used type of capacitor, so they are used only in applications where the small size or better performance are important. Tantalum capacitors have very low electrical leakage (high leakage resistance), so will retain a charge for a long time. They tolerate hot operating environments up to 125 °C, unlike most aluminum electrolytic capacitors. Because most tantalum capacitors being made are solid (no liquid electrolyte), there is no known wear-out mechanism. Tantalum electrolytic capacitors are less prone to "drying out" than aluminum capacitors, which tend to decrease in capacitance particularly when used in hot environments. When operated within their design limits, tantalum capacitors can maintain their designed capacitance under such conditions for decades. Tantalum capacitors can replace aluminum electrolytic capacitors in situations where the external environment or dense component packing results in a sustained hot internal environment and where high reliability is important. Equipment such as medical electronics and space equipment that require high quality and reliability makes use of tantalum capacitors.
Tantalum capacitors are, under some conditions, prone to self-destruction by thermal runaway. The tantalum oxide layer may have weak spots that undergo dielectric breakdown during a voltage spike. The tantalum anode then comes to direct contact with the manganese dioxide cathode, and the leakage current causes localized heating; a chemical reaction then produces manganese(III) oxide and regenerates (self-heals) the tantalum oxide layer.
However, if the energy dissipated at the failure point is high enough, a new self-sustaining exothermic reaction may initiate, similar to the thermite reaction, with tantalum as fuel and manganese dioxide as oxidizer. This can destroy the capacitor, and occasionally produces smoke and possibly flame.[1] To prevent catastrophic thermal runaway failure, auxiliary protective devices (e.g. thermal fuses, circuit breakers, or current limiters) may be used to limit fault currents.
This came from the same source as yours. Not a catfight, I don't want to have that type of incident one day, to prevent it, I don't buy tants, that's just my opinion.
From the test results graphs I've seen, tants are also noisier than electrolytics (and just about everything else except for the cheapest of cheap ceramic disc caps).
But in real-life tests (that is, with guitars and amps and human ears), I can't hear any difference between tantalum and aluminum. I'm sure it's better for missile guidance systems, but for pedals I can't tell.
Tantalum costs more because the raw material is primarily mined from warn-torn Congo. It is also, in many cases, mined by children and used to finance very unsavory activities.
So enjoy your blood tantalum caps! ;D
Aluminums can (and more often DO) fail by thermal runaway as well as evaporative failure (which tants don't), and are just a prone to reversed polarity failure. google "blown capacitor" and see how many results are of aluminum vs tantalum.
Quote from: culturejam on July 11, 2012, 03:22:25 PM
Tantalum costs more because the raw material is primarily mined from warn-torn Congo. It is also, in many cases, mined by children and used to finance very unsavory activities.
So enjoy your blood tantalum caps! ;D
I'm for anything they can do to keep the cost down for the consumer.
Quote from: calciferspit on July 11, 2012, 03:43:37 PM
I'm for anything they can do to keep the cost down for the consumer.
I hope you're just joking...
I have to weigh in on the tantalum. I've seen on plenty of data sheets, "Do not use tantalum in any noise sensitive application."
The only benefit is that they used to be quite a bit smaller, but electrolytics are getting pretty small these days. Check madbean's mini board build guide for suggestions.
Expensive caps won't lead to a greater sound in all cases. Big mojo colourfull vintage caps do look cool and they are an argument for boutiquers to raise the prices of their box, but I like to buy some sometimes just for fun ;D
Quote from: jubal81 on July 11, 2012, 04:30:20 PM
I have to weigh in on the tantalum. I've seen on plenty of data sheets, "Do not use tantalum in any noise sensitive application."
The only benefit is that they used to be quite a bit smaller, but electrolytics are getting pretty small these days. Check madbean's mini board build guide for suggestions.
Size is the least important benefit they have. And fuzz pedals aren't "noise sensitive", they are noise generators. Any (if any) distortion introduced by caps in a dirt pedal should be welcomed. IMO. Not trying to convert ANYBODY, just stating what works the best for me. Aluminums just feel frail and fragile to me.
Fuzzes are not noise generators, they are ampliflying the signal till distortion, they amplify noises from the previous stages of your signal chain too... That's why professionnal gear include well shielded guitar and cables. They still produce a little background noise, amplified by distortions and fuzzes, leading to using noise gates.
I don't speak about wild crazy effects and noise generators but about white noise that sucks.
If you like to add noise in your boxes, I suggest not to filter your PS and even not to add a pulldown resistor to add a cool popping noise when acting the footswitch...
Yeah! new baby build idea. call it the jalepeno popper. No circuit per say, just a popping footswitch. for all of your audiophile studio and stage popping source needs.
Most fuzzes I have (prefer) have a natural gate that even gates the other pedals in the chain. There simply isn't any noise until there is a signal. high gain distortion circuits are really the only thing I notice needing "noise correction" but I don't tease my hair or wear neon spandex, so not really a concern of mine.
BWAHHAHAHAHAHA
Jacob
Quote from: calciferspit on July 11, 2012, 05:59:26 PM
Aluminums just feel frail and fragile to me.
Sure, if you step on them. ;D
I try to avoid any polarized caps in the signal path (one less thing to worry about). I go with box caps for everything up through 1µ, and I occasionally use SMD ceramics for up to 10µ. Anything bigger than 1µ is
usually either just an AC path to ground (emitter bypass) or a ripple cap on the power rail. I can hear neither frailty nor fragility on a power supply or bypass cap. I also can't hear tonal differences.
But, I'm judging on sound, not feel. So your mileage will certainly vary.
Quote from: calciferspit on July 11, 2012, 06:35:57 PM
Yeah! new baby build idea. call it the jalepeno popper. No circuit per say, just a popping footswitch. for all of your audiophile studio and stage popping source needs.
Man.. that's so yesterday :D I've made a couple popping brickets that i keep next to my pile of broken glass diodes and burn salve. It's the beauty of having just picked up a soldering iron for the first time last October'ish... I'm the accidental designer of future fads ;)
That was really funny.. I got a good laugh on that one calciferspit.
Quote from: culturejam on July 11, 2012, 06:39:08 PM
Quote from: calciferspit on July 11, 2012, 05:59:26 PM
Aluminums just feel frail and fragile to me.
Sure, if you step on them. ;D
I try to avoid any polarized caps in the signal path (one less thing to worry about). I go with box caps for everything up through 1µ, and I occasionally use SMD ceramics for up to 10µ. Anything bigger than 1µ is usually either just an AC path to ground (emitter bypass) or a ripple cap on the power rail. I can hear neither frailty nor fragility on a power supply or bypass cap. I also can't hear tonal differences.
But, I'm judging on sound, not feel. So your mileage will certainly vary.
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