Just wondering your take on changing out TLO72s and 74s with better chips?
You're playing guitar through a guitar amp, right?
Well, I understand the bandwidth limitations.
The answer is "maybe in some sense of the word improve." A TL072 is possibly the last place I would look to improve fidelity in a circuit, and you'd probably need a scope to notice the difference even assuming that they exist in the circuit. You're better off focusing on ideal impedance matching and noise reduction techniques, that is, making the circuit itself as good as possible. (Noise is the main problem with electric guitars, and humbckers have poorer bandwidth.) If you're worried about headroom, you're also hitting a brick wall in your interface.
Actually, come to think of it, most decent modern interfaces have better instrument DIs than we can build. What are you using?
http://nwavguy.blogspot.fr/2011/08/op-amps-myths-facts.html?m=1
http://nwavguy.blogspot.fr/2011/08/op-amp-measurements.html?m=1
Here is an article aimed at debunking myths for the HiFi guys who normally ignore science anyway. Can be applied to pedals also but not really in distortion pedals but possibly for preamps, boosters etc. But us in the guitar world often like opamp with outdated or weird specs because of their anomalies. We don't always try to faithfully amplify the signal.
Still an interesting read. The main points. Certain circuits are designed around a certain opamp and changing it for a more HiFi one won't necessarily make it better and sometimes make the circuit unstable which I guess goes with what Jon said. And for the money he says it's hard to beat the ne5532.
Its all about Discrete Op-Amps now man! Embrace the mojo!
(https://www.bursonaudio.com/wp-content/uploads/2014/10/Burson-supreme-opamp.jpg)
(I love those ridiculous buggers. Extreme audiophiles are adorably bizarre sometimes ;D )
Someone should miniaturize those discrete op amps, add some more parts to improve uniformity, stability, and reliability, and package them into a standardized plastic or ceramic carrier to make them easier to incorporate into existing designs. :P ::)
I do home automation installations for work. And we do many high end audio installations. I get all types of weird audiophoolery questions. Like "I've heard online that bypassing the fuse in the amp makes the sound way better" (sure if you wanna risk frying your 10,000 euros amp and burning you house down), "I've heard that replacing the metal knobs on my amp to wood reduces the resonance and helps with the transients", 1000 euro power chords with silver coated wire, etc. Then the same guys wanna do something dumb like placing the speakers at opposite corners of the room facing each other.
Anyway back on topic. A friend asked me to build him a sonic maximizer (madbean bloviator). I was pretty skeptical going in after either reading online that it is garbage or magical. I built it on vero thinking I was just gonna huck it in the either garbage afterwards. I was plesently surprised by the results. Different results than I've gotten from an eq pedal. I hate to be that guy but it really was like "a blanket was lifted off the speakers", well maybe not quite that strong, maybe a thin blanket. It might just be the gear we tried it on. But it really shined with modulation pedals and brought a lot of clarity to bass and treble. It works well with dirt too but really took away some of the balls from some of the fuzz pedals I tried it with. Anyway, if you wanna try something more "hi-fi" sounding might be worth giving this a shot.
There's a good EEVBlog video on youTube about techniques you can use to minimize noise in audio amplifiers. Couple things I remember from it: instead of doing a single high gain stage, do two or more lower gain stages in series. Second thing was adding a small amount of series resistance at the output of each stage, like 100R to 1k, to reduce noise. First tip is not so effective in guitar pedals like overdrives because we are typically using them "the wrong way" to create distortion, not minimize it. It's probably more helpful when working with something that's supposed to have fidelity (which ain't guitar pedals). Second tip is useful though and you will see it over and over in circuit designs.
Quote from: bsoncini on January 26, 2018, 01:56:48 PM
I do home automation installations for work. And we do many high end audio installations. I get all types of weird audiophoolery questions. Like "I've heard online that bypassing the fuse in the amp makes the sound way better" (sure if you wanna risk frying your 10,000 euros amp and burning you house down), "I've heard that replacing the metal knobs on my amp to wood reduces the resonance and helps with the transients", 1000 euro power chords with silver coated wire, etc. Then the same guys wanna do something dumb like placing the speakers at opposite corners of the room facing each other.
Also gotta make sure those directional cables are plugged in the right way!
Opamps can be designed for better performance in different applications. It's become a trope to swap different ones in an overdrive to show they 'all' sound the same.
That being said, there are opamps designed for audio with definite benefits - lower noise, rail-to-rail operation and immunity to phase reversal when overdriven. Take a look at the OPA1642 (SMD only). I used a quad to replace the opamps in an MXR EQ pedal and the noise when from unbearable to almost undetectable.
Of course, overall circuit design plays a bigger factor than opamp selection.
If I stuff a pedal with Fritos should I wear a sombrero when I play?
Quote from: midwayfair on January 26, 2018, 06:42:47 AM
The answer is "maybe in some sense of the word improve." A TL072 is possibly the last place I would look to improve fidelity in a circuit, and you'd probably need a scope to notice the difference even assuming that they exist in the circuit. You're better off focusing on ideal impedance matching and noise reduction techniques, that is, making the circuit itself as good as possible. (Noise is the main problem with electric guitars, and humbckers have poorer bandwidth.) If you're worried about headroom, you're also hitting a brick wall in your interface.
Actually, come to think of it, most decent modern interfaces have better instrument DIs than we can build. What are you using?
I'm using a Scarlett at the moment. For some reason I was thinking that the opamp played a more central role. But now that you mention it, I can see that circuit design would be the obvious place to improve a circuit.. uh, anyway I was thinking that because changing out the opamps in a Urei comp I have laying around here somewhere was something that people did back in the day hmmm.. OK So there is nothing to be gained in broadband phase coherency through opamp selection that you wouldn't look first to the surrounding circuit itself to improve. Is that sorta what you're saying?
Quote from: bsoncini on January 26, 2018, 08:23:21 AM
http://nwavguy.blogspot.fr/2011/08/op-amps-myths-facts.html?m=1
http://nwavguy.blogspot.fr/2011/08/op-amp-measurements.html?m=1
Here is an article aimed at debunking myths for the HiFi guys who normally ignore science anyway. Can be applied to pedals also but not really in distortion pedals but possibly for preamps, boosters etc. But us in the guitar world often like opamp with outdated or weird specs because of their anomalies. We don't always try to faithfully amplify the signal.
Still an interesting read. The main points. Certain circuits are designed around a certain opamp and changing it for a more HiFi one won't necessarily make it better and sometimes make the circuit unstable which I guess goes with what Jon said. And for the money he says it's hard to beat the ne5532.
Glad I’m not one of those Hi Fi guys.
I have an old English Hill Audio mixer in the garage with a ton of chips in it. I keep saying I’m going to rummage through it and salvage them. I’ll have to look to see if they are 5532s... That’s what I remember. Ha! Good luck with that.. I can’t remember what I had for breakfast much less a hyped glossy one sheet I read 40 years ago...
I mean, ne5532's are like 75 cents a piece new, if you want to source them without having to de-solder things.
Quote from: blearyeyes on January 29, 2018, 10:27:10 AM
Quote from: midwayfair on January 26, 2018, 06:42:47 AM
The answer is "maybe in some sense of the word improve." A TL072 is possibly the last place I would look to improve fidelity in a circuit, and you'd probably need a scope to notice the difference even assuming that they exist in the circuit. You're better off focusing on ideal impedance matching and noise reduction techniques, that is, making the circuit itself as good as possible. (Noise is the main problem with electric guitars, and humbckers have poorer bandwidth.) If you're worried about headroom, you're also hitting a brick wall in your interface.
Actually, come to think of it, most decent modern interfaces have better instrument DIs than we can build. What are you using?
I'm using a Scarlett at the moment. For some reason I was thinking that the opamp played a more central role. But now that you mention it, I can see that circuit design would be the obvious place to improve a circuit.. uh, anyway I was thinking that because changing out the opamps in a Urei comp I have laying around here somewhere was something that people did back in the day hmmm.. OK So there is nothing to be gained in broadband phase coherency through opamp selection that you wouldn't look first to the surrounding circuit itself to improve. Is that sorta what you're saying?
I'm saying I wouldn't expect it to make an audible difference.
I don't know how old your Scarlett is ... if you have an old one with 22k input impedance (something like that), almost anything will be an improvement over the stock DI. If yours is one of the newer models, they already claim to have a 1M input impedance. You'll end up going into the line inputs in the back when you make yours, which ends up going through the tail end of the inputs in the front, with, IIRC, a single current driver followed by the converter circuitry.
I will preface this by saying that I made one of my favorite albums on a Scarlett in a handful of days with approximately one microphone: The shortcomings in the Scarlett are in the places you can't really get to, their drivers, the line input balancing (they may have fixed this, but it was the main reason I changed interfaces), and the final noice specs that come from the converters, though again the version 2 models are all better.
I'm sort of rambling, but what I'm getting at is that it might take a bit of extra work to figure out what you need to build and identify exactly what your circuit needs to correct for.
Chips all sockeded. I have a chip puller. Just have to clear away the cobwebs and kill whatever is living in there. I have 30+ analog meters and a ton of Alps sliders if they are in any shape to re-purpose. I don't know, it's just difficult to let go of obsolete stuff that was so cool and expensive back then.. Probably just separate one pile of crap I wont ever use into three or four piles of crap I will never use.
Quote from: blearyeyes on January 29, 2018, 09:04:41 PM
I don't know, it's just difficult to let go of obsolete stuff that was so cool and expensive back then.. Probably just separate one pile of crap I wont ever use into three or four piles of crap I will never use.
I know the feeling ;D ;D ;D
Hey can anyone tell me how you determine the impedance of an Input?
Quote from: blearyeyes on January 29, 2018, 10:08:29 PM
Hey can anyone tell me how you determine the impedance of an Input?
I'm far from an expert. There is some math involved that looks more complicated than it is. Check out www.electrosmash.com and click on some pedals for examples. He/she always calculates impedence.
And GEOFEX! http://www.geofex.com/Article_Folders/impednc.htm
Re: Topic: Can you up the fidelity changing out opamps?
Yeah, you can, but you might not like the results. (I have some recent posts regarding that).
There are people who say that changing opamps doesn't make a difference. That's like color-blind people saying that there is no such thing as color, or people who can't have orgasms saying that there is no such thing as orgasms.
.
What are orgasms?
Quote from: blearyeyes on February 08, 2018, 08:25:19 AM
What are orgasms?
They're one of the three fundamental logic gates, along with andgasms and xorgasms.
Quote from: midwayfair on February 08, 2018, 04:40:05 PM
Quote from: blearyeyes on February 08, 2018, 08:25:19 AM
What are orgasms?
They're one of the three fundamental logic gates, along with andgasms and xorgasms.
Don't forget norgasam. That's what you get when your wife has a headache.
Forget about andororgasm
One of the electronics faculty members at the college where I work assigns a final project for students where they have to build as hi-fi an audio amp as they can using only LM741s for the opamps. I drop by once in a while to see how it goes. Some of them have surprisingly good results! Pertinent to this thread, I like that his whole point is to emphasize circuit design over part numbers.
Quote from: Govmnt_Lacky on February 08, 2018, 06:09:24 PM
Quote from: midwayfair on February 08, 2018, 04:40:05 PM
Quote from: blearyeyes on February 08, 2018, 08:25:19 AM
What are orgasms?
They're one of the three fundamental logic gates, along with andgasms and xorgasms.
Don't forget norgasam. That's what you get when your wife has a headache.
;D ;D ;D