Author Topic: Can you up the fidelity changing out opamps?  (Read 1258 times)

midwayfair

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Re: Can you up the fedility changing out opamps?
« Reply #15 on: January 29, 2018, 07:34:17 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?

Iím 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 wouldnít look first to the surrounding circuit itself to improve. Is that sorta what youíre 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.
Myself's music & things I make: http://jonpattonmusic.com. My band: http://midwayfair.org. PCBs of my designs from: http://www.1776Effects.com (Bearhug Comp & Cardinal Harmonic Trem); http://www.jmkpcbs.com (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: www.madbeanpedals.com

blearyeyes

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Re: Can you up the fidelity changing out opamps?
« Reply #16 on: January 29, 2018, 03:04:41 PM »
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.
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HamSandwich

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Re: Can you up the fidelity changing out opamps?
« Reply #17 on: January 29, 2018, 03:25:21 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

blearyeyes

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Re: Can you up the fidelity changing out opamps?
« Reply #18 on: January 29, 2018, 04:08:29 PM »
Hey can anyone tell me how you determine the impedance of an Input?
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bsoncini

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Re: Can you up the fidelity changing out opamps?
« Reply #19 on: January 29, 2018, 05:08:58 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.

HamSandwich

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Re: Can you up the fidelity changing out opamps?
« Reply #20 on: January 29, 2018, 05:15:42 PM »

Now they tell me

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Re: Can you up the fidelity changing out opamps?
« Reply #21 on: February 07, 2018, 04:02:32 PM »
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.
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blearyeyes

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Re: Can you up the fidelity changing out opamps?
« Reply #22 on: February 08, 2018, 02:25:19 AM »
What are orgasms?
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midwayfair

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Re: Can you up the fidelity changing out opamps?
« Reply #23 on: February 08, 2018, 10:40:05 AM »
What are orgasms?

They're one of the three fundamental logic gates, along with andgasms and xorgasms.
Myself's music & things I make: http://jonpattonmusic.com. My band: http://midwayfair.org. PCBs of my designs from: http://www.1776Effects.com (Bearhug Comp & Cardinal Harmonic Trem); http://www.jmkpcbs.com (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: www.madbeanpedals.com

Govmnt_Lacky

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Re: Can you up the fidelity changing out opamps?
« Reply #24 on: February 08, 2018, 12:09:24 PM »
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.

blearyeyes

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Re: Can you up the fidelity changing out opamps?
« Reply #25 on: February 08, 2018, 02:48:02 PM »
Forget about andororgasm
« Last Edit: February 08, 2018, 06:12:35 PM by blearyeyes »
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Bret608

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Re: Can you up the fidelity changing out opamps?
« Reply #26 on: February 14, 2018, 08:57:09 AM »
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.

warriorpoet

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Re: Can you up the fidelity changing out opamps?
« Reply #27 on: February 14, 2018, 08:04:55 PM »
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
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