I would like to discuss what available discrete class A single and dual channel opamps exist out there that are designed for hi-z input and low-z output for use in a guitar pedal buffer circuit for driving long pedalboard cabling.
The first google result I found was the
Sonic Imagery Labs Model 995FET-Ticha
but I'm hoping there more options. 70 bucks seems kinda steep for an opamp, unless this is normal for discrete ciruitry. hmmmmmmmmmmm
It has to be a hi-Z input and a low-Z output. I'm looking to make a 1Mega ohm in and 100 ohm out. the OPamp can deviate between 90-120 ohm out. Will need to design a circuit for this.. cuz heck, custom is cool, yeah? 😎
edit:
slightly off topic but related link for peeps who don't have ADHD like me: https://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf
The first google result I found was the
Sonic Imagery Labs Model 995FET-Ticha
but I'm hoping there more options. 70 bucks seems kinda steep for an opamp, unless this is normal for discrete ciruitry. hmmmmmmmmmmm
It has to be a hi-Z input and a low-Z output. I'm looking to make a 1Mega ohm in and 100 ohm out. the OPamp can deviate between 90-120 ohm out. Will need to design a circuit for this.. cuz heck, custom is cool, yeah? 😎
edit:
slightly off topic but related link for peeps who don't have ADHD like me: https://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf
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Is there anything wrong with a unity gain follower employing a standard FET input opamp (maybe OPA1678 or OPA1641 or similar)? A fair few of them should be OK with driving a more than decent length of cable given 100 ohms of series resistance. How much capacitive loading are you shooting for? What's your intended power supply setup / power budget?
Should you have really extreme driving needs, you could always add a discrete buffer to the loop, maybe a MOSFET with current source. (Might need a bit of feedback capacitance to slow the opamp down.)
Should you have really extreme driving needs, you could always add a discrete buffer to the loop, maybe a MOSFET with current source. (Might need a bit of feedback capacitance to slow the opamp down.)
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I'm still learning the ropes. I'm quite wet behind the ears. Thanks for alternative solutions! Will what you suggest color the tone in anyway you'd think? define "OK" 😀 . maybe I'm just sold by snake oil products that dicrete circuitry is the way to go..
I had to do some googling to figure out what you meant by capacitive loading.. bare with me.. the typical guitar and patch cable has about 70-150pf and i'm guessing that's per meter.
My power supply is a CIOKS DC7. it has Voltage options up to 18v DC 300ma. I'd like to make a discrete, or the best transparent hi-Z to lo-Z buffer. after reading online about cable capacitance and such.. idk why guitar manufacturers don't all put active buffers inside the guitars. i've seen a few though. one of my guitars has active pickups so a buffer wouldn't be needed for that one. but it's still not a bad idea to have an always on buffer at the front.
I hope I clarified my guitar to line level buffering needs. 😎
I think I found what I was looking for:
Basic Buffers
To insert a discrete opamp into the equation is what I wanted. I just didn't understand what other parts were needed in the circuit. I must seem very un-knowledgeable.. 😀 apologies.
I think I wasted a lot of time looking for complex schematics and articles to realize it's probably not needed to get the end result. I only hope others find my ignorance helpful.. haha!
Basic Buffers
To insert a discrete opamp into the equation is what I wanted. I just didn't understand what other parts were needed in the circuit. I must seem very un-knowledgeable.. 😀 apologies.
I think I wasted a lot of time looking for complex schematics and articles to realize it's probably not needed to get the end result. I only hope others find my ignorance helpful.. haha!
Orman is good stuff.
I would note that in 2002, JFETs were cheaper than chips; today the situation is reversed. And the chip is truly a better amplifier. Design around TL072 opamps.
It's amazing how satisfying it is to read their clear and to the point article. Bless that personage.
Why are JFETs more money and OPAMPs cost so little? Also isn't the TL072 in the tube screamer? Or the Klon? I know they have different chips. Time to surf some more.. Dan and Mick (That Pedal Show) had a really cool video talking about opamp slew rates and what makes those two pedals so awesome. I think it was a Klon shootout video.
..but nah. I don't know much about the TL072 tbh and I need a high impedance input to a low impedance capable IC/discrete opamp. What's the fun in just buying one? Where's the adventure?
I have much to learn.
Off topic, what's your favorite drive pedal PRR?
Why are JFETs more money and OPAMPs cost so little? Also isn't the TL072 in the tube screamer? Or the Klon? I know they have different chips. Time to surf some more.. Dan and Mick (That Pedal Show) had a really cool video talking about opamp slew rates and what makes those two pedals so awesome. I think it was a Klon shootout video.
..but nah. I don't know much about the TL072 tbh and I need a high impedance input to a low impedance capable IC/discrete opamp. What's the fun in just buying one? Where's the adventure?
I have much to learn.
Off topic, what's your favorite drive pedal PRR?
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