Like in the sense of providing greater than unity gain? If so, not really since an emitter follower has a gain of ever-so-slightly-less-than-one, but if you like the sound of the buffer you could follow it with a separate gain stage
NSFW What's up with the buffers in cornish designs?
- Thread starter lrgaraujo
- Start date
This idea actually makes for a decent design starting point - if you limit the gain of almost any gain circuit to unity (or thereabouts, to make up for perceived volume changes due to EQ changes), you’ve created a buffer.
So if there’s a boost or overdrive you particularly like the sound of, tweaking it so it sounds good at unity and then replacing all the pot values with fixed resistors could be cool
marksescon
Active member
A while back I had traced the Skeptical Buffer and shared the schematic on Reddit, this forum, and my blog. The gentleman from 29 Pedals reached out to me on my Discord and Reddit on Aug. 29, 2023 and did not seem happy (understatement) for tracing the circuit and leaving out the power supply. He went on to criticize Robert for leaving out the power supply which apparently contributed sonically to the pedal. (Unsure if it does.) From what he wrote, it appears Robert was very close except for one vestigial component in the signal pathway and the power supply.
But most of all, he seemed discontent that the circuit was ever traced - which I find contradictory because the PCB on the EUNA itself sports verbiage encouraging a DIY ethos.
Regardless, I could tell he was distraught because he sent the messages at 5 AM in the morning, leading me to remove a lot of my posts regarding the EUNA/Skeptical Buffer.
Last edited:
Laundryroom David
Keyboard Cowboy 🤠
I’m not an engineer, so although this will sound like I’m being a troll, I’m genuinely curious: why would one want a power section to contribute sonically to an audio circuit?
marksescon
Active member
I do not know but the answer I received was: “The omissions from the power supply will decrease the headroom, slow down the transient response, and generally be significantly noisier.”
Bricksnbeatles
Member known well
Now this one is NSFW too 
Well, as the OP, I consider that an achievement (even though I'm not the one responsible for the tag)Now this one is NSFW too
Wear this badge of honor with pride my friend!Well, as the OP, I consider that an achievement (even though I'm not the one responsible for the tag)
In other words, “no, it doesn’t affect the sound, but I refuse to admit it.
Here’s a bunch of magic word bullshit that doesn’t correlate with reality. Please don’t look into it any further.”
Bricksnbeatles
Member known well
I don’t know about that— I read on the Steve Hoffman Forums about the profound impact a $25k iec cable for a hifi system really makes the top end sparkle, and really brings out the analog properties of some $300 45rpm “ultradisc 1 step” box set of some crummy SRV album or whatever
Robert
Reverse Engineer
The working voltages are similar and I think we can feel fairly confident the power supply rails aren't buckling under the heavy load of a single TL072 based clean buffer.
Look, 18V is just *better* when it comes from a Rube Goldberg machine of rectifiers and regulators.
They’re fancier volts. Higher-headroom volts.
cdwillis
Well-known member
Let's say my bridge humbucker puts out about 0.4v on average and an op amp buffer is running just on 9v and biased at half that. Either side of the waveform would have to hit 4.5v to begin distorting, right? I don't think even hitting the strings hard would generate 1v at it's peak.
mzy12
Active member
Yeah but what if you replaced the guitar with a 25Vpp sine wave from a function generator? Checkmate pedal nerds
Robert
Reverse Engineer
Yeah but what if you replaced the guitar with a 25Vpp sine wave from a function generator? Checkmate pedal nerds
... and it's still going to draw about 130mA less current ...
I supposed I could add an optional 2W 70 ohm resistor across the 9V line for those who want the full authentic experience.
mzy12
Active member
"Okay now plug mains into it."View attachment 58556
... and it's still going to draw about 130mA less current ...
I supposed I could add an optional 2W 70 ohm resistor across the 9V line for those who want the full authentic experience.
JTEX
Well-known member
I've often seen brief 2v peaks on hot guitar/bass pickups when hit hard. Guitar straight to scope. Of course, just about any op amp buffer running off 9V should still handle them with ease. Especially one with R-R output.
JTEX
Well-known member
As usual, I am of the strong opinion that TL072 has no business being in a top notch guitar buffer in 2023. It's just too noisy at 18nV/sqrt(Hz) (same as the thermal noise of a 20k resistor). I would pick something with less than half that noise. And of course, it would also have to have very low current noise to do well with high impedance sources, so either JFET input or super beta bipolar (my new favorite). My best suggestions as a guitar buffer: OPA205/206/207, OPA145. Or, if you have all the money and want the quietest possible op amp that can handle high source Z, get an OPA827, or even two of them in parallel if you're nuts (I am, and I've done it).
jhaneyzz
Well-known member
that’s a great quote…
