NSFW What's up with the buffers in cornish designs?

Meanwhile, back in Cornwall ...

Can the Tillman Pre be configged as a buffer? Why yes, yes it can.
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
 
But let's be charitable - credit where credit is due, 29Pedals dude's "real" innovation is his "whatever" power supply (which in my estimation creates more problems than it solves, but-), not the analog circuits he hooks it up to.

Maybe if he wants so badly to be a power supply designer, he should go off and be a power supply designer (hell, sell your tech to Strymon or Eventide, high-draw DSP is an *actually* good use-case for a well-protected power supply).
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.
 
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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?
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.”
 
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.”
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.”
 
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.”
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
 
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.”

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.
 
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.
 
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.
 
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.
Yeah but what if you replaced the guitar with a 25Vpp sine wave from a function generator? Checkmate pedal nerds :cool:
 
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.
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.
 
[...} single TL072 based clean buffer.
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).
 
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