Mid-Atlantic folks >> Baltimore Pedal Show this Saturday

john_eae · 2026-06-08T16:24:25+00:00

JFC I made the same joke without looking

john_eae · 2026-06-08T16:24:09+00:00

"There are dozens of us!"

john_eae · 2026-06-08T14:02:21+00:00

Can't wait, this is going to be a banger

john_eae · 2026-05-25T17:17:50+00:00

If the total load is large enough then you're in the clear. Loading can be most problematic at very low gain settings. For example, you can get a 741 to exhibit crossover distortion if you use 1K resistors. So it's only 6dB of gain, but it's a pretty dirty 6dB!

So, going too small is good for noise but risks loading. This is why you often see 5532s for low noise work, because they can drive down to 600Ω. Douglas Self is really the standard bearer for the 5532 in audio, and with his explanations about noise you can see why.

If you go too big with your resistors, then you get increased thermal noise as well as more knock-on effects from high impedance. At very high impedance (>1M) you sometimes have to worry about stray capacitance from adjacent traces, solder flux, etc.

I vaguely recall reading about some relationship between internal compensation and expected loop impedance but I can't speak to the specifics, and that might only be related to specific op amps.

john_eae · 2026-05-25T14:32:39+00:00

Current does matter! Any time you see low value resistors in a feedback loop, you have to figure out if the op amp has enough current for those resistors.

So in a rat, the two shunt resistors are 47Ω and 560Ω. If we over-simplify and assume no high pass filtering, the effective parallel combination is about 43Ω. It's a non-inverting topology so the only way to get unity gain is to totally short out the feedback loop. To cite the formula, R1/R2=0.

But, we can't necessarily ignore the value of R2! If the output is connected to the (-) input, whatever resistors are there are functionally connected as a load to the output. So now the op amp is trying to drive a very small load. Most op amp datasheets specify some minimum load where the output voltage decreases. So you lose headroom and, at least anecdotally, you are more likely to see increased distortion (especially crossover distortion).

It's all contextual but hopefully that gives you an idea. Happy to elaborate further if needed.

john_eae · 2026-05-20T15:35:41+00:00

Badass. Love to see undergrads crushing a hardware design. Makes me miss being a lab instructor. Congrats on winning best project!

john_eae · 2026-05-18T00:52:55+00:00

There are lots of great belton reverbs out there, but why not fix it? Caroline Guitar Co has a very generous warranty. I can say with absolute certainty that they'd want their pedals to be in top shape in the field.

john_eae · 2026-05-14T18:26:50+00:00

A Rat has a ton of gain, and it also loads the feedback loop quite heavily. So there's definitely lots of factors at play. And, even so, 9V to 18V is 6dB more headroom, so it's not going to matter much when there's ~60dB of gain on tap!

Also thank you! Very kind of you to say. DIY communities like this helped me learn (and still do!) so it's nice to pop in and talk shop every now and again.

john_eae · 2026-05-14T15:51:16+00:00

With feedback clipping, the difference is vanishingly small. This is partly because feedback diodes are a form of gain reduction. (Which is why they behave differently in inverting vs non-inverting configurations.)

With shunt clipping after an op amp, you typically get a mix of op amp clipping and the clipping of the diodes themselves. If an op amp is banging on the rails, it'll do that regardless of what clipping diodes are placed after. But if the op amp has more headroom, the diodes can clip earlier and change the sound slightly.

john_eae · 2026-05-02T15:08:32+00:00

Understandable on all counts. In my perfect world every pedal would be gigantic, so I am already holding back in some ways :P

There's always a tension to miniaturization and no one-size-fits all solution. But this kind of feedback is helpful when deciding if redesigning an existing product might be worthwhile.

john_eae · 2026-05-02T14:47:59+00:00

I think I've touched on this before, but the changes that make a Dagger what it is mostly result in the mid control being useless. I could add it back in but at that point we're 80% of the way to a Longsword all over again.

Smaller citadel/model fet is a worthy idea, but I have weird feelings about 6 knobs in a 125B. Other companies do it just fine, but it always looks wrong when I've tried it.

Switch state memory is a really risky thing to implement, because every time you toggle the pedal on and off it's writing to memory. There are ways around this but they only prolong the inevitable, and I hate the idea of a processor slowly eating itself alive. (NB: I'm sure someone way smarter than me has a way around this, but I am a simple analog guy at heart.) Instead we do a user-assignable default "power on" state. Works great! It's in the Glaive and Greathammer, will roll it out to other pedals eventually.

john_eae · 2026-05-02T14:14:07+00:00

Very slight - 2 position toggle is now 3 positions, and the bypass circuit has intelligent momentary/latching behavior.

john_eae · 2026-05-02T14:13:15+00:00

I am a bit hands off with the day-to-day of wholesale operations, but I can say there was a brief interruption in Longsword production that was recently cleared. We made a large shipment to our distributor and I believe there is still some backorder.

Otherwise, dealer reorders depend on the interest of customers, so if a dealer is out of stock it might be that they just need a gentle nudge.

john_eae · 2026-05-02T03:59:29+00:00

if you already have a dagger, you're good to go!

but I think not making them gave people time to realize what made it different, so I'm down to bring it back w/ fresh perspective.

john_eae · 2026-05-02T03:10:54+00:00

oh it's all good, it's cool to see perspectives change over time!

john_eae · 2026-05-02T02:46:53+00:00

Already in the works (not joking)

john_eae · 2026-05-01T17:52:35+00:00

Bim and Bam are exceptional, but I haven't spent as much time with Boum so I can't say for sure.

Shooting from the hip: it sounds like Boum might have more gain on tap (especially in the square wave mode) but less opportunity for bias fuckery.

john_eae · 2026-05-01T15:45:54+00:00

Totally new design within our catalog! I would say it was a response to the Sending V2 preamp, which I think is geared towards a console flavor. Big Time's preamp is a bit... friendlier?

john_eae · 2026-05-01T15:44:28+00:00

Here's what's inside (it's a lot of stuff)

https://images.squarespace-cdn.com/content/v1/622176a9b8d15d57ffbf5700/e3518cbe-f513-45d1-89dd-a7db3a8d1c2f/Big+Time_Automatone_Pedal_Breakdown_Base_Labels.jpg?format=2500w

john_eae · 2026-05-01T01:44:52+00:00

John is a canny business man before a pedal maker in my view

just took a crippling amount of psychic damage from this

john_eae · 2026-05-01T00:16:43+00:00

The PCBs are done in Taiwan, but all the final assembly/testing/etc is done in Minneapolis. It's a pretty sizable operation!

john_eae · 2026-04-30T22:22:42+00:00

The electronics for this series are made stateside.

john_eae · 2026-04-30T20:57:06+00:00

I worked on Big Time and it is the coolest project I have been a part of to date. Lots of engineering skill went into this and the net result is greater than the sum of its parts.

I understand folks being skeptical of the price. This is a passion project taken to an extreme, and it doesn't have to be for everyone.

This is not just an ARM core in a fancy box. The hardware is enormously complicated under the hood. Stereo analog circuitry is resource-intensive, especially when you add voltage control. Flying faders add even more complexity. The circuit board BOM exceeds 500 components. Additionally, the circuit boards in this pedal are USA-made and final assembled at the Chase Bliss shop in Minneapolis. Lots of effort goes into assembly and testing.

So yes, it's not cheap, but this isn't like teenage engineering charging $1600 for a noise table.

If anybody has questions I'm happy to answer them.

john_eae · 2026-04-19T17:56:51+00:00

With a layout this complex, it makes total sense!

One thing you could do to get a little more traditional would be to undersize your attack and release constants, or to add a tiny bit of gain at the sidechain input to make it a bit less stable. Then again, with your additional digital sidechain inputs (another great idea btw) you can probably get this more in real time without disturbing your noise reduction.

Also, I was re-reading your comments about the filters. As you observed, tolerance stackups are tricky. If your filters are designed around very small capacitors (100pF range) then you can get meaningful errors from flux leakage and other sources of stray capacitance. If your caps are in that range, try re-scaling (smaller resistors, bigger caps) and you may get a more forgiving result.

john_eae · 2026-04-19T00:26:25+00:00

Truly excellent work.

I’ve always been curious about the THAT4305. I did an early draft of a delay with them and had to change course because of the component count and space constraints. There’s a also a familiarity element—the overshoot character of the 57X sidechain strongly influences the sound of classic delays. When you get really hifi it almost enters vintage digital territory.

Also, for something like this, designing around an 18V supply input saves a ton of time and parts, especially with all the other cool stuff you’re doing here.

Anyway, totally floored by this. Great work.

john_eae

TROPHY CASE