Messages

[Is this expected, or should I adjust R2 or R6? Or perhaps swap in a different LM1458?]

I'm very happy with this Setback build, which I posted about last month in the "Build Report" section.

https://www.madbeanpedals.com/forum/index.php?topic=34453.0

Here's a demo video where I compare it to a stock version of the (totally unrelated) MXR Analog Delay; I used the case of a dead one for my build. I chose the Setback because it's also a 3-knob delay with about 300 ms max delay time

I want to make some improvements, and would like to know if they sound doable

• There's a pronounced volume drop in the dry signal path on my Setback. Is this expected, or should I adjust R2 or R6? Or perhaps swap in a different LM1458?

• I'd like to fill the second output hole in the case with a "Delay Only" signal. The behavior of the MXR is that the "Output" jack always carries a dry/wet mix as determined by the Mix knob, and the "Delay Only" jack always carries just the wet signal at full volume with no regard to the Mix knob. So to get full wet/full dry on the outputs you set Mix at zero. There does not appear to be any jack switching going on. Should I be able to tap another output directly from R33? Or do I need a separate output buffer?

• Finally, I was able to crank the CLOCK trimmer full counter-clockwise without getting any undesirable artifacts at all (even on my scope), reaching a max of 366 ms. Maybe I got a good MN3005? Or a good compander chip? I'm wondering if I can squeeze even longer delays out. The Setback's repeats are very bright compared to my MXR's, so I'd be OK with rolling off more highs. I'm running at 12V so I have R40 = 2M2. Can I increase this for even longer delays? Would adjusting the filter/compander help with this?

Thanks for watching, this was my first build in many years and I'm really pleased with the result!

FYI there was an American company that made a Tri Stereo Chorus clone:

http://www.rtelectronix.com/pThreewaychorus.htm

I have one, but have never ABed it against the TERC, which I also have

Quick demo video, comparing my build to the MXR original that I have (which is a totally unrelated circuit built around a Reticon chip, but still an interesting comparison...)

https://youtu.be/jgx5RQF5Lkc

Thanks all for the love. Imagine if they brought back a SAD1024 reissue. BBD Renaissance

So excited - completed my first build since college days 20 years ago!

Prompted by a retail experience. Bought a late 70s MXR Analog Delay from a local shop. A couple of days later I noticed a minor switching issue, which I probably could have fixed myself, but I thought "I just bought it, and their tech is surely more skilled than me."

Womp-womp...

Phone call from them: "I think we've destroyed the pedal." It seems their tech was probing around and shorted the 120V AC (it's a plug-in pedal that includes a transformer to 12V DC) to the signal ground, in the process frying every IC on the board. Including the unobtainable Retcon R5101 delay chip. A "Charge Coupled Device" - subtly different from a BBD, in terms of implementation. Bummer!

I am fortunate enough to own a couple of other pedals that use the Retcon R5101, and by swapping them around, confirmed that it was indeed fried.

The shop were super cool about it. Gave me my money back, and the fried pedal for free.

So now I have this sweet vintage 70s enclosure, and no hope of obtaining another Retcon R5101, without cannibalizing another pedal. I saw some posts about retrofitting these pedals using PT2399-based circuits (like here https://www.freestompboxes.org/viewtopic.php?t=2332).

But that approach felt so... 2010's. We have CoolAudio, Belling, and Xvive BBDs now! And the MadBeanPedals Setback promised about 300 ms and self-oscillation, so similar specs to the MXR original!

My skill level is closer to "Cowboy" than "Genius" but I dove in anyway...
                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
So I ripped out the dead guts, set them aside in case someone makes a drop-in replacement for the R5101 (my money is on "not in my lifetime"), and built a Setback into this case. It rips!

Build notes:

• It's true bypass now which is cool

• I used the 12V value for R40 and am powering it at 12V with my Strymon Ojai R30
• Soldered the bypass LED straight to the board for diagnostic testing but the finished pedal acts like the original, with no LED
  Didn't detect any clock noise even with the "Clock" trimmer cranked, so I'm getting about 380 ms max delay. Is that because I got a good compander? Or because the new Xvive chips are really clean? Makes me wonder If we can get even more delay out of that chip
• Found a panel-mount DC jack that perfectly covers the hole that held the AC cable strain relief. Don't know why this makes me so happy
• Didn't have an easy way to mount this tight little board into this giant enclosure, so I found some vintage MXR-style crappy foam to wrap it in. It definitely gives the tone that extra push off the cliff. As they say, "the toan is in the foam"
• I "rocked before I boxed" and had only the dry signal coming through. I thought I'd screwed up somewhere; the clock circuit looked good on my scope, but the audio input and output around the BBD didn't sound right on the audio probe. It turned out both my compander and my MN3005 were sketchy because I got them from eBay. Noob mistake. Got replacements from Cabintech and now I'm stylin'. Very glad I socketed all ICs

Minor issue:

• Noticing a slight volume drop with Mix at full dry

In any case, this was an awesome fun build.

https://photos.app.goo.gl/1yGQVZMm3euhaJjq8

Thank you! So max it out, instead of setting it to 50%. I think the PDF instructions have a minor error, then.

Can't wait for my batch of MN3005's to arrive so I can finally finish the build 

[should the instructions perhaps read "Starting conditions: Set the Delay knob to maximum, and all other knobs and trimmers to 50%"?]

I've built the Setback and am starting calibration.

It looks like the clock circuit is happy - my little pocket scope shows a nice clean square wave of about 11 V peak to peak coming off the MN3101.

The calibration instructions state "Starting conditions: Set all knobs and trimmers to 50%." Presumably this includes the Delay knob. But no twisting of the Clock trimmer gets me anywhere close to the stated 6.5 kHz target frequency.

By my reckoning, 4096 stages = 2048 pairs of stages, divided by 6.5 kHz gives 315 ms, which I would expect as an approximate value for the Delay knob at max - should the instructions perhaps read "Starting conditions: Set the Delay knob to maximum, and all other knobs and trimmers to 50%"?

With Delay at max, the Clock trimmer gives me about 5.5 kHz at full CCW and about 8 kHz at full CW. Which looks like a perfect range to dial in for step 3, when I'll dial it back to around 6 kHz or until I don't hear artifacts. With Delay at 50% I see around 25 kHz (82 ms) and at minimum I see around 50 kHz (4 ms).