Setback delay

[jjjimi84]

That looks really goodand I know I have said it before but this rack idea is really great.

[KMRO]

To build an enclosed pedal board with the pedals as modules is a great idea.  I'm really impressed with your design and layout (not to mention the wiring work).   Honestly this looks like a really creative project and the kind of thing that could get massive. 

Do you also have a Eurorack system?  I'm enjoying my Eurorack voyage and have been building some modules.  I put a PT2399 echo/noise circuit (from diystompboxes) behind a Eurorack panel this weekend and I feel like my world has opened up.  I think the guitar pedal/ synth exchange is a healthy one.  I know that the DIY communities have some venn diagram cross-overs. 

[Scruffie]

I may not be active here any more but I do still lurk and this one is bugging me.

R9 and R48 can't just be trimmed, they're part of the de-emphasis network and set the cut off of that low pass filter with the 33n, they counteract the pre-emphasis set by the input op amp and are part of the filtering.

If you want to increase the output level, you need to either equally reduce the value of R6,7,8 & 33. Simulation tells me the frequency response isn't flat in this, but you can try about 6k8. Technically you may need to increase C3 to about 1.5uF and C27 to 470nF to keep bass the same doing that but... probably not that noticeable.

Or, make R48 - 33k, R9 - 6k2 and C4 - 18n, not exactly identical cut-offs but close enough, you'd need to tweak the aforementioned resistors up or down to tweak it further, or there's a hair of extra gain to be had by reducing R10 to 470R.

And with that, I'll leave you all to it.

[gordo]

Miss you Scruff.  I had my board on the bench so thought I'd give the mods a shot.
Here's how if finished up:

• R4 150k
• R9 6k2
• R10 470R
• R32 22k
• R40 2M2
• R42 47R
• R48 33k
• C4 18nF
• C12 0.47uF Tant
• C18 1uF Electro
• C19 0.47uF Tant
• C28 1uF Electro
• C31 27pF

I'm able to dial it in at 12v and the mods got me close enough to unity that I'm going to call it a win.  This also got rid of the 6th string THUMP.

One thing I did find a bit confusing was the docs state to set all controls to 50% to calibrate and on mine (if it's working correctly) I was only able to get the clock to 6.5 if I had delay maxed.  It varies upwards of that with lower delay times.

This sounds good now and once my 1590BB's are in from SB this one will get boxed up.

[Aentons]

This is great, thanks guys! I had to look up the emphasis network, that's new to me. It makes a lot more sense now. I'll try changing R9/C4 and see how that works out.

Reading about how pre/de emphasis works I noticed that it is stated that the cutoff frequencies should match but I'm not sure they do in this case or if it even matters in this application.

Im not sure if I'm reading it right, but I think the output lpf (R8+R48/c4) is 1.7k and the input hpf (r5/c2) is 1.5k. I'm not sure how (or if) a mismatch would sound but I still have the trim pots in so I'll play with it when I get a chance and see if I can  get them to match.

[gordo]

I suppose in a perfect world it would be nice to leave a bit of the exaggerated highs intact in the de-emphasis to keep the delays as bright as possible without adding too much noise.  But then again, I guess that's best left to the digital world...

I've never really been an analog delay fan, starting with the original MXR green box, but this one is very nice and I can see getting some use out of it once boxed up.  My FAVE analog by far was the old Yamaha e1010.