Equinox II - sound but no reverb.

[Slowpoke101]

DIY Bass is correct. You have wired the control pot to the mounting holes.
Wire the pot correctly and put R4 back in correctly and this may work properly.

[mark2]

the holes where you have soldered to pot are grounded connections for soldering the support lugs

Oh my goodness! Wow. Yeah. Thank you.

What makes matters more embarrassing is I keep referring to a big full-page layout of the copper that clearly shows they're both grounded.

I'll fix this tomorrow and report back. Thanks again!

[mark2]

I couldn't wait for tomorrow. I went back and fixed the pot and reattached R4 and....

REVERB!

Thank you all so much for your help.

This problem has had me so focused on the things I don't yet understand (nuances of how this circuit works), and teetering between discouraged and motivated to learn more.  All along it's been something that, with a little more attention to detail, was well within my grasp and definitely not over my head.

It pushed me to learn a lot about the PT2399, though, which is good. But lesson learned: Don't immediately jump to assuming the problem lies in the mysteries I don't understand. Chances are good it's an old-fashioned boneheaded mistake.

[Slowpoke101]

Works !!! 

You are quite right. The problem is usually a mistake. Don't feel too bad or silly as everyone makes mistakes. But we do learn from them.

Enjoy the pedal and don't run it from a 9V battery. Two PT2399 chips do use a fair amount of current (about 45mA ). A good 9V battery would last a couple of hours before being excessively drained.

[duck_arse]

OK, this is nowhere near C4, but is an issue.  It looks to me as if the holes where you have soldered to pot are grounded connections for soldering the support lugs for a board mounted pot, and are not at all where the electical connections from the pot should go.  If you follow through the schematic and the board, it looks as if there are three holes underneath that are unused in your build, but are where the pot should solder to.  If you refer to the schematic you will see that all three lugs from the pot should be in use.  If you follow the schematic you will see which lug should go the which hole.  I have ringed the holes I am talking about in red - hopefully they will show up.

nice one, well found.

and well done on the "fixing".

[PRR]

Don't immediately jump to assuming the problem lies in the mysteries I don't understand.

This may the THE most important lesson of your career.

My first day at a radio studio, record player didn't play. I had half the studio torn apart. Then elder Stan pointed out a loose plug. Power to the phono preamp. Duh!!

I don't make those mistakes any more... well, any more than 13 times a day. (If I get that far, I take a nap.)

[PRR]

> I don't fully understand yet how the pt2399s are supposed to be adding the delays

_I_ don't understand all the inside and outside parts of the PT-. But at some level we can see it as "Echo Point in a chip". You shout "YO!" and "...oy!oy!oy!" comes back from the cliffs (must be very tiny cliffs inside).


We want to use this with a guitar. We want the dry signal and the PT- echos mixed to taste. Because the split/mix action and the low impedance of the PT- chip would load-down a guitar, we first buffer the input. Split. One path, Dry, goes to output mixer/buffer. That much worked.

The other split goes to a PT-chip. "Good" is not enough so it goes to a second PT- chip. They are marked short and long. So one is a tile shower, the other is a hard bare cellar. Now we have a long dense "wet" reverb. But because "enough" is still not over-the-top, he adds a "recirculation" path which feeds wet back into the echo path for really-really wet-wet-wet. We *may* not need to delve too deeply in these details.

We need to trim this wet signal from nothing to Lots. The 10k mix pot takes Wet on top and passes 0% to 100% of this to the output mixer/buffer.

When you mis-wired that pot you get 0% to 100% of ground, no-signal. In this case, the problem was nothing to do with the PT- chips but "simple" audio mixing. The mix pot was fed a "nothing". The "...oy!oy!oy!" was right there on the pad NEXT to the pot. And yes, it is natural to look at that 99 times and still not see the slip-up.

[PRR]

Simpler drawing:

[tubegeek]

Don't immediately jump to assuming the problem lies in the mysteries I don't understand.

This may the THE most important lesson of your career.

My first day at a radio studio, record player didn't play. I had half the studio torn apart. Then elder Stan pointed out a loose plug. Power to the phono preamp. Duh!!

I don't make those mistakes any more... well, any more than 13 times a day. (If I get that far, I take a nap.)

I've heard this expressed as - don't expect a zebra when it might simply be a horse.

Mark2, you owe DIY Bass a (virtual) sausage. Them's the rules.

[mark2]

Great illustrations showing the path, and very helpful to avoid getting lost in the details!

I've heard this expressed as - don't expect a zebra when it might simply be a horse.

That's good, and very apt!

Mark2, you owe DIY Bass a (virtual) sausage. Them's the rules.

Happy to pay up! That was a good find, and spot on.

[duck_arse]

there's more oy's there than at the 2000 Olympics.

[edit :] oi!