Need some help tweaking Stereo Echobase

[Radamus]

Hello

I just completed the stereo echobase (http://www.diystompboxes.com/smfforum/index.php?topic=71201.0). It sounds really great, and I managed to modify the switching (with some help from around here) so that a separate stomp switch changes from long delay to rhythmic or ping pong. I just played with it for about an hour or so. Really great sounds. Gotta love that modulation.

I'm having a couple problems, though. One, I can't get it to bypass at all, but I'll probably spend some time tomorrow tinkering with that. I probably fried the transistor there. The other problem is a question of volume. On a whole, things aren't quite as loud as they should be. Also, I'm a bass player and I built the schematic almost exactly as shown, and I'm losing bass. I did some research and I found that as long as the next resistor in the signal path is big, like bigger than 52k, .1uf will be fine even for my low b. Most of the resistance to ground is sufficient, but the outputs both have .1uf going into a 100k resistor to ground. I'm thinking that's probably a big part of my bass loss. I'm not an expert, though. Are there any specific areas where I might want to up the size of my capacitors or resistors? I have some 10uf hanging around, but I don't have enough to replace every cap in the thing, so the places where I'll get the most bass back are the places I'd like to start first.

If there's a specific equation I can use here, I'm more than willing to do the work, but the equation f=160000/(uf*ohm) doesn't send up any red flags except at the output.

Any ideas? Anything would help.

Thanks in advance.

[Radamus]

Also, any recommendations for Chorus, Flanger, and any other favorite settings would be awesome.

[cpm]

a lot of caps may be removed since all the paths around opamps can be referenced to the bias voltage, pots included
bass may be lost when going through some of the DC blocking caps. The other half of the caps are part of low pass filters to tame the high frequency nastiness from the delay chip, so those should'nt be a big problem for lowest frequencies.

do you have a schematic with your modifiations? I'll try to have a look, (even if it may come a bit late )

[Radamus]

Hey, thanks for the reply. Sorry I never responded. Once school got really going for the semester, I got pretty busy. 

Anyway, let me take a look at what I changed. By the looks of it, I did the exact schematic except I changed around the switching. I don't think I made any compromises on the parts list at all. I ordered enough parts for two, and where I made mistakes in the order, I usually had enough for at least one.

The switching changes: CtrlD is a spst toggle. CtrlC is a footswitch as well, but it's slightly more complicated. One side of the footswitch serves the purpose of CtrlC, except that it doesn't go straight into the mixdown. Instead, there is a switching jack that completes the mixdown if no switch is present, giving me the option to have rhythmic or pingpong repeats, depending on whether there is a jack present, and in the other position, it gives me extra long repeats (had to switch A and B outputs to avoid a fast repeat, then slower). Then on the other side of the DPDT footswitch, output A connects to output A in one position, and connects to output B in the other position, so that it gets repeats on both sides always. One position is long repeats, the other side is pingpong/rhythm. Anyway, the switching works like I wanted it to, except for no bypass. I haven't tried to fix it since I built it, so I haven't tweaked the bypass or anything else.

One thing that concerns me is the 100n capacitors that usually go at the beginning or the end of a switch. I replaced some of the electronic switches with actual switches, so I don't know if these capacitors are necessary or helpful.

If there are a couple of capacitors that I can take out without any problems I will do so to see if I can help anything.

Also, I heard that putting a capacitor after the modulation pot keeps it from affecting the delay time linearly, rather than as a sine wave. Can I do this? I fel like it would make this more versatile.

Before I forget, I did do the modulation wave shape mod. It's from the original echobase forum.

Again, sorry for the month and a half delay.

Thanks,
Conrad