| several tremulous questions [message #2594] |
Thu, 04 November 2010 01:38  |
 alan
Messages: 2
Registered: November 2010
Location: San Francisco Bay Area |
Junior Member |
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I've just read through the entire thread and didn't see answers to any of these:
1. With the 7809 regulator, if feeding from a supply, my assumption is that I should use a 12v input, so that the reg. can put out 9 v to the pedal—or should I just use the 9v input? I'm used to there being a voltage drop with regulators.
2. Looking at the rate doubler mod diagram, I don't understand why this needs a 3pdt switch; it looks like a spst switch would work fine. Or am I missing something?
3. This has sort of been answered, but I'm still confused: I'm planning on the symmetry mod, and was also interested in the sawtooth switch, but is it one or the other? One person had a photo of their Moog inspired pedal that looked like it had both. It also sounds like 4ms has begun to prefer the ramp up/down switch over the symmetry pot (mainly in terms of keeping the level more even, I think...). I had been planning on not having an external gain control, but it seems liek with the sym mod, it may be a good idea.
I've got the parts all mounted on vero and hope to wire the pots etc. this weekend; I'm really looking forward to this design. Several years back I built the EA trem, and have never been fully satisfied with it. Finding the commonsound site (and 4ms pedals) has been very inspiring. Thank you very much for all of this.
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| Re: several tremulous questions [message #2595] |
Sat, 06 November 2010 13:22  |
dann
Messages: 829
Registered: December 2002
Location: Austin TX |
Senior Member |
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| alan wrote on Thu, 04 November 2010 00:38 |
I've just read through the entire thread and didn't see answers to any of these:
1. With the 7809 regulator, if feeding from a supply, my assumption is that I should use a 12v input, so that the reg. can put out 9 v to the pedal—or should I just use the 9v input? I'm used to there being a voltage drop with regulators.
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Yeah usually you feed greater than 9V into the unit, and the 7809 will output 9V. But the confusing thing is that a unregulated power supply that's labeled "9V" will actually output 12V or more unloaded (measure one and see for yourself).
If you're using a regulated 9V power supply, then it will already be outputing 9V, so you can skip the trem's internal 7809
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2. Looking at the rate doubler mod diagram, I don't understand why this needs a 3pdt switch; it looks like a spst switch would work fine. Or am I missing something?
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Sure, a spst is enough. I get a better price on 3PDT stomp switches, and I have a ton of them already so that's why I use them. But if you have a spst stomp, then that'll work fine
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3. This has sort of been answered, but I'm still confused: I'm planning on the symmetry mod, and was also interested in the sawtooth switch, but is it one or the other? One person had a photo of their Moog inspired pedal that looked like it had both. It also sounds like 4ms has begun to prefer the ramp up/down switch over the symmetry pot (mainly in terms of keeping the level more even, I think...). I had been planning on not having an external gain control, but it seems liek with the sym mod, it may be a good idea.
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Electronically, you can wire both mods, but in practice it's hardly useful and sometimes confusing because in ramp mode, symmetry will act like a speed pot. We switched to just doing the symmetry pot and not offering the ramp switch on our pre-built units because the sym pot gives theoretically infinite waveforms, while the ramp switch just gives 2 (or 3).
good luck!
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| Re: several tremulous questions [message #2597] |
Sun, 07 November 2010 23:13 |
alan
Messages: 2
Registered: November 2010
Location: San Francisco Bay Area |
Junior Member |
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Thanks very much Dann. I have a pretty well regulated supply, so just put in a jumper between holes 1 and 3 in the socket; I can drop the regulator in if I lend it out. Decided you were right about the pot v. switch with symmetry, and left a wire dangling from smooth 3 to add the doubler switch in later.
Your "good luck" proved prescient. When I first tested it, I got a steady on LED and no sound at all. I'm used to making butt stupid mistakes, no matter how careful I am. I decided to go over my strip board translation of the schematic once again—everything seemed to check. All caps in correctly. No shorts anywhere. Checked the voltages around the board. Realized that I had wired the input and output grounds to +9 at the DC jack rather than ground. That took care of the no audio, but the LED was still on solid, and when I clipped a second LED onto the optocoupler (used the NSL-32 from Small Bear), it was lit solid also. No swings at the 1 pin (4558). I decided it must be a bad IC. (Maybe I fried it with the +9 to input and output jacks (there was no contact with the board ground though; I always start projects on a Plexiglas scrap and don't wire in the jacks or stomp switch until its all working. Then I usually use it for a while to see if I have the controls where I want them, trying to ignore the lack of shielding). Had some 072s around, popped one in, and there it was. (I got off easy!)
Well, this is so much better than any tremelo I've ever used! No need for the speed doubler switch, it already goes from around 1 beat per second to a machine gun stutter. The knobs' interactivity will take a while to fully understand, but I was able to get whatever I was looking for pretty fast, and found sounds I wouldn't have thought to look for too. I just need to decide about the gain—internal or external...
So, does the Triwave work at all as ring mod for guitar?
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