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Topics - HamSandwich

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Open Discussion / Hypothetical Flanger Questions
« on: July 13, 2018, 06:29:57 PM »
From what I understand, your basic through zero flange is taking the dry signal of a flanger and slightly delaying it so the modulating flange’d signal gets to slower delay speeds than the delay’d dry signal.

So what happens if you split the signal into three - one dry signal, and two then paths into flanger circuitry, but have the flanger driven by bipolar LFO’s? So as one path increases in delay time, the other decreases. Once the signals are summed, would something interesting happen, or would there be a lot of cancelation?

General Questions / H11F1 with LFO?
« on: March 24, 2018, 10:17:54 PM »
Anyone had success using an H11F1 with an LFO for use in a tremolo or delay mod? Can’t seem to find any projects using them for this purpose. I see the multiple. Uses one for the ramp switch, and plenty of bypass schemes. Does it not easily work in pace of a vactrol when fed a LFO?

Open Discussion / LFO / LED Relations
« on: March 10, 2018, 06:11:23 PM »
Or, how to drive an LED with an LFO.

I've been goofing around in LTSpice. Below are four schematics of a couple of ways to drive an LED from an LFO. LFO is 0-5V. The LED specs are If=25mA, Vf=3.6 (not a lotta choices in LTSpice). The opamp can supposedly swing down to ground.

On a DIYStompboxes thread, the fourth schematic was recommended as the LED in the opamp loop gets a constant current in exact proportion to the LFO. I've read that the issue with the first three schematics are that the brightness of the LED won't track with the LFO as it won't turn on until the LFO reaches a certain voltage/current.

So I simulated them and plotted the current.

Note that D1 doesn't appear because it is exactly the same output as D3.

The problem with D1 (and D3 as it's basically the same thing) is the LED won't turn on until it hits that magic voltage number, so you get the big bottoming out in the troughs.

D2 and D4 appear to be similar, but flipped along the x axis. Is it safe to assume the flatline of D2 is because the LFO isn't turning on the transistor at that point?

The clipping looked a lot like headroom issues. So I tried biasing the LFO in the transistor up a few volts and messed with the CLR and base resistor, and it looks like the current tracks pretty well with the voltage from 0mA up to the If 25mA. Besides trying to get 3.1V as a bias voltage, is there anything inherently wrong with this?

The headroom issue also seemed to fix the LED in the IC loop problem. I had to guess at the CLR in this case, as I'm not sure how to determine it in this setup. They both seem to be opperating similarly. Is there any reason that one is better than the other? Real world problems that don't show up in a simulation? Transistor circuit should take up less space than a big ol opamp.

How Do I? Beginner's Paradise. / SMPS Project?
« on: January 10, 2018, 07:36:02 PM »

Are there any SMPS projects out there? I see there's a few posts here and there about them, but no 'here is the schematic, layout, parts lists' etc. I don't expect to find them on a pedal building site, although Grind Custom used to have one I think, but that seems gone. An available PCB isn't critical, but from what I understand, a good layout can make a huge difference in one of these things.

Ideally it could produce 250-300VDC, and maybe enough current to power 3ish 12A#7 tubes? I'm not looking for one to fit in any particular project, but a basic SMPS circuit that could be used in a number of different ideas.

Thanks for your help!

Open Discussion / What to put in old TV Antenna?
« on: July 19, 2017, 09:13:36 PM »
Hello all,

I had an impulse buy of some weird looking rabbit ears, wondering if anyone has any suggestions for effects to put in. I have a single antenna theremin already, so probably not one of those. It's got two knobs and a switch and looks like this

Is there some weird fuzz/theremin/oscillating debauchery that fits the bill?


General Questions / Current Lover LFO mod
« on: March 04, 2017, 09:29:52 PM »
Hola Everyone,

I'm looking to work on a PWM LFO, and I wanted to test around on the Current Lover / Electric Mistress. I'm not sure how to filter the PWM into an analog voltage, so I was going to use a Vactrol. Might help with sharp edges as well. I was thinking somewhere in the R28/29 vacinity. Any tips? Thanks!

Open Discussion / 3 Way Amp Splitter
« on: February 05, 2016, 02:08:09 PM »

Nothing too new here, but I thought I'd see if anyone with experience could comment on this schematic for a 3 way splitter. Used with at least 2 amps, possibly three, or used to send to a DAW, etc. Loops added to each channel for using effects on specific outputs.

I don't think all three need to be isolated/ground lifted, even if it's three amps. Is that correct? I was looking at the radial switchbone, which seems to only ground lift and correct phase on one output. Would the output without the transformer's sleeve be grounded to the enclosure, or would that need isolation too?

Thanks for any advice.

Open Discussion / Dear Person who PM'd re: Echorec
« on: February 02, 2016, 05:37:10 PM »
Sorry for taking out the personal ad, but a member here PM'd me about an echorec, and I had PM'd back, but it seems to have gotten erased in the latest round of crashes. Shoot me another PM if ya want!


Open Discussion / Where do you buy bulk cable?
« on: April 27, 2015, 06:47:04 PM »
To anyone who makes their own patch cables, etc. Where do you buy bulk cable? I'm looking to make a bunch of 3.5mm or 1/8" cable, and figure they probably sell it at places that sell the 1/4" cable, but I'm not having much luck even finding that. Not really looking for George L's or Monster cable, cheap bulk please. It's used for remote switching, so not a lot of fidelity needed there.

Is there a certain gauge that goes with the 3.5mm plugs? Tayda has them but they don't have a lot of info about them.
A specific gauge may unlock the key to finding the stuff. I could just buy a 75ft cable and cut it up, but wanted to see what the other options are.

Thanks in advance.

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