The Sweep waveform is a hyperbolic sinewave. It looks like this:
The breadboard has a trimpot, but the schematic has fixed resistors. R51 & R52 provide the correct voltage to select this waveform. Other waveforms can be used, but this is the best match to the sweep used in the GP8.
A client asked me if I'd ever heard the Roland GP8's phase shifter section. I hadn't, but I found a schematic and breadboarded one. It bares some similarity to the MXR Phase 100 in that it contains both variable and fixed phase shift stages. The Phase 100 uses LDRs and has 10 stages; the GP8...
The Mu Amp does two beneficial things for us, compared to a simple one-transistor amplification stage.
1. More Gain! *
2. Nearly symmetric clipping.
* HamishR increased R6 in his Mongrel pedal to moderate the 2nd stage gain.
Why not just buy low-HFE transistors? They are neither expensive nor hard to find. High-voltage, high current or high freq transistors all have reduced HFE because they are optimized for something other than HFE. 2N2369 is an example of a high-freq transistor. 2N6517 is a high-voltage...
I remember a time when Tayda discounted the shipping for large $ orders. Did Tayda separate out the tariff costs? Or maybe they're rolled up in the shipping cost?
My personal policy is that the merchandise should cost more than shipping. I choose the quantities accordingly.
My friendly neighborhood Electronics Store has 4000-series CMOS. I already bought all of the "good" CD 4049s & CD4069s. They have CD4007, but I already stocked up on a Mouser order.