Easy Vibe Oscillator Question

Started by GibsonGM, December 29, 2006, 02:28:40 AM

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GibsonGM

I built an EV using the original hand-drawn Hollis schem with TL064's...it worked well, but clicked and nothing would get rid of it, so I re-built the oscillator section on a separate PCB, to be mounted away from the filter sections.  Just tested it, and it is oscillating  :D   

I am wondering, out of the 3 OA's used for it, what controls the Rate (beyond the 100K rate pot...).   Mine doesn't want to go faster than about 1 Hz.   Could the pot be backwards??  Used a wah pot, log.  Or is there another component in there responsible for the rate?  I tied the unused portion of the TL064 to Vbias, -input to output.   
Thanks  8)
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

The Tone God

At my site under the downloads area there is a schematic of the LFO with a bunch of mods I made. You can give them a shot. Its been awhile since I played with though.

Andrew

GibsonGM

Thanks, T.G., I'll look at maybe modding it after I can get it running right.   It seems to be doing its thing, is flashing an LED, but the rate doesn't go over about 1 Hz.  I've built this before, just not off-board, so probably did something wrong!   Reversing the pot doesn't help.   I used 22uf instead of 10uf to ground on the schem for added 'click insurance';  in simulation it doesn't change the rate.  Can't figure this one out...
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...