Introducing The Biped, a 9v Biphase workalike using 4049 and simplified LFO.

[Unbeliever]

I havent finished designing all the PCB's yet.

Fair enough ... but might I suggest that building the LFO and connecting it to three LEDs (or using a CRO) might be quite useful? And I still think you need to trim back the amplitude of the square wave on the LFO , especially now you are going the LED / LDR route. Also, have the LFO(s) running from their own decoupled power supply, and have separate Vb supplies for the LFO and audio sections (experience talking here). You will need a 'firm' Vb supply here, not just the standard resistor divider with cap, IMHO.

[nelson]

I havent finished designing all the PCB's yet.

Fair enough ... but might I suggest that building the LFO and connecting it to three LEDs (or using a CRO) might be quite useful? And I still think you need to trim back the amplitude of the square wave on the LFO , especially now you are going the LED / LDR route. Also, have the LFO(s) running from their own decoupled power supply, and have separate Vb supplies for the LFO and audio sections (experience talking here). You will need a 'firm' Vb supply here, not just the standard resistor divider with cap, IMHO.

I left the power supply out of the schematic.

I am going to go for a decoupled 7805 Vb for the LFO's.

I agree decoupled supplies are a must, I learnt that with my EH polyphase + clone theory repros. I plan to have decoupled supplies for every functional block of the circuit.

I am also hoping any ticking caused by layout issues will be minimised by seperate vertical PCBs.

Anything carrying LFO couldnt be further away from anything carrying audio the way I have it planned.



I am going to take your advice, populate the LFO board and work out how much attenuation is needed for the square wave.


Thanks Mike

Paul

[Unbeliever]

Let us know how you go .... I am merely passing on the info I have 'discovered' after (sometimes) many hours fiddling with LFOs, decoupling and so on. There is nothing worse than firing up a new PCB layout only to discover a 'thump' in time with the LFO!!! 

Mike (shhh)

[bioroids]

I am also hoping any ticking caused by layout issues will be minimised by seperate vertical PCBs.

You may have to isolate the two pcbs. An extra board of ground plane between the two is a good way if you get ticking caused by EMI (it happened to me).

Luck!

Miguel