Suboscillator

[Altitude]

Ok, time to CPR this thread.

I am planning on running some boards (slim SMT like my elekra boards) for my next run of midiot b0xen

Listening to Mome's demo it sounds like this thing is loading the VCO quite a bit, would buffering the saw be a good idea?

[bcbox]

would buffering the saw be a good idea?

that would be good, but I would caution if you plan to use an op amp you might want to test it first, the extra current draw from IC23 may very well cause problems. You may try a single transistor buffer instead. On the x0xi0 kits there's a completely independent 12v supply to power everything except the original analog circuitry and the 2nd VCO, that's how I get away with it.

[Brassteacher]

would buffering the saw be a good idea?

that would be good, but I would caution if you plan to use an op amp you might want to test it first, the extra current draw from IC23 may very well cause problems. You may try a single transistor buffer instead. On the x0xi0 kits there's a completely independent 12v supply to power everything except the original analog circuitry and the 2nd VCO, that's how I get away with it.

If you do a single transistor buffer as bcbox suggests, consider using a JFET rigged as a source follower. It'll give you a higher input impedance than a bipolar transistor. What would most likely be loading down the VCO is it not only feeding about half the impedance as it normally would, the additional circuitry of the sub-oscillator makes even less current available.

I think bcbox's idea of an independent power supply to drive the sub-oscillator circuit would do wonders with this setup as well. The amount of improvement would depend on how much current your power adapter provides as well.

[Altitude]

Ok, do you have a schem of that?

I tried this circuit with the raw, powered separately, and powered separately and buffered via TL071 opamp and it sounds like donkey banned equally in all versions.

[Brassteacher]

Ok, do you have a schem of that?

I tried this circuit with the raw, powered separately, and powered separately and buffered via TL071 opamp and it sounds like donkey banned equally in all versions.

The ground of your separate power supply is connected to ground of the x0x supply, yes? If so, check and make sure the incoming signal still has enough DC offset to keep the entire signal well above ground, and check various places in the subosc circuit to make sure the signal is staying well above ground there also.

[Altitude]

Yep, I take it right off the big cap. It looks good on the scope but not so good to the ears