ASM-1 LFO symmetry problem

[Haible_Juergen#Tel2743]

> Also does anybody know which manufacturer of 7915/7815 voltage regulators
> produces the most accurate (in terms of output voltage) devices?  I 
checked my
> data sheets for these and found they are allowed to vary between 14.6 and 
15.4
> V.  I guess they are true "regulators" but not necessarily "voltage
> references".

In the usual LFO circuits the positive and negative values of the rectangle
function are also determined by the voltage drop over the opamp's output
stage which can be very different for both rails, and is also temerature
dependant. So even with accurate supply voltages you'd sitll have a
problem.

JH.