[sdiy] Arp Quardra Phaser

[Stewart Pye]

Hi....



I haven't been on the list for a couple of years, some of you may remember 
me.....

Looking at the J.Haible Quadra phaser schematics, For output 1 the phased 
signal is mixed with the inverted dry signal. For output 2 the phased 
signal is mixed with the Non Inverted dry signal and the output of the 
resonance amp/limiter. The question is, why the 301k 1% resistors. Because 
it's a passive summer with 203k:1k5 so the error could be large with 5% 
resistors. But is there a reason they want the levels to be equal?? Does it 
sound much better there??

I was thinking about using a virtual earth summer and having 100k pots on 
the inputs to mix the levels. That should work ok but if it's not worth 
doing it I'll leave it off the PCB.

Also, the ARP schematic mixes the Input to the res amp (post att) with the 
phased and dry signal for output2. This would increase the phased signal 
level when the res is increased, where'as JH mixes the output of the res 
amp (inverting), with the phased and dry signal.... Decreasing phased 
signal with increased resonance, but it will be a bit square when res is up 
so that could make it interesting. Has anyone heard this??? Is it worth 
having both options?


Thanks,

stew.