Spin Semiconductor

Hi, I'm new here, I've a lot of experiments with the fv-1 demo board. I'm using a 44kHz crystal, and tried to add a dry/effect pot, and with all effect tested, internal and external eeprom, there is always a kind of "phaser" effect when the mix is around mid position.
This pot (22k) is connected between the input of the board (connected to the output of an Aop buffer, very low Zout) and the output of the board (about 500ohms as seen in the pdf), the cursor goes to an amplifier (Zin 30k).
On the dry side, the tone is pure. Completely turned to the effect side, the tone seems to be normal, and when adjusted from 30 to 70%, I always hear a bit of that strange dissonance, looks like the output is a bit not straight in phase with the input.
Am I wrong with my manner to mix both signals ?

Hmmm, it could just be due to the delay through the FV-1 causing this when mixed back in with the dry. Could you post a sound file using a built in program? Then I could also try to recreate it here. I know we there are a number of companies using the built in reverbs with no problem using a simple mix pot and no ones noticed any issue like this so I am interested to see why you are seeing this.

Thanks for your quick answer frank.

I recorded a short sample with a guitar, played 3 times the same lick, first with the mix at 0 (dry), then with full effect (internal rom #5 > test program, just pass through the FV-1 without treatment), and finally in mid position (50% dry + 50% effect)

You can clearly hear the signal is cool sounding through the FV-1, but is a pain when mixed to the original.

[url]http://s260858675.onlinehome.fr/int.5_dry-fx-mix.mp3[/url]

I'm afraid it is the delay through the FV-1 too, is there any method for resolve it ?

I think now of a method... using a second FV-1, fixed on the #5 program to built the dry side of the mix, which will create the same phase shift, so the mix course should be homogeneous... a bit expensive method, don't you think ?
By the way, will the phase shift be the same for all programs ?

Anytime a signal is split and run through multiple paths you run the risk of cancellation when they are re-combined (true in any application, not just FV-1). In this case, program 5 will really point this out, it will cause a comb filter effect when the signals re-combined. When doing effects you will need to consider how they will be used and decide if you want to mix wet and dry in the chip or outside the chip.

For example, you can generally mix reverbs externally like you are doing due to the nature of reverb. But mixing a delayed signal with the dry will always result in a comb effect no matter where you mix it. A pitch shift may sound better if mixed in the chip, it may still have some cancellation but the dry and shifted signals will both suffer the same delay through the ADC and DAC.