Stereo channel isolation of fv-1? Isolated instructions for L and R channels?

J

jwin615

Well-known member
Pondering some ideas and can't find the answer to th3 following curiosities.
1)does/can the FV1 operate in isolated dual mono? I.e., can a signal flow from LIN -> LOUT -> RIN ->ROUT without creating a feedback loop internal to the FV1?
1b) if so, what's the best practice to accomplish this in spincad?
. 1c) can LOUT be routed to RIN internally or is it necessary to route the DAC back to the ADC?

2) can a program process the L and R channels independently? i.e., two completely different instruction sets per channel.

3) are the 128 instructions/sample per channel, or cumulative? I assume the later.

Thanks.
 
jwin615 said:
Pondering some ideas and can't find the answer to th3 following curiosities.
1)does/can the FV1 operate in isolated dual mono? I.e., can a signal flow from LIN -> LOUT -> RIN ->ROUT without creating a feedback loop internal to the FV1?
Click to expand...
Yes, but such potential feedback must be managed with control blocks.
jwin615 said:
1b) if so, what's the best practice to accomplish this in spincad?
Click to expand...
Use the left & right channels with independent processes between the In and Out blocks in SpinCAD.
jwin615 said:
. 1c) can LOUT be routed to RIN internally or is it necessary to route the DAC back to the ADC?
Click to expand...
SpinCAD's "IN" block actually has two inputs and two outputs. Similary so does the "OUT" block have two outputs, but it can be configured in Mono or Stereo.
So, it can be done internally or externally thru the DAC.
jwin615 said:
2) can a program process the L and R channels independently? i.e., two completely different instruction sets per channel.
Click to expand...
Yes.
jwin615 said:
3) are the 128 instructions/sample per channel, or cumulative? I assume the later.
Click to expand...
Correct, cumulative. The FV-1 can manage only 128 lines per patch, regardless of routing.

When I get back to one of my PCs, I can grab & drop some SpinCAD screen shots to demonstrate.
 
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Not exactly the same, but similar concept, some delay pedals tap the output and run the feedback back into one of the inputs. (Example: Deflector)

Can confirm the above, you can operate the inputs and outputs totally independent within the same program code, limited to 128 instructions total.
 
Apologies - coming in slightly late on this...

I have created a patch with spinCAD that has 2 separate effects, chorus on the 'left', and min reverb on the 'right'. I'm currently using the fv-1 development board, which ties both the inputs and the outputs (of left/right) together, so my solution was to add a volume command to both signal paths internally, and assign 2 of the pots to control volume for each.

The downside is that I don't have real time control of reverb delay, or chorus width - the only adjustment is chorus rate. The width and delay are assigned constants, which I determined by trial and error as to what sounded best. Currently set to .3 for width, and .38 for reverb delay.

The hardware pots for mix and volume I don't change, it works best with the wet/dry mix at appx 80%.

It works well for the jazz guitar style I play, I have full independent control of both reverb and chorus.

Some of the issues would be solved if the board hardware broke out left and right inputs/outputs separately, which you would think a dev board would do. I'm hoping to do this shortly and will keep the community here posted.

I'm fairly certain the dev board from Spin Semiconductor does this.

I'm planning to embed the board into one of my Polytone MiniBrute II amps - I'll post details on that soon.

Have not tried the concept of looping back the signal from left out to right in, etc.

Here is a screenshot of the patch - SpinCAD is amazing!
SpinCAD_1.png
 
philbrooksjazz said:
Some of the issues would be solved if the board hardware broke out left and right inputs/outputs separately, which you would think a dev board would do. I'm hoping to do this shortly and will keep the community here posted.

I'm fairly certain the dev board from Spin Semiconductor does this.
Click to expand...

The Binaura is full stereo, if you don't need the USB connection.
www.pedalpcb.com

Binaura Stereo FV-1 Platform - PedalPCB.com

Stereo FV-1 Multi-Effects
www.pedalpcb.com www.pedalpcb.com
 
phi1 said:
The dev board doesn’t tie L and R outputs together. R output is unconnected.

Anyway, cool project, thanks for sharing
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Ah - yes, you're correct, only inputs are connected together. I'm wondering how this is working correctly? I'm definitely able to get reverb and chorus to work independently.
 
philbrooksjazz said:
Ah - yes, you're correct, only inputs are connected together. I'm wondering how this is working correctly? I'm definitely able to get reverb and chorus to work independently.
Click to expand...
don't know. You could export the SpinASM code and analyze it. It should have text commands for:

WRAX DACL, 0 (which means write some signal to the Left Output (Digital->Analog Converter Left) (pin 28)
WRAX DACR, 0 (which means write some signal to the Right Output (Digital->Analog Converter Right) (pin 27)

If not, maybe it's actually summing them to the L output. Or, you have a solder bridge from pin 27-28...
 
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