FV-1 Multi effect full forum project ready for this

Hardware questions and issues with the FV-1

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FV-1 Multi effect full forum project ready for this

Post by Vellywio » Fri Nov 11, 2016 12:24 am

FV-1 Full project for DIY multiFX pedal by Mick Taylor 2013

First a brief description of what this is about.
I'm sure many of you have heard about or experimented with the Spinsemi FV-1 reverb/multi effects DSP chip just like
I have myself. I have been meaning for a while to bring a complete DIY'able project that anyone can easily build to
the diy pedal forums that I visit. So basically here it is.
I have managed to get this finished with the help of quite a few other members here as well as from other forums
whom I will give mention and thanks to as I go along. The pedal is a simple mono design that has true bypass and has
two different build options. As well as being able to etch a single sided PCB easily at home I have a fabbed double
sided PCB which I can make available.

I believe this makes a great development platform for a simple DSP FV-1 pedal as it has built in ability to
reprogram the software without removing the Eeprom from the circuit.

OK on to a couple of basic sound samples trying to demonstrate a little bit of what to expect, recorded using just a
phone to capture sound and video.

The first vid is of FV-1 pedal loaded with the tape echo firmware called eTap2HW written by Piet which emulates the
sounds of the 'MeazziEchomatic' multi head tape loop echos. The patches have been written to emulate the sounds of
Hank Marvin of the Shadows and his unique sound, but are not restricted to this as many other artist used these tape
echo machines.

The video starts with a clean bypassed sound followed by a couple of bits to try and demo how the echo sounds.The
rest of the vid is pretty much just a single muted strum to capture how the echo's fall with different settings, the
bits where the feedback is turned up is so the tape decay of repeats can be heard.

The second Vid is the same pedal loaded up with a delay and a Shimmer reverb.
Again the vid starts in bypass then has a little bit of the delay effect, the rest is of the Shimmer Reverb as I try
to show what all the knobs do to alter the effect from very little shimmer all the way to a synth like effect.
Schematics of both versions of the circuit, one has the output opamp in a non-inverting gain stage for any gain
recovery that might be needed in certain firmwares, but by leaving out a few components and inserting a jumper link
it can be converted into a straight non inverting buffer as in the second schematic. (right click and save
schematics and to view better res.)
Description of schematic
The circuit based around TR1, R1,R2 and D1 form the PSU polarity protection circuit which was described in some of
R.G.s advanced power supply reverse polarity article, different diode type protections can be subbed if preferred.
this is then followed by a standard voltage divider network and filtering for 9V, ground and Vref, and 3.3v voltage
regulator for powering the FV-1 circuit.

Audio to the DSP is input is taken care of by IC1.1 (TL072) working as a straight forward non inverting buffer.
Audio out from the DSP goes through a non inverting gain stage around IC1.2. to convert to a standard non inverting
buffer on the output simply leave out C9,C10,R11,R12 and put a link in place of C10 or R12, which will make the
circuit as in the second schematic.

The digital side of the circuit has at the heart an FV-1 DSP (IC3) with a 24LC32A Eeprom (IC2) which holds the code
for upto 8 programs. These programs are controlled by the PIC12F683 which outputs the 3 bit binary code that the
FV-1 needs to select any of the 8 different programs. The programs are selected using a potentiometer (VR4) on the
input of the PIC chip. It is also possible to use a toggle switch to select a program if sat you wanted 2 or 3
programs only (say you wanted 3 reverbs Room,Hall and plate etc)There are wire points on the pcb that would allow
for this.
PIC12F683 PDF: http://www.kynix.com/uploadfiles/pdf879 ... _64315.pdf
PIC12F683 The code for the pic has been written by another forum member called Ian or better known as slacker and
is a great bit of glitch free code. So thanks Ian for allowing me to use this code.

Slacker has also done much FV-1 coding and has been a great source of information regarding the FV-1 both here and
at the Spinsemi website forum, as well as having his FV-1 project on the go.

24LC32A chip is the chip which holds all the external programs that can be loaded into the main DSP and I have
provided a way to re-program the chip with new effects code without having to remove the chip or dismantle the
pedal, and it takes about 10 seconds to read/erase and reprogram the chip with new code.[/url]

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Post by ice-nine » Mon Nov 14, 2016 12:09 pm

Hi Vellywio,
I am wondering why you have have just copied and pasted my old diy thread directly into this forum, do you have any questions abou it ? I'm not sure if the post is relevant at all here. The original thread is huge and has all the needed info there.

Margaret Dominguez
Posts: 1
Joined: Mon Nov 21, 2016 3:00 am
Location: UK, Chester

Post by Margaret Dominguez » Mon Nov 21, 2016 3:04 am

ice-nine wrote:Hi Vellywio,
I am wondering why you have have just copied and pasted my old diy thread directly into this forum, do you have any questions abou it ? I'm not sure if the post is relevant at all
here. The original thread is huge and has all the needed info there.
Frankly speaking, situation is a strange. Sometimes people do stupid things...

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