FV-1 Multi effect full forum project ready to go. (ShimmerVerb Also)

[Rebel_88]

Hi,
I have finally built my fv-1 pedal but i have some troubles.
I have not used the pmos because i can't receive that...it is lost somewhere, so i have used only the zener with a current limiter (1Watt 100Ohm resistor).
When i play the instrument i can hear a latency and a bup or buf sound on the guitar.
If i turn pot 0 and pot1 there is no change in the sound but i have cheched them and i think the wire is ok.
The last problem is about the EEPROM, i have loaded your file "final FV-1 project with octave.hex" but when i switch to it i can't hear sound.
I have double checked the circuit before soldering and after soldering to check everything is ok and i had no trouble.
What is your opinion about this?
There is some Voltage reference someone could give me to be sure i have no circuit mistake?
Thankyou for your help.
This is my eagle file sdvpedali.altervista.org/DIY/FV-1%20DSP%20Pedal.rar

[Ice-9]

I'm not sure what you have done around the polarity protection but you can use a 1n400x in a normal way for protection if you can't get the components in the schematic.
First check for correct voltages at the opamp
between pin4 and pin8 = 9v
check the voltage on the 3.3v regulator =3.3v
I can't download your eagle file to check whether it is correct.

Post some pictures of your build also.

*EDIT* I managed to get your pcb layout, It's quite difficult for me to read as I don't use eagle but having a quick look over the layout the first thing that I see is that it looks like your 3.3v regulator is the wrong way around.

[Rebel_88]

Hi,
for the power protection i have used a simply zener voltage limiter with a 10v zener ad 100Ohm 1 Watt resistor.

I have created pdf files so you can see what i have created. The schematic is the same of your pedal i have copied it in eagle.
http://sdvpedali.altervista.org/DIY/FV-1%20DSP%20Pedal_pdf.rar
I have 3.3V on the attiny (used to have the 3 bit for the effect address) and other pins that require this voltage.
But i think i have a problem with the 10v Zener, it gives me only 4.5V out of the regulation. Tomorrow i will change it.
I don't think the photo of my circuit will help you so much because the top is so full. If you nedd a better quality or zoomed photo i will do it.
The bottom side is more clear.

[Rebel_88]

I have changed the zener diode but the problem is the same, on the output of the zener i find 5V instead of 9-10.
I can feel the 1 Watt resistor getting warmer it is possible i have to use 2 watt zener and 2 watt resistor to let it works good?
Is this circuit absorb so much?

[slacker]

A 100 Ohm resistor is too big,  the FV-1 draws about 50mA which will cause about a 5 Volt drop across 100 Ohms. That's probably why you're only getting 4.5 Volts. If you want to use that setup you need something like 10 Ohms which will only drop about half a Volt.
I would remove the zener and replace the 100 Ohm with a 1N4001 type diode, that will provide reverse polarity protection.

[Ice-9]

Yeah if your not using the p-Mosfet protection, then a standard diode protection circuit is just fine, 1N400x 100ohm resistor will drop the voltage.

As slacker says ^ remove the zenner and put a 1n400x in place of the 100 ohm resistor for in line diode protection.

In your eagle drawing your 3.3v reg traces look the wrong way around . CHECK THIS FIRST before powering up again.

[Rebel_88]

Hi,
I checked the 3.3V regulator (78l33) according to this datasheet
http://html.alldatasheet.com/html-pdf/22618/STMICROELECTRONICS/L78L33AB/3249/2/L78L33AB.html
This is my regulator

it seems to be not correct! I didn't see that in the datasheet was written "Bottom view" I have to rotate it!
The 78l33 has the same pin of 78l05?! And i have used 78l05 in several projects without problem i don't know why i have opposite pin.
Now something seems to be better but i still hear click sound on my effect.
This is what i hear on every effectsdvpedali.altervista.org/DIY/click.mp3

[Ice-9]

@Rebel_88 Do you get this click all the time or only while you play,

FIRST CHANGE C8 polarity Positive side towards R10 and the op-amp negative towards pin 28 FV-1 This was revised in a later schematic which I can't seem to find in the thread. It shouldn't cause too much trouble in the short term but swap Do this before going further.

If you can you might try to bypass the FV-1 chip so that only the analogue circuit is involved in the audio path (this can be done by Placing a jumper wire from +end of C6 to + end of C8 after changing C8 around first.


Possible problems
1. Bad opamp. the test above should indicate this.
2. while reg was incorrect way, it would have put the full voltage of the psu to the FV-1 Chip possible damage to chip.
3. dry solder joint on FV-1 chip.

[Rebel_88]

Yes i have this click only when i play guitar.
I did wat you told me.
I have reversed polarity of C8 and after i have byassed the FV-1 Chip.
The sound was clean..so you have bad news for me?
have I broken fv-1 chip?
I think Eagle mirrored the 78l33 and i didn't know it, because watchin the photo i posted on this forum i can see rectangular pin  instead circular ones around phisical pin of the ic.

[Ice-9]

Well at least you can now be sure the analogue stuff is ok so that only leaves the digital, I would first go over the solder joints as it has been known for a solder joint to cause this sort of problem, check the other components around the digital are all correct values and orientation as well.

Do you have a good clean steady 3.3v line now ?

I'm sure there was another thread on here about a similar clicking problem with a SKRM unit, I'm not sure if it was solved but worth checking the thread to see.

Failing all this i'm afraid the FV-1 could be damaged. Although they are quite a sturdy chip so fingers crossed.

[Digital Larry]

I'm sure there was another thread on here about a similar clicking problem with a SKRM unit, I'm not sure if it was solved but worth checking the thread to see.

My recollection is that the problem went away after swapping the SKRM module.  I think that one was on  the Spin Forum.

[slacker]

That sounds like clipping to me, seems to be roughly in time with the modulation, does it do it if you reduce your guitars volume? Posting the voltages from all the the FV-1 pins might help.

[Rebel_88]

Hi i don't think it is a problem with clipping because it is periodical peak found on the sound so there is some other reason.
Those are my voltage referring to GND.
I can't understand what are you saying about the SKIM module...What i have to search?

Voltage In   8,23
TL072   
1   4,13
2   4,13
3   3,39
4   0,00
5   4,06
6   0,00
7   0,00
8   8,23
   
FV-1   
1   1,65
2   1,65
3   1,65
4   0,00
5   3,32
6   3,33
7   0,00
8   3,33
9   1,51
10   1,10
11   0,00
12   0,00
13   0,00
14   3,31
15   3,31
16   3,34
17   3,33
18   0,00
19   0,00
20   0,68
21   0,00
22   3,33
23   3,33
24   0,00
25   0,00
26   3,31
27   1,70
28   1,70
78l33   
1   3,34
2   0,00
3   8,23
24lc32a   
1   0,00
2   0,00
3   0,00
4   0,00
5   3,31
6   3,31
7   0,00
8   3,33
Attiny85   
1   3,33
2   0,00
3   0,61
4   0,00
5   0,00
6   3,33
7   3,33
8   3,33

[Digital Larry]

I can't understand what are you saying about the SKIM module...What i have to search?

The SKRM modules are offered by Experimental Noize as a pre-built circuit with an FV-1 and minimal external components.  You are not using one.  The analogy is that some guy had what sounds like possibly a similar problem, and once he replaced the SKRM module, with the FV-1 and other components, the problem disappeared.  It suggests that this problem MIGHT be in the FV-1 chip.  However that is just a guess.

[Ice-9]

I can't understand what are you saying about the SKIM module...What i have to search?

The SKRM modules are offered by Experimental Noize as a pre-built circuit with an FV-1 and minimal external components.  You are not using one.  The analogy is that some guy had what sounds like possibly a similar problem, and once he replaced the SKRM module, with the FV-1 and other components, the problem disappeared.  It suggests that this problem MIGHT be in the FV-1 chip.  However that is just a guess.

Yes, that is exactly what I was saying Larry,
I found the thread and it is on this forum, the problem looks like it was the FV-1 in this SKRM case. Here is the thread if it helps.

http://www.diystompboxes.com/smfforum/index.php?topic=107393.0

@Rebel_88  You of course have built your own PCB and not used the SKRM module but the problem sounds similar to the SKRM thread I talked about.  The other tests you have tried means I would suggest/guess that you have a faulty FV-1 chip, but first if you haven't tried as I suggested earlier to re do the solder joints on the FV-1 etc then do it first before replacing the fv-1, I also just noticed a trace on your eagle layout that passes between the pads of the Eeprom which looks pretty close to one of the pins so maybe worth checking it isn't shoring.

[Rebel_88]

Hi, I did everything you told me but the click sound is still here.
It is possible a proboblem with the clock or something similar?
I think the chip doesn't work  good i have to order another one and try.
Thankyou for your help and patience, if someone has something else to try i will do

[Ice-9]

Hi, I did everything you told me but the click sound is still here.
It is possible a proboblem with the clock or something similar?
I think the chip doesn't work  good i have to order another one and try.
Thankyou for your help and patience, if someone has something else to try i will do

Hi,
Can you post a longer sound clip, as the other one wasn't long enough to determine if the click had a set tempo or not (what happens if you change pot setting while playing etc? ) The clock for the FV-1 really only has the watch xtal and a 47p cap around it.
It would be worth trying another xtal if you have one. The FV-1 datasheet recommends a 15p cap but I know this to cause problems with some xtals so that is why I use a 47p cap in my schematic.
It is looking like a problem with the FV-1 chip in my opinion.

[Digital Larry]

Also, try the bypass program:

Code Select Expand

RDAX ADCL,1.0000000000
WRAX DACL,0.0000000000
RDAX ADCR,1.0000000000
WRAX DACR,0.0000000000

[Rebel_88]

Hi
Thank you for your work.
Yhis is a longer clip when i play all the effects and at the end im' rotating also pots to let you kwnow what appens.
sdvpedali.altervista.org/DIY/ClickOnEffects.mp3
You can hear the click is like a clock that is modulated by the current effect.
Yesterday i have used the effect N°5 of the FV-1 that is celan and should be a test effect and on this i have not this click, but this morning i can't choose it i don't know why.
On the N°3 (Tremolo) this click is so low but in the reverb-delay is maximum.

[Digital Larry]

When I was using my old PC motherboard to supply power to my Spin Dev board over USB, I got all sorts of weird noises that turned out to be coming up the USB power supply.  It seemed to depend on the patch that was selected so I assumed that it was the dev board itself. So I'd be real sure that your power supply is really clean.

However in your case it does seem to be synchronized with the LFO sweep, which is unlike what I was hearing.