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Building your own stompbox / Re: Fuzz output issues
« Last post by soma89 on Today at 02:27:22 PM »
I should probably clear something up.. My circuit has 2 grounds n opposite ends of the board jumpered together.

Im thinking theres a ground loop issue causing oscillation through the transistors?
Pictures / Re: pix of Custom built guitar amps/cabs
« Last post by deadastronaut on Today at 02:13:02 PM »
bruno, yeah, they are lovely cabs... 8)
Pictures / Re: pix of Custom built guitar amps/cabs
« Last post by stallik on Today at 02:03:13 PM »
Well that's not true. Your boxes look really good to me but thanks for letting us down gently ;)
Pictures / Re: Etched enclosures
« Last post by deadastronaut on Today at 01:34:43 PM »
weird, i can see them now.. 8)

excellent... 8) 8) 8)
Pictures / Re: Etched enclosures
« Last post by stallik on Today at 01:31:06 PM »
I can see them and they look fantastic. Nice job
Building your own stompbox / Re: Preamp suggestions for piezo pickups?
« Last post by canman on Today at 01:08:49 PM »
Right, so I did some testing.  All the traces look clean, no burrs or shorts.

I get these voltages on the transistor:

D: 2.8v
S: 2.8v
G: 0v

I suspect I need to change a couple resistors to get the bias up to the proper voltage.  2.8v seems too low, correct?  We should be around 4.5v right?  I'm not sure how the bias affects the amount of hum, but 2.8v definitely seems wrong.

I had considered buying one of those fabricated preamps but thought I'd try to build one first.  Will those allow you to plug into line level speakers?

EDIT: OK, so with a 1k resistor in place of the 2.2k resistor, the bias is at 4.2v and hum is gone through my acoustic amp.  Sounds fine...a little high pitched whine but I'm not worried about that right now.  The problem is still that when I play through computer speakers, the hum is there and now the uke hardly even comes through.  SO...I'm thinking the Tillman preamp isn't going to work.  Which is a bummer cuz it's so small and easy.

But this one looks like it should do the trick:
Ok, thanks for the hints, I will test it right away
Building your own stompbox / Help modding my CS9 chorus?
« Last post by acobberson on Today at 12:50:44 PM »
Hey all!

Recently the flip-flop circuit on my Ibanez CS9 quit flipping and flopping. While I was in there I figured I would mod it for true bypass. After looking at the schematic I figured it would be simple enough. Here is what I did.

1. removed Q105 and jumpered Drain to Source.
2. wired in a 3pdt switch, just like I have done 1,000 times. Input jack to switch, switch to circuit input, circuit output to switch, switch to output jack... that's when it hit me... Stereo output.
So then I simply sent circuit output 2 directly to the second output jack. If the signal is bypassing the circuit anyway (in bypass mode) this shouldn't effect anything, right? Then when the signal hits the circuit, both outputs are being sent to their respective output jack.
For now I'm just running it mono, but it ain't working.

Any ideas as to what the problem could be? Should I have left Q105 in the circuit and THEN jumpered Drain to Source?

Here is the schematic. And a crude drawing of my own signal wiring.

Are you getting about 1.65 volts on pins 1,2,3, 27 and 28?

You can test for communication between the FV-1 and the eeprom by probing the SDA and SCK pins with your scope, at startup and when changing programs you should see brief bursts of activity on both pins.
You can try probing the x1 and x2 pins to see if the crystal is working, you should see about a 32KHz signal, this isn't a very good test though because the extra capacitance from the probe could be enough to make it start working or it could load it down and stop it working.
As this is the most referenced topic in regards to mods for this pedal, I thought it would be good to post about it here.
I have added the time control to my FAB Echo, and I love it! I thought I'd want to do the other mods, but I'm happy with just this one.
I simply soldered two wires in place of the resistor on pin 6 of the PT2399 (at 3AM, and I managed to NOT destroy the pads!), and ran them to a 100k Linear potentiometer, which I installed on the empty spot on the pedal:

The pot I used came from a fried Danelectro Honeytone (which will become another project, very soon). These miniature potentiometers work very well for this purpose.
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