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Hey guys,
So I've tried my best to understand the clipping mods for the orange distortion but I'm still struggling. I've read some of the other posts regarding this, I've read some other things online as well and here I am haha.

My question is symmetrical vs asymmetrical clipping. So if I'm understanding this correctly, symmetrical clipping would mean an equal number of diodes on either side? Conversely, asymmetrical would mean an unequal number of diodes on each side?

On the image here in the green and blue spots, to achieve asymmetrical clipping one scenario might be an LED on the left green, a diode on right green, and either a diode or an LED on the left blue then jumper the right blue?

I apologize as I have a habit of overthinking things and I've read so much about it that I may have confused myself.

viewtopic.php?f=9&t=58763&hilit=orange+distortion+mods

This is the thread that I read that seemed to make the most sense.

Not quite. Symmetrical clipping would mean an equal number of THE SAME KIND(S) OF DIODE on each side. By "side", we mean the positive and negative polarities of the signal, which is AC by its nature. So if you assume a pure monotonal signal, this would cause the positive and negative nodes of the sine wave to be clipped equally, i.e. the resulting clipping is symmetrical. So while a single 1N4148 silicon diode on each side of the clipping array would give symmetrical clipping, a 1N41448 on one side and a red LED on the other would most definitely NOT clip symmetrically, even though there's one diode on each side. This is because the forward voltage threshold of the 1N4148 is much lower (~0.6V) than that of the LED (~1.5V or so), resulting in much more of the signal being clipped by the 1N4148.

Good reference reading: http://www.geofex.com/effxfaq/distn101.htm

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

So then left to right its green +, green -, blue +, blue -? Or is it both green make up the positive and both blue make up the negative? So for symmetrical clipping it would be 2 of the same diodes on both greens and both blues?

This is like math to me haha, I've always struggled with it.....hoping for a light bulb moment here soon.

The green spaces are two diodes in series in one polarity direction and the blue are two in series in the opposite polarity direction. So it would be +, +, -, - using your description.

Diodes connected in series have additive voltage thresholds, so if you were to install two 1N4148 diodes (~0.6V clipping threshold) in the green spots, you'd have a combined voltage threshold of ~1.2V and that combination would clip less signal (and therefore sound louder) than if you installed one 4148 and a jumper. So as one of many possible diode combinations, you could install a pair of 4148's in the green spaces and a single 4148 and a jumper in the blue spaces and therefore have asymmetric clipping.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ok I'm starting to grasp this now.....I think.

led and led in series with 1N4148 is the mod I would like to do.

In this scenario, reading the diode slots left to right, it would be:
Green+1=LED
Green+2=jumper
Blue-1=LED
Blue-2=1N4148

Or am I still wrong hahaha. Again, I am sorry as I know its frustrating holding hands through something relatively simple.

Yes, that's correct.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ok, thank you. I appreciate your help. Hopefully this build goes well. I finished the 855 Drive kit last weekend and to my surprise it worked first try.

The two most important things in getting those first couple of pedal builds to work:

• Carefully following the instructions.
• Sufficiently good soldering technique.

If you've had some soldering experience before and have a decent iron and good quality solder (NOT the lead-free stuff!), you should be successful as long as you take your time. Sure, other things can go wrong, but those two factors are the biggest source of problems we see here with novice builders.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Here I am again. LED doesn't turn on. I measure 9.34v at far right power connection and at the LED. I've tried with both a power supply and a 9v battery. I was very careful and took my time with this build as it is more complicated than the previous 2 builds I have done.

Other than the LED, is the pedal working correctly?

Do you have a multimeter and know how to measure circuit continuity with it?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

When the pedal is engaged, I get no sound at all. When bypassed signal goes through.

I have a multimeter yes. I put the ground in a screw hole in the box and took measurements at the LED and far right power connection and both were 9v

That's fine, but I want to know if you have continuity between the round (upper) solder pad of the LED and ground when the footswitch is engaged. This ground connection is necessary for the LED to light up.

To measure continuity, set your meter to the continuity mode, usually indicated by an icon that looks like sound waves emanating from a point. Test the meter by touching the two probes together--this should cause an audible beep/tone from the meter. then, with the footswitch engaged, put one probe into one of the enclosure screw bosses and touch the other to the upper solder joint for the LED. If it beeps, you have continuity and chances are that the problem is that the LED is installed backwards. If it doesn't beep, then you have some other connectivity issue and we can work on fixing that.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I'm blown away, but my multimeter doesn't have continuity mode. It shows the diode symbol but no soundwaves. I went through every setting and touched the probes together and nothing sounded. Am I screwed and have to get one that does?

https://www.menards.com/main/electrical ... 272&ipos=1

this is the one I have

No, you can do it a different way. Set the meter to its lowest resistance setting and measure between those same two points. Continuity just means a direct connection with almost no resistance, so you should get a reading of a few ohms, at the most.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

When I test the top square pad of the LED it tests at.09-1.3. When I test the bottom circle pad the multimeter gets no reading.

Did I mention that I lose signal when I activate the pedal?

I swapped the LED around and it works now. I still get no signal when the pedal is active though

I thought I did a good job soldering everything. I thought the wiring looked good, I didn't tin the ends of the wire this time because when I did the 855 Drive the tinned wires wouldn't thread through the footswitch or the dc jack. But nothing frayed, I think all my connections look good........not sure what's next here.

A set of pin voltages on the IC might be useful, if you can get at the pins with your meter probe. Also, please get a voltage reading at the top leg of either of the side-by-side 10K resistors near the bottom left of the PCB.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I've got the pedal pulled apart so I can get to the bottom of the IC. I will test those areas and let you know what I find.

Top leg of both 10K resistors is 4.2v

Pins (top to bottom, solder side down):
1. 7.67v
2. 5.04v
3. 5.11v
4. 0v
5. 3.97v
6. 5.08v
7. 5.70v

I want to mention that even though the positive sides of both the LEDs for the clipping section test at 3.63 and 3.54 (left to right) they don't light up when the pedal is active. I see a small flicker from one of them when I disconnect and reconnect the battery.

Your voltages are mostly lower than I'd expect--how are you powering the pedal? What is the voltage on the right-side + eyelet at the top?

The voltage on the 10K resistor tops look very close--those two resistors form a 50/50 voltage divider, so you should see one-half of your power source voltage there.

The LEDs in the clipping stage are not there to light up, but may flash briefly when hit with a strong guitar signal.

I'm not sure what to make of your IC pin voltages. The top pin (which is actually #7, not #1, which is at the bottom) should be at your power source voltage.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ok, you're right, I think we just flip the pin numbers here. So it's this:
7. 7.67v
6. 5.04v
5. 5.11v
4. 0v
3. 3.97v
2. 5.08v
1. 5.70v

Right now I'm at work so I'm using a battery to power it. The top right eyelet measures at 8.08v

Updated pin voltages:

7. 8.03
6. 5.45
5. 5.38
4. 0
3. 5.21
2. 5.32
1. 5.98

Top leg of both 10K resistors: 3.97

When I test the battery, it tests at 8.47v

Got a better 9V power source or at least a fresher battery than that one?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I am off work here in an hour. I will use a wall connected power supply when I get home and report back again.