@barry
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Glad you like it.
This is Cornish Tone Filter.
Think of it like your Guitar Tone Knob. Start all the way up then dial it back to preference.
Good question: The Diamond Drive is much brighter, less Gainey sounding than the 69 Stones.
The architecture of the circuit is commonly used in many amp/tube sounding circuits. Catalinpedals comes to mind. These while similar in that manner do have several key differences that matter.
- Gain modification, how the Gain reacts when turning the Knobs which is done by Taper.
- Gain Value which is perfectly set for each circuits namesake.
- Equally important are different Coupling Caps allowing different frequencies through each circuit.
The 69 Stones Drive has more Gain and will get there much quicker and is darker sounding while the Diamond Drive holds onto the cleaner chimey tones you would find in a Vox.
Then of course playing them brings certain tones to mind which I hope is demonstrated in the demos.
That is about it. We offer two boards that have unique sounds despite the similar topology just like we have a Dr. Phybes and The Vibe. There are only four values which turn it from a Phaser into a Vibe.
Sorry for butting in but I figured you may need this info asap. (late at night) Looks like a Micro Amp Build.
So you cannot use a TL072 with that circuit. That is a Dual Opamp.
You must use a TL071 or the suggested LM741 which are Mono Opamps. Always look up Datasheets before substituting. The pinouts are different and that is why you are getting no voltages.
The extra pad above C5 is there in case you want to use a Film Cap instead of an electrolytic.
I did not check anything else.
If you still have problems after changing to a proper Mono Opamp then you will need to report voltages again.
I am glad too.
Curious you had 1K + 10K Trim (11,000 ohms) and 7v bias – then 100R +10K Trim (10,100 ohms) then 5v Bias.
So the only actual needed resistance was several hundred ohms using J201s?
Was there some other change or difference you can think of?
I am assuming you tried to turn the trimmer both ways with each change?
The J201 substitution I imagine would have made up some of the difference.
“I think at this point the circuit is working correctly. Thanks for all of your input.”
Sure.
Just to be clear for anyone reading a simple way to spread out the Sustain through the rotation of the potentiometer would be done by using a Linear Pot B as opposed to a Log Pot A. To add more available distortion you can additionally up the value to 100K as opposed to 5oK.
So a B100K Sustain Pot would be a good mod.
You could also switch to Silicon Diodes if you wished to add a bit more fuzziness.
Finally change R36 to a Jumper for more available volume if you feel you need it.
Adding more resistance should allow you to Bias to half the supply voltage. Not reducing it.
Make sure that the board is fully populated before you test.
OK after checking voltages and listening to the demo I have a few thoughts.
I believe the circuit is working fine.
In my demo I am using a Les Paul with about 1ok on the pickups. Also I may have a bit of dirt on my amp. That said the Guitar to the circuit to the amp and everything in between is the complete circuit.
So I am guessing that is a single coil pickup with about 7k on the pickup in the demo. That would reduce the overall sustain. Additionally this circuit is only 3 Stages of a 4 Stage Muff circuit so it will not have as much sustain as a Muff. Silicon Diodes would further add to the “Fuzz” sound. Remember this was designed for Gilmour who commonly stacked pedals. We did not modify this one intentionally.
The original circuit uses a Log pot and that will bunch the Sustain all up at the end of the rotation but that is the way the circuit was designed and not my idea. Further the value could be increased.
That said there are even more Mods you can make to make it more suited to you.
I will discuss with Bruce and get back with you.
Here is the 2021 Build Document for convenience.
So no Mods or anything different from the original $1000+ pedal except for transistor type which is 2N5088 and is very similar to the original BC549C.
First things first.
Take voltage readings of all transistors.
Show them like this:
Q1 E: 4.72 B: 4.53 C: 9.18
Q2 etc.
Be sure your power supply is 9v.
In regards to sockets I always use them for multiple reasons and troubleshooting is one of them so do not solder straight to the board. I may need you to test open socket voltages etc. I’ve built thousands of circuits and I still troubleshoot my own stuff from time to time.
Most of your solder joints look great but here are some spots to Re-flow that catch my eye. Simply take your iron and reheat the joint to let it flow again into the pad. You may or may not need a little extra solder handy when doing this. The ones in Red I am especially concerned about but I would go over all of them as it just takes a couple minutes. I suggest pushing the component in from the component side of the board while doing this. The component lead should show a bit while also avoiding a Bulb of solder.
Thanks for providing detailed photos. That helps a lot.
Now just re-flow and report your voltages of all transistors.
You can get the desired Bias by adjusting R3, R6 and R9 currently all 1k if you cannot get there with the 10K Trimmer. Do this by increasing resistance to say a 10k or anything close to that. You may want to start with just R3 before you de-solder R6 and R9 and test one Q at a time.
This is caused by tolerance of parts. Most of the time this works out but not always.
Note: You will not be able to test and bias a board that is not fully populated.
The drill template in the Doc shows pots under the board. It is an easy mistake to make. Just remember we have a silkscreen on all boards to indicate lug numbers and thus the orientation. I see why you wanted them to be mounted that way to fit under top mounted jacks.
Nice Combo!
Try squeezing a Buff N Blend in there for a Marshal Fest that won’t influence the other when playing circuits in Tandem.
Very nice combo!
Glad the Mini-Me is working and the Reverb by design really should require a long delay brick.
The Stage 3 making everything sound better.
Thanks for sharing.
The tit always points to the emitter.
The board has a silkscreen as well. The pads are also in an orientation for easy insertion.
You should post clear pictures so we can see what is going on.
So at the end of all that it was 2 counterfeit chips, wow!
I am glad I could assist for my part.
I 2nd Cybercow’s idea above.
Hi Stevie K,
I think 100ohms as a guideline in our situations is more than adequate but would require an opamp buffer.
All of our circuits feature a 1M resistor at the input.
We carry opamp versions as you know. That said the simple fact is they all will work great. If you want an exact number you will have to measure it but it will be in the 100’s of ohms. More than awesome.
Let us know your results.
From Jack Orman at AMZ:
“An opamp is an even better buffer amplifier, though many believe they are somewhat colder sounding and more sterile than the transistor versions.”
Again we carry both types in various formats. I hope that helps.
