So why circuit boards, I always hear that point to point wiring is so much better? I think the person that said this, probably has never designed a circuit board in his or her life. I have been designing circuit boards since the late 70’s. Back then you used red and blue tape to describe the top and bottom layers. Today with Altium, I can do circuit boards in a couple hours that have only rounded traces and fitted ground planes to reduce noise. This creates a duplication method that is better than point to point wiring.
Octane Tube Clean Boost Pedal
Octane seemed like a good name for this pedal for 2 reasons. One since the site name is guitar-engines.com it seemed fitting to make the pedals oriented towards engine stuff. The more octane you have the more output and believe me this pedal can output.
The Octane uses a real tube for all the (18dB) gain with a 6418 tube strapped in triode mode. First off, unlike other triodes the 6418 is directly heated. That means it has no cathode. The description of the tube in the data sheet goes something like this…. This tube is designed for audio use in portable or wearable products. It’s widely misunderstood because of it’s lack of cathode and therefore much different than commonly used tubes like 12AX7/ECC83, 12AU7/ECC82 or 12AT7/ECC81. I have designed 300B and other directly heated amplifiers for decade so this tube was easy for me to understand.
Unlike our other pedals and amplifiers this pedal only comes in Turbocharged mode. The best components are used through out this pedal to give it a clean output to more than 3Vac which will overload any tube amp I have ever seen.
Any active tube circuit will invert phase and that to me would end it’s clean ability. So I created a folded cascode inverting buffer. So the signal goes like this:
Input->6418 Grid->6418 Plate (18dB of gain)->Custom Precision Components Volume control->Folded Cascode buffer->Out
The 9V supply has a DCDC converter for high voltage and a regulated supply for the filament. Only 35ma is used for the whole pedal including the relay driven full bypass circuit. There is a switch on the circuit board to turn the unit on at power up. Many users are using this option because they are using the product enabled all the time as a buffer. The directly heated triode adds a lot of air to any system and the folded cascode inverter can drive cable.