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New Roger Mayer purple haze octavia

Posted: Mon Apr 18, 2022 8:19 am
by frenchie
https://www.youtube.com/watch?v=q7IQGzlvks4
https://www.youtube.com/watch?v=7WSK5kbgEZs

I guess we'll finally get to know a bit more about the actual BOG circuitry .
From the looks of it inside , all the old Octavio topic's participants claiming BOG was a totally different circuit were right ! There's an additional amplification stage behind the ferrite core transformer and then an output stage eerily similar to that of RM's transformerless octavia ^^ , that and apparently two transistors stuck between the jacks that I have no idea what they can do !
Reverse engineering fun ahead !

Re: New Roger Mayer purple haze octavia

Posted: Thu Jun 16, 2022 6:46 am
by frenchie
So with the invaluable help of spaceace76 , lots of sleuthing , deduction , comparison with other Roger Mayer designs , deep diving into google images to find as many gut shots as possible , adjusting the photogrammetry to get some resistor values that were a bit blurry or dark ( the hardest , or not , since in the end he used them in other pedals , part was finding which types of transistors he used , in a tiny corner of ONE picture it's zoomable and by increasing the contrast you can get it ) , we've been able to , I think , approximate the main functional blocks of that 1700 usd ( gasp ! ) blue pcb :

https://www.mediafire.com/view/rgkjezh0 ... 2.png/file

Didn't wire everything in the power section because the design is plain Jane enough and there are several other Roger Mayer designs that utilise that type of setup , of which you can get the the schematics everywhere , plus I have the right to be lazy at times too .

Well in the end Mayer is pitching the fact that it's a 6 layers pcb , but honestly there might be just 3 he used mainly to cram all those parts in the geometry of the box , not improve rf rejection of whatever supposed voodoo quality of the multi layer design , a ground layer , the blue traces layers and the tiny green layer ....
There's what appears to be a 47ohm resistors I have no idea how to wire , or why it's even there also , but don't hesitate to pitch in if y'all wanna improve the layout of that (outrageously pricey) board , if you got more infos or knowledge ...

So here we go , it's as previously guessed : a section that permit him to wire the on/off lamp on a 2PDT carling switch ( makes gut shots look like there's more to the circuit than meets the eye , makes the pedal more expensive to produce unless inflation tripled the prices of Chinese 3PDT switches , I guess obfuscation wise it might be useful tho ) ---> a negative ground ( nice ! wonder why no one thought of doing that before ....convenience ! )) dunlop Octavio ----> weird clean boost section ---> out