Wednesday, November 4, 2015
Tychobrahe Octavia
The Octavia is one of the many legendary effects to come out of the late 60s. It is also one of the rarest pedals of the era, as there weren't many built. Like most effects of its day, the Octavia is a positive ground effect. There are several schematics for it floating around, but the one I based this layout on can be found here. Most positive ground effects I layout I also post a negative ground effect version as well. I haven't done so for this one to keep the classic mojo of the original. If you want to make it negative ground, just rotate electrolytic caps, the 1N4001 polarity protection diode, and use NPN transistors for Q2 and 3.
Hi, this is my 3rd effect which I made with your layouts. DBD and Superfuzz are awesome. Can you make layout in version with negative ground like in other effects. I'll be very thankfull for that. I make efect in this layout and when i pluged it i noticed that iit is negative ground and i had no power suply for that. To solve this problem i can make inverter using ICL7660s but other effect (with negative ground) will not work in chain of loop.
ReplyDeleteRead the last sentence of the post. ;)
DeleteWhat npn transistor should I use?
ReplyDeleteTry 2N3904s or similar medium gain NPN.
DeleteDo also I need to change the Q1 MPSA18 also if I want to make it negative ground? Do I need to use a P-chanel darlington here?
DeleteYou can leave Q1 as is for negative ground.
DeleteThanks man, effect sounds great with 2n3904 transistors. I added switch between D1 and D2 like in fulltone Octafuzz and replace 42tm022 with LT44 (is easier to get).
ReplyDeleteNice!
Deletejust built one of these. Insane amount of gain with the listed transistors in the positive ground configuration. Might rework it into negative ground after i reassemble one of my guitars. Right now I'm all about the bass.
ReplyDeleteHi. Congratulations on your work. I have built several pedals and most work well. I am interested in building this pedal but I cannot find the circuit in TRANSFER IMAGE LIBRARY. What folder is it in? Thank you very much!!
ReplyDeleteIt's in the Misc. folder
DeleteThank you!!!!!
DeleteHi! I built it recently in negative ground configuration where according to your description I replaced Q2 and Q3 with 2n3904 besides caps. It was working but Boost pot was not working at all just one level of gain. I checked schematics and other projects and it turned out that MPSA18 has to be also replaced by PNP transistor. I put for Q1 2n5087 and Boost pot start to work fine. I put also for Q2 and Q3 2n5088 and I achieved better fuzz and also fixed a little loosing of volume when I was picking fast. Thanks for your work! Amazing website!
ReplyDeleteI tried to swap Q1 out with a 2n5087 using the positive ground configuration, and checked Q2 and Q3 with multiple combinations of 2n3904, 2n5087, BC327, and 2n5088, but could not get the gain working at all. I did not have any MPSA18's. The only combination that I could find in the positive ground setup to get the gain working was with Q1 = 2N5088, and Q2 and Q3 = BC327. It works well, though!
ReplyDeleteAlso, the EHX Bit Commander layout on this website uses the same transformer, so if you're going to order one you may as well order at least two and build that pedal as well. That's what I did.
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ReplyDelete