Event Horizon, or a Rotobone puts on a space suit

[kamadude1216]

I made inferences based on what sounded good and feedback from people who had originals. I used to use 11-position rotaries and make “RotoClones” that were patterned after the original:

View attachment 76679

These days I’ve distilled it down to my own recipe and leaned into the whimsical:

View attachment 76680

I’d be happy to share any info. The CC has the same feature set, mostly. It’s a way cool circuit!

I've actually been following your work for a year or two now on this circuit and was inspired at some point to take a crack at it while using your findings as a base lol. However, a combination of life and laziness kept putting that on the back burner. That combined with how I've yet to hear a bad thing said about the Rotobone finally made me cave and get the actual thing. If you're interested, I could send it your way if you wanted to see the real deal and study the missing links? Assuming you're in USA lol.

*Mine is the V2 dual Ge

 

[coltonius]

I've actually been following your work for a year or two now on this circuit and was inspired at some point to take a crack at it while using your findings as a base lol. However, a combination of life and laziness kept putting that on the back burner. That combined with how I've yet to hear a bad thing said about the Rotobone finally made me cave and get the actual thing. If you're interested, I could send it your way if you wanted to see the real deal and study the missing links? Assuming you're in USA lol.

*Mine is the V2 dual Ge

I left you hanging on this one, and that's a good example of why I'm not the guy to trace your pedal. Even though I'm on summer break from teaching, I've somehow been even busier than I am during the school year. I swear this Honey-Do list is enchanted; any time I get close to the bottom, new items appear.

I'd love it if someone traced it though! And speaking of PTD Roto pedals: I've found several RotoFace listings on Reverb with visible manuals- enough to figure out what's happening in there. I'm building up a prototype this week.. Hopefully.

Meanwhile, my inner self:

 

[PedalBuilder]

I’m seconding this—I’d love to see this traced. @kamadude1216, it might be worth creating a separate thread about this to get more eyeballs on it.

 

[Robert]

Have a Rotobone coming in a few days. I was wondering if anyone wanted to take a crack at tracing it?

Just noticed this today. Send me a pic of the internals.

 

[kamadude1216]

No worries. I got delayed as well lol. Here's the best I can do. Hopefully it helps! Like I previously mentioned to the other members, I'm not opposed to sending this in for de-gooping and analysis. I trust you guys! Haha

 

[jwin615]

No worries. I got delayed as well lol. Here's the best I can do. Hopefully it helps! Like I previously mentioned to the other members, I'm not opposed to sending this in for de-gooping and analysis. I trust you guys! Haha

Ahahahahaaahaaahawhaaaaaaaaaha@a

 

[PedalBuilder]

No worries. I got delayed as well lol. Here's the best I can do. Hopefully it helps! Like I previously mentioned to the other members, I'm not opposed to sending this in for de-gooping and analysis. I trust you guys! Haha

That is quite the goop job! And a thorough job photographing it, too. Do you have a sense of how hard the goop is? My copy of the manual says this:

If it's fairly soft rubber, it should be easy to remove it. I'd defer to @Robert, but it might be worth trying to scratch the body of what looks like the polarity protection diode (circled in red below) and seeing whether the goop comes off easily. If it comes off easily, then I think that it should be pretty easy for one of us to de-goop and trace it.

 

[kamadude1216]

Update on this. You were right. It's a pretty soft rubber. I'll try peeling most of it off myself and I'll post the uncovered components again! Apologies on the delays for those eager to crack this one. I've been a bit busy lately.

Also, while we're on the topic of PTD stuff, has anyone attempted the Tornita? I believe there's two versions with the KS2 being the latest?

 

[Ginsly]

I'm just seeing all of this now, and anything involving @PedalBuilder and Bosstones instantly gets my attention. @kamadude1216 I think it's incredibly cool of you to offer your help in tracing such a great pedal! I'm hopeful this bears fruit, although I will say Pedal Builder's version looks fantastic too!

 

[kamadude1216]

Well, this was quite the de-goop job. Not difficult, just tedious. Here's a Google drive link to the album of the pedal

Rotobone De-Gooped - Google Drive

drive.google.com

Also, there's a very minor issue I ran into. It's the Hi/Lo power switch/toggle that came off during disassembly. If someone could maybe deduce where this wire goes to, that would be great so I can solder it back on. It's also in the folder but I'll single it out too in this post.

For the Y input rotary, the capacitors read OL-823 or 0L-823, 123K100, 473, 8F9 223J, some gray film cap with the label rubbed off unfortunately, and the 6th yellow one reads MKT .01 from what I can tell.

For the X output rotary, I can see 224J 50V, that same/similar gray film cap with the label faded again unfortunately, 473, 8F7 223J, another yellow MKT .01, and finally one that says 0L-823 or OL-823.

Q1 toggle has what I think is a Ge AC130 with what I think is 114 Hfe written on top and a 2N5088 Si transistor. For Q2 I see a 2n404 Ge transistor with unknown Hfe and a 2N2907A Si transistor.

From left to right looking at the pedal internals are the following pot values.

Gain: B100K

Octave: B100K

Volume: A100K

I'm sure color decoding the on board resistors should be easy. The cap on the board says 8F7 223J, can't quite read the polarity protection or over voltage diode, and I'm not quite sure what that solid yellow component is on the far right of the board (I can't see a label of any kind).

Hopefully this helps! Photographing was a bit tough but I can take more specific angles if you guys need it! I'm excited to see what you guys have to say about this circuit!

 

[kamadude1216]

Apologies on what will be 3 posts in a row, but in case the photos look weird. Here they are as direct attachments

 

[kamadude1216]

Part 2

 

[PedalBuilder]

Awesome pics! I'll take a look over the weekend and see if I can piece it all together. It might be worth moving this to a dedicated thread so that anyone else who's interested can find it more easily.

 

[kamadude1216]

Quick question, in general, when biasing a transistor. Sending it through a resistor of some value with the other end going to ground would raise its gain, right? I'm guessing the wire that I need to resolder just goes to ground



*I'm pretty sure it goes to ground since it comes off Q1 emitter. I'll let you know my findings

 

[PedalBuilder]

*I'm pretty sure it goes to ground since it comes off Q1 emitter. I'll let you know my findings

That seems likely. Increasing the resistance between emitter and ground decreases gain in a common emitter amplifier, which is what Q1 (probably) is here. It’s how @coltonius and I implemented it in our builds.

 

[kamadude1216]

Ok I think I've got it. In Hi position, it connected Q1E directly to ground. The exact same thing happens in the Lo setting except that there's a 1.2K ohm resistor between Q1E and ground. I haven't measured the actual resistance, but that's what the band color coding is telling me.

I also have a capacitor meter on the way so I'll be able to measure actual cap values on the rotaries. I'll also carefully desolder the Q1 and Q2 transistors so I can take Hfe readings. I may also try to take Vf readings on the pair or diodes arranged symmetrically (it's an even pair but looks like it's arranged in opposite directions based on the black top bands).

 

[kamadude1216]

Awesome pics! I'll take a look over the weekend and see if I can piece it all together. It might be worth moving this to a dedicated thread so that anyone else who's interested can find it more easily.

Can we move portions into a brand new thread or do I have to create a new one myself? Not too familiar with thread functions here lol

 

[PedalBuilder]

Can we move portions into a brand new thread or do I have to create a new one myself? Not too familiar with thread functions here lol

I think you might need to call upon the powers of @Robert for this one.

 

[Feral Feline]

Whatever happens, just make sure there's a cosmic-thread link between the two...

 

[Stickman393]

A+. Beaufiful