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Geoff's Amateurish Pedal Tinkering Workshop
http://maplifiers.net/forum/viewtopic.php?f=8&t=3151
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Author:  Unstrung [ Sun Mar 05, 2017 3:00 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

I ordered the bits. I went with clear knobs, I think they'll look hot against a purple sparkled pedlol. So since I'm going to laser engrave text let's get more ambitious... is there an image you like? It'd have to be just an outline. Fucking pentagram. Naw j/k. Maybe. Or just a phrase, a name for the pedal. Snaxbasser? Etc.

Author:  Snaxocaster [ Tue Mar 07, 2017 1:06 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Hrmmm... I'll have to give that some thought.

I'm enough of an asshole a big ol' pentagram is a possibility. :lol:

Author:  torgeot [ Tue Mar 07, 2017 1:24 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Snaxocaster wrote:
I'm enough of an asshole a big ol' pentagram is a possibility. :lol:

Well I would agree with this. In the :love: kinda way.

Author:  Unstrung [ Fri Apr 14, 2017 1:58 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

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Snaxie's pedal has taken form.

Author:  chris_d [ Fri Apr 14, 2017 7:37 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Perfect! :dukes:

Author:  Snaxocaster [ Fri Apr 14, 2017 1:05 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

:love:

:unstrung:

I suppose I have some cash dollars to send ye. :snax:

Author:  Devtron [ Fri Apr 14, 2017 10:48 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

That's fantastic.

Author:  Unstrung [ Tue May 30, 2017 2:15 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop



Do you remember Unicorn Turd Fantastic Distortion? It stopped working and I couldn't fix it. So it's been trashed and I'm using the enclosure.
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Painted. I opened the lid on the laser engraver so it skipped part of 'Mars', so I went over again with the laser and lo, I get this ugly streak. So the big text will get painted over.
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Author:  chris_d [ Tue May 30, 2017 8:08 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Nice! Like the wiring cleanliness.

You know, you coulod probably up the output by ensmallenating that 33k at the tail. Without looking too closely at the schematic, it might change a frequency filter a bit, but going for a lower value like 10k would allow a lot more volume out of the thing. :idk:

Author:  Unstrung [ Tue May 30, 2017 9:47 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Hmm, that is perhaps something to look into. I'll have to calculate the frequencies to see if it's something I'd be okay with.

The level is okay, you just do have to get into maxed range.

Dig that I got the TS-5 rehouse working again huh? Turned out there was a little shred of solder that was connecting 9V to the chassis. I picked it out and voila, aint she a beaut. :unstrung:

Author:  chris_d [ Tue May 30, 2017 10:01 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Nice, that is way fucking better than having to swap out the 3pdt.

I don't remember too much about the insides of that rehouse, other than the pc board was huge.

Leaving solder bits in there is a rookie move though. :red:

Author:  Unstrung [ Fri Feb 14, 2020 3:52 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

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"There are so many sounds in this pedal. I was sad to see it go but it was commissioned by another person. And indeed I probably wouldn’t have put so much work into the visual aspect if it were just for myself."

Algal Bloom V2 + LPB boost. I made a decent buck off it. Then the guy decided he wanted to take it up himself. I don't know about his soldering but he quickly surpassed me at dressing up these enclosures.




Got a few more to share when I have time. A couple choruses, they were BYOC kits so it's nothing techie to talk about, just look at the artwork.

I do have a RAT clone that I can talk at length about. It's all about getting around having to source that LM308...

Author:  Unstrung [ Sat Feb 15, 2020 3:25 pm ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

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SlewerRat. I made this uhh, around Thanksgiving of '18. The name is a spinoff on a controversial comment the mayor of Toronto said around that time. The idea was that I wanted to build a RAT but I didn't want to have to source an LM308 opamp. Luckily, Ibanez figured this thing out in the eighties when they made their Fat Cat, which is essentially an improved RAT isn't it? It uses a different opamp.

I'm going to go into a bunch of detail so I have something to copy paste into my blog, at least for Chris this is probably not any new knowledge...

So the reason the RAT and the obsolete LM308 opamp have such a legendary relationship is that the opamp has a pretty abysmal performance. Its slew rate, which I understand is the rate at which it can uh... slew... its signal... is very low by general standards. So that gives the RAT its signature sound. The opamp you could say is very 'low resolution'. For anything but making rock music its a garbage part.

In the Ibanez Fat Cat they instead used a NE5534 opamp which has a much better performance, higher slew rate, but you can actually tune the slew rate of it by putting a cap joining legs 5 and 8. And that's what they did, there's a 1nF cap there doing the job. So it's still performs like a RAT.

Cool! So I can make a RAT with existing layouts, without having to source an LM308. All I have to do is add a cap in there and I'm open to use this much more common opamp.

But wait... let's take it one step further... Let's put a switch on there, so I can switch different caps and vary the slew rate!

Okay, so now there's three slew rate settings. One is the 1nF, like in the Ibanez Fat Cat, which I'm calling RAT mode, under the assumption the engineers at Ibanez did their maths correctly and chose the one that slows it down to the LM308 slew rate.
One is no capacitor. So the NE5534 opamp is performing at its normal speed, which is much faster than the LM308.
And one is, I forget what cap I used, maybe a 10nF, so the slew rate goes way way slower than even LM308 speed.

RAT mode is probably the best mode. You can see why it`s such a big deal what opamp is in your RAT. In this mode the pedal sounds fat and balanced and has a nice, spongy feel.
With no cap for a faster slew rate, the pedal is a bit brighter and stiffer feeling. You can hear the pick attack much better. It`s a much clearer sound. A bit harsh. Probably good for black metal.
With it slowed the fuck down with the higher rated cap, it`s a sludge machine. With the tone filter all the way open in this mode I thought it sounded like a really fucked up IC Big Muff. Definitely a cool sound.

So that was my experiment, a Rat with three `modes` that aren`t your usual different clipping diodes or whatever.

Author:  chris_d [ Sun Feb 16, 2020 9:19 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Ooh, i really like that concept. I have never really felt that having multiple clipping diode options was something that i got a ton out of(usually, only one set of clippers will sound right to me for how i intend to use a specific pedal, and in most cases i find that they might as well be hardwired to the one setting that i like).

But i still really like the idea of "free" simple mods that can change the character of a pedal, and fucking with the slew rate(especially at extreme ends of the spectrum) seems like an interesting one to play with!

Personally, i have loved everything that i have built that uses the LM308, but have never really spent much time comparing the chip itself to others in the same circuits. I have a pretty bad habit of using lots of multi-opamps(i really love using quads) in my own designs and haven't done nearly enough with singles, even though several of my favorite circuits are essentially single opamp-based.

Author:  chris_d [ Sun Feb 16, 2020 9:20 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Also, what is the form of graphic on the algal bloom build? Sticker?

Author:  Unstrung [ Mon Feb 17, 2020 12:50 am ]
Post subject:  Re: Geoff's Amateurish Pedal Tinkering Workshop

Yeah same, when it comes to switching between different diodes it's kind of like, 'okay this is the good one,' and that's it.

If you have the time, try out the slew rate thing. It's surprising to me actually that people haven't made a thing of it, it's very easy and very effective. And yeah, I can see what you mean about the Lm308. It just has a very gratifying feel, and I think it might be the slew thing.

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