Friday, September 25, 2020

EARTHQUAKER DEVICES: Terminal Fuzz

The Earthquaker Devices Terminal Fuzz is based on the Shin-Ei Companion Fuzz, with a few tweaks to improve performance and versatility.  The first section is actually a lot like a silicon Fuzzrite.  Q1 feeds directly into Q2 - they feed into either side of the treble control with quite small capacitors.

The treble pot is followed by a notch filter, found on many fuzz circuits of the day, but the EQD Terminal Fuzz has included a voice control, to adjust the filter.  The notch filter is followed by a gain recovery section, as a notch usually drops a bit of level from the signal chain - a common issue in many old fuzzes with notch filters.

 EARTHQUAKER DEVICES TERMINAL FUZZ - VERO LAYOUT

  

EARTHQUAKER DEVICES TERMINAL FUZZ - VERO LAYOUT


Read the comments below, as there has been a bit of disappointment with this one.    A good suggestion was made by Tom, the 4n7 capacitor should be increased to 47n, which is the same as the Shin-ei.


15 comments:

  1. Thank you! Where is the gray L?

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    1. Sorry - I missed that. That goes to ground, I would suggest the top row

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    2. Just what I thought - Thank you!

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    3. Hope your build works well - please let me know how you go

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    4. Well it’s all boxed up and I got nothing but hum. Triple checked my placements, scraped all my cracks and holes. 🤷🏻‍♂️ Just to clarify, IN has a line going to the switch and going to ground with 1M res? Other than that question I’m at a loss. Thanks in advance for any insights!

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    5. Hello - the 1m resistor should go from the IN on the pot to ground. Just hum is not a good sign at all.... Do you have an audio probe and/ or a multimeter? Time to start tracing the signal. Do you get signal in bypass?

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    6. Also feel free to send some photos to guitar.vero.p2p (at) gmail dot com and I'll have a look.

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    7. Thanks for the help Andy. Only a few pedals under my belt so I appreciate the patience. Gonna bust out the ol’ multimeter and see what I see. I’ll email you if I’m still struggling.

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    8. Good luck - build an audio probe if you don’t have one. Takes five minutes, as it’s just a capacitor connecting to a jack (still needs to connect to ground).

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  2. Layout updated - it was also missing a cut behind the collector of Q1

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  3. Hey, the layout works. I've tried another Terminal layout and it just doesn't operate as it should. I think there must be an error on the schematic. It sounds cool as is though. Nice enough for me to try it twice. Thanks, I just discovered this blog.

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    1. I'll search around and see if I can find any updates on the schematic. Thanks for the feedback, I might add a warning to the post

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    2. It matches the schematic on PedalPCB, and they're usually pretty reliable.

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    3. One change that has been suggested is increasing C3 from 4.7nf to 47nf. But the character of the fuzz still isn't the same as the demos. As is, the fuzz tapers off very quickly. Most of the demos show heavy fuzz with the pot set below noon.

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    4. Thanks Tom - I'll add that to the blog. 47n makes way more sense

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