Earthquaker Devices - Arrows  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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bc108
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Post by bc108 »

Anyone?

Another modified Electra?

palomaeki
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Post by palomaeki »

_20190224_024026.JPG
_20190224_024048.JPG
Here's some shots kindly provided by PGS. I'm also interested in this since I was asked to if I could build something like it for a friend. Surprisingly nobody seems to have traced this?

Nothing too complicated - haven't compared it to the Black Eye etc. yet but it must be a revision of something familiar? AMZ Booster maybe?

Bononoob
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Post by Bononoob »

So a buddy lent me a EQD Arrows so I traced it
Here's the Eagle Schematic and some gutshots
Attachments
IMG_20190511_160442.jpg
IMG_20190511_160430.jpg
IMG_20190511_160353.jpg
EQD Arrows Schem.png

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storyboardist
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Post by storyboardist »

You're really close. I traced this about a year ago, and the value off the resistor off the emitter in your schem is way too high. Should be 1.3k. And the 100k at the output goes to ground. If anyone needs a PCB I still have a few. Schem attached.

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Arrows.PNG

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storyboardist
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Post by storyboardist »

Aw heck, here's vero, perf, and etch layouts too.
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Arrows vero.png
EQD Arrows.png

Bononoob
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Post by Bononoob »

Damn how did I mess this up
Anyway thank you for the corrections and boards that's awesome
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FeVeR2112
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Post by FeVeR2112 »

What does the R2 100R resistor do here? Seems unnecessary.

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Post by guiddruid »

FeVeR2112 wrote:What does the R2 100R resistor do
Limit current through D1 to ~90mA when the power is connected backwards.

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Post by FeVeR2112 »

guiddruid wrote:
FeVeR2112 wrote:What does the R2 100R resistor do
Limit current through D1 to ~90mA when the power is connected backwards.
Would you not just use the diode for polarity protection? A 4001 diode (1A) can handle pedal supply which are mostly 500mA at best.

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Nocentelli
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Post by Nocentelli »

I always understood that a ~100 ohm resistor + large electro capacitor together form a filter for the power that reduces hum.
Steven_M wrote: 21 Jan 2011, 17:52
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I'm not? Well fuck this site then. I only want meaningful conversations with myself.

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Post by guiddruid »

FeVeR2112 wrote:Would you not just use the diode for polarity protection? A 4001 diode (1A) can handle pedal supply which are mostly 500mA at best.
Without the resistor, you're relying on the power supply to gracefully limit itself - not pop a fuse, burn out a voltage regulator, or blow D1. Best practice is to assume worst case conditions, which for this protection circuit would be a very low output impedance for the PSU.
Nocentelli wrote:I always understood that a ~100 ohm resistor + large electro capacitor together form a filter for the power that reduces hum.
C4 would need to be moved to be in parallel with D1 for R2 to help with filtering noise. That would also protect C4 - the only polarised component in the design (other than the diode) - from reverse voltage.

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