madbeanpedals::forum

Projects => Build Reports => Topic started by: storyboardist on June 08, 2018, 06:45:32 PM

Title: EQD Dirt Transmitter - A De-build Report
Post by: storyboardist on June 08, 2018, 06:45:32 PM
Not a build report, but a dissection report I guess. Grabbed one of these off Reverb a little while ago and traced it this past week. Made a video while I was at it and thought I'd share it with you guys. Etch-able layout on my blog and it's also on my store if you want to go that route (links below).



Schematic:

(https://4.bp.blogspot.com/-y1NYpJ7iyFE/WxasJ9_UKKI/AAAAAAAAGFI/HpnrE4U90QkbgJcJpzh3Ky8p2S-uLTXuwCK4BGAYYCw/s1600/Dirt%2BTransmitter%2Bschem.png)

Layout (click the image):

(https://2.bp.blogspot.com/-WygVUDqbc14/WxaxiVJw-jI/AAAAAAAAGFU/1UabDmHGGsweesY3zREy03OY5aMp5EZDgCK4BGAYYCw/s640/EQD%2BDirt%2BTransmitter.jpg) (https://effectslayouts.blogspot.com/2018/06/earthquaker-devices-dirt-transmitter.html)

Fabricated board (click the image):

(https://i2.wp.com/effectslayouts.com/wp-content/uploads/2019/10/Soil-Slinger-4.jpg?fit=801%2C801) (http://effectslayouts.com/product/soil-slinger/)
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: joltjrs on June 08, 2018, 06:49:40 PM
nice. just got one in for repair, coincidentally.
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: Ralfg on June 08, 2018, 07:43:03 PM
Nice! I was curious about what was going on inside this pedal, now I know thanks to you!
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: jubal81 on June 08, 2018, 07:52:04 PM
Very nice work!
I'd think C2 should be flipped since the input is at ground potential and the base of the first transistor is biased with positive voltage.
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: storyboardist on June 08, 2018, 08:12:24 PM
Quote from: jubal81 on June 08, 2018, 07:52:04 PM
Very nice work!
I'd think C2 should be flipped since the input is at ground potential and the base of the first transistor is biased with positive voltage.

That was my thought too, but the negative side of that cap definitely goes to the base of Q1.

Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: somnif on June 08, 2018, 08:41:32 PM
Huh, the goofy metal can low gain silicon transistor is actually still available retail. That's awesome.
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: cooder on June 08, 2018, 09:40:14 PM
Very interesting, thanks for dissecting it! Just trying wrap my head around it...
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: Rockhorst on June 11, 2018, 08:34:25 AM
Inspirational video to watch man. Your board routine is different from mine. I usually place all components first in the best way I see possible and then start the wiring. Your method doing both simultaneously makes total sense though. Cool to watch.
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: pickdropper on June 11, 2018, 11:14:30 AM
Quote from: storyboardist on June 08, 2018, 08:12:24 PM
Quote from: jubal81 on June 08, 2018, 07:52:04 PM
Very nice work!
I'd think C2 should be flipped since the input is at ground potential and the base of the first transistor is biased with positive voltage.

That was my thought too, but the negative side of that cap definitely goes to the base of Q1.

They really shouldn't be trimming the leads far into the solder joint like that.  That can cause issues.
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: selfdestroyer on June 15, 2018, 06:23:05 PM
Awesome work David.. Great job on the video also!

Cody
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: MadMike on June 15, 2018, 08:05:38 PM
Nice work - interesting arrangement of the dirt knob. I'd like to try that!
Title: Re: EQD Dirt Transmitter - A De-build Report
Post by: madbean on June 15, 2018, 08:39:41 PM
Quote from: storyboardist on June 08, 2018, 08:12:24 PM
Quote from: jubal81 on June 08, 2018, 07:52:04 PM
Very nice work!
I'd think C2 should be flipped since the input is at ground potential and the base of the first transistor is biased with positive voltage.

That was my thought too, but the negative side of that cap definitely goes to the base of Q1.

R1 doesn't seem necessary, either, being in parallel with the Dirt pot.