I guess it's kinda like a fuzz face but it started as two gain stages running into each other with an input gain control and a sag on the second stage (bias). Voltage feedback was added and it became similar to a fuzz face in topology but it sounds nothing like one IMO. In this case the sound is totally dependent on the transistors, replace them and it's a whole different beast.
Here's my video on tracing the circuit as well as a demo:
Here's the schematic:
And the layout:
You can also order a fabricated version in the store here.
Update:
Added a perf layout for this based off the Eagle board above.
Update:
Added a perf layout for this based off the Eagle board above.
Wow, well done! You are a treasure for DIY community!
ReplyDeleteThanks!
DeleteYou're a stud, David! Thank you for all you do!
ReplyDeleteEpic post. I already ordered some components. 🙃😬
ReplyDeletejust an FYI. on your perf layout the 100p from the base to collector of Q1 should be a 470p according to your schematic and your top layout.
ReplyDeleteFixed!
Deletebuilt it. verified! it sounds awesome. thanks for drawing up the layout!
ReplyDeletehttp://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/DirtTransmitter/DirtTransPCB-01.jpg
here's pic pf my finished build:
ReplyDeletehttp://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/DirtTransmitter/DirtTransmitter-600.jpg
VERIFIED!
ReplyDeleteAwesome job.. good video! Good to follow you!
ReplyDeleteFriend how do I leave the value of the components on top of them? how does this layout. I use Eagle 7.6.0
ReplyDeleteHey there, I'm having trouble finding the 2n1711 transistors anywhere, are there any alternates? Thank you so much great help !!
ReplyDeleteLow gain silicons like 2N2369, 2N5550, etc. Use sockets and experiment.
DeleteThanks !!
DeleteWud bc108b work?
DeleteI should think so. This circuit will work with a bunch of different transistors and each will sound unique.
DeleteHey david can you show a diagram that shows how to wire up the dirt transmitter. Thanks
ReplyDeleteWas there a special way that eartquaker wired up the 3pdt
DeleteNot really. Their method is about as simple as it gets. And they don't ground the effect input when it's in bypass mode (which is generally a good idea). Just use the method laid out in the General Layout Notes tab and you'll be fine.
DeleteThanks
DeleteOk so iam about to populate my pcb that I ordered from Oshpark which are amazingly built. I just wanted to know which caps should I use? Multilayer ceramics, polyfilm, or box? I have all the values in the multilayer ceramic but I wanted to make sure before I solder. Thanks
ReplyDeleteYou can use whatever you want. The original used a mix of film and box, but I've got not hing against multilayer ceramics.
DeleteOk so I built this with the pcb provided by osh park and it sounds awesome!!! One question? Iam wanting to place a rotary switch that selects different components to change the sound of the circuit. Where would be the best place to put this? Thanks
ReplyDeleteThere's already a lot of control over the circuit. One of the few things left would be the input cap. You could put a couple lower value and higher value caps on a rotary.
DeleteI tried putting the pedal together and my output volume and gain are both super low. Quieter than the bypassed signal, even. Doesn't get even vaguely fuzzy. I'm pretty sure the power is hooked up right, the signal is flowing the right way, the 3PDT switch is wired up right, all polar components are installed properly. I'm dumbfounded. Do you have any ideas as to what could be causing this?
ReplyDeleteSounds like it's misbiased. Try adjusting R3 (22k)
DeleteI've build it and it works when i'm not putting it in the enclosure. As soon as i but the pots through the drilled enclousure it dosn't work. It goes silent or weird.
ReplyDeleteMy guess is that i've done something wrong with the enclosure grounding.
Any ideas for that? :/
Have you isolated the back of the pots from the back of the board?
DeleteYes i have.
DeleteThe Sound cuts out when the pots aren't really screwed in.
Hi,
ReplyDeletefirst of all, thank you for the layout!
So, I'm having troubles to get the 50k linear pot for the tone control. (I mean, I ordered the components online in january and that one is still backordered since then..)
Would it be better to get a different taper or a different value of pot? My options are 50k log or REV log, or 25k and 100k linear.
Any help is much appreciated.
Thanks!
Nic
You could use a B100k by itself or add a 100k resistor from lug 1 to lug 3. That will turn it into a 50k pot essentially.
DeleteThank you very much, I'll go with a B100k then..
DeleteCheers!
Built this from your PCB in the store. Killer!
ReplyDeleteTried Q1 hfe=300, tried germanium - working nice, but not enough mud, even 2n7000 will work with above gain. But the best resault is 2n 3904, hfe=115-150.
ReplyDeletebuilt this up on Vero - it's a good sound but the bias control seems strange, from 0 to noon there's no sound, then kicks in abruptly with almost no range in the "sputtery" territory. Also, it's quite noisy even on those low bias settings.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteAll the CLR does is to drop +9v down for the on/off LED indicator. And yes, I've designed an new board for the store since the initial one shown in the video.
DeleteHowdy! What's up with the input next to the 9v? I've never seen that before. What do I connect with? Also why are there two ground inputs? Thanks!
ReplyDeleteI put it together. It just another spot the ground wire can connect I guess. This is a nice pedal. Thanks for the layout!
Delete