BJFE - Dyna Red Distortion [traced]

[Ichabod_Crane]

Helloe, I am buildind this pedal right now, I am using a vero layout of dirtyboxes. https://dirtboxlayouts.blogspot.com/201 ... mment-form
I noticed two things, Its curious that the designer used Electrolytics for a 1 uf, its a value that usually its fitted with a mkt cap etc.. I dont know if there is a reason specific And the other thing its I spotted a suppodsedly diferent valor in the input cap in the original schematic by bjfe (22n vs 47n on the bearfoot). I will try both of course...
http://revolutiondeux.blogspot.com/2009 ... rtion.html

What do you think of this?

Hello. I don't know well this pedal, but I don't find so weird the 1uF eletrolytics cap, some circuit uses those, maybe the older ones. Anyway, non-polarized should be better, indeed.
About the differences between the two version are minor, some value adjustment more than else. Except the input cap, but I guess 22n vs 47n there's no much difference, or just little more bass with the 47nF.
A meaning difference could be the 220pF (221) cap instead the 470pF (471). The second one should be tame some treble, especially at higher gain setting. And eve more the 6.8uF + 10k to the ground added in the BJF version. But the version of the layout you build has the mid pot that should be make the about same effect.
That's it all, I guess.

I finished this build, sound fine¡¡ but I have a strange behaviour, if i raise the gain, a high pitched squeal appears, but if the pedal is after a buffered effect in bypass is absolutely silent¡¡ . Maybe because it isnt boxed yet is the cause??

Also the output is low compared to other effects and, if i have to say something, the tone could have a little more deepness i dont know if is the character of the design..the clips I see on yt are somewhat lookalike so I think is along the lines..
But the responsiveness and amplike tone live to the hype

I can't tell you anything about the overall volume and tone range, if you give me one day I can make me an idea. I assume you're using all the parts layout suggest, right? IC, jfet...
About the squealing it's an issue sometime occurs to the high gain pedal. Did you try to power up it with the battery? Honestly the layout is well filtered by PSU issue.
The squealing could be an oscillation problem caused by long wires, unshielded circuit, too closeness of the input and output wires or layout design.
The layout is verified, so just to begin you should check your build in case of mistake, bridge soldering, missing or mismatched parts or wires, orientation...

[sopapo1]

Thanks for your answers Ichabod_Crane!! Yes the squeal I think its rf related or maybe becouse the vero layouts, sometimes the vero layout put certain traces very close each other... I put this on hold until the circuit will be boxed...
But I am confused by two "variables" found on the different versions, the 220p/470p on the feedback loop and the 0,47uf/0,1uf on the filter....
Bjf himself talk about the 470 pf being a mod to tame certain fq problems related to use a celestion v30 with this pedal, in the rest of the units is a lower value (220p) (a post in diystompboxes)
The other value change is the filter with 0,47uf that appear in both schematics the bfe and the bearfoot, i don t know why in the veros layput and pcbs it doesnt appear, instead it put 100n....
Any ideas?

[Ichabod_Crane]

I got the squeal issue with the Dr. Boogie on veroboard layout here, once. I solved magically making the input and the output trace shorter.
Those, incidentally, passed side by side (see the input and Treble 2 & Volume 3 stripes). When I interrupted both until the useful spot those were no more side by side, and this solved completely the issue.
In this case, the layout you built has the input stripes widely unused, after the 47nF. So you can add a cut track after that, though I don't think that stripes passes too much close to some other trace that could cause interference.
You can do the same thing making short the output stripes, too.
I'm not sure if this we'll really help you, I just shared my experience with a extremely high gain pedal where the input and the output was evidentially too much close.

I invite you, again, to search some mistake in the layout. I didn't build it, but some yes, without this problem, apparently.
In case you could use shielded wire for input and output ans see if this help.
The last chance is to solve the squeal once the circuit is into the box. Else, you should try another layout.

I don't know why the 1k + 0.47uF part of schematic is different in the layout. It could be a mistake, or another version of the schematic. You should ask to the author the source of the schematic.
Of course you could try the 0.47uF and the 100nF caps and choice the one you like.

Update: Ok, I see the confusion about the 0.47uF - 100nF cap. Though, the schematic shows a 0.47uF, everybody seems to think that the original cap is instead the 100nF, this is why all the layout show a 100nF.
It's only PedalPCB that follows the Bearfoot schematic (with the 0.47uF cap) and some just minor change in the power section.

[sopapo1]

Yes, i was thinking the same, the pedal is traced of a unir that os moded, It had a 470pf instead of a 100-220 pf in the feedback loop, the people mistaken this with tthe 0'47 uf on the filter and sub it with a 100n.
Very interesting about the traces, i am going to try to cut a little.
Thanks for your help ichabod!!!

[sopapo1]

Update¡¡ I cut the input and output stripes and voila¡¡¡¡ no squealing¡¡¡ Thank you very much Ichabod¡¡¡
And change the 100n in the filter to a 470n and now it have much more body and less nasal sound and brittle, more like it should be, i think its safe to say that is the correct value for this cap¡¡
However I have several Doubts:
The biasing of the 5458, bje himself says that its working only like a buffer and its selfibiasing, it dont need to be biased at half supply(4,5v) when its selfbiasing itself, its biaseing to a 1,8 to 2,3 v and this create certain nonlinearities that add to the sound.....
My readings are. g=0 s=1,84 d=8,64, its correct this biasing?? how can I to fix this biasing?? I notice that the level isnot quite on par with other pedals ,, I have it maxed. Its maybe because of the biasing???

Thanks for your time
Best regards

[Ichabod_Crane]

I'm glad that "my trick" worked.
But I can't answer you about the biasing of the transistor. I hope someone else will do it. Later I'll try to tell you something more about the voltages, enyway.
I find strange that you have low output.
Stupid question: did you check the pinout of your transistor? Look the datasheet and the schematic. And the value of the resistors around the transistor, in case of mistakes.