Hey team,
it's been a while since I've been able to sit down to fully assemble a pedal, but over the course of the past two months I've managed to find bits of time to piece this guy together. You've probably figured my appreciation for DBA stuff, and this is the result of my examination of multiple DBA schematics and ideas.
It's a combination of ideas from the newer Evil Fuzz/Harmonic Transformer/Interstellar Overdriver.
It is comprised of 2 reverse beta gain stages, with level controls for each, that way you can turn level1 all the way down and get fairly clean overdrive tones, or max it out for fuzz, and anywhere inbetween. The density knob controls the input capacitance for thin treble all the way to bass bass bass. The toggles are for switching out a transistor stage in the 1st gain stage, and the second is an output pulldown resistor to give a slight volume boost.
I'm pretty happy with the way this turned out, My main goal was reducing my issues with offboard wiring, which I think i can now say I will try to do that with my pcb designs from now on as often as possible.
In addition to this, for the enclosure I tried a couple new aesthetics. I screenprinted the sides of the pedal with a lion logo, and used some brass parts from the hardware store to make portions of the pedal pop a little bit. Kind of like character design, I wanted to have a primary dominant color(black sparkle), secondary less dominant color (White), and tertiary highlighting colors (gold/brass/silver from the hardware).
I dig the sound, although it may not be for everyone, but for me its a really cool feeling to have taken this from looking over schems, slowly understanding how to create a circuit, and taking the design from concept to completion. Heh, I goofily gave myself a pat on the back, it still makes me smile thinking about the process.
(https://4.bp.blogspot.com/-V9L-t6dh5cw/V4qKqzk-9dI/AAAAAAAACT4/dGK20oqRx7UTMB99jC0MJyrBCu40N0cIwCLcB/s1600/20160704_125402.jpg)
(https://3.bp.blogspot.com/-rmGLRTthCho/V4qKt7c2hzI/AAAAAAAACT8/4gibFKVBJ_8Afgb24ruodCe75CI0FoLFQCLcB/s1600/20160704_125452.jpg)
(https://4.bp.blogspot.com/-MvUf-hKbz4o/V4qKuPn_txI/AAAAAAAACUA/z28bdLY51EIhIBt2FeRl2bGR9qtas5rxQCLcB/s1600/20160704_125508.jpg)
Best,
Lubdar
Very cool Lubdar. I am really digging the enclosure aesthetics. The screen printing looks so pro. Also very interested in the circuit, any plans on doing a group buy on the PCBs?
Cody
Beautiful build.
Excellent job! I like the brass parts, too.
Quote from: selfdestroyer on July 16, 2016, 01:40:31 PM
Very cool Lubdar. I am really digging the enclosure aesthetics. The screen printing looks so pro. Also very interested in the circuit, any plans on doing a group buy on the PCBs?
Cody
I'd be interested, too. The circuit concept is intriguing. Really cool build, the enclosure is great!
Heh thanks you guys for the compliments! It means a lot :)
I'll work on getting a demo up of the different sounds coming out of this guy.
If there is still interest I'll figure out how to make the pcb better and more accessible, either via OSHPark sharing or trying to have some boards printed.
The Gold ink didn't stick too well, even the higher quality ink doesn't last over a certain period of time. Heh I've had that ink for about 3 years now and I finally had to replace it. Not bad considering the very slow rate of printing that I do.
I like the brass look too. at one point I'd seen powdercoated hex nuts and the like, and thought that was pretty cool, but I can't do any powdercoating right now.
great looking pedal. while the pcb might be bigger than necessary it is very functional! cool design
Great build man! Are these going to be available on oshpark? Love those bypass boards too.
Very cool, and congrats on your design! Looking forward to hearing it.
This is great!
Do the three pots make a Master Volume unnecessary?
Thanks you guys!!
I'll try and get something recorded ASAP and post it this week.
Quote from: Tremster on July 18, 2016, 02:03:55 AM
This is great!
Do the three pots make a Master Volume unnecessary?
The "Gain 2" pot is more or less a volume control, there isn't a volume control at the end of the circuit, the "Gain 2" pot is limiting the signal that goes into the last 2 transistors. I was trying to make "controlling gain stages" more accessible. ALternative label choices were "pre", and "post", or "input" and "output". Just something to describe the position of the signal limiters in the circuit. I'll post the schem after hours when I get off work.
Hello from Cullman, AL!
I dig the idea and sounds like you nailed what you were after - also eager to hear this guy and possibly do a build. Nice work!!!
I'm not sure if I should have started this in a different section of the forum, but if a moderator wants me to redirect it I will.
Below is the schematic for the pedal for any of you breadboarders out there curious to give it a whirl.
You can see the common "DBA" biasing method on the transistors in reverse active orientation.If you max everything out, you get a fuzz sound close to the 7 tranny fuzz war. Look close and you can easily see why. MPSA05s handle the 910k to base biasing approach better than 2n5088 and 2n5089s...
I'm not so sure about the toggle switch at the end, really it just lifts the signal shunt to ground, which in effect gives a little boost in volume.
If anybody has a chance to look over this schematic and has any suggestions on improvements, let me know what you think. I would greatly appreciate any/all feedback.
Like I said I'll try and record a clip probably Wednesday night and post it up here for those interested.
I use Diptrace to create the schem and then layout the board, I have yet to try eagle, but so far Diptrace works out great for me :)
best,
Lubdar
(https://3.bp.blogspot.com/-QtTAconaFmg/V41vqaUi59I/AAAAAAAACUY/V66Su8tloncCsW_7pd319Rmwr3s8qOFZwCLcB/s1600/BAku_schem%2Bv1.14MAY2016.png)
Quote from: mrclean77 on July 18, 2016, 09:14:26 AM
Hello from Cullman, AL!
I dig the idea and sounds like you nailed what you were after - also eager to hear this guy and possibly do a build. Nice work!!!
Another Alabamian!!
Nice and clean guts. I'm with you, I hate offboard wiring. Thanks for sharing the schematic. Seems like you've figured out the weird biasing of DBA designs. Wonder if MPSA05s will make building the 7 transistor version of the Fuzz War easier...
It will, i did a youtube video comparing different types of 2n5089s for the fuzz stage. Apparently the beta parameter is a part/(result?) of the manufacturing process, which may be why national semiconductor 2n5089s worked better in reverse active mode than TI, or ON.
The 7 transistor fuzzwar wasn't designed that well. The whole reason I got into this hobby was because of the DBA Armageddon Pedals. Over the next couple months I'll be posting my progress thus far.
Using the 910k, 180k, 390 ohm bias setup works for the MPSA05s. It should work in the 7 transistor fuzzwar that exists on your layout. It will be darker than when 2n5089s are used, but that could be taken care of with the tone stack. If biased properly, in reverse active mode, 2n5089s have higher gain and more treble content than MPSA05. If you socketed your transistors, you should be able to put in MSPA05s (i got a roll from mouser) and they should work.
Also, test it out, but the diode configuration after the tonestack in the fuzz war doesn't do what people think its doing based off of the schems i have seen. Early DBA stuff was largely just cascaded boosts. That's why in some pedals I've seen the diodes not actually functioning in the post tonestack. Either someone traced it wrong, or DBA implemented the idea incorrectly....
Hope this helps.
Lubdar
Thanks man. Cody, you payin' attention? ;D Cody and I have been talking about the 7-tranny Fuzz War for the better part of a week. It seems a lot of the 680n caps are actually 100n from gut shots. Might help with the dark tone with MPSA05s. In those same gut shots, those diodes after the tone stack are populated but with the 27k resistor connecting them to the base of Q6 removed, or just completely removed from the circuit board in later pcbs.
HAHA I am all over it. Still have the layout populated and ready to try the suggestions. I will report back!
Cody
100nf gives it more crunch, i used a mix of 100nf and 470nf for coupling caps. 680 is just way to much mud for the sound I was looking for.
Heh, I have pages and pages of my attempts at schems and my documentation of sounds and the components going into it....
But yes, at the end it was 7 boosts in a circuit.
As i mentioned before the gain pot from the collector of q1 is an idea not implemented correctly You're going ! you'd be better suiting using a 1M pot as a signal limiter at the beginning of the circuit, and setting that pot as a 390 ohm resistor instead.
Fyi the 410k/100k resistors to V+ in the first couple of stages can be set so all are 910k/180k if things don't work out right. The 410K/100K is just an off biased value, which may or may not sound good to your ears...
This looks great, and kudos on such a neat design and layout (love the 3PDT PCB).
I just finished a build for some one that was a
DBA Sound Saw -> DBA Harmonic Transformer -> order switcher -> Moodring -> FX loop / Blend
Long story short, the HT sounds AWESOME! I'm very interested in hearing this too.
I made a perf/single sided pcb layout for this if anyone's interested. I think Cody's already etched it, but not sure if he's populated/tested it yet.
(https://3.bp.blogspot.com/-4FcJBloPNMM/V4-U8p-jv8I/AAAAAAAAD7o/o_s9Xk6URNkgQvvO2tKIwUqFNDQnbMRLgCK4B/s640/Evil%2BHarmonic%2BOverdriver.png) (http://effectslayouts.blogspot.com/2016/08/evil-harmonic-overdriver.html)