Hello everybody,
I love high gain pedals, I built the Triple Wreck and Tight Metal.
In my DIY history I skipped the Dr. Boogie because while I learn to build pedals it was kind of "outmoded" for some reasons, most important was the the not so efficient tonestack. People thinks others high gain pedals has better tonestack, probably it's true.
Now I'm sorry I missed that, I don't know if it has worth, but I want to try it. Probably, I'll use the tagboard veroboard layout. I know it could be problematic, but it's a verified project and some people built it succesfully, and the V2 (same Chunk Chunk schematic) is less prone to have the well known problem it had in the previous version like squeal, hum, maybe poor bass and too much treble.
I want to try to buy for the first time J201 smd version with the PCB adapter and pins do solder it.
I still don't know if I will build it with the stock tonestack, probably I'll try.
I would like "design" some alternative tonestack, too.
1. Without tonestack, I think it need just a high roll off.
2. With a Big Muff tone style, even with a mid/scoop control pot.
3. With a simple Baxandall 2-band, maybe 3-band.
Who tried to do something like that?
Peper's pedals do a Dr Boogie with a Tonemender attached to it. It's ok, but I've built the Br Boogie twice, and found it to be pretty noisy in both instances.
What layout?
I know about some tricks.
Shielded wire for input and output between jack and footswitch, and between footswitch and board. Maybe even from other wires pot.
I heard that enlcosure jack are better.
Original schematic has two 100uF for two root in the power supply. Tagboard has just one, so a second can be added. Maybe 220uF is better?
PS Is there some document to download of this Peper's Dr Boogie version?
Not really a Dr. Boogie, but a BSIAB/Okko Mashup, that I did... Just as an inspiration:
https://www.madbeanpedals.com/forum/index.php?topic=27408.msg265388#msg265388
And a video of me playing that thing into a matchless amp: https://www.youtube.com/watch?v=eh4FevjBdWE
Nice, but I'm not really searching an alternative high gain distortion.
I built once a BSAB II, I don't have it anymore. Maybe, I'll built it again, sooner or later.
Finally, I built the Dr. Boogie board using V2 veroboard layout from this page:
http://tagboardeffects.blogspot.com/2012/03/dr-boogie.html
I'm testing it out of the box. I soldered the jack directly on the input and output wire. I tried shorter wire I can, I twisted the gain wires (shouldn't I?). With the JB jr. pickup to the bridge in my Stratocaster I got oscillating. I got with the other pickup if I rise up some of the pots.
The drain voltages are setted around 4.7v.
I had some parts on sockets, now I have less parts, just the 4.7nF in the power suspply filter, I'm thinking about to change it with a common 100nF. Then I still have on socket pin the much discussed 3.9k, the 1nF in parallel with the trimmer of the third stage, and the bypass 1uF cap in the first stage, maybe I'll use a toggle siwtch for it.
In my first test (the one with a lot of parts on socket pin), after a while and for some minutes I got a sound with not the oscillating.
I prefer build it stock and don't change anything. Maybe I'll solder a 1n5817 in line with the 9v, anyway, but this doesn' tsolve the problem. I could use some shielded wire: input and output. Some other wires?
Do you think the the issue can be solved after the circuit is into the box?
That's a lot of words, what is the problem with it?
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I don't know about your vero layout, but I've built a few of the pedalpcb boogie moster pcbs and they are dead quiet and very heavy with no issues whatsoever. One of my faves that I only recently discovered because I too assumed it was overdone and outdated years ago.
I didn't have too much expectations from this pedal, but I have to say that it sounds huge and with tons of gain. The eq, instead, is... a disaster. I'm ready to build another one with an alternative tone section.
Sorry for all the words, I wasn't so clear! ::)
My problem is the oscillations. It squeals when I don't play. Typical. (I tried with battery, but it it's the same).
Probably with the PCB the problema is solved at 99%, but a lot of guys built it on veroboard, in some different layouts succesfully. I would like to do it, too.
Ah, thank you for the clarification. With vero, it could be anything. It's hard for me to look at the solder side without extreme magnification.
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I'm sure enough my built is ok: every control works, the sound is very good, and the hum is surprising low, at least the max setting I can get before the the circuit starts to squeal.
I replaced the 3.9k with a 39k (it helped a lot of people) and after I set the trimmer I got I guess about the same amount of distortion, indeed I don't know what exactly the difference it does. But the squeal is not completly tamed. I still have some trouble at higher setting of the controls.
I tried to use some piece of shielded wire, in the input, output, between the Treble pot and the Volume pot. I soldered transistors and the Presence cap directly on the board withouth using socket pin. All these don't help too much.
Now I noticed that if put my hands over the circuit almost touching it the squeal get low significantly. I think this is just a shielding problem.
Anyway, with a Boss pedal in front the circuit doesn't squeal anymore.
I could go over, hoping that closing the circuit into the box I solve the problem, in case I will built a jfet type buffer, like my Boss pedal.
I totally solved the oscillation problem with a little mod of the layout, with no changing of the schematic.
It sounds ok and very aggressive, but I would like to have more dynamic without losing gain. Every touch of the string soft or hard give me about the same amount of the gain, and I can't clean up with the volume guitar pot unless I set very low. I remember you that the drain coltage is around 4.7v.
Using a charge pump 18v or more in this circuit, I read, makes the circuit louder and maybe adds distortion, but doesn't give headroom or dynamic.
What do you know about it?
My Dr. Boogie build cleans up nicely, but I set the drain voltage a bit hotter to around 6.5/7 (for 9v) (especially for q4).
Thanks for the info. Honestly, I don't remember, with that voltage setting it sounds less gainy and aggressive, it isn't? I guess that is the reason it clean up better.
(I assume the big amount of gain doesn't allow to clean up well. I still didn't build a JCM800 fet emulator, but maybe it doesn't have this kind of problem because it should be smoother.)
Setting of J-Fets is important here - always is usefull to set at Drain (output electrode) cca 1/2 of power supply. For 18V this would be cca 9V. Less value says that transistor is too opened, what will raise inner noise and higher sensitivity for signal - less dynamics, all is quickly overloaded. So, set min. 9V. After it you can solve some oscillations or low dynamics.
Thanks.
My Dr. Boogie works at 9v and the drain voltage setting is about 4.7v. Not oscillation problem for me. I got it, but I solved easily.
After some experiments I didn't get a lot of dynamics, but it's fine enough for this pedal. Not really touch sensitive, but I guess this is the circuit.
There are caps 1uF in source electrodes (emitors) which define gain of stages. Serially with (some of) them you can add resistors cca 1kOhm, so it will lower overall gain according your needs. This is way, how some valve stages define gain too.
For wheening oscilations I would add caps 100nF to power output point. See picture.
I experimented on the filter in the power supply section, but my initial oscillations issue was caused from the layout design.
I tried to change the value of the 1uF caps, but in the end I like the original. It was more difficult to include resistors in the veroboard layout I used.
I included a three way switch to change the value of the cap in the first stage.
Sometimes is enough to set there this serial resistor only at first stage.