Darkglass Electronics - Microtubes B3K  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.

Re: Darkglass B3K

Postby POTL » 20 Jun 2018, 06:06

izikg wrote:
jmwreck wrote: I am having a problem with the Drive (B3k) because I got a cutting out sound, it seems that the distortion sound will get disconnected and all that's left is the clean sound,


Hi
I also get this cutting out when at high gain , I found that high frequencies noise is amplified and causing this problem on the drive opamp.
I suspect it has something to do with the filter before that opamp , but I just can not understand it.

does any one know this filter design or can explain that
B3K_pre_drive_filter.png


I also noticed that the BDDI has a similar filter
BDDI_PRE_DRIVE_FILTER.png


Thanks,


Hi
The first figure - R8 C8 - controls high frequencies.
1) When the switch is in the center position, the high frequencies do not change.
2) When the capacitor is connected to ground, the high frequencies are cut off, this is the classic RC-filter
3) When the capacitor connects to the resistor, this parallel RC-filter, like the Marshall, in this mode, high frequencies rise.
The second picture is Bandstop filter - the filter does not let pass a certain frequency. In this case, this filter cuts low-mid freq, the frequency of 320 HZ is cut completely and the frequencies near it are also severely cut off.
You do not have the required permissions to view the files attached to this post.
POTL
Resistor Ronker
 
Posts: 302
Joined: 26 Sep 2016, 04:11
Has thanked: 65 times
Have thanks: 61 times

Re: Darkglass Electronics - Microtubes B3K

Postby POTL » 20 Jun 2018, 06:22

Hello everybody
I watched the circuit today and read Douglas's reports on the forums, at first I thought this pedal was an original development, then I realized that Douglas collected it based on the MXR M80, Sansamp Bass Drive Di and CMOS amplifier as Red Llama.
So, if you want to copy B7K, then I advise you to look at the equalizer circuits from m80 and bass driver di.

Regarding the control of the middle frequencies, you can change the frequencies using the DPDT toggle switch (as in the original).
Below is the scheme, you just need to connect the toggle switch to C2 and C5
You need to copy the central part of the circuit 2 times and select the components for the desired frequencies, I hope this helps you to copy the circuit :D
Image
POTL
Resistor Ronker
 
Posts: 302
Joined: 26 Sep 2016, 04:11
Has thanked: 65 times
Have thanks: 61 times

Re: Darkglass Electronics - Microtubes B3K

Postby ray86 » 26 Jun 2018, 15:57

CD4049????
ray86
 
Posts: 3
Joined: 08 Mar 2018, 14:05
Has thanked: 0 time
Have thanks: 0 time

Re: Darkglass Electronics - Microtubes B3K

Postby POTL » 26 Jun 2018, 17:55

ray86 wrote:CD4049????

Yeah, it's here.
POTL
Resistor Ronker
 
Posts: 302
Joined: 26 Sep 2016, 04:11
Has thanked: 65 times
Have thanks: 61 times

Re: Darkglass B3K

Postby zyu » 09 Aug 2018, 16:25

Harold wrote:Here's another schematic based on the GUMA: http://peperspedals.blogspot.nl/2017/02 ... cb-to.html and the update on that: http://peperspedals.blogspot.nl/2017/03 ... pdate.html

I also made a Vero out of it, but I still haven't checked it: http://diyl.sait.nl/guma-drive-darkglass-b3k

Hello!
One small mistake.
R5 should be installed before R4, and not AFTER it, as in your scheme.
zyu
 
Posts: 4
Joined: 22 Jul 2018, 20:13
Has thanked: 0 time
Have thanks: 0 time

Re: Darkglass Electronics - Microtubes B3K

Postby jhergonz » 10 Feb 2019, 21:03

will try to build b3k with "ERA" knob like the Vintage microtubes, i'll just put B100k pot in series with the 33k(R23) resistor ... hope this will work just fine.
jhergonz
 
Posts: 39
Joined: 29 Mar 2018, 07:28
Location: Philippines
Has thanked: 59 times
Have thanks: 0 time

Re: Darkglass Electronics - Microtubes B3K

Postby Pedro_Mariz » 08 Oct 2019, 22:56

I have some sugestions that worked for me:

- Increase the 220pF of the grunt switch to 470pF
- Reduce the 4049 feedback resistor from 470k to 330k
- Increase the 100R 4049 supply resistor to 1k
- Also make a boot's trap before the 9V input of the board, it means, put a 100R in series, like the rat, that gonna improve the noise performance

Yet, all these mods didn't worked well to me, and the pedal was more like a gate distortion, the oscilations stopped, but it could be more, I espected it.

So, my final solution was to replace all the 4049 section, to a mosfet muff distortion block, and gess what? Sounded lika a charm! ahahah No oscilations, giant sustain, all the switches did they role super well, I'm super gratful to all the mates that inputed so much information about this thread, that's my 2 cents.

For this message the author Pedro_Mariz has received thanks:
karul (08 Oct 2019, 23:30)
Pedro_Mariz
 
Posts: 1
Joined: 04 Jul 2018, 21:28
Has thanked: 0 time
Have thanks: 1 time

Re: Darkglass Electronics - Microtubes B3K

Postby jhergonz » 25 Oct 2019, 20:48

Pedro_Mariz wrote:I have some sugestions that worked for me:

- Increase the 220pF of the grunt switch to 470pF
- Reduce the 4049 feedback resistor from 470k to 330k
- Increase the 100R 4049 supply resistor to 1k
- Also make a boot's trap before the 9V input of the board, it means, put a 100R in series, like the rat, that gonna improve the noise performance

Yet, all these mods didn't worked well to me, and the pedal was more like a gate distortion, the oscilations stopped, but it could be more, I espected it.

So, my final solution was to replace all the 4049 section, to a mosfet muff distortion block, and gess what? Sounded lika a charm! ahahah No oscilations, giant sustain, all the switches did they role super well, I'm super gratful to all the mates that inputed so much information about this thread, that's my 2 cents.


May I know what do you mean by "mosfet muff distortion block"? I mean did you put the whole mosfet version of big muff or just one stage of it?
jhergonz
 
Posts: 39
Joined: 29 Mar 2018, 07:28
Location: Philippines
Has thanked: 59 times
Have thanks: 0 time

Re: Darkglass Electronics - Microtubes B3K

Postby Whoismarykelly » 26 Oct 2019, 00:33

I'm having a weird oscillation issue with the level and drive controls at max on this circuit that I can't really figure out. I've seen a few folks mention a similar issue but no apparent resolution. Im wondering if it could be an issue with the JFETs since the rest of the circuit should have much variability between components.
Whoismarykelly
Resistor Ronker
 
Posts: 380
Joined: 22 Oct 2007, 19:26
Has thanked: 2 times
Have thanks: 7 times

Re: Darkglass Electronics - Microtubes B3K

Postby alexradium » 27 Oct 2019, 08:03

Whoismarykelly wrote:I'm having a weird oscillation issue with the level and drive controls at max on this circuit that I can't really figure out. I've seen a few folks mention a similar issue but no apparent resolution. Im wondering if it could be an issue with the JFETs since the rest of the circuit should have much variability between components.
oscillation can be anything from jfet,trace layout,long wires to the pots,poor decoupling of opamp rails.
alexradium
Resistor Ronker
 
Posts: 297
Joined: 31 Jan 2010, 14:31
Has thanked: 63 times
Have thanks: 68 times

Previous

Return to Boutique Stompboxes dissected...

Who is online

Users browsing this forum: art7710, Ichabod_Crane and 4 guests