Orange Bass Butler

tuck · Post by **tuck** » 18 Jan 2023, 21:33

bmxguitarsbmx: the source resistors are 2k7 for the dirt channel its the resistor towards the gate pin. At least for Q2.
The resitors are not aligned with the transistor pins.
bajaman: already ordered a few

I ordered them around the time when there was th einformation that they are getting discontinued.
Ordered on ebay directly from china when the price went up. Lesson learned.

In the meantime I will get some J201 from some old pedals that I never use...

bajaman · Post by **bajaman** » 18 Jan 2023, 22:50

Hi Tuck - in the meantime, you could always adjust the drain resistors (R10,17,25,30 ) for the jfets that get you closest to 10v dc at the drain (your measured Q3 and Q5 would be ideal candidates) - try a 100k trim pot and see how you go

cheers
bajaman

tuck · Post by **tuck** » 19 Jan 2023, 12:27

I used an old cheat code I remembered when playing Doom many many years called IDKFA and received a little drawer packed with J201, 2N5457 and MPF102. So I reloaded my Bass Butler, grabbed my bass, turned up the gain and tore down the walls

edit: that joke means that it works

Okok, not packed but it will last for a few more pedals. maybe I should sell them.

Code: Select all

q1 idss 0,32mA I 0,21mA Vgs 0,15V 13,3V
q2 idss 0,47mA I 0,30mA Vgs 0,21V 7,65V
q3 idss 0,47mA I 0,34mA Vgs 0,24V 6,5V
q4 idss 0,78mA I 0,44mA Vgs 0,30V 4,5V
q5 idss 0,23mA I 0,22mA Vgs 0,15V 4,4V
q6 idss 0,55mA I 0,32mA Vgs 0,22V 13,3V

I still did not bias the transistors.

Next step: Biasig, checking XLR Out and drilling the enclosure.

tuck · Post by **tuck** » 20 Jan 2023, 16:56

Let's call it verified.
Everything works as it should. I still have to compare it to the original Pedal.
No trim pots, waiting for them to arrive. No GND lift yet.
It runs like a charm with a pedal board power bank and a charge pump.
There are only hundreds of pre cut wires on my desk that came with multiple stompbox kits so I had to make longer wires out of them.
Don't mind the holes, it was a pre drilled enclosure of another kit.

: IMG_5274.JPG (150.99 KiB) Viewed 1156 times

: IMG_5271.JPG (128.08 KiB) Viewed 1156 times

Does anyone know a jack with a switch as slim as the Lumberg KLBM 3 ?
The expression jack is not installed. My amp style jacks which don't fit with this kind of compact build.

: IMG_5272.jpg (81.09 KiB) Viewed 1156 times

temol · Post by **temol** » 20 Jan 2023, 17:14

Something like this?

: jack1.jpg (55.38 KiB) Viewed 1150 times

: jack2.jpg (74.47 KiB) Viewed 1150 times

tuck · Post by **tuck** » 20 Jan 2023, 19:14

That would be the maximum because the tip is almost touching the PCB
https://downloads.lumberg.com/datenblae ... /klbm3.pdf
The width is also critical here. Well I think I will never use an expression pedal but it woul dbe nice to have it complete.
No priority for the jack.

tuck · Post by **tuck** » 20 Jan 2023, 19:29

tuck wrote: ↑12 Dec 2022, 23:28 Thonk uses the dots as model marking
Two yellow dots = RoHS compliant VTL5C3
https://www.thonk.co.uk/wp-content/uplo ... 3-RoHs.pdf

I ordered a 5C3 and received one with no dot/dots so either I received a Xvive5C3-2 Non RoHs compliant or the 5C1 but either way it's already soldered in.
https://www.thonk.co.uk/wp-content/uplo ... 20RoHs.pdf

According to the manual the compressor is based on the Kongpressor viewtopic.php?t=30805
Does anyone have an idea of how to modify the compressor to squash the sound a bit more?

karter2000 · Post by **karter2000** » 20 Jan 2023, 20:33

bajaman wrote: ↑22 Dec 2022, 00:34 Ok Tuck
Thanks for those corrections
here are hopefully the final schematic and sprint layout pcb gerber filesBass Butler final sprint layout corrected gerber files and kicad schematic.zip
cheers
bajaman

Are these gerbers the final version?

bajaman · Post by **bajaman** » 20 Jan 2023, 20:50

hello karter2000 - yes

tuck · Post by **tuck** » 22 Jan 2023, 20:22

I tried to add a PedalPCB charge pump to the Rockerverb part to get a distortion pedal.
Does this look ok or is it flawed ?

rockerverb.pdf: (68.24 KiB) Downloaded 56 times

tuck · Post by **tuck** » 23 Jan 2023, 21:01

So many questions....

What would be the best practice for the biasing of the rockerverb part?
Replacing R5 with a trim pot and keep R6 fixed or vice versa?

: bias.PNG (8.05 KiB) Viewed 943 times

Is this a usefull approach?

The source trimmer sets the bias current through the JFET, the drain trimmer sets the slope of the load line. Two very different things. If the goal is to produce repeatable results, you want to have the source trimmer in order to fix the big variations of JFETs. The drain trimmer then sets the gain and sound of the amplifier.
Of course they are interactive, but in a properly designed amplifier, one would first choose a bias current and then determine the load line. So a fixed resistor would be used for the drain, and a source trimmer to get the current right.
Just biasing any JFET to a certain drain voltage, which is done with a drain trimmer alone, would result in different amplifiers for each different JFET due to the parts variations. It's unfortunate that so many circuits in the effects world chose this approach and it became the standard way to do it.

bajaman · Post by **bajaman** » 24 Jan 2023, 04:51

Hi Tuck
Just choose the best J201 you have (the ones that bias up closest to 10v dc) and adjust the drain trim pot (100k)(R5) - ok, in theory this alters the gain, but with 4 cascaded stages there will always be more than enough to give you some nice jfet crunch
cheers
bajaman

Tassieviking · Post by **Tassieviking** » 24 Jan 2023, 15:17

There are this style of socket, they are 15.8mm x 15.8mm squarish, but fairly long.
I have used them on a build but I cut half the solder pads of.
I got cheap ones from Tayda, but there are better ones around.

https://www.taydaelectronics.com/hardwa ... -jack.html

Would you be willing to share your KiCad files for your board?
That is one impressive layout on that PCB of yours.

tuck · Post by **tuck** » 25 Jan 2023, 09:33

Edit: symbol and footprint libs now in archive

This is so bad. I corrected some footprints e.g. the bi polar caps and transistors.
Then installed a nightly build of a Kicad 7 release candidate and converted the files.
After that I had to correct the connections to the transistors.
A design rule check gave me so many errors.... I already ignored all the warnings for the printing on the silkscreen but there are so many more...
I can no longer guarantee my verification as there is no backup of the Kicad 6 project files.

bassbutler_bajaman_small_res.7z: (450.41 KiB) Downloaded 46 times

Offboard wiring is not exactly like it is in the schematic. The LED is mostly directly soldered to the switch, only red is connected to the board as it is triggered by the compressor.

I don't dare to swap the drain resistors for trim pots for this pcb and I also did not change the footprint for the ceramic caps they are still polyester film caps.

tuck · Post by **tuck** » 03 Feb 2023, 13:02

MIsison accomplished

Tassieviking · Post by **Tassieviking** » 04 Feb 2023, 15:28

Tuck, have you thought of looking in the KiCad Backup files ?
Every time I use KiCad it keeps backing up my files and storing them in .zip format.
Look in the folder that your BassButler KiCad files are stored and you might have a backup of the old files.

I would love to build this one for myself, but it will take me a long time to do the layout in KiCad.
I can not open your files because I only use the last stable release of KiCad (6.0.11)
I am not brave enough to use the unstable daily releases like you do.

I am wondering if you might be able to measure the current used by this circuit at the 18v supply for me ?
Is it 18v that the power supply puts out to the BassButler ? The voltage at the input is not marked.
I want to know if I can boost 9v up to 18v with an LT1054 IC and run this one ok.
Otherwise I guess an old laptop power supply would work.
Last week I stuck a 100watt TPA3116 D2 mono amp module into a 125B box and I'm running it on a Dell 19.5v power supply.

Thanks

Tassieviking · Post by **Tassieviking** » 04 Feb 2023, 15:36

Tuck, I just thought of a small mod that might be ok on this one.
The Expression pedals I have seen are usually a 10k to 50k pot inside a variable foot pedal.
I have seen people make a pedal with 2 pots in it and a stomp switch to switch between the pots.
It just means that they have 2 fixed settings instead of one variable setting.
It would be easy to install 2 pots in the BassButler and a stomp switch to switch between them.
And you could over-ride them if you plugged an expression pedal in the back

tuck · Post by **tuck** » 04 Feb 2023, 22:28

Unfortunately there was no backup folder. I really don’t know why this happened because all the other projects have one. Maybe it’s because of the conversion?
Just install the latest nightly build. Nothing wrong with running two versions in parallel.
You need to run it with 18V. The iriginal unit comes with a 18V power supply. I did not try to run it with 9V maybe I can try it tomorrow.
I used a 9V power bank and a charge pump as you can see in the pictures a few posts before.

Nice Mod

bajaman · Post by **bajaman** » 04 Feb 2023, 23:06

I downloaded the zip file - opened Kicad beta version 7 and saved the project's gerber files.
Then I opened my trusty favourite Sprint layout V6.0 and imported the saved gerbers and drill data - i had to do a little editing but eventually came up with this - i manually tidied up the track routing and added part values - here are some pictures of the front and back of the board
cheers bajaman

tuck · Post by **tuck** » 05 Feb 2023, 00:11

The 16V for 1000u makes sense. I think I used the unnecessary larger 25V version.

Orange Bass Butler [schematic]