Orange Bass Butler  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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bajaman
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Post by bajaman »

What did you use for your front panel label Tuck ?
It looks real nice
cheers bajaman
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tuck
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Post by tuck »

Thanks for the kind words!
Inkscape - the best. My last printer died a few years ago so I use a laser service for this.
I export the pcb (with enclosure footprint) with pots to a pdf, then import it to inkscape to have the proper scaling.

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Post by bajaman »

Hi Tuck
Okay - I do the same with my pcb layouts to CorelDraw
So the actual print was done with a commercial laser printed direct to enclosure service ? How much did that cost for a one off, if you don't mind me asking ?
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tuck
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Post by tuck »

Two german based sellers:
https://www.tube-town.net/ttstore/custo ... ndard.html
For the large face plates I use 150x300mm for 17,50€. If I select New Zealand if that's your location it's 21€ + 51€ Shipping..... :-(
https://tweakable-parts.com/en/home/804 ... rator.html
They both have a few different colors but basically use the same material. Expensive for one pedal but I put as much face plates on the panel as possible.
The only downside is that I have a lot of pedals with the same color. Selling is also an option but I only did it once.
I think the tayda printing service is a better option to have the enclosure printed and drilled in one go.

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tuck
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Post by tuck »

Ok to answer correctly it’s not printed it’s laser engraved. I should read the posts more carefully ;-)

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Post by Tassieviking »

I have made some front panels from a PCB.
I always get my PCB's from JLCPCB so I always end up with 5, so I order 5 front panels as well.
I have made some footprints up in KiCad just for front panels, I label them as Through Hole footprints.
I find it really easy for stomp boxes as I change the original PCB into the front fascia PCB to keep all the pots and switches in the right place.
My pots and switches footprints use the shaft as center of the footprint.
For stomp boxes you have to remember to make the PCB 1mm thick.
I have made one for my Sunn Beta stomp box as well but I don't have a photo yet, front of PCB Lead, back of PCB Bass
If you keep the spacing uniform on 2 different designs you could make one fascia and have a different design on the front and the back.
Here is one I made for a small amp I am making,
Attachments
Marshall 12watt Faceplate PCB.jpg

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Post by Tassieviking »

I just downloaded KiCad 7 released yesterday and I can now see your files perfectly, thanks for sharing Tuck and Bajaman
:D :D :applause: :applause: :D :D

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Post by Tassieviking »

If anyone wants to make some front or rear PCB panels in KiCad here are some of the footprints I made up for that purpose.
Look for the MountingHole_Pot footprints, they might give you some ideas, or just use mine.
I have only made a few like this but it works for me, I don't know how durable they will be but I am going to try varnishing some.

Here is a pic of some 1590BB boxes I'm working on, the blue Chunk Systems one I have had for years and is scratched.
Notice on the Sunn Beta the same faceplate has Bass on one side and Lead on the other so I use them for either one.

Vasily Kashirin has made some really great 3D pictures of some parts that I use all the time, you can find them at GrabCad.
Alpha pots, Stomp switches, even the socket I mentioned in an earlier post, look them up.
https://grabcad.com/vasily.kashirin-1/models?page=1

Cheers
Mick
Attachments
WP_20230213_19_38_43_Pro[1].jpg
Micks Footprints.zip
(188.92 KiB) Downloaded 74 times

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Post by bajaman »

Hi folks
I edited Tuck's Kicad pcb layout - imported his gerber and drill files into Sprint Layout V6.0 and made the traces a little wider and generally tidied up the distance between tracks and pads - still essentially the same - I sent the gerbers off to the fab house and have a few spare boards (as the pictures show) .
If anyone wants one, send me an email: baja002steve@gmail.com with your name and postal address details please.
Price is US$10 and includes airmail postage Worldwide.
cheers
bajaman
bajaman edited Tuck pcb front.JPG
bajaman edited Tuck pcb back.JPG
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Post by Tassieviking »

Those PCB's look great BajaMan, if I wasn't going to try to make my own layout to fit into a 1590XX box with 2 foot switches I would buy some right away.
I want to add 2 pots to my layout that acts as expression pedals switchable by a foot switch, when an expression pedal is not plugged in the signal goes through one of the pots.
It should give me 2 different levels of dirt signal, switchable by the foot switch.
I have no idea why I want to do this, my daughter has the Bass guitar, not me.

Are you going to use TO-92 J201's, or are you going to try another type of NFET ?
I would prefer through hole myself but I have none.

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tuck
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Post by tuck »

Bajaman that's awesome!
The only real downside of my 1590XX PCB is that the pots are to far in the middle so I have to be carefull when stepping on the footwsitch.
Otherwise I would not be able to put the jacks on the top side... Feels like a horizontal B enclosure :-)
The other issue I found is that the expression pads are to far away. putting them near to each other would be a clean jumper solution in case that the expression function is not used.

I have to verify the standalone Rockerverb section but will probably not be able to finish it in the next weeks:
IMG_6500.jpg
Also a BB version of the Bass Butler without the DI section. Faceplate finished but not PCB or parts yet.
I wonder if it makes sense when I have the big box :hmmm:

Is there an ethic about printing the trace helpers names on a pcb? I'm a selfish guys...

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Post by mediy »

Hi Tuck, which charge pump did you use to power the prototype? I am tempted to try and build a charge pump into the box and run the whole lot off a daisy chain from my tuner when I don't feel like taking a full pedal board. Did the power from the charge pump manage to stay at 18V or does it sag a little?

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Post by tuck »

Hi Mediy,
LT1054 output of 18,23V goes down to 16,5V when powering the pedal.

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Post by mediy »

Cool, that's about what I expected. If it still works OK at that voltage though it might be a good option rather than splashing out on a decent 18V supply

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Post by Tassieviking »

I have some old laptop computers that have a 19v power supply, there are plenty of old power supplies for laptops that run on nearly 18v and they are usually good quality.
Just change the plug and off you go.

I stuck a TPA3116D2 mono amplifier module in a 125B box for a cheap pedal board amp, powered by an old Dell power supply that puts out 19.5v.
That little amp can go up to 100watts with a power supply at 26v, but it will work with as little as 4.5v.
I run it with my Sunn Beta pre-amp stomp box I made.
I have to finish some of the Bajaman pre-amps I started a while ago and try them with the little TPA3116D2 amp.

If I ever make myself a Bass Butler I could run that and the amp on the same 19.5v power supply.

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Post by CodeMonk »

Looks interesting.

I really miss this place.
Life (family issues, elderly mother, and other crap) has kind occupied much of my time lately.

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Post by bajaman »

Here is some hopefully helpful advice to those using J201 njfets
As i mentioned previously in this thread, it is usual practice to bias the jfet similar to the triode vacuum tube - bias to approximately 2/3 of the supply voltage. So if you are using an 18 volt supply rail you would ideally adjust the drain resistor to give a reading of 12 volts at the drain terminal of the jfet. Similarly with a vacuum tube running off 300volts you would ideally adjust the plate resistor (or cathode resistor) to enable a reading of 200 volts at the plate terminal. I am not going to go into the reason for biasing at 2/3 here - that is a subject for another post ;-)

Okay, now for the bad news and the good news - unless you purchase NOS Fairchild J201 jfets for a King's ransom you are unlikely to get genuine J201s, especially if you order them from Aliexpress ! I recently purchased 50 from IC chip quality+++ Store and they all tested as pnp transistors - NOT EVEN JFETs !!!
Before we go any further it is worth mentioning that you purchase one of these testers though - I have had a TC 1 model for a few years now and it is a very useful device to have

https://www.aliexpress.com/item/1005004 ... 1111504860

And now for the good news:
If like me, you have purchased J201 jfets from Aliexpress and actually received jfets then with the TC 1 tester you can examine their working drain current (I don't fully understand how this corresponds with their idss or vgs cut off specs but at least the tester will give you a figure to work with) I do have some GENUINE Fairchild J201 jfets (shiny black plastic unlike the satin finish counterfeits) and i was able to compare them to the Chinese ones. The Fairchild jfets I had ranged between 0.13mA and 0.37mA, whereas the Chinese ones ranged between .79mA and 1.2mA - quite a different device ! ;-)

So, I built a single stage Jfet amplifier section on a piece of stripboard using a three pin socket for the jfet, a 100k preset pot for a drain resistor, a 2k7 source resistor, a 680n source bypass capacitor, a 100k gate to ground input resistor and a 2n2 output capacitor connected to a 240k to ground resistor - this is essentially the same as a single stage used in the bass butler overdrive section.
Setting the preset to 43k and running the preamp from two connected 9v batteries for 18 volts, I inserted a few of the Chinese J201 jfets and measured the voltage at the drain terminal - no surprises here - approximately a spread of 2.3 to 4 volts - way to low to be useful, so i adjusted the trim pot until I obtained 12 volts on the drain terminal (the scope signal came up in level and looked a LOT better - more like that lovely 2nd harmonic distortion on the top of the waveform as it should be, instead of the gate source nasty cutoff seen with the badly biased jfet)
I tested a few of the GENUINE Fairchild J201s and not surprisingly they biased up much closer to the required 12 volts at the drain terminal with the trimpot set to 43k (they measured 11.5v to 15.66v)

Okay - hopefully you are still reading this - how do we use these fake J201s in this circuit ? Answer: we adjust the trimpot ! it is that easy ! I found a drain resistance between 12k and 19.5k worked well for me ! So if you have a TC 1 tester, a drain current reading of 0.78mA requires 19.5k and a reading of 1.1mA requires 13.9k ( a value of 14k to 20k)
But if i lower the drain resistor value, won't i get less voltage gain from this stage ? In theory - yes, but in practice with four cascading gain stages you would be very hard pressed to notice any loss of distortion, but you will hear a much sweeter tone.

In conclusion: If you don't own a tester or multimeter to measure the voltage at the drain, just use 18k resistors instead of 43k, or if you have a multimeter, use 50k trim pots and adjust them until you read 12v on the drain terminals

Hope this helps you get good tone ;-)

cheers
bajaman
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Post by mediy »

The other option (which I will probably go for) is to use the SMT version and an adapter PCB. I have 3 spares but will need to get a few more. I am pretty sure I have a few old VTL5C3 out in the shed as well. If not I can definitely rustle up an NSL32 of some description and try that out

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Post by tuck »

Tassieviking, I got 50% off at this one but didn't check it so far
https://www.az-delivery.de/en/products/ ... er-platine
Then noticed that this would fit inside the Butler.......
https://www.berrybase.de/en/tpa3116d2-c ... erkeregler
But I think a power amp in a seperate box is more usefull :-)

Bajaman, that is a nice experiment. I will definitely try the fake J201 with a trim pot when I build the rockerverb section in a small pedal.
Regarding the tester there is a good read from the two inventors of the original tester
https://github.com/Mikrocontroller-net/ ... tester.pdf
I own a T4 and all of the cheap chinese testers are more or less clones of the avr tester from the guys mentioned here (many languages)
https://www.mikrocontroller.net/article ... stortester

Regarding hte JFET testing the manual states the following:
next keypress before showing the current amplification factor. With cooling the cutoff current can
be reduced significant for Germanium transistors.
3.7 Measurement of JFET and D-MOS transistors
Because the structure of JFET type is symmetrical, the Source and Drain of this transistores can
not be differed. Normally one of the parameter of this transistor is the current of the transistor
with the Gate at the same level as Source. This current is often higher than the current, which can
be reached with the measurement circuit of the TransistorTester with the 680Ω resistor. For this
reason the 680Ω resistor is connected to the Source. Thus the Gate get with the growing of current a
negative bias voltage. The Tester reports the Source current of this circuit and additionally the bias
voltage of the Gate. So various models can be differed. The D-MOS transistors (depletion type) are
measured with the same methode.
There was a discussion in another forum because the T1 usually show the correct pins for the JFET but the T1 display shows a schematic with the pins like my T4 but not the additional pin "discovery" (?) like my T4.
IMG_5915.JPG
IMG_5915.JPG (102.21 KiB) Viewed 238560 times
Other than that the transistor tester is one of the most useful tools in my drawer. For quick measurements of resistors and caps etc I don't power up my DMM.

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Post by bajaman »

Hello Tuck
Thanks for that information - I did not know of the T4 existence and unlike my TC1, it displays the idss of the jfet which is a much better piece of information ! - I have just ordered one from China ;-)
cheers
bajaman
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