Small Good Distortion in 1590A box

[thomasha]

Ok... I probably made a mistake there, the layout was 10x18...


In the first stage shouldn't it be 100k and 330k? You can reduce this 100k resistor to see how much gain you can get from it.

[JackSkellington]

Thanks for the layout of the Rat.

In the first stage shouldn't it be 100k and 330k? You can reduce this 100k resistor to see how much gain you can get from it.

Do you mean in the Rust Driver, right? The fact is there are two version, 100k and 330k are in the one I guess should be the first version without tone switch.
In the version that includes the tone switch we can find a 10k in front of the inverting-input of the opamp that I guess add gain and let pass more high, while the 33k is on the feedback loop, that I guess gives low gain (and there's even a 22pF caps to tame a bit og highs). Also the second let passes further highs, and maybe a stronger signal, reaplacing the 22k in the output with a 10k.
This is what I got by myself, I could make same little mistake, but this should be how those circuits work.

This is the emulation of v.1, v.2 and the Juansolo version I got with the software I use:



The three version are in "Bright" mode.
The v.1 seems to have less output and more low end.
The Juansolo version though the input and output cap are increased, looking at the v.2, should be just a slightly boost of the lowest end, but it's very similar to the v.2, and of course with more output, seeing the LEDs clipping. Rather, it seems have a mid-low a bit scooped. Of course the LEDs will have a different voice to the pedal, too.

[Willybomb]

Don't forget to try the Superjudge, with is based off the Hao Rustdriver but with tone and drive controls...

[JackSkellington]

Ok, I took a look to the Superjudge, too. A tweaked Rust Driver with tone and drive controls, and a doubler voltage. Just to have an idea about it, but I don't need it now.

[JackSkellington]

I built few days ago a board of a Protone Body Rot II (because I liked the idea). It's a clone of the Krank Maximus Distortus with some difference. Ii sounds heavy, gritty and raw. Probably I'll make some adjustment, it sounds a bit too much shrill.
(Looking at the Krank schematic the Body Rot II has a smaller coupling cap that cut a bit of bass, and a cap added that increase further "presence" frequencies, how if it needs!)

Anyway, the Smash Drive is a bit like the Krank/Body Rot II, but without the NPN booster/buffer in front. Change a bit the way to control the gain amount. I could work on it.

[vasilis]

- Acapulco Gold
I didn't want LM386 based distortion pedal, indeed this has two! But it sounds good. Maybe a bit peculiar distortion, I hope that the layout I can found it's not too much large.

I've built one. I bought the PCB from Coda Effects and it was pretty easy to built. I only had one problem with that. This pedal is stupidly loud. I have a 10Watt mini amp and even with the volume at 2, I could not play with it in my apartment. I finally got the time to mod it to lower the output. I changed an output resistor from 22-something-K to 1M and lowered the output cap to compensate to the tonal differences. Apart from all that, I added an additional pot for volume because the already existing one was not making that much of a difference.

If you ever built it I'd like to hear your mods (if you do any).

Happy pedal making!

[JackSkellington]

I know the Acapuclo Gold is loud, is the another reason I wasn't so sure about it. Even if I think it sounds really good into a gain channel, probably. I assume there it should be less loud, but... We have to pay very attention to not disengage the gain channel before disengage the pedal! Else: Boom!

Thanks for sharing your mod.
I thought the 1M in the output is a very high, so, did you noticed less treble? Do you remember the value of the new output cap?
And I don't understand how you added an additional volume pot? A Pre-Gain how some mods I see?

[junkemail86]

How about a DAM Sonic Titan?
It's a nice medium/high gain Marshally sounding circuit
http://tagboardeffects.blogspot.com/2012/01/dam-sonic-titan.html

[JackSkellington]

Thanks. It's an alternative. I prefer just two pot (Gain and Volume) becuase the room inside and outside. The DAM Sonic Titan is always about the same LM386 based circuit, this has a JFET preamp in front. I find easier a BJT preamp.
I'll try anyway the Smash Drive first, just because it's more simple.

[vasilis]

Thanks for sharing your mod.
I thought the 1M in the output is a very high, so, did you noticed less treble? Do you remember the value of the ew output cap?
And I don't understand how you added an additional volume pot? A Pre-Gain how some mods I see?

At first it was pretty muddy. But then I finally used one of the equations I learned in highschool I thought I would never use:
F(cutout)=1/(2πRC)
I put the original values and then I replaced the resistor value and solved for the new capacitance.
(I don't remember what exactly I changed but I'll search and post them bellow)
So now the output is lower but it has the same frequency response as the stock.

About the additional pot you asked.
It's kind of stupid but I was in a hurry for a rehearsal that day and I just installed an new A1M pot after the original. Kinda worked for the rehearsal and didn't give it more thought after that.

After I replied to your post I went back and checked again the schematic - because even thought modded it I'm still not 100% pleased with how I interact with it - and found out that in the PCB I bought for some reason the pot was not connected to ground although it is in the schematic. So even if I was settings the pot to 0 the volume was still pretty loud. So I guess if I connect that to ground it will work better and I'll get rid of the additional pot.

Hope I helped anyway!

[vasilis]

This is a pic of the output stage of the schematic I used.
I replaced the C5 and R3 to 20 nF and 1M respectively.

[JackSkellington]

Thanks!
I expect a muddy sound with a 1M in the output, indeed. But my software said no. If I will build it I will make some experiment.

[vasilis]

Thanks!
I expect a muddy sound with a 1M in the output, indeed. But my software said no. If I will build it I will make some experiment.

Kinda late response but, what software do you use?

[JackSkellington]

I use Tina TI. I learnt to use it in a few of days.
Sometime it is very useful to make some test before to try the real board. Though in certain circuit, especially fuzz, I got weird responses of the frequencies.

[JackSkellington]

It's been a while, but something moves, or a sort of.
I still doesn't try or breadboard the Smash Drive, that it's still in pole position as distortion.
Meanwhile, I built the SHO with gain and volume control in a 1590A box, my first serious 1590A type box. I doesn't have built the IC buffer yet, though it doesn't have pots nor footswitch I had some difficult to get enough room for the PCB, beacuse I'm a bit maniac.
The stripboard is narrow but a bit longer, the electrolytics caps are tall, I decided to place the jacks not to much down but almost in the middle of the side the DC jack and the LED bezel occupy a bit of space placed in the middle up half of the box. But I'll do it, problably I'll use a 3mm jack with a tiny plastic frame LED bezel, and it should be ok.

Just a details, I bought the 9mm pots from two differents shop to find the right value. Both had a little bump, I don't know how I can call it, but you know, even the 16mm potentiometer had it, we break it to fit it into the box. Just the one on these 9mm is enough tall to make the pots crooked but too much short to break it. This time I menage try to dig a cavity (not a hole) on the inner side of the box and trying to gride with a 240 grit sandpaper. I just struggle a bit.
Is there some better way to do that?

Thanks!