Hi everyone,
what with the state of the world and all, I started revisiting the music of my youth. Particularly Nasum, Krigshot, Skitsystem, Victims, and the like, and I realized that I had no appropriate guitar sound for that sort of thing. I just bought my first guitar a month ago or so, so there was never a need for it. I particularly like the guitar sound of the late great Mieszko Talarczyk on Nasum's 1998 album Inhale/Exhale. While he apparently did not use a Boss HM-2 but a DS-1 into a Fender Dual Showman Reverb into a Marshall 4x12, it sounds pretty dang close to the classic Swedish Chainsaw sound of the HM-2. Entombed"s Left Hand Path would be the reference implementation for the HM-2, if you want to have something to compare to. So I took a look at the HM-2 and decided that that kind of sound can be achieved with a much simpler device. In the end, all you need is a bit of crossover distortion, a metric ('cause Sweden :icon_lol:) $#!+ton of clipping and some deliberately drastic tone shaping. Since I always liked the sound of opamp clipping for high-gain sounds, I went with that instead of diode clipping. The end result of my experiments does not sound exactly like an HM-2, nor is it meant to. It's a different flavor but for the same kind of music/guitarist. It's tailored to my taste but can easily be modded to suit other tastes. It does not have tone controls because it is only meant to have one sound. You wouldn't dial back the Bass or Treble on an HM-2 either, would you?
So enough blah blah, here is Minisågverket:
(https://i.postimg.cc/Z0PnsBp1/Minisagverket.png) (https://postimg.cc/Z0PnsBp1)
The layout is unverified at this point. If anyone builds this and can verify or correct the schematic, I shall be most grateful. The Gothic font, if someone is interested, is called Gotenburg (yes, "Gotenburg" not "Gothenburg") and can be obtained for free here: https://www.1001fonts.com/gotenburg-font.html
"Chug" is technically a gain control but only really sounds like a gain control before about 9 o'clock. After that everything is just extremely distorted and you can't tell anymore if it gets more distorted. After 9 o'clock, the most noticeable effect it has is increasing the bass, so palm muted chords get fatter and, at some point, fuzzy. What setting gets you the appropriate metal distortion depends strongly on the pickups. Chug on full gets you there with a low power bridge single coil; for anything else, backing of a little may be wise. So the Chug control is mostly there to adjust the pedal to your pickups, not to have different sounds. You might want to use a trim pot instead of a normal pot. Therefore the Layout is such that you can use an in-line trim pot here.
"But Andy", I hear some of you cry, "you forgot the switching circuit!" No. No I didn't. This thing is for music where you NEVER turn the distortion of and it goes straight between guitar and a very(!) loud, clean amp with no other shenanigans. If you think your music needs more than one guitar sound, this is not for you. Ok, ok, I'm being overly dramatic. You can add a switch if you want but I'll have nothing to do with it.
Some haphazardly recorded sound samples:
https://www.aronnelson.com/DIYFiles/up/MinisagverketDemo.mp3
Not a guitar player -> Yamaha Pacifica 311 -> Minisågverket -> Focusrite Scarlett 2i4 -> Audacity. No post-recording modifications of any kind. First Riff: bridge humbucker, Chug at 10 o'clock. Second: neck P90, Chug at 10 o'clock. Third: bridge humbucker, Chug full. Fourth: bot pickups, Chug full. The fadeout at the end of each is done with the Volume pot on the guitar. It may be worth noting that the bridge humbucker has a very low output, much less than the P90, noticeably less than a PAF. I will replace it with a Dimarzio Super Distortion at some point, which would probably sound much more appropriate for this demo. Maybe I'll do another one then. Unless someone beats me to it, which I would not be opposed to at all.
As always: Please tell me if you find errors and have fun with this thing. Let me know if you need help modding it to your personal needs and tastes.
Yours,
Andy
It sounds good - with crossover distortion, the distortion increases as the signal gets smaller so you always notice it.
Interesting. I like crossover distortion with bridge pickups. And since the sound relies heavily on asking more gain of the op-amps than they can manage, I'll suggest using 1458s as a way of warming the tone. Basically, anything with a poor gain-bandwidth product should be good-sounding.
I'd agree with Mark. The 1458 is basically a pair of 741's which if you must do it, is one of the best sounding clipping opamps, but you have to bear the noise which can be too much in the decay. The crossover diodes mitigate the first stage noise by gating it out. This could be a case where designing with single amp packages is a good idea to get maximum flexibility.
Hi Mark, hi Jim,
interestingly, the choice of opamp seems to have very little impact on the sound for this one. I started designing with an NJM2068 because I really like its clipping sound. When the whole thing was done, I swapped it for an NE5532, a TL072, a TLC2262, and an NJM 4556, thinking I would get noticeably different sounds. But TBH, I don't think I could tell the chips apart in a blind test, which is rater remarkable because normally an overdriven TLC2262 sounds nice and fat, almost tube-like, whereas a TL072 sounds like nails on a chalk board, and the BJT types are somewhere in between. But not here. I guess the intense pre- and post-clipping frequency shaping just kills most of the differences. Nevertheless, people should try out different opamps and see if they can spot the difference. My ears just aren't golden enough.
Cheers,
Andy
Quote from: Fancy Lime on August 17, 2019, 02:41:45 PM
You can add a switch if you want but I'll have nothing to do with it.
Lol, love it.
I suspect the TL072 sounds ok in this because its inputs don't look like they can be pulled outside their operating range, even when the outputs clip. You have included a divider going into the second stage plus the diode drops so it's +in won't get the full swing from the first stage clipping.
I see the low pass filtering makes op-amp speed almost irrelevant!
woah, nice
that sound great!!
funny that i also build a grindcore/deathmetal/crustpunk pedal recently, with almost the same line of reasoning, also incorporating crossover distortion.
although mine has less gain on tap (the gain before the crossover distortion is fixed) and has active tone shaping to sound closer to the chainsaw sound (28dB of boost around 1kHz, thats 9dB more than the HM2 has!!!).
i think building your Minisågverket would be a nice project to add to my grindcore pedalboard!!
Quote from: iainpunk on August 21, 2019, 12:23:37 PM
woah, nice
that sound great!!
funny that i also build a grindcore/deathmetal/crustpunk pedal recently, with almost the same line of reasoning, also incorporating crossover distortion.
although mine has less gain on tap (the gain before the crossover distortion is fixed) and has active tone shaping to sound closer to the chainsaw sound (28dB of boost around 1kHz, thats 9dB more than the HM2 has!!!).
i think building your Minisågverket would be a nice project to add to my grindcore pedalboard!!
Thanks!
Yeah, it's definitely more for grindcore, crust and similarly raw styles than for "modern" metal, which always sounds too nice and polished to my ears. Developing this thing was a ton of fun. I am already thinking about the next high gain distortion. This time with a 3-band tone stack. As in "what if the Metal Zone had better tone shaping and controls with less absurd ranges?" We'll see how that goes.
When building Minisågverket keep in mind though that the layout is unverified. I did trace the schematic back from the layout and got the same schematic that I started with, but one is often blind to ones own mistakes. So checking before building is advised. Also: it would be super awesome if you could post a verification (or correction, if necessary) here, once you've built it.
Cheers,
Andy
Quote from: Fancy Lime on August 21, 2019, 01:22:50 PM
Quote from: iainpunk on August 21, 2019, 12:23:37 PM
woah, nice
that sound great!!
funny that i also build a grindcore/deathmetal/crustpunk pedal recently, with almost the same line of reasoning, also incorporating crossover distortion.
although mine has less gain on tap (the gain before the crossover distortion is fixed) and has active tone shaping to sound closer to the chainsaw sound (28dB of boost around 1kHz, thats 9dB more than the HM2 has!!!).
i think building your Minisågverket would be a nice project to add to my grindcore pedalboard!!
Thanks!
Yeah, it's definitely more for grindcore, crust and similarly raw styles than for "modern" metal, which always sounds too nice and polished to my ears. Developing this thing was a ton of fun. I am already thinking about the next high gain distortion. This time with a 3-band tone stack. As in "what if the Metal Zone had better tone shaping and controls with less absurd ranges?" We'll see how that goes.
When building Minisågverket keep in mind though that the layout is unverified. I did trace the schematic back from the layout and got the same schematic that I started with, but one is often blind to ones own mistakes. So checking before building is advised. Also: it would be super awesome if you could post a verification (or correction, if necessary) here, once you've built it.
Cheers,
Andy
unholy shit, thats the same feeling i have about modern metal!
it starts to be creepy right now, both building a heavy distortion pedal at the same time, with the same line of reasoning, both utilizing crossover distortion, both of us think that most modern metal sounds to processed and polished... hmmmm...
yeah, im probably building it next week, or maybe i can start on it tomorrow, if i don´t get any big assignments at work. I do still have a left over enclosure but no jacks and no 100k log pots. i think ill opt for a 250k log pot for the volume. i am going breadboard it tonight though.
ill definitely prioritize it over my fuzz with shitty overkill eq project.
It sounds good to me too. Nice solid chug and softened top fuzz. I think it sounds a lot nicer than any motorsåg I've heard.
Quote from: anotherjim on August 21, 2019, 03:56:33 PM
It sounds good to me too. Nice solid chug and softened top fuzz. I think it sounds a lot nicer than any motorsåg I've heard.
Thanks, man! I would really like to hear it in front of an amp with a cab, though. Maybe someday... In the meantime I'm working on that cab sim.
Andy
BTW, I was thinking about alternative names for metal pedals. i remembered a thread we had some time ago and typed "The Swedish chainsaw" into www.talktotransformer.com
Here is the glorious result:
"The Swedish chainsaw was fitted with four blades, each with eight cutters. Each cutter was fitted with a screw which could be tightened to tighten a cut. A large rotating blade could be turned on or off and the saw was made so that the blade could be adjusted in the same way as to achieve desired blade spin and cut. The size of the blades was determined as the blade thickness could not be specified using current computer modelling techniques because of the size of the blades. In the 1970s Swedish companies developed machines which could make these blade sizes and use them as template designations. The most commonly known model name for a scalawr saw is the Ettan-Döpfner (SV-Döpf-en-D). This was sold under several names until it changed to the new model number 4500 in 1976.
"The scalawr saw was an important tool for scalawr cutting, but in the past year or two it has been replaced by the high-speed saw (HSW). Although most of the scalawr models are still available, there are also several other models, including the Ettan Döpfner 3, a two-blade model of similar features as the SV-Döpf-en-D but the new saw appears to have been introduced earlier. In 1994, a machine capable of cutting through"
So my next high gain pedal is definitely going to be called the Ettan-Döpfner and will feature a "scalawr" control, whatever that is. Something to do with cutting, I suppose.
Cheers,
Andy
What gets me is the tremendous lengths people will go to to avoid crossover distortion in hi fi amplifiers because with a lot of program material it sounds horrible but it is a great sound for heavy metal guitar. It tends to act as its own noise gate so when the note fades away on the guitar, it seems to stop more abruptly with crossover distortion. I keep having to rethink a lot of ideas that are firmly entrenched in the hi fi world.
Quote from: amptramp on August 22, 2019, 10:32:48 AM
What gets me is the tremendous lengths people will go to to avoid crossover distortion in hi fi amplifiers because with a lot of program material it sounds horrible but it is a great sound for heavy metal guitar. It tends to act as its own noise gate so when the note fades away on the guitar, it seems to stop more abruptly with crossover distortion. I keep having to rethink a lot of ideas that are firmly entrenched in the hi fi world.
Not just Metal distortion. I find crossover distortion sounds great with almost any overdrive or distortion that is "seriously distorted", meaning not straddling the brink of distortion. I have done this with back-to-back BAT41 Schottky diodes in Tube Screamer type overdrives and it's great. It adds more apparent drive while leaving more of the dynamics intact. I have never tried Ge diodes but would imagine them to be interesting ass well due to the (often) softer knee. The noise gate effect is definitely a bonus. Having a cap to ground after the diode pair (like C7 in the schematic of the first post here) makes the noise gate much more effective for hiss frequencies. Right choice of value is a bit of trial and error, though. Should be large enough to kill as much noise as possible when the diodes are closed but small enough not to cut too much treble when the diodes are open. Depends on the diodes, obviously. Easier wit low-leakage diodes. I am amazed this is not done more often. Even more amazed that there are tons of really noisy high gain pedals out there for no good reason.
Andy
I am giving this thread some CPR and resuscitating it!
Was finishing up some old pedals, and I came across a printout of your layout and schematic. So, naturally, I decided to give this pedal a shot.
Started with the breadboard. Kind of funny, because I added an LED to it to see when it was on. I guess your comment on the stompswitch and how this pedal is NEVER off was correct, because I had issues, and it was caused by the CLR leg touching the leg or R9! LOL! Anyway, corrected it, and I liked the sound, so I decided to build one. Seeing as no-one has verified the layout, I am giving it a shot. Board is populated, by the way, but still need to connects pots and jacks (and stompswitch... yeah, yeah, I know...). Will report back when finished building.
I drew up a layout and posted it about half a year ago because it was almost impossible for me to make out the layout on the original schematic:
http://guitar-fx-layouts.42897.x6.nabble.com/Minis-gverket-A-simple-metal-distortion-project-td47957.html
The layouts have been corrected and verified.
I'm uploading it here as well.
(https://i.postimg.cc/Jt0nmky4/Minis-gverket-Layout-V1-4.png) (https://postimg.cc/Jt0nmky4)
RE: changing the opamps.
I've increasingly come to take the view that, in some instances, what we are hearing is the sound of an op-amp that has simply run out of headroom, subsequently getting re-clipped with diodes. Given that the "Chug" control can theoretically increase gain by as much as 1000x, even very modest settings of the control exceed the headroom of the op-amp used, when powered with 9VDC. So, while a superficial glance would suggest that "all" it does is crossover distortion, in fact the crossover distortion from the 1N4007 pair is simply supplementing the hard clipping produced as higher gain settings run the signal smack up against the ceiling on voltage swing.
All of which would suggest that, yes, in an application like this, varying the op-amp type can make an audible difference.
Finished the board, but I have issues (I do not think it is the layout).
First time around, no sound even in bypass. Corrected that. Then no sound when engaged (a resistor leg again rubbing, this time with a diode); fixed that. Then sound was going through, but it sound was way off (lots of interference). Thought it was a bad solder or something, so I went through the board once again with the soldering iron; now I don;t get sound once again... Must be a solder bridge somewhere, but I can't find it!
Here's the overall shot:
(https://i.postimg.cc/281WXPLw/20200618_154305.jpg)
Board (component side):
(https://i.postimg.cc/wMvNzrf9/20200618_154146.jpg)
Board (copper side, after latest "fix"):
(https://i.postimg.cc/7Ps79xhh/20200618_161557.jpg)
Stompswitch:
(https://i.postimg.cc/L5b18VwL/20200618_153653.jpg)
Voltage check confirms a short... I get 9.5V at source, but if I change the negative lead to the ground at the jacks, voltage starts fluctuating and never goes near 9V. I have to take my time with this one (of course, eyesight going down the drain makes finding these harder and harder!)
I can't see it good enough, but I thimk you have one of your jacks wired signal to sleeve. check resistance between the sleeve and the other sleeve.
Quote from: duck_arse on June 19, 2020, 12:09:14 PM
I can't see it good enough, but I thimk you have one of your jacks wired signal to sleeve. check resistance between the sleeve and the other sleeve.
Sh!t! Was SO focused on the board, did not even see that one! LOL! You are absolutely right! Well, that fixed the problem!!!
Layout is verified. Just one thing, the LOUD pot should be wired backwards (assuming I am looking at the back of the pot) so that clockwise is louder. But it certainly works.
Quote from: jfrabat on June 19, 2020, 01:25:03 PM
Quote from: duck_arse on June 19, 2020, 12:09:14 PM
I can't see it good enough, but I thimk you have one of your jacks wired signal to sleeve. check resistance between the sleeve and the other sleeve.
Sh!t! Was SO focused on the board, did not even see that one! LOL! You are absolutely right! Well, that fixed the problem!!!
Layout is verified. Just one thing, the LOUD pot should be wired backwards (assuming I am looking at the back of the pot) so that clockwise is louder. But it certainly works.
Great, thanks for checking!
Are you sure about that Loud pot wiring, though? I am tired so my brain might deceive me here but I think it's correct on the schematic.
Quote from: Mark Hammer on June 18, 2020, 01:37:57 PM
RE: changing the opamps.
I've increasingly come to take the view that, in some instances, what we are hearing is the sound of an op-amp that has simply run out of headroom, subsequently getting re-clipped with diodes. Given that the "Chug" control can theoretically increase gain by as much as 1000x, even very modest settings of the control exceed the headroom of the op-amp used, when powered with 9VDC. So, while a superficial glance would suggest that "all" it does is crossover distortion, in fact the crossover distortion from the 1N4007 pair is simply supplementing the hard clipping produced as higher gain settings run the signal smack up against the ceiling on voltage swing.
All of which would suggest that, yes, in an application like this, varying the op-amp type can make an audible difference.
Yes, all the clipping comes from the opamp hitting the rails so different opamps sound quite different. That is kind of the whole point of this thing. Not so much difference at maximum gain but quite noticeable at "moderate" gains. With the 2M2 bias resistor, an NE5532 is actually very starved for bias current, which leads to an asymmetrical working point and audible "sag" when the s#!t hits the rails, so to speak. With 4M7 that is even more prominent. Misusing opamps is fun... A regular old 4558 with 470k or 1M bias should sound a bit more civilized, if someone who is after that actually considers building this thing here. Making the coupling cap C2 larger also makes it more civilized and less noisy, making it smaller produces more sag. Lots of fun to be had. Sticking antiparallel diodes in parallel with R6 makes it distort a lot more but obviously drops the volume and changes the sound. May be a good switchable option.
Andy
Quote from: Fancy Lime on June 19, 2020, 04:09:31 PM
Great, thanks for checking!
Are you sure about that Loud pot wiring, though? I am tired so my brain might deceive me here but I think it's correct on the schematic.
Ah, seems like my dyslexia got the better of me again. I was the one who had it backwards! Your diagram is correct. Sorry for the confusion!
Boxed it up. Here is the final version:
(https://i.postimg.cc/hGt6ZWRs/20200619_191710.jpg)
And here is the mandatory clip (chug at about 2 o'clock, home-made Les Paul clone with Seymour Duncan Jazz pickup, using bridge pickup, through the Minisågverket to a Vox AC-5 clean and recorded with Cell Phone):
https://drive.google.com/file/d/1LEKPTjAXXnT4AWgrEAMxFiD11IvKDzhp/view?usp=sharing
I tried to do a riff similar to the one you posted, to compare (a not so accurate reproduction, but similar!)
I just now realized that the original schematic got downsampled somehow when I uploaded it, making it pretty much unreadable. Here is another try:
(https://i.postimg.cc/s1M9N260/Minisagverket.png) (https://postimg.cc/s1M9N260)
OK, looks good in the preview now. Let me know if you guys still have the issue with the low resolution. Really strange, never happened to me before...
Andy
Quote from: Fancy Lime on June 21, 2020, 01:30:55 PM
I just now realized that the original schematic got downsampled somehow when I uploaded it, making it pretty much unreadable. Here is another try:
(https://i.postimg.cc/s1M9N260/Minisagverket.png) (https://postimg.cc/s1M9N260)
OK, looks good in the preview now. Let me know if you guys still have the issue with the low resolution. Really strange, never happened to me before...
Andy
Wish I had had this before killing my eyes with the other one! LOL! No kidding, I had a blown up version (for the board), and a smaller one on which I used the phone's magnifying glass to read the numbers (they were too soft on the blown up one).
Sorry for the resurrection. I have been wanting to try my hand at etching boards, and have been able to visually verify some basic layouts, but really wanted to do this circuit.
I wanted to make a layout without jumpers, and with all components laying flat.
If anyone, especially Fancy would be willing to look it over, it would be most appreciated.
If it checks out, you all are free to use it. Won't fit smaller than a 1590B, but OCD kicked in for me.
Made some corrections.
(https://i.postimg.cc/0MkX1jxN/Minisagverket-PCB.png) (https://postimg.cc/0MkX1jxN)
Hi Liaztraht,
Thanks for the layout, looks great! I cannot find any errors. However, the two 1u film caps could probably do with a bit more space. These things are usually about twice as wide as in your layout. Not really a problem, the will fit with a bit of bending of some leads but if you give them more space, the assembled circuit will look a lot better. Also, the 100n cap C13 should sit as close as possible to pin 8 of the opamp. It's pretty close already, almost certainly close enough, but my OCD says it could be a little closer still :icon_wink:
Cheers and thanks,
Andy
P.s., just the other day I thought I should try making a PCB layout for this thing but I am so darn slow at that... Really appreciate you taking the time and putting in the effort!
Just realized Andy's schematic flaw.. :icon_wink:
Pin 4 (and not 3) should be grounded..
Pin 3 should be biased to +4.5V via 2M2 resistor..
or am I missing something relative to mis-bias distortion..??
One of the things to remember about crossover distortion is that all the clipping wants is a signal that exceeds the forward voltage of the diodes. Unlike clipping diodes going to ground, that provide harsher sound the harder you pick, crossover distortion occurs when you reach threshold, and doesn't increase appreciably beyond that. However, your signal dynamics WILL be preserved. In other words, strum harder and you'll be louder, rather than simply more distorted.
That said, the use of op-amp gain that greatly exceeds the headroom of the chip, using that supply voltage, means you'll still get some clipping and compression from the op-amp. Seems to me that, unlike setups using a pair of diodes in the feedback loop of an op-amp, like your Novice Driver, ( https://www.diystompboxes.com/smfforum/index.php?topic=126297.0 ), that varying the supply voltage of the circuit will yield different feels and degrees of headroom-related clipping. Looks to me like a job for a charge-pump.
Quote from: Fancy Lime on February 01, 2021, 05:03:01 PM
Hi Liaztraht,
Thanks for the layout, looks great! I cannot find any errors. However, the two 1u film caps could probably do with a bit more space. These things are usually about twice as wide as in your layout. Not really a problem, the will fit with a bit of bending of some leads but if you give them more space, the assembled circuit will look a lot better. Also, the 100n cap C13 should sit as close as possible to pin 8 of the opamp. It's pretty close already, almost certainly close enough, but my OCD says it could be a little closer still :icon_wink:
Cheers and thanks,
Andy
P.s., just the other day I thought I should try making a PCB layout for this thing but I am so darn slow at that... Really appreciate you taking the time and putting in the effort!
I will make some room on it, and see about getting C13 closer. Also noticed the pads on the trace side are too small. So it shouldn't be used just yet. A drill would just cut them out :icon_lol:
Antonia is right, as usual. The grounded pin is 4.
The circuit relies on the opamp itself clipping, so a charge pump would decrease the clipping. It was originally designed with a bit opamp like the njm2068 or NE5532 in mind. These have relatively high bias currents, meaning the 2M2 bias resistor cannot bias them "properly". As a result, the clipping is quite asymmetrical and gets even more so, the higher the gain pot is set. This gives an interesting sagging component to the sound that disappears when an opamp with higher input impedance like the TL072 is used. That one sounds tighter in this circuit. Basically the whole thing is a study in what happens if you use an opamp wrong :icon_wink:
Andy
Quote from: Fancy Lime on February 01, 2021, 06:00:43 PM
Antonia
I definately have to re-count my Y chromosomes .. :icon_redface:
Quote from: Fancy Lime on February 01, 2021, 06:00:43 PM
Antonia is right, as usual. The grounded pin is 4.
I noticed that while laying out the board. Kept referencing your mini layout. Ran around in circles for a bit! It threw off this noob.
But as I may not have conveyed clearly enough before, increasing the supply voltage will have an impact on the op-amp clipping, but NOT on the crossover distortion. So one should be able to vary the relative contribution of the two types of distortion, and get ONLY X-over by increasing the headroom and setting the gain for just enough to exceed the forward voltage of the series diode, but not so much that you crash into headroom limits of the op-amp.
I tried to do this (i.e., get different proportions of X-over and clipping) with the Contrafrizz, however: 1) I used a "normal" 9V supply, 2) varied the clipping, using clipping diodes, and 3) varied the contribution of crossover distortion by allowing greater and lesser amounts of that distortion to pass in parallel with the clipping.
Nice layout, Liaztraht. Just a small tip, it's a nice idea to avoid those traces with right angle curves. While they do work, they are easier to be damaged and removed out from the board by overheat. Not an issue if you have some soldering skills, but anyway.
Quote from: Marcos - Munky on February 01, 2021, 07:00:51 PM
Nice layout, Liaztraht. Just a small tip, it's a nice idea to avoid those traces with right angle curves. While they do work, they are easier to be damaged and removed out from the board by overheat. Not an issue if you have some soldering skills, but anyway.
Thanks for the tip! This is only my third attempt at trying to create a layout. I am tempted to go over everything with curved traces for a neater look.
Should I be bothering with keeping the ground fill out of the center? Or just not bother? It's a pain redoing it after making room for the 1uF caps :icon_eek:
Quote from: Fancy Lime on February 01, 2021, 05:03:01 PM
However, the two 1u film caps could probably do with a bit more space. These things are usually about twice as wide as in your layout. Not really a problem, the will fit with a bit of bending of some leads but if you give them more space, the assembled circuit will look a lot better. Also, the 100n cap C13 should sit as close as possible to pin 8 of the opamp.
I was able to move both 1u, but C13 is staying. Would have to move a lot of things to get it to work.
Also thickened the traces and pads a bit. Should be more durable for my first attempts at etching.
Updated layout in my first post.
Quote from: antonis on February 01, 2021, 06:15:16 PM
Quote from: Fancy Lime on February 01, 2021, 06:00:43 PM
Antonia
I definately have to re-count my Y chromosomes .. :icon_redface:
Ah, well, we need do something about the gender imbalance on this forum anyway. Damn autocorrect does not know greek names. I keep accidentally calling my friend Petros "Pedro" in text messages.
@Mark, ah, now I get it. Adding a pot for variable voltage, say 4-18V may indeed be interesting. But the way it is set up, you already get very prominent crossover distortion with most pickups if you stay below 10 o'clock or so on the gain pot. I really like pure crossover distortion for bass. Extra harmonics without loosing punch.
Cheers,
Andy
Quote from: Liaztraht on February 01, 2021, 08:58:58 PM
Should I be bothering with keeping the ground fill out of the center? Or just not bother?
I'd just won't bother with that.
Quote from: Fancy Lime on February 02, 2021, 04:59:12 AM
Damn autocorrect does not know greek names. I keep accidentally calling my friend Petros "Pedro"
This autosmell has to be in your
browser. In mine, if I notice an embarrassment, I carefully spell it correctly, right-click the red-lined "error", and "Add to Dictionary".
(https://i.postimg.cc/sMw692J9/Add-Dict-42.gif) (https://postimg.cc/sMw692J9)
(Which opens the problem of accidental entries. It is actually possible to find and edit FireFox's user dictionary.)
QuoteI keep accidentally calling my friend Petros "Pedro" in text messages.
is it the same Petros that still has my copy of Das Kapital?
probably not tho,
cheers, Iain
Quote from: PRR on February 02, 2021, 11:16:11 PM
Quote from: Fancy Lime on February 02, 2021, 04:59:12 AM
Damn autocorrect does not know greek names. I keep accidentally calling my friend Petros "Pedro"
This autosmell has to be in your browser. In mine, if I notice an embarrassment, I carefully spell it correctly, right-click the red-lined "error", and "Add to Dictionary".
(https://i.postimg.cc/sMw692J9/Add-Dict-42.gif) (https://postimg.cc/sMw692J9)
(Which opens the problem of accidental entries. It is actually possible to find and edit FireFox's user dictionary.)
It's my phone's keyboard autocorrect. I got my real computer under control, so there are no "helpful" features there that tell me that they know better what I want to write than I do myself. Alas, phone operating systems are the bloody worst and are not designed with users in mind who are not complete and utter morons. I should probably invest some time figuring out how to stop my phone from being "helpful".
Andy
Haven't had time to get the materials to try etching a board, mostly because I can't afford a darn laser printer! I did a test print on one at work, but the toner smudged in transit.
So I started teaching myself Diptrace, and I put the same layout in there. Also corrected the pin 3 to ground in the schematic, that way I had the rats nest to help.
I set it up for use with standard box caps, and it should still fit in a 1590b.
I have the Gerber files if anyone wants it. Its not confirmed yet, but I am willing to take the plunge as I am thinking of doing an Oshpark order.
(https://i.postimg.cc/NKyN0FdT/Capture.png) (https://postimg.cc/NKyN0FdT)
Quote from: Liaztraht on February 05, 2021, 03:18:49 AM
I have the Gerber files if anyone wants it.
Of course we want the gerbers! Yes, please.
Quote from: Axldeziak on February 05, 2021, 08:47:49 AM
Quote from: Liaztraht on February 05, 2021, 03:18:49 AM
I have the Gerber files if anyone wants it.
Of course we want the gerbers! Yes, please.
What site would you recommend to host the file? preferably free.
You could try mega.nz.
Alot of folks here also use google drives.
Quote from: Axldeziak on February 05, 2021, 09:07:53 PM
You could try mega.nz.
Alot of folks here also use google drives.
Thanks. I have to make a small adjustment first. Can't upload to OSHPark due to the symbol above the a on the silk screen layer.
Will get it done after work.
I am also making a BOM with Smallbear SKUs for easy reference for those that can shop there.
Here is the gerber files and the BOM list. Gerbs already zipped, PDf has BOM, notation, and a screenshot from GerbV for reference.
https://drive.google.com/drive/folders/1M7gnFbSkOF3aY4hnYsAvJQjC0BE7sCom?usp=sharing (https://drive.google.com/drive/folders/1M7gnFbSkOF3aY4hnYsAvJQjC0BE7sCom?usp=sharing)
Hopefully I set up the link correctly.
Also flipped the CHUG pads around. I had it upside down.
Here is the OSH Park link to the shared file as well https://oshpark.com/shared_projects/MBCDaL2J (https://oshpark.com/shared_projects/MBCDaL2J)
I also placed the Diptrace Schem in the google drive link with everything, and did a slight update to all files as I made the board a hair narrower.
And the rendering of said board:
(https://i.postimg.cc/r00dFkNw/1.png) (https://postimg.cc/r00dFkNw)
(https://i.postimg.cc/D418LPDV/2.png) (https://postimg.cc/D418LPDV)
Got an oshpark order in of my layout. They flipped the chug pads around, which works because they way I had it the chug pot worked backwards :o
It's darker, more gated, and a little less gainy than the original example. Could be because of the tl072 maybe? Or perhaps because I was running it into a darkish Marshall Origin...
Either way, at low volume, into a dirty amp with the knobs maxed, or boosted by my SD1, I was getting buzz saw tones. It needs a kick in the pants, or to slam an amp to get there. With the chug down low, it is more of a gated overdrive.
Not sure if changing components other than the chip will help. Too much pushing the front end and stuff gets crazy and splatty. Pretty sure it's just overloading.
Either way, it's cool that my first PCB layout actually works!
I'm going to get loud in the AM and see if it's just the late night volume making it sound off.