I think I would make one this way. Verified on experimenters board.
http://www.rickviola.com/images/CrunchRV.jpg
I think that 2.2uF on pin 7 could be a 1.0uF.
Quote from: Goodrat on April 15, 2012, 10:32:13 PM
I think I would make one this way. Verified on experimenters board.
http://www.rickviola.com/images/CrunchRV.jpg
Hey Rick,
A lot of different values from the original crunch box..? Also, I tried many dual op-amps and seemed that the LM833 sounded the best to me anyway. No presence trim? You have any sound demos?
BTW - Nice antenna stuff man! :icon_wink:
~Jim
I made some changes since yesterday. A few errors. I replaced the file with the 4/16 version so all good now.
For better noise, I changed the second feedback resistor from 1M to 100K and changed the 2nd input cap and resistor accordingly to give the same gain and response. I did not like where the power supply 100uf was on the schematics floating around and there is less hum where I put it. The bias resistors I think are better at 100K for less battery draw and a smaller cap can be used there. The bias feed to the first stage should be quieter at 100K rather that 1M.
I don't really get the presence thing so I put a nice functional treble control.
I use the TLO82 because I have some. I will plug in others and compare, including an OPA one.
I just drew up a layout for a Radio Shack IC experiment board 276-159 that can be purchased real cheap. I will post that after I double check it.
Maybe I will but a Joyo version and do a compare and film that.
BTW, If you come across my "Scooch Box" I have many changes to that design (less switches) to get around to also.
This is interesting. The Crunch Box is one of my favorite distortions. Do you have any particular goal in mind with this version?
Well I spent a year or so playing with my "Scooch Box" and I still have improvements I want to do with it.
I heard some demo's on the Crunch box and I liked it. I bought a Joyo Clasic Overdrive today because I wanted a nice basic Tube Screamer sound. I figured the circuit was simple enough on the Crunch box, so I built it on one of those press on experimenters boards. I want just a basic treble control with the Crunch so I put in a "Stupidly wonderful tone control" in place of the tone/presence and that was fine. Now I'm thinking that the drive control sounds useless on the lower end of the control, so I compromised and put a 20K there. Normally this is shorted to the wiper but in the Crunch box it is open and the response is a little weird and gets muddy. Then I just did a few things I learned with all my experimenting.
It is simple enough to solder on one of those Radio Shack 276-159 boards so maybe for about $20 for a box, jacks, switch etc. I can have a nice fuzz box.
Although, with these Joyo pedals on the market, for only slightly more I can skip all the trouble and modify that if I want.
But what fun would that be? :)
Maybe I should make my version and lend it to someone who has an original to compare.
Update: OK, I ordered a Joyo crunch box which should sound just like the MI version (most say). I will compare and tweak if I need to.
I'll know in a few days if my tweaks are any good.
Update 2:
After looking more carefully at the second stage and drive pot, I put some values back to original. I realized that the drive pot would behave worse if the second stage feedback resistor was 100K instead of 1M, because the right side of the pot adds to the series input R of the second stage when turned CCW. In combination with the cap in series is why the bass roll off gets lower and the second stage gain is drastically cut. (muddy).
I will experiment with a cap on the right side of the pot to wiper, as this will become in series with the other cap and roll off lows at a higher frequency when the drive is CCW, or at least put some resistance there to lower what is on that side of the pot for less gain cut. Anyway, my current thoughts are in the updated diagram (Dated 4-17-12).
I will have the clone tomorrow and have a better opinion.
Is there a particular LED preferred for clipping? I noticed the 3mm's I have light up more than a 5mm, but the 5mm sound better.
I have no specs on either. (at least I think those are the dimensions). All I know is the 3mm's I have when used as a power on indicator, I can get away with a 10K resistor and still plenty bright.
Quote from: Goodrat on April 17, 2012, 10:30:05 PM
Is there a particular LED preferred for clipping? I noticed the 3mm's I have light up more than a 5mm, but the 5mm sound better.
I have no specs on either. (at least I think those are the dimensions). All I know is the 3mm's I have when used as a power on indicator, I can get away with a 10K resistor and still plenty bright.
I use the 5mm red... I think they sound the best on the CB.
I got the Crunch box clone today (Joyo). Good news... Success! It sounds and behaves the same as my prototype.
I had to make sure I used a linear pot in the tone. I increased the 9V filter cap from 100uF to 470uF.
It should even be a 1000uf but it has to fit in the box.
I have to check if there is any weird pop at turn on since I actually turn power on and off with the switch.
I like the 250K lin pot/50K resistor combo at the volume control. It should be better than a cheap log pot (so they say).
I need to swap IC's to see how a better one will hiss less when the volume is at max.
The Joyo is slightly less hiss. I'm not sure what is in there yet, but I am using a TLO82 at the moment in my proto.
The drawing link is updated on this thread and I have a layout I am verifying and tweaking.
The Joyo has an 833 op amp and all parts I read match the schematics.
The trim should be on the other side of the board, I would think.
http://www.rickviola.com/images/Joyo1.JPG
http://www.rickviola.com/images/Joyo2.JPG
Yup, that's a Crunch Box and you got it for a fraction of the price...:icon_mrgreen: The CBv2 is like $139.00! I have to say the Joyo looks really well built... I like to use a 16mm B20K pot for the presence control mounted with the vol, tone and gain rather than the 20k on-board trimmer... I have also tried different combinations of LED's and other diodes and some sound really good. One combination that sounds pretty good is 4 - 1n34a's. There are a lot of possibilities with the Crunch Box and I am surprised that there has not been more interest in the forums!? MI Audio has a new Super Crunch, I don't know if it's for sale yet but I got a pic of it... Looks like they did some pretty cool updates/mods..
(http://dl.dropbox.com/u/11178619/CB2.jpg)
Quote from: J0K3RX on April 19, 2012, 11:28:31 PM
There are a lot of possibilities with the Crunch Box and I am surprised that there has not been more interest in the forums!?
I agree, its my "standard" against which I compare other dirt creations. The Joyo is the same circuit (I own both). The Joyo is not built that well when you are close up, but its good enough. You don't want to start substituting parts on a Joyo, the PCB breaks up pretty easy, you get a couple of goes and thats it. The MI crunch box uses medium brightness LED's, 9 to 10mA @ 2.0V, 19 to 22mA @ 2.2V, and the lenses are milky red, not clear red. The circuit is so close to a Marshall Guvnor its not funny, but MI really nailed the tone control (and pres control), the tone control is very versatile and the slightly metallic midrange of the marshall tone seems to be there.
Nice mods!
Yes, I do NOT intend to mod the Joyo. Although I may put the trim pot on the other side of the PCB.
I wanted to keep a golden unit around to compare what I build.
I'm need to compare the tone control more closely. So far, what I hooked up in my proto has the same range.
I don't know why they keep using lower values in the bias resistors.
The 47 ohm I put on the 9V input and a higher cap also reduces hum more.
I need to order an 833 chip. I'm using a TL072 at the moment.
I also bought the Joyo Classic overdrive. Nice. I'm all set. Too bad I never play live, but I'll be ready.
This is how I intend to build one for the fun of it:
http://www.rickviola.com/images/CrunchLayoutRV.jpg
Small pots:
http://www.diystompboxes.com/smfforum/index.php?topic=97114.0
A/B test today, I am pleased. The tone control works just as well, gain, all fine.
Max volume is slightly less with the 250K pot linear with 50K on lower leg to make it log, but just slightly and who needs max output volume?
I could always put a 100K log.
The 47 ohm on the 9V input with a larger cap will clean up any hum from a wall wart much better.
The 100K's with 1uF rather than 22K with 10uF on the bias should make less hiss and hum , but I have to get an 833 to be sure.
The tone control is an easier build and has a full range and the volume will not drop off when at min.
It seems this is a nice quick and easy Crunch box.
Update: after playing for a while, I notice a slight difference. It's hard to explain. I will wire up the presence pot to see what that does.
If I still notice it, maybe it is the chip.
(http://www.rickviola.com/images/CrunchProto.jpg)
OK, I give up. I'm putting the presence control back in.
Schematic:
http://www.rickviola.com/images/Crunch2RV.jpg
Layout:
http://www.rickviola.com/images/CrunchLayout2RV.jpg
Why mess with it.
So basically, the only thing I am doing is changing the 9V input with cap and resistor and the bias resistors and cap.
If I didn't get the Log/Lin notes right, someone let me know. It matches my Joyo now. All seem to be linear except the tone is anti-log (CW to wiper increases from zero slowly).
I also noticed they set my presence trimmer full CCW.
That threw me off because it was bright and I could not recreate with my proto half way up.
Hmmm, maybe we don't need no stinken presence control.
soundclips?....comparison?....just curious. ;)
I'll try a video tonight. I wanted to make sure all the drawings were correct. They are now.
So if anyone saved a drawing I linked on this thread (any version), save a new one dated at least today (4-23-12).
Here is a quickie. The right pot on the proto in the simple tone control from my first link with no presence. The left pot is gain.
The Joyo Crunch box has the presence full so it is basically not in the circuit anyway.
Sorry, I never know what to play in these vids. I'll do a better one when I have an 833 chip which may be brighter. This has a TL072.
http://youtu.be/1VU04ZxYTN4 (http://youtu.be/1VU04ZxYTN4)
http://rickviola.com/images/CrunchRV.jpg (http://rickviola.com/images/CrunchRV.jpg)
Quote from: Goodrat on April 23, 2012, 10:07:45 PM
Here is a quickie. The right pot on the proto in the simple tone control from my first link with no presence. The left pot is gain.
The Joyo Crunch box has the presence full so it is basically not in the circuit anyway.
Sorry, I never know what to play in these vids. I'll do a better one when I have an 833 chip which may be brighter. This has a TL072.
http://youtu.be/1VU04ZxYTN4 (http://youtu.be/1VU04ZxYTN4)
http://rickviola.com/images/CrunchRV.jpg (http://rickviola.com/images/CrunchRV.jpg)
That sounded real good man!!! Good side by side comparison...
+1 sounds the same to me!!!...nice work man!... :icon_cool:
Here is a CB variant... See what you think?
(http://dl.dropbox.com/u/11178619/BOX%20OF%20HAMMERS.jpg)
Transfer
http://dl.dropbox.com/u/11178619/BOH%20Transfer.pdf
I think you will like this...! It doesn't sound much like the Crunch Box but rather has more of a ENGL Fireball - Mesa Treadplate sound... Still nothing more than a modded Crunch Box :icon_twisted:
This would be a good post for other "Crunch Box lovers" to post their builds, mods, ideas etc...?
Have you tried the LED's in the feedback loop of the second op amp? ;)
Quote from: WGTP on April 24, 2012, 01:46:01 PM
Have you tried the LED's in the feedback loop of the second op amp? ;)
Thought about that but haven't tried it with this... You think it will sound much different? Sounds damn good like it is but I am curious now... :-\
I should have a video demo coming soon... :icon_wink:
Got a schematic of it?
I put led's in the feedback of this one which is all original:
http://youtu.be/xxpLJRRc_yw
Oh, and I tried swapping the 100K bias resistors for 22K like the original Crunch. No difference in noise or sound. Maybe the 833 chip doesn't like it.
I receive those tomorrow. Why would they want to drain more battery I wonder? Maybe habit from 741 op amp days, or if the voltage gets low.
Crunch version (4-26-12)
http://rickviola.com/images/Crunch3RV.jpg
http://rickviola.com/images/CrunchLayout3RV.jpg
After looking at how the Joyo does the bypass, I thought I would also kill the op amp input in bypass.
I also decided I like the simple tone version.
I did not receive the 833 so I don't know if I'll need any changes for it.
BTW, don't ignore the capacitance of any LED's you experiment with.
Back to back 3mm are about 25pF and I think 5mm are 100Pf.
Thanks for the heads up on the JOYO version. Just got it in the mail and it sounds very good. Much like the lead channel of my tube amp. According to LT Spice sims, the Tone and Presence control sum together in resistance and capacitance, rather than creating a sharper/different roll off. You may want to leave off the Presence and change the Tone cap to .01-.033uF depending on issues. C8 can also be raised or lowered for more or less Treble.
Putting the LED's in the FBL of the second op amp has a smoother rounder tone IIRC. Instead of both the op amp and LED's clipping, it is just the LED's. Nice tone. ;)
A hum I was trying to squelch was just the way I was grounding. You have to be suspicious of these experimentor boards.
I wasn't crazy about the resistor though on the 9V input, even though it works very well.
So I am back to a Schottky in series and put C1 back to 100uF. C2 can stay at 1uF.
The 5819 schottky has a low Vf at these low currents. About 0.2V and I have a big bag of them.
Some may want to use them when experimenting with germanium diodes.
I'll play with the feedback cap C8. 100pF does seem high.
The LM855 came today and yes, it has less hiss at full volume. All else looks fine. At this point it needs to go in a box.
The drawing are updated again and dated 4-27-12.
Here is another great spin off of the Marshall Gov'nor/Crunch Box whatever... I think the ToneFreak Severe is one of the best sounding out there...
The Severe has clipping at the feedback loop...
http://rapidriotboxes.blogspot.com/2011/01/tonefreak-severe-distortion.html
Sorry, no schematic... You can probably google it and find the schematic, these things are easy enough to trace out anyway...
Very simple build and well worth it!!!
I'll check it out.
Darn, I ordered a log pot instead if reversed log for the tone. Now I'm backwards.
I have tons of mil caps, M39014.... I believe they are ceramic. I noticed Radio shack has poly film at the store:
http://www.radioshack.com/family/index.jsp?categoryId=12648753&allCount=1308&fbc=1&f=PAD%2FProduct+Type%2FPolyester+film+capacitors&fbn=Type%2FPolyester+film+capacitors&filterName=Type&filterValue=Polyester+film+capacitors
I should give them a try.
Yeah, I find myself running to Radio Shack from time to time. Those caps are pretty good just expensive and they only have certain/limited values in the store..
I get most of my stuff from here.
http://www.thaishine.com/servlet/StoreFront
Sometimes they have my orders at my door in 3 days, no more than 4 days and shipping is always free! They don't carry some special stuff but they have just about all you need and they are here in the US.
Mouser took Sunday night order, to Friday on Priority mail. I thought that was slow.
I just put the two on the a scope with a signal gen. Perfect! Both have the same response. The Joyo tone CCW cut the lows a little bit more but that is good. I get more play on the high end with mine.
I think it is interesting how they control the gain to both stages with the same pot. When I saw the schematic I wondered why they did that.
I think the Crunch box does a good job of keeping the character of the guitar without a lot of bad inter-modulation when playing chords.
I think the presence control is not needed.
So, this was fun. The design is a keeper.
I retrack what I said about the Tone and Presence controls summing. They have slightly different overlapping action. Looking at the original Matsumin version, The Tone control is similar to a Rat and rolls off the highs at 6db/oct. The Presence control is more of a shelving control that lowers mids and treble, but leaves the bass. I'll sim tomorrow and report back some more. Going to Rock On at the Norman Music Festival at the Midnight Hour. ;)
I still think something is different here. It is not the bias resistors or supply caps. I tried substituting and even simulated the presence full up like in my Joyo. The only variation now is whatever LED's they used.
After looking at a few layouts, I drew a severe schematic.
Does this look right?
http://www.rickviola.com/images/SevereRV.jpg
Yeah man, I looked at it real quick seems to look good! I will tell you what I have done differently from the original - 500k for the gain pot and either 2 red 5mm LED's or 1 yellow 5mm and 1 red 5mm LED. I didn't really like the 2 yellows but that just maybe the cheap radio shack LED's I don't know? In any case it sounds excellent...! I really like the 500k for the gain and I use that all the time now when I build one of these.. I have built 5 of them now, killer pedal!
Simmed the tonestack with LT Spice and the Tone and Presence interact a lot. The Tone control has the greatest effect with the Presence altering the roll off slop. For the least mid-range, try the Presence trim pot about midway. Might increase the cap in the presence control, to 47n for more action. The 220n cap can go up or down for more or less bass and gain. The 100pf cap in the first FBL could go down to 1n or more to reduce some highs and further smooth things out. ;)
Might suggest a single 2N7000 or BS170 for clipping diodes.
Might try the diodes in the FBL in the second op amp. ;)
I'll look into that. Down to 1N? Don't you mean up? (1000pF). I hate the nano farad thing. It makes me do math.
OK, I know the difference now.
The "Stupidly wonderful tone control" extra resistance was somehow cutting my highs slightly.
Which doesn't make much sense since the volume control, if not at max, would do the same thing.
It is a very slight difference. I can hear my higher strings slightly better.
So this is a mystery, but in any case I changed my drawing to a typical tone control by shorting the wiper to the cw leg (or moving one wire).
Now you have to tweak the volume if you change the tone, but it sounds better. Ever so slightly, but better.
Update: Nope, I can't do it. Maybe it was my imagination.
Maybe it's the orange paint :)
On the severe, what's the deal with the 100 ohm in series with the 1K?
Did I get something wrong there?
That makes no sense.
With those 3 position switches you use, you should take a look at my idea using an on-on-on switch (SP3T).
Skip ahead to diagram G
http://rickviola.com/electronics.htm
Quote from: Goodrat on April 29, 2012, 01:52:36 AM
On the severe, what's the deal with the 100 ohm in series with the 1K?
Did I get something wrong there?
That makes no sense.
Yeah, that looks like a goof if you ask me... Here is one of many schematics I have found for the severe.
(http://dl.dropbox.com/u/11178619/severeschematic.png)
Here is a video demo of the "Box of Hammers" layout (CB variant) that I posted on page 2. This is a double distortion being boosted with a TS808 circuit... The right side is the exact layout as on page 2.
It's being used as a preamp going direct into the fx return on a Blackstar, so it's only going into the power section bypassing the amps preamp.
I sent it to Mark Thompson of ShredKnowledge and he sent it to Sam Bell to demo... Sam is a Beast \m/ :icon_twisted: \m/
Quote from: Goodrat on April 29, 2012, 02:05:25 AM
With those 3 position switches you use, you should take a look at my idea using an on-on-on switch (SP3T).
Skip ahead to diagram G
http://rickviola.com/electronics.htm
I have used and still use the on/on/on switches on some configurations but I like the sound without diode clipping so I use on/off/on... No diodes give a more vintage sound where the diodes give a more compressed modern sound. Plus on/off/on are easier to find.. You could always use a 6 way rotary switch as well is you want to have a lot of configurations...
The extra 100 ohm is on this one too.
http://3.bp.blogspot.com/_XBLxtjUxez0/TSaZ1pRQGdI/AAAAAAAAAFM/z4EeVEZAFUM/s1600/SEVERE.PNG
Quote from: Goodrat on April 29, 2012, 12:19:43 PM
The extra 100 ohm is on this one too.
http://3.bp.blogspot.com/_XBLxtjUxez0/TSaZ1pRQGdI/AAAAAAAAAFM/z4EeVEZAFUM/s1600/SEVERE.PNG
I believe you can leave out the 100 ohm... The original Severe has them both so it's not a goof.
I think when I get some time I am going to try what WGTP said and try the diodes in the FBL of the second op amp! I haven't really done much of that for whatever reason but I know that all of the pedals that I have built that use this seem to sound and feel better! Maybe have it switchable from fbl to gnd? I also have quite a few BS170's... Gonna try that also as suggested..!
I thought I would add this:
http://www.rickviola.com/images/CrunchLowRV.jpg
I lowered the resistors but kept the same gain and freq response.
It sounds the same, but less hiss.
So here is the latest and greatest of my Crunch Box with simple tone:
With Presence
http://www.rickviola.com/images/Crunch2RV.jpg
Layout:
http://www.rickviola.com/images/CrunchLayout2RV.jpg
Without presence:
http://www.rickviola.com/images/CrunchRV.jpg
Layout:
http://www.rickviola.com/images/CrunchLayoutRV.jpg
I'm done with this :)
Well done lads. You guys are my heroes :icon_biggrin: