Zvex - Box of Rock  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
madbean
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Post by madbean »

I haven't really noticed any change in bass response with the gain, but definitely it is not the clearest sounding pedal right off. An easy fix would be to get rid of one of the 1M to ground input resistors and change the input cap to 22nF.

Then maybe tweak the high pass filter after the first mosfet stage. Get rid of the 22nF and 470k/470pF filter. Use 100nF cap with a 10k resistor to ground. That gives you a roll off at around 160Hz, which is lower in frequency than the existing one, but if you follow my first suggestion, then you will already be rolling down at 72Hz instead of 3Hz (the original) at the input of the circuit. This lessens the part count, still takes care of decoupling and provides you a bass reduction all in one shot. If it's too much reduction, then just increase the 100nF cap to 220nF. Or try a different cap/resistor combo.

I think the overall effect will be a gentle lessening of bass without too much compromise. But, let your ears be the guide :)

orogeny
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Post by orogeny »

Wow, Im shocked you don't hear the bass response increase as the gain goes up. Its a known issue with this pedal that has been discussed ad nauseum on the gear page. The bass is overbearing when the gain is at 3:00 - its muddy on the low strings. It clears up considerably when the gain is at noon.

madbean
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Post by madbean »

Honestly, I typed that reply without having touched my clone in a while. I'm sure you're right. My build is fairly low gain until it hits about 3 o'clock on the drive and after that I notice the lack of clarity, so I probably never identified it as increased bass. Someday, I will open this thing back up and try out some mods, but it is not a go-to box for me atm.

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Post by chris_d »

orogeny wrote:Wow, Im shocked you don't hear the bass response increase as the gain goes up. Its a known issue with this pedal that has been discussed ad nauseum on the gear page. The bass is overbearing when the gain is at 3:00 - its muddy on the low strings. It clears up considerably when the gain is at noon.
Now that i have mine put together with the right caps(doh) i have to say, that i don't see a problem with the bass response of this pedal at all. I actually have done away with the gain pot for now. I'll put it back in later, but lately i had just been leaving it cranked full, so i took the pot out out and wired it straight in.

I guess it really depends what amp you are running it into, but it sounds really nice cranked into my fenderish homebrew.

Also impressed by what kind of heavy sounds you can get by hitting the front of the BOR with a light OD or dirty boost. Definitely brings it from JTM-45 to modded JCM territory.

A very nice-sounding design, IMO.

-chris

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Post by fusionid »

excited to build this one guys
can anyone link me to the project file with the perfboard/print board layout??

thanks

sliberty
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Post by sliberty »

Torchy - I assume I can build just the top part of your layout, right? I don't really need the bost section, assuming that the rest of the pedal can work without it.

Also, I noticed that your vero layout indicates to connect both Gain-1 and Gain-2 to ground. The Rox of Bock schematic shows only the wiper connected to ground. Is this significant in any way?

Torchy
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Post by Torchy »

sliberty wrote:Torchy - I assume I can build just the top part of your layout, right? I don't really need the bost section, assuming that the rest of the pedal can work without it.

Also, I noticed that your vero layout indicates to connect both Gain-1 and Gain-2 to ground. The Rox of Bock schematic shows only the wiper connected to ground. Is this significant in any way?
Yes, I left the boost section off mine as well.
I dont like leaving pot tracks floating. The pot is only used as a variable resistor so its ok to connect 2 & 1 to gnd.

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Post by Beedoola »

I can't find the 2nf caps needed for the BOR on Small bear, can an alternative be used??

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Post by sliberty »

Beedoola wrote:I can't find the 2nf caps needed for the BOR on Small bear, can an alternative be used??
I bought all Wima caps from Mouser for my build, mainly because they are small and I've heard that they sound great. They carry a 2200pF(2.2nF).

I still don't have yu pedal working though, so I can't tell you how they sound :(

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Beedoola
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Post by Beedoola »

hmm I'll keep that in mind. Will it sound the same? what about the diodes?

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Post by sliberty »

Beedoola wrote:hmm I'll keep that in mind. Will it sound the same? what about the diodes?
2.2nF vs 2nF won't make a difference.

For diodes I used a 1N4001 and a 1N914 which are available anywhere.

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Post by noelgrassy »

yes, i'm eagerly awaiting to see what's inside of that one[/quote]

Madbean, I realize this is an old thread.
There's this if you're still curious....
Image

That's the only shot I've seen and IIRC it was in tandem with a dare from some snapperhead on tgp. :horsey: Vexack certainly has shoehorned those components has he not? Is that a CMOS chip hovering over those 1/8thW resistors?
[there's a couple of new "smilies", yay.]
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Post by analogguru »

I don´t know why, but I like the "outfit" of this clone more than the original:
http://cgi.ebay.at/Moresound-Bock-auf-R ... dZViewItem

Funny the title:
"Bock auf Rock" is german and means:
"I am up for rock " or "fancy for rock"

analogguru
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Post by Beedoola »

sliberty wrote:
Beedoola wrote:hmm I'll keep that in mind. Will it sound the same? what about the diodes?
2.2nF vs 2nF won't make a difference.

For diodes I used a 1N4001 and a 1N914 which are available anywhere.

Does it matter where they go?


Will the tone pot work with a 100k Audio? I thought I had an extra 100k Linear but no. I have the Audio pot installed but the BOR isn't working.

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Post by chris_d »

Beedoola wrote:Will the tone pot work with a 100k Audio? I thought I had an extra 100k Linear but no. I have the Audio pot installed but the BOR isn't working.
It will work fine with a 100k-A pot. You have something else going on, i'd say. Check your wiring(input, output, switching, and controls), check your solders, check your pinouts, check your volts.

-chris

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Post by Beedoola »

Signal gets through when on but there is a hum going on, the tone control almost acts like a volume control...

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Post by chris_d »

Beedoola wrote:Signal gets through when on but there is a hum going on, the tone control almost acts like a volume control...
Pictures of your build? Are you 130% sure that you have the correct pinout of the transistors you are using? Have you quadruple checked the wiring and solder connections from the input to the switch, from the switch to the board, from the board to the volumes, from the board to the tone, from the board to the switch, from the switch to the output?

Is the signal that passes when the pedal is on, a good distorted one? Or is it more clean-sounding, like a treble-cut bypass?

-chris

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Beedoola
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Post by Beedoola »

Problem fixed. I had the wrong value cap for the 470pf, I have like, I don't remember what it wasn't 470 pf, I got one, plus I went over the veroboard and cleaned up some solder points, and made sure the cuts in the board were good.

It works now. Is the tone pot supposed to be reversed? - Mine is counter clockwise more treble and clockwise more bass....


Sounds pretty sweet. I took it to my practice space and played it through my Ampeg v4 head, pretty nice. I compared it to my General Guitar Gadgets BSIAB II wich is pretty sweet too, both are real nice. I also compared it to my 86- small box Rat.

Silberty - does it matter where those diodes go? I got the ones you recommended...

Thanks for the help ya'll

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Beedoola
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Post by Beedoola »

Also, if the tone pot reversal is correct, is there a switch I can ad to reduce the bass? Still too much low end even when turning up the treble...

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Post by sliberty »

Note: I haven't gotten mine working yet (haven't worked on it in a while though).

The layout doc I have says that D1 is a 1N5187 or a 1N4001. D1 sits across the 9V supply.

It also says that D2 is a 1N4148 or a 1N914. It sits across Q1.

If your tone pot is reversed, it probably means that you wired it backwards. take the wire from pin 1 and put it on pin 3, and take the wire from pin 3 and put it on pin 1. Leave the wire on the middle pin right where it is. Since the tone pot is linear (did you use linear), it won't make a difference at all except for the direction you turn it.

Please post the layout you followed. I want to see if it is the same as the one I have. This will help me when I get back to debugging my build. If it is the same, at least I'll know the layout I used is OK. Currently, I have no sound on the output, but I probed my way through the circuit, and get sound everywhere up to the part of the circuit that includes the volume and tone pots. i suspect its just a mistake on my part, but you never know until you solve it.

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