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Zvex - Box of Rock [traced]
Posted: 27 Jun 2007, 15:41
Posted: 27 Jun 2007, 21:43
One mistake? with the Box Of Crock schematic
The 10n on the tone control should be 100n
Otherwise everything from the drain of the third mosfet to the output would not be the same as the BSIABII
Did you spot the Marshall circuit snippet in there
(470k parallelled with 470pf) a treble boosting filter used by Jim before the great Z was probably born
Back to the Future again AG
Okay then - what is this last mosfet gain stage?
Is it - no it can't be... but..... yes - it is another SHO stage
ps: I wonder if he paid any royalties to Ed Guidry and his designer friends for DIRECTLY copying there tone control and output filter design
(that is assuming this schematic is correct!)
Posted: 27 Jun 2007, 21:54
I wonder if he paid any royalties to Ed Guidry and his designer friends for DIRECTLY copying there tone control and output filter design
I don´t think so, somebody wrote me this:
I found it funny that Zach Vex copied the 'back end' of the BSIAB component-for-component. Is this really correct?
If so, I don't resent it, I posted the schematic, after all. I'm actually kind of flattered that he used it.
The rest is private talk....
Posted: 11 Jul 2007, 20:09
Thank you, igloo, looks cool to me!
Posted: 12 Jul 2007, 20:14
I think it's quite funny. Every time you buy a zvx you are basically buying a multiple of the SHO - x2 x3 x4! C'mon Z give us something to get excited about!
Posted: 15 Jul 2007, 07:43
Hey Igloo thanks for perf layout. Is it verified?
Posted: 15 Jul 2007, 07:55
It is a new draw.
Two people have carefully checked it and it looks good.
See at the top of the thread the schematic?
Check for yourself!
I am keen to hear any build reports. :
Posted: 15 Jul 2007, 08:46
I cannot see any layout???
The original schematic at the top of the thread cannot be correct with that 10n in the tone control surely???
I think it needs to be 100n - to match the BSIABII circuit - can someone confirm please!!!
Posted: 15 Jul 2007, 09:27
Posted: 19 Jul 2007, 15:03
i built this circuit based on the first layout (by FcKw) posted above, i used 100n cap at the tone part...
both the FckW and Igloo's layout is not same as the schematic posted here... (100n tone cap and 47K output resistor)
as soon as somebody verify the actual values used in the commercially available units, i will update the schematic and post it here for everybody's reference.
anyway, the circuit using 100n tone cap sounds quite nice... i didnt try 10n... it sounds...uhmm.... it sounds like 4 cascaded SHOs
with maximum drive at low volume settings, i couldnt get enough grainy distortion, so i tried pushing it with a clean boost from the eternity clone i built recently... there, im satisfied...
.. thanks guys for the info. someone please verify the actual values so we could update the schematic posted.
Posted: 19 Jul 2007, 15:30
100n seems to be the correct value for the tone control.... This would fit to the BSIAB II.... but who knows ? In boutique-pedals you can find many things.... sometimes also cloning-mistakes. I know one unit which was sold for years as a 100% clone, until the builder found one of my schematic... Now the unit has been updated
If the Zvex Octane schematic shows the real content of the unit, then i assume, Zvex never has seen a real unit, only the printed schematic which contains mistakes. Also the printed Kay Fuzztone schematic supplied with the unit is incorrect. If you take this schematic for cloning...it wil never be a real clone. Sunn Buzz factory schematic is incorrect....the list can be continued.
Since the output capacitor is 10µF (nobody knows why) it doesn´t make a difference to the unit itself
if the output resistor is 47k or 100k. (even with only 47k the LF-response will be linear down to approx. 2 Hz and the load difference on the output stage is neglicible
). Maybe it can have an influence on the following guitar amp if this guitar amp has no DC-decoupling and no 68k input resistors.....only then.
Posted: 23 Jul 2007, 18:17
Posted: 23 Jul 2007, 18:36
Posted: 25 Jul 2007, 04:05
I've got a verified pcb layout of the dirt side of the schematic (I didn't put the boost in) if anyone is interested and it's kosher. I've built it but not boxed it so it's verified.
Posted: 25 Jul 2007, 15:09
Posted: 25 Jul 2007, 15:20
madbean wrote:I've got a verified pcb layout of the dirt side of the schematic (I didn't put the boost in) if anyone is interested and it's kosher. I've built it but not boxed it so it's verified.
I was going to do mine without the boost too.
Posted: 25 Jul 2007, 16:56
Nice stuff bean, very clean layout! When are you releasing your stuff? Can we have a go at de-gooping that
Posted: 26 Jul 2007, 15:26
On th first pic there's a resistor added (not in the original) to the volume pot in order to "taper" from linear to audio.
Posted: 29 Jul 2007, 18:15
Interesting that ZV switched to Fairchild BS170.
I was on the NS-site and IMHO they don't manufacture those Mosfets anymore.
Posted: 29 Jul 2007, 22:59
I like post #55 from the HC thread:
I know it is more ££'s, etc, but a Super Duper 2 in 1 (or a SHO) in front of the Box of Rock is a wonderful thing. The BoR responds wonderfully to it, and really does give you full on gain that is controllable from your volume.
Maybe that'll be the next design - just keep adding SHOs!