Blackout Effectors - Mantra Overdrive

[jeffnl71]

Love to build one of these if you have the time to draw one up. There seems to be schematics around which may help. Sounds like a nice one! Cheers.
http://revolutiondeux.blogspot.co.uk/2012/07/blackout-effectors-mantra-overdrive.html
http://freestompboxes.org/viewtopic.php?f=7&t=14562&start=40

[IvIark]

Yes this is in the list

[dgmz]

Even if you do not have time to design a vero layout of this, could you advise on possible ways to implement a "low gain" mod of this? (more info at http://www.blackouteffectors.com/?page_id=319)
would it be simply an increase in R2 from 10k ohm to 100 k ohm? If you did this, would it affect the highg end of the signal?
Thanks.

[jeffnl71]

I'm being super childish here but...pretty please😉.

[stringfellow_Hawke]

The other guitar player in my band uses one of these. Can confirm the awesomeness.

[stringfellow_Hawke]

Reviving an old one here. Still planning on taking a stab at this one lvlark? It really is a killer sounding pedal.

[johnk]

rather than wait, I think that i'll just draw up a vero for it myself.

[stringfellow_Hawke]

I was secretly hoping you would say that!

[johnk]

I drew up the vero late last night, built it this morning, just finished testing it, and it sounds just like the videos online.  I prefer the bias on the drains to be set at 4.5V on the J201's (I tuned them by ear). the schematic posted by RNFR actually has anerror in it where treble control in the bandaxall tone stack will not work if wired as shown. I found that out after I drew up the vero (!!!!) so I had to mod mine to make it work right. I just need to update my vero with the correction now.

here's a pic of the circuit board which measures 20 x21. i'm sure that Mark can make it smaller (since he's an expert at it) but it'll still fit easily in a 1590B.

[johnk]

okay, here's the corrected vero. rather than completely redraw it, I just added a jumper to make it right.

[johnk]

here's a newer one without the jumper with a few less cuts and one less link:

[stringfellow_Hawke]

You're the man John, much appreciated!

[johnk]

DONE! This pedal sounds AWESOME!

[johnk]

BTW, here's a link to the CORRECTED schematic. The correction is that wiper of the treble pot goes to the output stage, whereas the one posted on FSB has it coming from the bass pot's wiper.

http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/MantraOD/MANTRASCH-corrected.png

[rocket88]

Hey guys, I noticed that Blackout changed the Mantra by having a "low/high gain" switch. I know that the "high gain" setting is the original stock setting, but not sure about the low gain. Any idea how to add a similar switch to the layout?

[rocket88]

I was looking on FSB and found a post about the high/low gain switch. Kismet said "We've done it a few different ways, but right now we're keeping it simple. Break the circuit after the 10k on the input and after the 100K just before the gain pot and wire a dpdt to bypass/add the first stage." My question is how can I do this using johnk's layout?

[johnk]

to remove the first amplifier stage for lower gain, make a cut under the 10n at the input, make the 10K at the input span only 1 row instead of 4, and wire the DPDT switch as shown:

[rocket88]

Nice, I'll give it a shot when I built it. I assume knowing you, you verified it.  I wonder how much of a difference it will make in tone.

[johnk]

I haven't actually verified it since the switch wouldn't fit in mine, but that is how you'd remove the first amplifier stage (as per the instructions that you posted).

[rocket88]

It's all good john. You  know what you're doing, so I'm sure it will be perfect. I found those directions in a thread on the FSB forum, and the guy that posted it said there is more than one way to do it, and that was the easiest and cleanest way to do it, so I'm not sure if it will sound like the actual unit with the mod.

I'll give it a try when I get a chance, and report back. Hopefully if someone gets to it first they will post how it works. As always john, thanks for making the layout, not to mention doing it so quickly.