Big Muff: new version

[drew]

So I have one of the reissue Big Muffs that came out a couple of years ago, with the original case design and logos, etc. I liked my old green tank BMP but it kept cutting out randomly and sounding like ass. It was built pretty badly, the knobs were glued on, and so forth, so I just got rid of it.

Now, the new one has a different design. It's the same one as on JD Sleep's site... almost. It uses 2N5088s, but instead of 0.1u coupling caps, it uses 1u NP electros. And, most importantly, instead of the 1N914 diodes, it uses 1N6263 schottky diodes. I figured these were the culprits involved in the "ass sound" of the new version. It was just too crackly, and sounded crackly even when the sustain was turned all the way down!

So I used a 2P6T rotary switch, mounted about an inch above the stomp switch, with several diode combinations. The BMP has two clipping stages so the 2P were used to switch between two separate sets of diodes, with 6 combinations each. I used:

1. 1:1 1N914 (two diodes, back-to-back.)
2. 1:2 1N914 (two in series going one way, one diode going the other way)
3. 1:1 red LEDs (again, two LEDs, back-to-back.)
4. One germanium diode (asymmetric clipping = "nicer" sound, right?)
5. 2:2 1N914 (two in series, back to back with another pair in series.)
6. The original schottky diodes.

I didn't have enough germaniums to experiment much with those... I just had a 1N34 and a 1N69. So I had one in each clipping stage.

The 1N914 pair, which is the same configuration listed on the schematic at GGG, sounded a lot like my old BMP. Very crunchy but not gross and crackly like the schottky diodes.

The others sounded more "open", with the 2:2 1N914 setup being more of a boost than anything. (But, that's what I expected!) The 1:2 1N914 and the single germaniums both sounded pretty nice... a little less constrained than the 1:1 1N914, and a little more responsive to dynamics. I was surprised that the single germaniums still sounded pretty distort-y. They did sound "darker" than the others- probably from having less harmonics, from half of the waveform not being clipped.

Finally, the Schottky diodes. I think they just died from being de-soldered and re-soldered. They just make the pedal click and pop like it's oscillating at about 4hz or so. Oh well, they sounded like crap anyway. (Does anyone use schottkies regularly? If I get some new ones, will they work well back-to-back in series with a cap or resistor or something to mellow them out a little?)

Okay, that's the end of the report! Thought I'd post in case anyone else hates their reissue BMP like I did.

I think reading the "warp control" article probably influenced me to do this, fwiw.

drew
www.toothpastefordinner.com

[jimbob]

Very cool idea. I want to do this and have a 2p6t but dont know how to physically do it. Any pointers or references?

[Elektrojänis]

How about trying with no diodes at all... I think I have tried that once and it sounded kind of cool. (Not my idea though, I read it somewhere, I just don't remember where.)

[drew]

I just soldered the diodes directly onto the switch, like this:

(diagram) http://www.toothpastefordinner.com/muff-2p6t.jpg

One end of each diode arrangement is attached to a common wire, which is run to the board along with the common pole on the rotary switch. They go to the space on the board formerly used by the clipping diodes. The top of the switch (diodes/connections not shown) is set up the exact same way, with the same diode pairs being opposite each other, so they are selected at the same time by the switch. See dotted line for switch connection. Turning clockwise moves both connections one step clockwise and vice versa.

This is by no means the neatest or best way to do it but it didn't take me too long and that usually wins out when I'm building projects...


drew
www.toothpastefordinner.com

[bobbletrox]

Thanks for the info!  That's a great idea.

I was just looking for some mods that would get a new BM sounding more like the originals.

[drew]

It would be pretty easy to replace the NP electrolytics with 0.1u poly caps, and change a few of the resistors back... maybe they used the larger electros to get a better bass response? Also, from what I remember (don't have it open still, or in front of me for that matter) the collector resistors were smaller, and the series resistors in between stages were 10k instead of 8.2k.


drew
www.toothpastefordinner.com

[aron]

Is this the NYC one? That one sounded bad too. So bad, that for a while I was thinking of modding it for my local shop.

Then it cut me - and I gave up that thought.

[aron]

HELLO, is the person that owns my Big Muff on this forum?  

He wrote me once. It was cool!

Can you believe I traded a great sounding 70's Big Muff for a Tube Driver? :roll:

[drew]

Yep, the NYC version is the one I modded, and yep, it sure does sound like ass...


drew
www.toothpastefordinner.com