Bearfoot - Model G  [traced]

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mmolteratx
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Post by mmolteratx »

Got this one on Monday and traced it today. Really similar to the Honey Bee, but even lower gain with less compression. Not my thing at all.
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ChargerSG
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Post by ChargerSG »

Looks a lot like the Sweet Honey OD in topology including the "Focus" knob which would be the Model G's "C" control (controlling the negative feedback networks similarly found in the Honey Bee and Model H as well) The additions would be a JFET Inverting stage instead of the Op Amp stage, a Honey Bee Nature Control, and JFET 2N5457 clippers to ground.

http://3.bp.blogspot.com/-UCNpsHI3j7M/U ... ematic.png

Any news on a EGDM schematic ? :)

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mmolteratx
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Post by mmolteratx »

ChargerSG wrote:Looks a lot like the Sweet Honey OD in topology including the "Focus" knob which would be the Model G's "C" control (controlling the negative feedback networks similarly found in the Honey Bee and Model H as well) The additions would be a JFET Inverting stage instead of the Op Amp stage, a Honey Bee Nature Control, and JFET 2N5457 clippers to ground.

http://3.bp.blogspot.com/-UCNpsHI3j7M/U ... ematic.png

Any news on a EGDM schematic ? :)
It'd be easier to say it's an HBOD with a pot in series with one of the feedback paths, a different taper nature pot and FET clippers. Nothing on the EGDM. I'll draw something up when I get the chance.

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ChargerSG
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Post by ChargerSG »

mmolteratx wrote:
ChargerSG wrote:Looks a lot like the Sweet Honey OD in topology including the "Focus" knob which would be the Model G's "C" control (controlling the negative feedback networks similarly found in the Honey Bee and Model H as well) The additions would be a JFET Inverting stage instead of the Op Amp stage, a Honey Bee Nature Control, and JFET 2N5457 clippers to ground.

http://3.bp.blogspot.com/-UCNpsHI3j7M/U ... ematic.png

Any news on a EGDM schematic ? :)
It'd be easier to say it's an HBOD with a pot in series with one of the feedback paths, a different taper nature pot and FET clippers. Nothing on the EGDM. I'll draw something up when I get the chance.
It also has the Sweet Honey's smaller 4n7 input cap, and the same 47k/47k voltage dividers.

And okay if you would that'd be awesome!

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Post by IvIark »

Cheers Matt. This is verified

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"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP

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Post by trumpetboy »

mmolteratx wrote:Got this one on Monday and traced it today. Really similar to the Honey Bee, but even lower gain with less compression. Not my thing at all.
I noticed R14's value is missing. Is R14's value 47k ?

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mmolteratx
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Post by mmolteratx »

trumpetboy wrote:
mmolteratx wrote:Got this one on Monday and traced it today. Really similar to the Honey Bee, but even lower gain with less compression. Not my thing at all.
I noticed R14's value is missing. Is R14's value 47k ?
Yes, just like the HBOD.

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Post by drbob1 »

I may be out to lunch here, but it looks to me like all the Bearfoot overdrives (and by extension, the BJFE and Mad Professor versions) consist of variations on the basic Rat circuit with a soft clipping circuit in the first op-amp stage and some form of clipping to ground between op amp stages. Then differences in bells and whistles create the slight differences in voicing/response? I've compared quite a few of the Bearfoot versions to each other and actually found them quite useful in general-the HBOD is a brighter, thinner tone that's flattering to some dark guitar/amp combos, like the original Bluesbreaker circuit and the DynaRed/RedHot are very nice takes on the classic Rat voicing.

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Post by bbkassel »

EGDM??

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Post by drbob1 »

To be fair, the EGDM is billed as an overdrive fuzz, and yeah, it's discrete transistors rather than an op amp.

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Post by HamishR »

Wow - old thread. I built this again just recently and it works perfectly with my set up. I love it! I love that it has minimal compression and it has way more dirt than i need. You should hear it with a Les Paul through a tweed Deluxe - super punchy and a great old-school blues tone. Fab.

The one change I made in the second one i built was to get rid of the C control as it does next to bugger all. I just replaced it with a 27K resistor to make it another 3-knob pedal. Also I like this pedal enough to go out and buy one, and I discovered that my original has 2N5952 trannies in all positions. So the clippers are 2N5952 as well - but of course it doesn't make a huge difference.

If anyone is interested I have drawn up a modified version of IVIark's excellent vero layout with my simple mods. If you are interested in punchy, clear but FAT old-school overdrive this is one of the best I have heard.
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HamishR
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Post by HamishR »

And after further experimentation I have found that you can replace the Jfet clippers with ordinary old 1N4001 diodes with little change in tone. The feel changes slightly - it's a tad stiffer with the diodes but equally usable - some may even prefer it. I like both. I guess the jfets-as-diodes gives a slightly more "amp-like" sag but it's subtle.

I tried BAT41s because I like how they worked in some other pedals but the volume drop is quite dramatic! The 1N4001 is very close to the original, so might be worth a try for anyone with transistors in short supply. :-)

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Post by maoriente »

Does the 5k6 drain resistor bias the "3rd" 2n5952 at the typical 4.5v?

I'm limited to using 2n5457 smds, which measure all over the place.

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Post by maoriente »

Has the power resistor R15 @ 470R been confirmed? Seems odd as every other Bearfoot pedal with this same topology indicate 47R.

In my build R15 @ 470R drops the supply voltage down to 8.2v, where 47R gives around 9.1v

And considering the other versions all have the same R13 Q3 drain resistor value of 5k6, leads me to think R15 in this pedal should also be 47R.

Also, with the 9.1v supply, I'm getting the 2n5952 biased at 5.3v. I needed to bump up the drain resistor to 6.8k to get closer to 4.5v bias.

Still messing with it to hear what combo sounds best, but hoping someone else can offer some insight.

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