Bearfoot - Model G  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
Post Reply
mmolteratx
Degoop Doctor
Posts: 510
Joined: 19 Dec 2009, 02:50
Has thanked: 97 times
Been thanked: 606 times

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.
Attachments
Model G.png
Model G.png

ChargerSG
Posts: 10
Joined: 02 Sep 2013, 21:57
Has thanked: 3 times
Been thanked: 1 time

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.

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

Any news on a EGDM schematic ? :)

mmolteratx
Degoop Doctor
Posts: 510
Joined: 19 Dec 2009, 02:50
Has thanked: 97 times
Been thanked: 606 times

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.

https://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.

ChargerSG
Posts: 10
Joined: 02 Sep 2013, 21:57
Has thanked: 3 times
Been thanked: 1 time

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.

https://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!

IvIark
Tube Twister
Posts: 2297
Joined: 02 Jan 2008, 00:59
Location: Manchester UK
Has thanked: 599 times
Been thanked: 608 times
Contact:

Post by IvIark »

Cheers Matt. This is verified

Image
"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

trumpetboy
Posts: 3
Joined: 28 Apr 2009, 15:37
Has thanked: 2 times
Been thanked: 1 time

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 ?

mmolteratx
Degoop Doctor
Posts: 510
Joined: 19 Dec 2009, 02:50
Has thanked: 97 times
Been thanked: 606 times

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.

drbob1
Cap Cooler
Posts: 471
Joined: 21 Dec 2010, 21:30
Has thanked: 6 times
Been thanked: 40 times

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.

User avatar
bbkassel
Posts: 29
Joined: 05 Nov 2010, 19:47
my favorite amplifier

Macht12-Klon, Princeton, Champ

Has thanked: 7 times
Been thanked: 1 time

Post by bbkassel »

EGDM??

drbob1
Cap Cooler
Posts: 471
Joined: 21 Dec 2010, 21:30
Has thanked: 6 times
Been thanked: 40 times

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.

HamishR
Breadboard Brother
Posts: 74
Joined: 31 May 2016, 15:51
Has thanked: 6 times
Been thanked: 36 times

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.
]
Attachments
Model The G.png

HamishR
Breadboard Brother
Posts: 74
Joined: 31 May 2016, 15:51
Has thanked: 6 times
Been thanked: 36 times

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. :-)

maoriente
Posts: 27
Joined: 20 Jun 2013, 19:02
Been thanked: 4 times

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.

Post Reply