Couple of modified BJFs

HamishR

Well-known member
As the International Mail Service Disruption is proving to be very real it's back to vero for me. I've been quite prolific and in a way having no access to PCBs has been a good thing, as I'm particularly happy with how these two particular pedals sound.

First is a modified Honey Beest, traced by Daeg who is a member here. Cheers Daeg! The Honey Beest is a pretty cool overdrive already, but I have discovered that for my use I prefer silicon diodes over LEDs as I like the bark on the low strings. There will be many who like the LEDs better and I can see why - I just prefer my silicon selection. :)

The Honey Beest has a gain, a pregain, a Nature control and volume. I guess the pregain control was made possible by the extra gain stage at the input. The Honey Bee has quite a low output, so I'm guessing this was Bjorn's attempt to increase volume and gain. It works. But I prefer to have just one gain so replaced the pregain with a resistor in my prefered range of gain and replaced it with a treble pot. So now Nature is two pots, a kind of treble and bass. I really like how they work in this circuit. It's a cracker.

Honey Bearext.jpg Honey Bear int.jpg

Then there's the Model G, which i always liked in stock form but felt the C control did next to bugger all and wanted to split the nature into bass and treble again. It works particularly well in this circuit too - it's similar to the Honey Bees but has a leaner midrange and tougher sound.. Again, the LEDs went and silicons stayed. Sounds killer with a Gibson. Loving this pedal! Thanks for the help Chuck!

G T+Bext.jpg G T+Bint.jpg

I'm still coming to terms with the slight crookedness of the board. Screwing the back onto the pedals helps, as does just playing it.
 
Sounds very interesting, I'd be keen to see schematics for these with the mods, like bass and treble. Wouldyou be abe to post them or do you have a link?
Thanks so much!
 
I can show you a schematic I drew for the Model G mod. FWIW I call it the Model The G because here in Australia the biggest sporting arena is the Melbourne Cricket Ground, which is known as the MCG or "The G". I can post the layout too if you want to try vero. I haven't got around to drawing a schematic of the Honey Beest mod - I call it the Honey Bear. But I can post a layout.

Model G T+Bschem.png

Model The G- T+B.png

Honey Bear.png
 
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"Hamish, your Veros look a Helluva lot better than a some people's PCB builds!"

Thanks Chuck! I just like neat. It makes it easier to troubleshoot for a start. And it's easy. I may not be the cleverest electronics guy (I still don't really understand how any of this works!) but I can do neat. And I must admit I think my veros are neater than BJF's PCBs - he could learn a thing or two from the folks here. I guess Bjorn knows rather more than me about how these things work though...
 
I have tried 1N4001s in the past in a Model G with good results. I used them because Bjorn has used 1N4007s in the same place - as you can see in the Honey Beest. In fact I intend to build another G with my T+B mods and 1N4001s. From my experience the differences are minimal - you can hear that something is different but it's not huge. The switch from LEDs to my silicon combo around the Drive pot is much more noticeable.
 
I think I know why there is a sonic difference between the diode pairs and LEDs. Take a look at this plot. Ignore the waviness of the red curve, it's an artifact of my curve tracer. Where the curves are horizontal at the bottom, the diodes are not conducting. As the curves bend up, the diodes begin conducting. The steeper the curve, the higher the conductance. Conductance is the reciprocal (opposite) of impedance. High conductance = low impedance.

LED vs 2 Si diodes.PNG

Besides the obvious difference in Vf, notice how the Si diodes begin to conduct very gradually, starting around 0.8V and it takes another 360mV (45%) to get up to 1mA. The LED turns on much more abruptly starting at 1.5V and only takes another 170mV (11%) to get up to 1mA. Diodes in the feedback loop see lower current than hard clipping diodes. They usually peak out below 2mA and spend most of the time well below 0.5mA. What all this means is that the diode pairs will have a smoother, more gradual transition from clean to dirty and less of the harsh high-order harmonics in the dirty region.
 
Wow - that's really cool! I'm surprised at how much difference you can see when it's graphed like that. The things I like about the Si diode combo is that there is a lot of room between hitting the string hard and hitting gently, and as you can see on the graph that area is smoother than with LEDs. Then there is the sound itself: LEDs give a kind of "blatty" sound; less distinct on the bass strings and rounder on the trebles, which can sound softer and less aggressive. I prefer a crisper sound where I can hear the definition, the twang, on the bass strings. I also find the Si combo to have a more vocal quality when used in these pedals.

One thing I have to admire about these BJF designs is how he has added clipping in different stages which is far more like how an amp distorts. Instead of having all the dirt appear in one place he spreads it out and gives it a different character in the different stages. I guess that's why it sounds more complex and "natural". It's not necessarily better but it is a great sound to have available. The G in particular I can see being used as a foundation sound, especially with a Gibson. I think using the Si combo rather than LEDs actually makes it a more of an "all-round" OD rather than a lead guitar OD.

I play with a pick and fingers style and the extra dynamic range with my mods makes these pedals a lot of fun and very expressive. I can go from clean to quite dirty just by how I pick and it all sounds very natural. The Honey Beest/Bear is a ruder sound with more mids which is fun but the G is a real old school rock'n'roll sound. Overall I still prefer my modded BB Preamp but these BJFs are seriously cool.
 
Awesome, thanks for posting schematic (I'm into schematics and see what I can learn from it, I'm personaly not into vero builds, although I admire what you do there. Great stuff.
Any links and postings of schematics is great for me to see, thanks for sharing!
 
I have a schematic for the Baby Blue OD as well if you would like that?

Today I built another G with treble and bass knobs, but used 1N4001 diodes where the original uses 2N5952 Jfets as diodes. Comparing them side-by-side has been interesting - so far I don't have a lot of time on them but with my Les Paul the all silicon diode version has more dirt and less volume, meaning that to get it to sound the same as the Jfet clipping version I keep the gain knob lower and the volume higher. They can sound very similar once I have adjusted them. Both sound fantastic! I think the all Si version is also a hair brighter, and that could be the increased high order harmonics I guess. Actually I have no idea but that sounded good to me.

I suspect that if I can find some diodes with a similar response to the Jfets it would sound more or less the same. I think I'll be keeping each as they are because so far I like both equally. And if you are getting low on 2N5952s rest assured that using 1N4001s will get you pretty close sound-wise and might just get you the extra dirt you desire. I am using gain at around noon on the original and about 10.00 in the new one.

Any suggestions for diodes to simulate Jfets, Chuck?
 
Awesome and yes I'd be interested in the Baby Blue OD schematic please!
Thanks so much for the in-depth description and observations with clipping diodes and jfets, very cool!
 
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