MP Blueberry Bass OD clone tech question

[fyred1]

Hello everyone :)  I'm new to the forum and new to building pedals.  

My first build is a BBBOD.  I used the vero layout for the Mad Professor version.  It works great!  Just wondering what's the best way to lessen the drive a bit.  I tried using a resistor across the drive pot, and it changed the sweep for the better, but it also seemed to change the sound of the effect.

Any help is appreciated.  Thank you!

[Silver Blues]

Welcome! I'm sure you'll love it here.

I too found the Mad Professor Blueberry to be overly gainy and not particularly nice sounding. As a bit of a tangent before the main point, there are two other versions of the Blueberry that are far lower gain and IMHO sound far nicer, the Bearfoot version and the original BJFE version.

Presumably you don't want to just build another pedal, so there are a few ways to reduce the gain on the MP version. Changing the gain pot for one of a lower value is probably the easiest way (perhaps try a 500K log). increasing the 1K that connects to the Nature control network (R10) will also reduce your gain but will definitely change the sound, as it is altering the corner frequency of the filter this resistor is part of at the same time. You will need to also adjust the corresponding capacitor (C7). Reducing or eliminating the 2K in the feedback loop (R9) will give you lower minimum and maximum gain (just adds to the pot's resistance at all points in the sweep), and if you happen to try the 500K drive pot and find your maximum or minimum is not enough then increasing this to compensate may help you. These resistors are what set the gain for the op-amp, although part of the problem with this circuit the way I see it is that the op-amp is already being driven too hard by the first JFET stage. You might try reducing the 4.7uF source bypass capacitor although this will change the frequency response. Increasing the value of R7 may also net you some attenuation at the op-amp's input.



I'd also like to point out that you've mistakenly posted this in the wrong subforum. Something like this would probably go in Open Chat; this subforum is for verified layouts of additions/modifications to other circuits.  

[fyred1]

Thank you for the great response!  I'll definitely look into the mods you've suggested, and I'll try to figure out the proper places to post...  

:)  

[rocket88]

honestly i would build one of the other blueberry ODs for a few reasons. as someone that's built all 3, and create the layouts for the BJFE and Bearfoot, the MP is terrible by comparison IMHO. the MP version is rather lifeless, and as you mentioned overly gainy, not in a pleasant way. trust silver and my suggestion of building one of the other 2. if you do, the BJFE is much warmer and natural sounding to my ears, while the Bearfoot has a little midbump. personally, i prefer the original BJFE version, i mean it's bass-ically the KLON of bass ODs. (see what i just did there?)

the main reason for it being higher gain is the JFET stage at the input, which drives the chip harder. you could try to remove the basically everything from the 1M pulldown at the input to the to 47nFcap (C5), which you want to keep. btw, comparing the MP blueberry schematic to the BJFE blueberry schematic, most of the values are the same. the MP has a larger input cap, as well as a few others, which should make it a little bassier then the BJFE.

no worries about putting this in the wrong section. i would put this in the open chat section, and just moved it for you.. btw, welcome to the forum and community.

[Silver Blues]

Yeah I've built the Bearfoot version and I like the sound although the mid bump is fairly pronounced as Rocket details and may not be up to the tastes/rig requirements of some. I'm just waiting for some relays to finish my build of the BJFE one.

A little mod I learnt of from JohnK involves placing one of Albert Kreuzer's preamps ahead of the MP Blueberry, which indeed makes it sound significantly better. You could opt to just try this with your MP and take a crack at one of the other two perhaps, or who knows, maybe you'll be satisfied with the mod.

[fyred1]

Thank you. :)

I'm going to try replacing the drive pot, first, for kicks, but I think I'll build the BJFE version. If i had known there were major differences, I might have built that one in the first place.  The MP version I built came in kit form, so it was a good place to start.

Looks like I can rob one of the transistors and the IC from the MP version.  

[traktop]

I´m not the bass player in my band, but I´ve been recording some ideas recently with the bjfe od into an ashdown evo II 500.
Just do it, it´s a real winner. I built Zach´s layout and you won´t find any unusable setting.
It hasn´t got much gain, but is quite dinamic. The left tone pot run will give you more bass grit and gain, perfect for turning a clean amp into a bassy tube monster. The right side will give you a cleaner sound with a very natural  slight mid hump at about 800hz, perfect for boosting an already saturated amp.

[fyred1]

Yeah, I'm going to build the BJFE version, later.  I'm really curious about it.  

Guys, I figured out why my gain was so far into the fuzz range.

WARNING!!! NEWBIE ON THE LOOSE!!!  

I was swapping out pots to see how different values affected the sound, and I thought I'd check the value against the layout (it was printed on the shaft side, so I couldn't see it).  I had the volume and the drive pots switched.  haha!  The pedal works much better. Still more drive than I would consider "overdrive", but it's no longer in Big Muff territory when it's wide open.  Live and learn...  I like the pedal much more now. :)

EDIT 5-13: Played with it more, today.  I'm super happy with it, now!   At low settings I think it sounds incredible!  I played along with a practice sequence of Al Green's "Let's Stay Together" with the drive at around 8:00 and the nature at between 10:00 and 10:30.  I played through the song 5 times, I was liking it so much.  Too cool!  

[negativefx]

Just make the BJFE.  It's wayyyyyyyyyyyyyy better than the MP.

[fyred1]

I will.  I went looking for a kit and couldn't find one, so I started looking up parts. I can see that the process could become quite a pain in the posterior region.

[Silver Blues]

At this rate I think I'm going to just build all three versions. I have two of them completed or almost completed already anyway.

[fyred1]

I really do like the way the MP version sounds. I keep the drive knob really low and it breaks up nicely.  I just wish it had a bit more sweep in the light breakup range.  

It might be a while before I build the BJFE version. I'm about to get poor.  My band doesn't play much through July and August.  I'll see about it after I get through the lean time.

[traktop]

Since there are some bjfe users here, I´d like to know what do you guys put in front and after this for boosting.
I´ve checked around the threads and found that Zach has the "Sagrado Poblano Picoso" as first boost option, (I guess in front of the bjfe). The thing is that I´ve tried some pedals in front of the bjfe and wasn´t so excited about how the bjfe ate them.
And what about after it? I guess that shoud be something with some gritt, but pretty transparent in order to keep the body that the bjfe provides...
Any idea?  

[rocket88]

Well the reason I like it the Picoso is that it's super clean and adds a bit of mids and dare I say tubeyness to my sound. It just opens things up. I haven't really used it in front of the bbbod cause it makes it distort more, and for me it's not really how I like my od to sound. Actually have the same thing happen when I turn the Jazz bass I made from passive to active. Not saying th sound is bad, just not what I've been after, ya know?

[fyred1]

I run my Sagrado Poblano Picoso last in the chain and use it to beef up my slap tone.  It works really well to fatten the sound some, even at very low settings.  I'm barely boosting at all.  Just enough.  My slap line  was getting lost when it was up against a synth that plays the same line.  

*I don't have the BJFE version of the Blueberry yet, but I think it might be interesting trying the Picoso in front of it.  My MP version of the Blueberry has plenty of drive on it's own.

[traktop]

So you are using it last in the chain. I´ve being watching youtube videos and if that gritty texture at higher gain settings comes without  a lowend loss, it could be interesting. The only problem I see is that huge volume boost, (I want gritt, but not a volume boost), should only work before gain pedals, unless a master vol pot was added to the circuit.

[fyred1]

Right. I use it for the sole purpose of boosting a clean signal.  If I was going for grit, I'd probably be looking for a different pedal.  But that's me.  We all have different ideas.

[traktop]

rocket88 wrote

Well the reason I like it the Picoso is that it's super clean and adds a bit of mids and dare I say tubeyness to my sound. It just opens things up.

We´ll see, I´m already on it ;)
Do you think is well worth a master volume on this one? I tried it on the EP booster but it worked awfully...

[rocket88]

with any booster into a pedal you'll get more volume. if you turn the boost down to where the signal is about the same as without the boost in front you will get less grit then when it would be full blast, but it should increase the grit of the effect. a booster may be what you're looking for, it's just finding the one you like, ya know? with a booster set high it's like having a lead tone when you turn it on, and rhythm when it's off.

imho, the thing with having pedals into the bbbod, really many od pedals is that it kinds sucks everything up and spits out something kinda blah. this is why most people put their od as the first effect, not counting tuners.

this is the "typical" pedal chain you'll see. by "typical" i mean most common.


OD, Distortion, and Fuzz at the beginning, and time based pedals at the end.

[traktop]

rocket88 wrote

with any booster into a pedal you'll get more volume. if you turn the boost down to where the signal is about the same as without the boost in front you will get less grit then when it would be full blast, but it should increase the grit of the effect. a booster may be what you're looking for, it's just finding the one you like, ya know? with a booster set high it's like having a lead tone when you turn it on, and rhythm when it's off.

I know what you mean with that. I use a naga viper myself into any of my od/distortions for soloing.
Anyway, I´ve just threw out the idea of the picoso in front of the od, so I would use it after it, to give some color and more gritt. My question about the master volume was because it seems that the pedal has a volume bump even in the lower setting of gain, so that´s what I´d like to prevent.