B.Blender parts/schematic query + some other questions...

[kissack101]

Evening all....

I play a little bass (i'm also a little new at this so please be patient...) and I'm gonna put my EHX Russian Muff and my EHX Bass Balls in one "Taiwanese 125C-Size" from Small Bear (to save space on my pedal board - both pedals have large enclosures with very little inside). I also wanted to add a 'blend' knob to mix a little uneffected signal with the fuzz to give it punch/clarity.

So, after combing the forum (this place is a real treasure trove) it seems a lot of people have had sucess with the B.Blender. My questions:

1) The schematic (this one: http://www.seanm.ca/stomp/bblender.html) looks reasonably straight forward with the exception of the large, triangle-like components which I think are OpAmps. If I was to order these from Small Bear, exactly which component would I need? And if it's a chip, would I need a socket or something similar?

2) The Bass Balls has a switch to turn the distortion on and off, the likes of which i've never seen before. I was hoping to swap it for something smaller but i've no idea what type of switch it is, any help would be appreciated.

3) *somewhat irrelevant* What type of tube does the Z.Vex Nano amp use and are they available to Joe Public? I have aspirations of making the Tube Wah on the GeoFex website and i'm trying to figure out a way of getting s tube inside a Cry Baby shell.

Well, that's pretty much it for now, thanks in advance...

Adam.

[Bernardduur]

1. normal TL-072 can do the trick (those are two "triangles" in one, so you need two). I would socket them.

2. a normal throw switch can be used (my guess it was a DPDT switch). The bassballs uses a slide DPDT switch.

3. Dunno

[gaussmarkov]

fwiw, i made a verified perfboard layout of the b. blender that fits into a 1590b box:



i also posted a progress reports on my build here and here.

[kissack101]

That schematic looks very helpful indeed, many thanks.

Just to double check: R4= resistor C3=capaciter G2= ground points? Also what to the grey strips by R4, R3 and R1 mean? I assume they represent resistors but there was no space to represent them on the layout?

Thanks again

Adam

[kissack101]

Also, the schematic calls for a 50k pot, is that just a standard pot (i.e. the type you find in your guitar) or is it some kind of special 'blend' pot? Also, do Small Bear sell 50k pots? I've checked the site and only some of the pots seem to have a rating, and none of them are 50k How essestial is the '50k' value over, say 100k? Lastly, the schematic talks about too much signal causing the opamp to distort, will a Russian Muff do this?

Apologies for all the questions, I am but a learner...

Thanks

Adam.

[gaussmarkov]

Also, the schematic calls for a 50k pot, is that just a standard pot (i.e. the type you find in your guitar) or is it some kind of special 'blend' pot? Also, do Small Bear sell 50k pots? I've checked the site and only some of the pots seem to have a rating, and none of them are 50k How essestial is the '50k' value over, say 100k? Lastly, the schematic talks about too much signal causing the opamp to distort, will a Russian Muff do this?

Adam.

hi adam,

no worries.  i completely spaced on posting that layout without a parts list.  occurred to me later and just now getting back to the forum.  here's the list of parts with names that go with the layout:

Component	Value
BLEND	50K
C1	.1uF
C2	10uF
C3	10uF
C4	10uF
C5	.1uF
C6	.1uF
C7	10uF
C8	10uF
IC1	TL072P
IC2	TL072P
R1	1M
R2	10K
R3	10K
R4	470K
R5	1M
R6	1M
VOLUME	100K

so R4 is a 470K resistor, etc. so my version has the volume mod.  G1-G4 are just pads for various ground hookups.  the funny symbols for some of the resistors represent the resistors standing on end.  you can see some in the pictures for aron's beginners project.  here's one particular example:



here's my version of sean's schematic (which goes with my layout):



i used a 50k linear pot.  you can used anything you like (see this recent thread on pots).  an audio pot will work too.  it will just respond differently.  small bear does carry linear, audio, and reverse audio pots.  i use the 16mm pots.  go here on small bear and you can see the drop down dialog box for the size of linear pot you want.  50k is listed.  a lot of folks would use log/audio for the 100k volume pot.

re a muff pi, someone else will have to comment authoritatively.  my guess is that the answer is yes, but not for all settings.  just when you crank it.

sorry for being so slow!  (for some reason, i got no email notification of your posts.)

[seanm]

I don't know how I missed this thread 

The blend pot should (must?) be linear or the blend will act weird. 50k is a stock pot value, although 47k is the stock value for resistors, go figure.

[gaussmarkov]

oops ... i see a mistake in my layout:  the volume pot is backwards.  you should hook up lug 3 to the pad marked 1 and vice versa.  (lug 1 should be going to ground.)  lug 2 still goes to the middle.  easy mistake for a first project. 

[kissack101]

wow... you lot are helpful.

Many thanks.

[kissack101]

Ok, apologies, but I have one last question...

I'm trying to figure out which capaciters I need from the Small Bear site and it doesn't seem to be making it easy. 0.1uF = 0.1 micro Farads right? If so, why does Small bear only measure in either pico or milli farads? I ordered some  Panasonic ECQ-B .001 mf for the 10uF capacitors, but I can't find what I need for the 0.1uF capacitiors? I've been staring at multiples of 10 for a good while now trying to get my head around it with limited success, any help would be appreciated...

[Bernardduur]

Ehm, I guess 0.001 mf = 0.001 µf because he can't find the µ sign and milifarads are not that often used here

Correct me if I am wrong

[kissack101]

he could perhaps use a "u" instead? It's a little confusing, given that one unit is 1000 times bigger than the other, I just want to make sure before I order - I live in England and those parts have to come a long way from New York...

[Bernardduur]

Isn't there in England a "closer" solution?

[kissack101]

Nothing local to where I live, so i'f i'm gonna order it by post, it may as well be from the best/cheapest place regardless of physical location. When I wanted to upgrade my cry-baby with no knowledge of modding pedals Small Bear did an excellent job sorting me out, so I guess if it isn't broke, don't fix it...

Has anyone ordered capacitors from Small Bear though? Does the 'm' mean micro or milli?

Thanks Adam.