Mad Professor - Blueberry  [traced]

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DimebuGG
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Post by DimebuGG »

Based on schematic V1.2...
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Blue Berry Bass OD PCB.pdf
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lohstah
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Post by lohstah »

On my telecaster it's like a less dynamic, gainer, low-middy honey bee
do you mean gainier like more gain than the honey bee ?

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Post by lohstah »

Important Update !

i finally had some time on my hands and wanted to build me self a blueberry from fuckyourmom´s vero, but the thing did not bias up correctly and sounded awful. checked on my scope and, sure enough, both fet stages did not produce the expected result. the 2nd fet was not so bad but did not have sufficient gain, while the first stage simply sounded horrible and messed the signal up. so i checked back on my pics and there are two mistakes in my V1.2 schemo:
R7.jpg
R7.jpg (12.23 KiB) Viewed 5587 times
R7 (R4 on my schemo and the vero) is not 10K7, but 14K7.
R20.jpg
R20.jpg (14.84 KiB) Viewed 5587 times
R20 (R21 on my schemo and the vero) is not 1K6, but 2K62 (2K6).

so here is the updated schematic 1.5:
MP Baya Azul V 1.5.jpg
i used 15K and 2K7 respectively, that´s what i had at hand.
with these values, both fet stages bias up well and it sounds like it should.

so, until dimebugg have time (and the notion) to update their project files, remember to change R4 on the vero to 14K7 and R21 to 2K6 !

cheers,
lohstah

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DimebuGG
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Post by DimebuGG »

Thanks for the info lohstah...
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Blue Berry Bass OD PCB(v1.5).pdf
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Post by lohstah »

i used BF244A. just listening to the output, it is not so obvious - there is distortion, but in a weird way. with minimal gain, the breakup was weird and fizzy. turning up the gain produced better results. but zooming in on the respective outputs of Q1 and Q2 with an audioprobe or scope, you hear and see it. also, there was much less gain on tap than with the original - so i figured something was wrong. now unity is around 11:00 of the vol pot. of course it helped that i had played the original, so i knew what to expect. btw i would not be surprised if the the defaced fets in the bee are bf244a as well...

cheers,
lohstah

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method
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Post by method »

I found this vero layout in a zip file stash I'd collected on my hard drive a few months ago. It is verified.
bjf_blueberry_OD.png

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Post by makispoll »

method wrote:I found this vero layout in a zip file stash I'd collected on my hard drive a few months ago. It is verified.
bjf_blueberry_OD.png

Sorry about the question I am a bit novice, I have only built a few easy pedals. What do we actually do with LEDs? Are they normal red LEDs?What size?And how do we wire them?I don't understand from the layout, is the + lug on the flat side of the layout?

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Post by jbgron »

Has DimebuGG's v1.5 PCB been verified? I just built it and I'm not getting any sound.

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Post by jbgron »

I got sound but it doesn't sound great. It sounds all gated and fizzy, the drive and texture knobs don't do much either. I'm using a TL061 and tried BF245C, 2N5457 and J201 but they all produce similar results. Any ideas anyone?

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Post by roseblood11 »

jbgron wrote:Any ideas anyone?

Yes, you might have made a ... mistake[/color] :secret:

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Post by jbgron »

Very helpful comments there :scratch: I've checked over this thing a dozen times and I'm sure I haven't made a mistake but I have made some component substitutions listed above. Has anyone else built DimebuGG's v1.5 PCB or am I the guinea pig?

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Post by roseblood11 »

Post pictures of your built and measure the voltages at all pins of the IC and the transistors...

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Post by ShortScaleMike »

I built it without problem, but did notice that the BF244As are shown in the wrong orientation I believe. I was expecting to reverse my 2n7000s, but instead realised they had to go in as the Fets are orientated on the layout and it was A OK.

Maybe start there?

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Post by jbgron »

Thanks Mike. I also noticed the wrong orientation. I've tried a variety of FETs and orientations to no avail. My build does work and produces overdrive sounds but it doesn't sound good and nothing like an original unit. I'll have another bash at it tonight after work and see how I go.

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Post by drbob1 »

So, this is the Honeybee/ModelH/DynaRed but with a single op-amp rather than a dual, and FET buffered output? The other 3 sound very similar with different amounts of gain and EQ choices but are pretty similar soundwise to the Rat (similar topology, different clipping). How does the Blueberry compare to them?

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Post by Seiche »

drbob1 wrote:So, this is the Honeybee/ModelH/DynaRed but with a single op-amp rather than a dual, and FET buffered output?
they all have single op amps and a fet buffered output.

this seems to just a honeybee with a fet buffered input.

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Post by briggs »

And indeed the FETs don't just buffer - they also boost. I'd always use a trimpot on the drain (or source) of those FETs and bias in a nice 5-5.5V on the drain, then you know you've got the sweet spot for operation. FETs vary quite a bit so it's worth taking the time, you'll get a better sound..
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Post by Seiche »

how does this compare to the BJFe version btw? I read here that one of them has been degooped. maybe this could help comparing the two (component values etc).

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Post by kalka »

Hi guys,

I built the vero, tripple-checked everything, traced all the connections, yet it doesn't work. I had to turn the input and output on my amp to 100% volume and then it just kind of farts.

The only change I made is I inverted the BF244A transistors according to the datasheet (http://pdf1.alldatasheet.com/datasheet- ... F244A.html)

The IC is CA3130E (only difference from the EZ is it's not lead-free).

Maybe I've toasted the transistors during soldering? What measurements should I take? What voltage should there be between d-g and g-s on the transistors?
I get 8.07V on pin 7 and 4.60 on pins 2 and 3 of the IC.

Here is the mess:
3BOD.JPG

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Post by Seiche »

take a picture of the trace side and link the layout you used :thumbsup

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