BAJA VH4 overdrive pedal project 290118  [documentation]

Original effect designs complete with schematics, layouts and instructions. Freely contributed by members or found in printed or online publications. Cannot be used for commercial purposes without consent of the respective owners of the copyright.
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bajaman
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Post by bajaman »

Hello fellow diyers :D
Here is my latest build based on the frequency response characteristics of the Diezel VH4 tube head channels 3 and 4, but scaled down into a 9v dc pedal friendly format.
I took it around to my friend's house last night for evaluation - we have a monday night four piece jam session where i usually play drums, but last night i got a chance to try using it on Neil Young's
"keep on rockin' in the free world" and needless to say it sounded awesome on very low gain setting Channel 3 - just the right amount of seering crunch and in my view one of my best pedals to date :!:
Again perhaps one of you may like to contribute a vero or stripboard layout and hopefully "rcustoms" will contribute one of his excellent pcb layouts :hug:
Here is the schematic and some pictures of my prototype build.
enjoy :thumbsup
bajaman
Baja VH4 pedal True bypass version ch3 and ch4 270118.GIF
IMG_3495.JPG
IMG_3494.JPG
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bajaman
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Post by bajaman »


Moderator: double post resulted from merging the two topics having the same subject.


Hello fellow diyers :D
Here is my latest build based on the frequency response characteristics of the Diezel VH4 tube head channels 3 and 4, but scaled down into a 9v dc pedal friendly format.
I took it around to my friend's house last night for evaluation - we have a monday night four piece jam session where i usually play drums, but last night i got a chance to try using it on Neil Young's
"keep on rockin' in the free world" and needless to say it sounded awesome on very low gain setting Channel 3 - just the right amount of seering crunch and in my view one of my best pedals to date :!:
Again perhaps one of you may like to contribute a vero or stripboard layout and hopefully "rcustoms" will contribute one of his excellent pcb layouts :hug:
Here is the schematic and some pictures of my prototype build.
enjoy :thumbsup
bajaman
Baja VH4 pedal True bypass version ch3 and ch4 270118.GIF
IMG_3494.JPG
IMG_3495.JPG
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rcustoms
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Post by rcustoms »

bajaman wrote:Hello fellow diyers :D
Here is my latest build based on the frequency response characteristics of the Diezel VH4 tube head channels 3 and 4, but scaled down into a 9v dc pedal friendly format.
I took it around to my friend's house last night for evaluation - we have a monday night four piece jam session where i usually play drums, but last night i got a chance to try using it on Neil Young's
"keep on rockin' in the free world" and needless to say it sounded awesome on very low gain setting Channel 3 - just the right amount of seering crunch and in my view one of my best pedals to date :!:
Again perhaps one of you may like to contribute a vero or stripboard layout and hopefully "rcustoms" will contribute one of his excellent pcb layouts :hug:
Here is the schematic and some pictures of my prototype build.
enjoy :thumbsup
bajaman
Baja VH4 pedal True bypass version ch3 and ch4 270118.GIF
IMG_3494.JPG
IMG_3495.JPG
working on it,mr baja ,it is a real pleasure to contribute in your amazing projects
http://www.rcustomspedals.blogspot.com
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JOHNO
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Post by JOHNO »

Really fantastic work your turning out bajaman, its much appreciated.
I was just wondering if its ok to drop the buffers off this circuit as i dont have the components. I was thinking i could drop every thing before and including the 10k resistor at the input and put the 1m5 before the remaining 1uf cap and do the same on the output. Would that cause any problems apart from possible interaction with surrounding pedals?

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bajaman
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Post by bajaman »

Hi JOHNO
thanks for the nice comments - the pedal should work fine without the buffers but may interact differently with other pedals :wink:
cheers
bajaman
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Post by FausterCraster »

Hi Baja,
another great job !!
In the hard clipping session for your last projects you are using mostly BC547C, can you describe the difference in using these trx Vs the diods ?
TX

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Post by bajaman »

can you describe the difference in using these trx Vs the diods
they (Philips brand BC547B) clip at a slightly higher Vf voltage than 1N4148 diodes - in this project it enables a slight asymmetry to the clip - (just as the Diezel VH4 amplifier clips because of the cathode follower stage following the final gain stage before the tone stack and the slight non-linearity it introduces). Another way of achieving this would be to use two BC547B and to set vbias slightly higher than half way by using an 8k2 resistor in place of one of the 10k resistors :wink: .
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Post by marcao_cfh »

I've added this one to my "to build" list! And I still didn't got time to build your other ODs...

Just another question on clipping. Did you tried the 2n5088/5089?

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Post by 287m »

waiting Liverpool match, draw this. Perf rules :evil: hahaha

Thanks BAJA!
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A4-baja-vh4-etch-300-dpi.pdf
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JOHNO
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Post by JOHNO »

Got this on the bread board and it sounds great, that is until I connect up the gain pot and most of the gain disappears and the gain knob acts like a volume knob. :scratch: I've been going over everything for hours now and i'm stumped. Any ideas?

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Post by JOHNO »

Turns out the 4k7 just before IC1c was bad, swapped it out and "sha bang" it"s time to rip, thanks for sharing bajaman.

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Post by rcustoms »

my quote
regards
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Post by rcustoms »

switch detail channel 3 and 4
channel.jpg
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Post by rcustoms »

corrected R11 is 33k
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Post by marcao_cfh »

Question: are the lugs 2 and 3 of the gain pot really connected together, or should I connect the switch to lug 2 only?

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Post by rcustoms »

are connected together and connected too to switch
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Post by bajaman »

Here are the frequency response and phase curves for the VH4 Ch3 first and then VH4 Ch4 second :wink:
cheers
bajaman
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Post by Danielys »

How does this compare to diezels own vh4 pedal?

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Post by Optical »

I have the VH4 pedal and VH4 amp and would like to know too :D Should be a good comparison when I eventually get around to building some

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Post by HEAD »

Guys, don't let this slip! The channel 3 of the Diezel VH4 is such a legendary sound.

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