BAJA REACTOR 010119  [documentation]

Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
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bajaman
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Post by bajaman »

temol wrote:Hah... what a surprise.. rev4.. and 4a.. I'll wait for the 5 and 6 :)

In the meantime - rev3 tested on a pcb.
IMG_9070_600.jpg
T.
i think I have gone as far as i need to now :wink:
nice looking pcb :D
cheers temol
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Post by temol »

Some noise from rev4 and rev4a :)





T.

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Post by blackboarcult »

Long time lurker, first time poster here :-)

Here's the DIYLC layout I did yesterday.
Another pair of eyes to check on errors would be really welcome!
I'm pretty new to making layouts, so I'm sure it can be downsized with standing resistors etc, but as I do all my boards adapted for 5mm pitch terminal blocks, miniaturizing is not my priority :)

I'll try to verify it as soon as possible.
In the meantime, many thanks for your great layouts Baja, the Mars Hall is currently my go-to pedal for everything hard & heavy related!

Cheers

/ZVDW
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Baja Reactor3.png

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Post by blackboarcult »

Verified version attached below :D

Revision is just minor changes in the wiring - two pots were wired backwards.

As temol pointed out, when the Presence knob is dimed it introduces some noise that oddly disappears when gain is maxxed out. Besides that, this circuit sounds great and I have yet to test it with some preamp emulators. It sounds a little darker and fuller than previous Presence & Resonance, which can also be a good thing for some rigs :P

Cheers!
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Baja Reactor3.png

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Post by bajaman »

Two small changes to rev 4 (and other versions :wink: )to tame oscillation in presence and roll off some extreme top end above 20kHz.
Changed feedback capacitor min final op amp to 1nF and added 220pF capacitor across 39k feedback resistor :D
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Baja Reactor 010119 rev 4 includes bass cabinets.png
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Post by blackboarcult »

... and final corrected version (verified) here!

Luckily I always leave spare rows and columns on each side of my boards, as I had to add one column at the beginning to fit the 220pF cap 8)

No noise now, works like a charm. Great, full sound on its own and with my jcm emu, can't wait to test it with other preamps.

Thanks again baja ;-)
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Baja Reactor3.2.png

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Post by bajaman »

Here is my finished rev 4 - I have some spare printed circuit boards available - (email me: baja002steve@gmail.com for details).
The silkscreen on the board is for the first edition - but will accept the rev 4 changed values ok.
I decided to not fit the clipping diodes for the increased presence headroom - the choice is yours :wink:
The enclosure used is the Daier 1590B equivalent - although the board should fit the standard Hammond 1590B
The board is double sided through hole plated - the pots are RK097 types with the pins bent downward. I super glued them to the board as well.
The 470k resistor is tacked on the bottom of the depth control because I did not have any 250k pots - I used a 500k pot.
The pcb jack sockets are Neutrik slim types - NRJ6HF - NRJ4HF will also work :wink:
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IMG_3743.JPG
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Post by jhergonz »

Thanks for another great circuit Mr Bajaman.

Just one question, in the differential amplifier part, do I need to measure the four 10K resistor and choose the same or closest value that I have?

Thanks again for this circuit. :D

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Post by bajaman »

jhergonz wrote:Thanks for another great circuit Mr Bajaman.

Just one question, in the differential amplifier part, do I need to measure the four 10K resistor and choose the same or closest value that I have?

Thanks again for this circuit. :D
No - standard 1% metal film types should be ok - cheers bajaman
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Post by EddieTavares »

Bajaman

As your circuit has clipping diodes, does it simulate "sag" of a power amp at loud volumes?

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Post by bajaman »

EddieTavares wrote:Bajaman

As your circuit has clipping diodes, does it simulate "sag" of a power amp at loud volumes?
I prefer to leave the clipping diodes out :wink:
You could always make them switchable, but no, it does not simulate "sag" , just distorts :!:
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Post by HEAD »

temol wrote:Hah... what a surprise.. rev4.. and 4a.. I'll wait for the 5 and 6 :)

In the meantime - rev3 tested on a pcb.
IMG_9070_600.jpg
T.

Temol? :D :wink:

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Post by sixthfloor »

Baja Reactor rev. 4, fixed gain and volume, always on. I think I've reached my limit in using up space in a 1590A :P

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Post by temol »

I like this small scrap of wood.. does it affect the tone? Is it a tonewood? :)

T.

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Post by bajaman »

like sixthfloor says - always on :wink:
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Post by sixthfloor »

temol wrote:I like this small scrap of wood.. does it affect the tone? Is it a tonewood? :)

T.
It is actually there for a much simpler reason - the jack plugs are almost entirely made of plastic and the thread is very short, so tightening the nuts destroys them. Hence its either superglue or wedges to hold them into place. Maybe I should make another pedal and use superglue this time, to check the impact on tone :scratch:

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Post by bajaman »

:lol: :lol: :lol:
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Post by sixthfloor »

I'm having a couple of problems with my build :

1/ When the presence pot is full CW (i.e. 5k pot bypassed by 100n capacitor) there is quite a big drop in both volume and highs. Some high-end fizz is also introduced. I guess this could be improved by placing a small resistor between the (presence pot + 100n cap) and the (100n cap - 39k resistor junction) in the circuit.

2/ Driving the Reactor circuit with a hot pedal, e.g. Baja MDR, gain 50% volume above unity introduces similar fizz in the background. In fact almost any pedal with the volume set above unity triggers this. I tried upping the supply voltage to 12v to have more headroom, but it didn't solve the problem. I also checked the presence pot with a multimeter, it isn't faulty. Swapping op amps for higher grade (OPA2134) didn't help either.

Has anyone encountered similar problems ?

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Post by mecmast »

Maybe very stupid question but i couldnt stop myself from asking :)

I am gonna use 9v power supply. What's the purpose of "Vbias" labels on the vero board?

Really sorry for my question. And thank you for your replies. :)

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Post by plush »

mecmast wrote:Maybe very stupid question but i couldnt stop myself from asking :)

I am gonna use 9v power supply. What's the purpose of "Vbias" labels on the vero board?

Really sorry for my question. And thank you for your replies. :)
Just for one's to remember where the bias rail is. That's all.

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