BOSS - BF2:
Moins de bruit :
remplacer B par 0.1uF metal film
remplacer E par 1uF metal film
remplacer H par 1uf metal film
remplacer I par 0.22 uF metal film
remplacer J par 0.22uF metal film
remplacer K par 1uF metal film
A et C sert à avoir un son plus couillu
A - cap .047 uf .01 uf cap Helps get rid of ‘boxy sound’
C – cap .047 uf .01 uf cap Helps get rid of ‘boxy sound’
D et F va changer le son d'un flanger vers des trucs plus "space"
D - trimpot(optional)Trim pot Experiment with position!
Will change the sound of flangerdrastically.
F – trimpot(optional)Trim pot Experimentwith position!
Will change the sound of flangerdrastically.
G va rendre la BF2 plus douce , un petit peu compressé et une meilleure attaque
G -diodes1n4148 D3=bs170
Mosfet transistor
G -diodes1n4148 D4=mpf102
transistor Makes flanging smoother, a little
compressed. Better attack.
L va ajouter de la profondeur au flanger
L – cap 47 pf 100pf Adds more depth to flanger
Pour les anglicistes:
a) C27 and C28 make up a non-polarized 16.5uf capacitor which sets the speed range. If the capacitance value is reduced, the speed range goes higher. Faster speed can produce an effect that sounds very much like a ring modulator. I would suggest a pair of 4.7uf caps, back to back, as a suitable replacement.
b) Maximum flanging effect needs a 50/50 balance between delay and clean signal, but sometimes you want just a taste of flanging. If the value of R29 is increased, the balance is shifted in favour of clean. If you replaced R29 with a 22k fixed resistor, and a 100k pot, wired as a variable resistor (2 lugs, not all 3), you would be able to get everything from a *perfect* 50/50 balance to a much softer flanging effect, even with very high regen/res.
c) R11, D3, and D4 form a soft limiter, to keep high regeneration/resonance signals from overloading the delay chip. If you shunt/short R11, the clipping of D3/D4 becomes "harder" and introduces more harmonic content. If you want to experiment with more interesting high regeneration signals, solder in a wire bridge across R11 on the copper side of the PCB, turn up VR5 a bit higher (VR5 is normally set so that turning up the RES control all the way puts you just below the point of oscillation).
d) C7 sets the lower bandwidth point (bass rolloff) of the regeneration signal. If you make it smaller in value, this will make high regen/res settings sound less metallic. A value of .01uf might be a good place to start.
e) The depth contol (VR2) adjusts the balance of voltages coming from the LFO and the Manual control to drive the clock (IC4). VR7 is used to adjust or fine tune the delay time by adding (or maybe subtracting) a small DC voltage on top of whatever comes through VR2/R48. C30 sets the delay range of the clock circuit. Values larger than 47pf will set the minimum delay time much longer. Smaller values will reduce the minimum delay time. You can change the sound of the pedal by changing the range of delays it can produce. Try a cap of 39pf and see if you like it. If there are problems with the sweep, you may be able to fix them with VR7. Alternatively, if you are able to find an MN3209 chip somewhere, you can take the MN3207 out and replace it with the MN3209 for shorter (X/4) delay times and more of a "jet plane" sound.
f) Vibrato is created when you use ONLY the delay signal, and leave out the clean signal. If you lift one end of R28, that will prevent the clean signal from being mixed in with the delay signal, and give vibrato. Unfortunately, because of how bypass is done in this pedal, this means that when you try to bypass the pedal, there will be NO sound coming out.
Solution: In modulation effects where dry and wet are combined, you can cancel the effect bi simply lifting the connection between the wet path and mixing stage. In the BF2, Q4 fulfills this function.
This means that while the "flip" part of the circuit is used to enable/disable the gate of a FET and an LED, the "flop" part of the circuit does nothing. We *can* put this section to work, though.
To produce vibrato, lifting one end of R28 will kill the dry signal and get you vibrato. When you hit the footswitch, though, there is no "flop" action to restore the bypassed/clean signal....but there COULD be..
Imagine that there is a second 47k resistor and a FET in series with each other, and in parallel with R28. Now, also imagine that there is a 1M resistor, .047uf cap, and diode connecting the gate of that FET to the junction of R55 and Q9, exactly the same way a resistor, cap, diode combo connects the gate of Q4 to the junction of R56/Q10. Step on the footswithc once, and the led comes on and Q4 goes low resistance. Step again and Q4 and the LED go off and our new added FET turns on and provides a low resistance path for the clean signal to the added parallel resistor and the mixing stage. More importantly for our purposes, that path exists independent of the toggle switch. So, if the toggle is closed, the added FET/resistor simply duplicate what is already there when you step on the footswitch. If the toggle is open, then cancelling the wet signal also results in providing a dry signal.
FYI, the C7, C21 mods have no effect at all when the res/regen is off.
I suggest you look at the BF-2B which does have less metalic sound. Roughly,
- a delay chip with less (512) stages. this reduces the delay time
- C7 mod (47nF to 10nF)
- C6 is reduced from 47nF to 15nF.
Now reducing the delay time can significantly reduce the metalicness. One way to approximate this is to reduce C30 (47pF). Unfortunately the clock frequencies are already pretty high so it's probably unwise to use a small C30 like 22pF to drop the delay to the BF-2B level. You could try 33pF and cross your fingers.
Tune the C6 mod first to your taste with res/regen off - try say 22nF or 33nF.
Then Tune C7 using some res/regen.
Another mod is to play with C8 and C9. For example you can get the filters to be quite close to the mxr flanger by changing only two caps: C8 from 12nF to 2.2nF, and change C9 from 150pF to 1nF.
In case you are still interested in attemping the mod on the BF-2, I studied the schematic available from the Free Information Society and came to the following changes in order to achieve the increased sweep after replacing the BBD for a 512 stage MN3204:
1) IC5 needs to be replaced with a full rail-to-rail output opamp like the TLC2262, TLC2272 or MAX492, to name some.
2) Then, resistors R36 (180k) and R37 (220k) need to be swapped with each other to increase the output voltage range of the LFO.
The use of a rail-to-rail output opamp is necessary, otherwise the LFO won't work with the extended output voltage range. Eventually, but not necessarily, VR7 might need a slight adjustment in order to center the new range of the sweep.
In summary, the required changes are pretty simple, except for the difficulty in getting the MN3204 and TLC2262 ICs (WHICH YOU HAVE ALREADY DONE!)[/u]
