- This topic has 7 replies, 4 voices, and was last updated 1 year, 3 months ago by
.
-
Posts
-
Hello DIY musicians friends.
First I’d like to thank Barry (and his collaborators?) for all his hard work and passion.
Thank you because it is possible to create a quality sound on a tight budget in exchange for a few strokes of a pleasant soldering iron.
I’ve built a lot of effects pedals, and this time I need the technical help of the community.
I’ve just finished the tight box.
It sounds incredible!
Only, in my opinion, it lacks gain and power.
My question is :
Is it normal to have the D7/D8 indicator LEDs light up according to the guitar signal,
but the other two D1/D2 indicator LEDs never light up?
I have, for all the TL072 chips:
Pins 1,2,3 , 6,7,8: 4.73v
Pins 4: 0v
Pins 5: 9v
I have the impression that all the components are well implanted, as are the diodes
Thanks in advance for any help you can give me.
Good evening to all.
<hr />
Lack of gain or drive could be caused by several things
Post some nice clear well lit images of your build so we can clearly see all component values and orientation and trace your offboard wiring
The LEDs are being used to clip the signal not all clipping LEDs will light up D1 and 2 as you can see are soft clipping diodes in the op amp feedback loop which won’t normally light up whereas D7 and 8 are hard clipping LEDs connected to virtual ground which will usually light up
Your op amp voltages look good aside from the pin numbers 5 to 8 are backwards
IC pin numbers are pin 1 left of the dot or notch down to 4 then up and around the other side in a U shape 5 to 8
hi billy,
wow thanks for your detailed and quick answer.
so indeed, concerning the numbering of the chip pins, I did not number them in the right order.
5,6,7: 4.73v
8: 9v
so the fact that the LEDs d1 d2 do not shine is normal.
i found that it lacked a little gain when the pedal is pushed all the way.
i thought that maybe the two LEDs that do not light up, could explain this.
but it is ultimately just a matter of taste, and I will probably need a transparent boost to compensate for this.
but I repeat this pedal sounds magnificent!
or maybe is there a way to change certain components to have a little more gain?
also I was wondering if it was possible to power the pedal in 12v, see in 18v, or in 9v500mA without risk of damage on the pedal?
thank you and have a nice day
All your component values and orientation that I can see look correct
Obviously I can’t tell the orientation of your LEDs if you look down on them the cathode negative side should be flat and go to the striped side
The internal cathode pin should be much thicker than the anode
Afaik this pedal should have a good bit of gain you could use 12v or more depending on the voltage rating of your capacitors etc
Are the back of the pots insulated it’s difficult to see if they have the plastic caps on them
How about replacing your footswitch with an AfterBlaster board:
That should be easy enough. You can set the AfterBlaster to a fixed boost/gain via a trim pot, or you can add a regular pot to vary the boost (provided you have room for the pot on your pedal).
I don’t know the db value the AfterBlaster adds; I was thinking it was in the build doc, but I’m not seeing it (that value should probably be in the doc).
thanks for your answers and valuable details.
i didn’t know the afterblaster and am interested in this project. it’s still a very good idea.
the LEDs are indeed in the right direction.i didn’t know the trick of the anode and the cathode).and the potentiometers are equipped with self-adhesive pads to avoid short circuits.to know if I can power the pedal in 12v, it seems to me that, from memory, chemical capacitors are limited to 25v but what about other capacitors (plates, disks) and resistors?
because I don’t have any information on the maximum voltage admissible by these.thanks! Have a nice day
I edited your post so it was readable.
Not sure what was used to create all the excess code.
————————————————————
As for your build, a properly functioning Tight Box has plenty of gain. No Afterblaster, or mods needed.
You will need to sort out the problem.
All GuitarPCB projects should be powered with a standard (neg tip) 9 volt supply. By using higher voltages you would increase the available clipping headroom and therefore end up with less available distortion.
If that doesn’t help then I suggest reflowing the entire project by using your soldering iron to reheat each of the pads and reflow the solder. While you are doing that have a little extra solder handy for any places where you might need it.
After doing that check to see how your project sounds.
Finally I encourage you to check out our Guides Page (Main Menu Bar)
It has a ton of excellent resources below the build manuals section.
<hr />
hello,
once again thank you for the time you gave me.the pedal has a lot of gain it’s true and an incredible sound.
the “lack” of gain I’m talking about is really light, It’s a matter of taste, I would miss a slight boost especially for the solo parts.
I think this is due to my single coil microphones which sound good in clean and crunch sound but are a little less powerful on my telecaster.if there is a mod to counteract that I’m interested.
Otherwise I’ll find a transparent boost later.thanks again and good luck guys!
peace
- You must be logged in to reply to this topic.