@Fast Eddie: I sense your plan, but I have only just started building such things. I have changed a few parts in a tube amp, but I am not there yet to build something like that on my own. But I want to do that sometime.
Of course.
An easier and safer project might be to build your own simple "Pignose" type amplifier. If you could find an old radio with an input/output transformer scheme, you could use the transformers. You could probably glean other parts. Then you'd have a small practice amp and an old school overdrive box. Pignose amp used small transformers. Its claimed output of 5 watts is when it's so overdriven that the output is a square wave.
Next time maybe. Now I am gonna play this one. 
As a last thing I have added 2 DC plugs. One is for power (pedal board), one for charging the batteries. They switch each other out, so power can never go the wrong direction.
Now I have to wait till everything is charged up ...
As a last thing I have added 2 DC plugs. One is for power (pedal board), one for charging the batteries. They switch each other out, so power can never go the wrong direction.
Now I have to wait till everything is charged up ...
Attachments
looking good.
Thx for the praise. I really feel satisfied now. This can play nearly anything from clean to ridicoulous distortion. Turning up the preamp distortion just a bit allows for somewhat clean tones even if the poweramp is at 200x boost (rolled way back of course). That was not possibly before, because the poweramp on its own was to quiet.
And this also plays nicely now with all my guitars. Even with my Les Paul P90 Goldtop (not a Gibson, cannot afford that), which tends to sound muddy, I get sounds I can play and practice with all day.
Even my girlfriend loves it, although that's more because of the color.
And this also plays nicely now with all my guitars. Even with my Les Paul P90 Goldtop (not a Gibson, cannot afford that), which tends to sound muddy, I get sounds I can play and practice with all day.
Even my girlfriend loves it, although that's more because of the color.
I see. So both ICs have to be wired to INPUT+?
Why should anyone then do it differently? Like with the mylk[386], where the LM386 is wired on INPUT-?
Why should anyone then do it differently? Like with the mylk[386], where the LM386 is wired on INPUT-?
An externally hosted image should be here but it was not working when we last tested it.
They don't have to be... each configuration has its own advantages and disadvantages. That is certainly true for standard opamps like the TL071.
The LM386 is a slightly special case as it is optimised for low voltage battery use and has ground referenced inputs.
It would be worth reading up on opamp basics and the theory of operation If you search for those two terms you will find lots of tutorials and resources. Its a big subject but quite easy to get into.
The LM386 is a slightly special case as it is optimised for low voltage battery use and has ground referenced inputs.
It would be worth reading up on opamp basics and the theory of operation
If you search for those two terms you will find lots of tutorials and resources. Its a big subject but quite easy to get into.
For LM386, as a guitar amp, NO difference. Both work the same.
Oh, the polarity is different. In a TWO-channel system you want both channels the same polarity. In a mono system, only very specialized conditions have "Absolute Polarity", guitars don't.
Rayma is (again) mixing the LM386 with conventional opamps. Yes on a '741 or TL072 the two input pins must be handled differently, by connecting gain-set resistors to them differently. The LM386 does it another way: gain-set is not done with the audio pins but with an internal resistor network on internal nodes.
Last edited:
I thought I better share some audio samples with you, so you can hear what it sounds like now. Recordings were made with my Starcaster on Neck Pickup (Single Coil) and Toneport UX2 on PAD Input with all Effects OFF.
1st recording is chords:
1: DRIVE 0, BOOST Low, LEVEL 5.
2 - 4: DRIVE 3, BOOST Low - High, LEVEL 5
5: DRIVE 5, BOOST Low, LEVEL 5
6-8: DRIVE 7, BOOST Low - High, LEVEL 5
2nd recording is lead:
1: DRIVE 0, BOOST Low, LEVEL 5
2: DRIVE 0, BOOST High, LEVEL 10
3: DRIVE 10, BOOST Med, LEVEL 5
4: DRIVE 10, BOOST High, LEVEL 5
1st recording is chords:
1: DRIVE 0, BOOST Low, LEVEL 5.
2 - 4: DRIVE 3, BOOST Low - High, LEVEL 5
5: DRIVE 5, BOOST Low, LEVEL 5
6-8: DRIVE 7, BOOST Low - High, LEVEL 5
2nd recording is lead:
1: DRIVE 0, BOOST Low, LEVEL 5
2: DRIVE 0, BOOST High, LEVEL 10
3: DRIVE 10, BOOST Med, LEVEL 5
4: DRIVE 10, BOOST High, LEVEL 5
Thanks, appreciated.
One last thing (hopefully): If i try to go all out (preamp distortion on max and poweramp gain on max) the amp starts to whistle (is that the right term? it sounds like feedback, like when you go to near a speaker with a mic) when the level (the pot in between amps) is raised over a certain mark.
What could that be? Is that the same problem again with the LM386 hittin' the rails?
One last thing (hopefully): If i try to go all out (preamp distortion on max and poweramp gain on max) the amp starts to whistle (is that the right term? it sounds like feedback, like when you go to near a speaker with a mic) when the level (the pot in between amps) is raised over a certain mark.
What could that be? Is that the same problem again with the LM386 hittin' the rails?
Could it be feedback. I'm not well up on guitar pickups but is it possible you are getting feedback of some sort ? If it were then it would be sensitive to moving the pickup around.
If it does it when connected to a more standard signal source then its not feedback. Same applies if it does it with nothing connected to the input, which leaves some form of instability. You could try padding the gain and distortion pots with resistors to ensure you never quite reach that point.
If it does it when connected to a more standard signal source then its not feedback. Same applies if it does it with nothing connected to the input, which leaves some form of instability. You could try padding the gain and distortion pots with resistors to ensure you never quite reach that point.
Finally I had the time to check this. Yes, this also happens when nothing is connected. And this also happens on my freshly built Acapulco Pedal, which is also LM386 driven.
I guess it is just a limitation of the circuit. But this really happens on levels I never quite reach (GAIN and DRIVE near MAX), so I will NOT try to fix it right now. Maybe later.
Thx again for your help, I have learned so much over these days. I'm really happy now with the achieved result.
I guess it is just a limitation of the circuit. But this really happens on levels I never quite reach (GAIN and DRIVE near MAX), so I will NOT try to fix it right now. Maybe later.
Thx again for your help, I have learned so much over these days. I'm really happy now with the achieved result.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.