Hi Guys,
This can be a stupid question but I don't know the best approach to follow here, so:
1. I have a simple Preamp based on 4 Op amps, it basically provides some gain and tone control. It works very well when I connect it between my guitar and my Orange Amplifier.
2. I also have a small amplifier based on TDA2003 Chip. It works very well also when I connect my guitar to my Zoom Multieffect pedal and then the Amp.
3. My problem is when I connect my preamp and my TDA amp together, Guitar -> Preamp -> Amp, it works well until I turn the volume near to maximum, at some point near to max volume the Amplifier start sounding like an Helicopter.
I don't know if the problem is impedance mismatch or just the level of the preamp output maybe is too high for the input of the Amp, but why it works with my Orange Amp without problem? I also have tried a small class D amplifier instead of the TDA2003 and it is worst, the helicopter appears with any volume level.
Thanks for your help.
This can be a stupid question but I don't know the best approach to follow here, so:
1. I have a simple Preamp based on 4 Op amps, it basically provides some gain and tone control. It works very well when I connect it between my guitar and my Orange Amplifier.
2. I also have a small amplifier based on TDA2003 Chip. It works very well also when I connect my guitar to my Zoom Multieffect pedal and then the Amp.
3. My problem is when I connect my preamp and my TDA amp together, Guitar -> Preamp -> Amp, it works well until I turn the volume near to maximum, at some point near to max volume the Amplifier start sounding like an Helicopter.
I don't know if the problem is impedance mismatch or just the level of the preamp output maybe is too high for the input of the Amp, but why it works with my Orange Amp without problem? I also have tried a small class D amplifier instead of the TDA2003 and it is worst, the helicopter appears with any volume level.
Thanks for your help.
Take a look at the suitability of your power supply. If a common power supply, it could be a stability issue.
Thanks JonSnell, I am using a laptop PSU, at 18 Volts and 3.5 Amperes. I think it is enough power, but how can I check?
[Solved] Preamp to Amp Connection
I have just reduced the gain in the last Op Amp stage and voila! problem solved.
I have just reduced the gain in the last Op Amp stage and voila! problem solved.
Yeah, some amps clip if overdriven. Everything sounds like a siren. Other amps howl at odd frequencies if overdriven. I have some of each.
Overdriven means more input voltage than specified.
Overdriven means more input voltage than specified.
Hi Indianajo, I think the problem is not clipping but op amp instability. The motorboat appears even with no signal applied (input grounded), I have reduced the Op Amp gain just a little and now it does not oscillate.
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