Post by solderdude on Apr 22, 2014 4:39:26 GMT
You cannot parallel outputs of amps into one headphone socket so this won't work.
You will either have to use a DPDT switch that can switch the output socket to either amp A OR amp B or use 2 output sockets.
You will need only 1 Schottky diode as they would be in parallel.
don't forget the ferrite beads when using 56pF caps !
I would not advise to use those caps without those beads !
You need to select beads that work at a low frequency already.
2 or 3 of these in series would work:
www.ebay.nl/itm/100pcs-Inductor-beads-3-5-9-0-8-AXIAL-FERRITE-beads-3-5x9x0-8-/231007409351?pt=LH_DefaultDomain_0&hash=item35c91d54c7
There are also beads with a bigger hole where you can run the wire through it a few times this is even better.
www.ebay.nl/itm/50-pcs-EMI-beads-ferrite-cores-3mm-diameter-/141237941938?pt=LH_DefaultDomain_0&hash=item20e26ff6b2
or ones with a few holes:
www.ebay.nl/itm/6mm-x-10mm-x-0-8mm-Axial-Lead-6-Channel-Ferrite-Beads-Inductors-10-Pcs-/121182511414?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c370a6136
The beads increase the resistance of the wire for frequencies > 100kHz if you do not apply them the amplifier board will be loaded with a very low impedance for the high frequency switching components.
a small inductor instead of a bead may also work well:
www.ebay.nl/itm/20x-1-4W-Color-Ring-Inductor-Axial-RoHS-1uH-1-uH-NEW-/141029489700?pt=LH_DefaultDomain_0&hash=item20d6033c24
These amps are designed to be connected to speakers using short wires (so little capacitance) and a headphone cord adds some capacitance as well as a different load.
You will either have to use a DPDT switch that can switch the output socket to either amp A OR amp B or use 2 output sockets.
You will need only 1 Schottky diode as they would be in parallel.
don't forget the ferrite beads when using 56pF caps !
I would not advise to use those caps without those beads !
You need to select beads that work at a low frequency already.
2 or 3 of these in series would work:
www.ebay.nl/itm/100pcs-Inductor-beads-3-5-9-0-8-AXIAL-FERRITE-beads-3-5x9x0-8-/231007409351?pt=LH_DefaultDomain_0&hash=item35c91d54c7
There are also beads with a bigger hole where you can run the wire through it a few times this is even better.
www.ebay.nl/itm/50-pcs-EMI-beads-ferrite-cores-3mm-diameter-/141237941938?pt=LH_DefaultDomain_0&hash=item20e26ff6b2
or ones with a few holes:
www.ebay.nl/itm/6mm-x-10mm-x-0-8mm-Axial-Lead-6-Channel-Ferrite-Beads-Inductors-10-Pcs-/121182511414?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c370a6136
The beads increase the resistance of the wire for frequencies > 100kHz if you do not apply them the amplifier board will be loaded with a very low impedance for the high frequency switching components.
a small inductor instead of a bead may also work well:
www.ebay.nl/itm/20x-1-4W-Color-Ring-Inductor-Axial-RoHS-1uH-1-uH-NEW-/141029489700?pt=LH_DefaultDomain_0&hash=item20d6033c24
These amps are designed to be connected to speakers using short wires (so little capacitance) and a headphone cord adds some capacitance as well as a different load.