Interference from output coils?

I am going to stuff a Buffalo II DAC into the casing of a Nakamichi IA-3 Amp
that is rated @ 40W @8ohm.

The dac circuitry will be very close to the output coils that are rated 0.8mH,
about 6mm / 0.23inches. Reason is that the dac is stacked above the amps pcb.
Any interference possible from the coils?
If so, can the coils and the inherent resistor (10ohm) been put close to the loudspeaker terminals? Or do they have to be close to the output transistors?
All the best,
Sal
 
the power amplifier output inductors should be located away from the output stage and away from metal panels. That usually puts it/them in the middle of the amp to terminal cabling. The two inductors should not be located near each other.

The DAC should be impervious to interference. It is the whole reason for going to noughts and ones. They are resistant to interference, they certainly don't give better analogue performance. But a badly designed DAC may be susceptable to interference.
 

Salar

Member
2006-02-08 8:40 pm
Germany
To shed some more light, I attach drawings,
The coils are not over the center of the dac board
but at the upper right corner. The closest part close to the firmware controller,
i would say about 15mm away.
Dac Board in the schematic is blue,
amplifier board is green. The amplifier bord will be mounted upside down,
thus the part on the right side facing down are the output transistors.
Dac is BuffaloII stacked on Ivy.
The Buffalo Board is drawn in 10mm thickness because of mounted parts.
Thus shortest distance of the coil´s surface to the Buffalo´s PCB-surface (actually the closest part is the mounting hole) is 9mm.

All other PCBs are around 29mm away.
 

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T117

Banned
2016-04-20 12:38 pm
The inductor is a magnetic antenna transmission. It induces a very large interference in the form of distortion at the amplifier's inputs. For example, if the amplifier has a distortion at the level of 0.001%, the inductor on the amplifier Board easily raise them up to 0.05%.
Keep the inductor away from sensitive circuits, wound it into the shape of a torus.
 
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