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Knowledge Base > Discontinued Products > 304 Headphone Amplifier

What is the pinout for the PS-3 power supply?

There are two separate AC supplies coming out of the PS-3: 8.5 VAC @ 1A and 34.5 VAC CT @ 250mA. Pinout is as follows: 8.5 VAC on pins 6 and 1, 17 VAC on pins 7 and 3, center tap @ pins 4 and 5 are connected to earth ground. This is when viewed at the end of the PS-3 7-pin DIN plug.

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How do I hook up multiple 304s if I need more than 4 headphone channels?

Simply use the “thru” jacks to feed to the additional 304(s). This connecter is also convenient to patch headphones into an existing audio chain, for example: the signal going to a power amplifier could be routed to the input of the 304, the 304’s “thru” output signal would go to the amplifier, thus the audio feeds both the amplifier and the headphones.

What is the power output of the 304 Headphone Amplifier?

Approximately 200mW at 60 ohms or 21dBm at 600 ohms.

Why are my 304 outputs distorted or not working?

Check input signal. Is it too hot, or is it already distorted? Check for output loading. Are you running too many headphones per channel or possibly one of them is shorted? Are all the channels distorted or dead or just one?

Can my Symetrix-manufactured unit normally powered by the PS-3 be battery powered for remote use?

No, the only option would be to use a 12VDC to 117VAC inverter with the supplied PS-3 inline power supply.

Where can I find AutoCAD files for the 304 Headphone Amplifier?