Aftermarket headphones & the T2.....

[Bill Ladd]

My Killer B's work great, but it seems there are some questions about certain headphones on both the F75 & T2......here's some technical info from Fisher.....
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On the Fisher F75 and the Teknetics T2, tip and ring are shorted together and the return is through the sleeve which is wired in series with a 274 ohm resistor. The pulses applied to T&R are negative with respect to the sleeve. Maximum voltage is 6 volts. Loudness is pulse width modulated but the volume control varies the voltage.>>>>>>>

HH,
Bill

 

[Jackpine Savage]

Don't know what all that means Bill. I gave a pair of freebie Fisher phones a try the other day and they seem to work very well with the T2. The sounds were clear and distinct the only problem is that the volume controls on the phones roll off way to quick in the range I was trying for. That made adjusting them to a comfortable level very hard as a tiny turn made a huge differnece in volume.

Tom

 

[BarnacleBill]

Most likely a combination of factors, the build out(limiting) resistor of 274 ohms is fairly high, along with the possible combination of lower impedance headphones ~60 ohms, and likely logarithmic(audio) taper potentiometers for controls on the headphones can lead to this type of response.

[attachment 55565 Log1.gif]

HH
BarnacleBill

 

[Jackpine Savage]

Hi Bill,

Thanks for the explanation. Thats the second time I have seen that. I owned a pair of Jolly Rogers for a while (very little while). Cell phone speakers and the wrong kind of pots made them all but unuseable.

Tom.