TS-850 Direct Injection questions
Posted: Thu May 01, 2014 7:36 pm
I modified my TS-850 for Direct Injected AM audio as per KA0KA's website http://www.ka0ka.com/am_mods.html.
I ran an audio patch cable between IC3 on the underside of the IF board and connected it to the RTTY port on the back of the radio. I disconnected the previous RTTY circuit and used a 4.7 ohm coupling capacitor just like the instructions on the above website.
I know its advised to use a Jensen Isolation Transformer but I don't have one yet. I'm curious why when I try to run audio from my Xenyx 802 mixer from its main TRS unbalanced line out to the direct injection port on my TS-850 the resulting audio is very thin/distorted sounding?
Is it absolutely necessary to use a transformer to fix the impedance mismatch between pro audio gear (low impedance) and the balanced modulator (high impedance) to get decent sounding audio with an 850 direct injected?
I've seen countless videos and posts of people who recommend hooking up a mixer like my 802 straight to the ACC/ACC2 jack on the back of whatever radio. I'm assuming piping audio into the ACC port is comparable to going straight to the balanced modulator IC.
I intend to buy the transformer (was thinking it was more for RF/HUM avoidance) but am curious if not having is why I can't even get halfway decent transmit audio out of my 850 or if I have something else wrong. I have double checked my 4.7 ohm coupling capacitor's polarity and the connections as per KA0KA's website.
Any input would be appreciated.
I ran an audio patch cable between IC3 on the underside of the IF board and connected it to the RTTY port on the back of the radio. I disconnected the previous RTTY circuit and used a 4.7 ohm coupling capacitor just like the instructions on the above website.
I know its advised to use a Jensen Isolation Transformer but I don't have one yet. I'm curious why when I try to run audio from my Xenyx 802 mixer from its main TRS unbalanced line out to the direct injection port on my TS-850 the resulting audio is very thin/distorted sounding?
Is it absolutely necessary to use a transformer to fix the impedance mismatch between pro audio gear (low impedance) and the balanced modulator (high impedance) to get decent sounding audio with an 850 direct injected?
I've seen countless videos and posts of people who recommend hooking up a mixer like my 802 straight to the ACC/ACC2 jack on the back of whatever radio. I'm assuming piping audio into the ACC port is comparable to going straight to the balanced modulator IC.
I intend to buy the transformer (was thinking it was more for RF/HUM avoidance) but am curious if not having is why I can't even get halfway decent transmit audio out of my 850 or if I have something else wrong. I have double checked my 4.7 ohm coupling capacitor's polarity and the connections as per KA0KA's website.
Any input would be appreciated.