Well gang, I imagine it happens to all of us from time to time. It is time for me to eat some crow. I have spent the afternoon testing the Magnum Dynalab MD 205 Signal Sleuth with my MR88 tuner and have discovered a major flaw in my testing procedure. I read the MD 205 owner's manual again this afternoon and there it was in black and white,
"The Sleuth’s POWER switch must be on at all times when you are using your FM tuner and the Sleuth is installed in your FM tuner’s line. If it is not turned on, the signal will not reach your tuner." I missed this on my original read of the manual. All of my testing was done by turning the MD 205 on and off. I had assumed the antenna signal passed through the MD 205 when turned off, but that was incorrect. I actually did receive several stations with the MD 205 turned off so my assumption was supported by that result.
I went through my testing procedure again this afternoon using the switch on the face of the MD 205 that amplifies or bypasses the amplifier while leaving the MD 205 energized. Sure enough, I got entirely different results. In fact, it made absolutely no difference to my MR88's signal strength or the sound quality from the tuner whether the MD 205's amplifier was in the signal path or bypassed. That was true for every station I was able to tune on my MR88. Then I took the MD 205 Signal Sleuth out of the antenna path, connecting the cable from the ST-2 antenna directly to the MR88. All of the stations I was previously able to tune were all still present with the same signal strengths.
I contacted Larry Zurowski of Magnum Dynalab and he told me that most digital tuners have an AGC (automatic gain control) circuit in the antenna input stage and this circuit usually negates the benefits that the MD 205 delivers to analog tuners. I wasn't aware that digital tuners have an AGC circuit in the antenna input stage so hence my confusion.
Member
AM123's posts with respect to what Larry told him are accurate. I stand corrected and a bit embarrassed. Had I been using the MD 205 properly during my original auditioning I would have made this same discovery. By turning off the Signal Sleuth instead of using the amplifier bypass switch to compare the tuners signal strength, my entire test was flawed as were the results and my review. In fact, from what I have discovered today the Magnum Dynalab MD 205 makes no improvement in the MR88 tuner's ability to pull in stations any better than it does on its own. I have removed the MD 205 from the studiio system and will give it a try on my MR85 tuner in the living room system.
I apologize for my error in testing and for those who may have purchased the MD 205 to use with their MR88 based on my review. Consequently, I am deleting my Magnum Dynalab review so that it will not misdirect others, but I will leave this post as testimony to my mistake.
