[AMRadio] 51J3 or 75A3?


david knepper collinsradio at adelphia.net
Sat Mar 4 17:32:14 EST 2006


In conjunction with this discussion concerning audio properties, I wonder if 
anyone is using any of the fine Eddystone receivers?

I own three of them and my favorite is the EA-12, which was expressly made 
for the hambands.

Would like to exchange notes with anyone using or owning any of the earlier 
Eddystone receivers.

Thank you

Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com - the CRA Website
Now with PayPal
CRA Nets: 3805 Khz every Monday at 8 PM EST
and 14255 every Saturday at 12 Noon EST
----- Original Message ----- 
From: "John E. Coleman (ARS WA5BXO)" <wa5bxo2005 at pctechref.com>
To: "'Discussion of AM Radio'" <amradio at mailman.qth.net>
Sent: Saturday, March 04, 2006 4:23 PM
Subject: RE: [AMRadio] 51J3 or 75A3?


I agree with you Brett.  The Collins rigs were strictly
communication rigs, not HIFI.  I had a 75A4 for a long time and compared it
to other 75A4 RCVRs at the time and all of them had poor audio reproduction.
A good bit of the distortion was with the detection and audio output stages.
I built a MOSFET source follower where I picked up the 455KC IF and fed it
to another AM/FM stereo HIFI radio with its on 10-15 watt audio output
stage.  I disable the mixer and OSC in the outboard HF and fed the 455KC
from the 75A4 into the IFs of the outboard HF radio.  This helped a lot but
found some of the distortion was from the mixer of the 75A4.  I understand
there is a modification for that now, requiring a tube swap to a dual triode
and rewiring.  The 75A4 and its type are famous for accuracy and stability.
As for as stock receivers go on fidelity, the HQ129, HQ145, S-85, NC303 (not
NC300) has outperformed all for me.

John, WA5BXO


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