Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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David -
I just had this conversation the other day...! :-)
I don't think anyone knows for sure, but I believe the AF board change
was made around s/n 6000 or so. Early 1980. According to Bill Frost,
the 1496 was originally designed into the R-7, and was then adopted as a
cost saving measure in the "second generation" TR-7. The IC replaced a
hand wound toroid and a couple of alignment problems. It's pretty easy
to spot in a TR-7, as it's right at the top "right" corner of the 2nd
IF/AF board at the rear of the card cage. Version 1 has the toroid up
there and a little U-shaped shield (yet another "costly" item not needed
with the IC) while the Version 2 board has the IC and a few resistors.
Personally, I doubt if you would notice the difference by ear. I have a
couple of each, and can't say that "I" can hear the difference. Yeah,
the 1496 has a wider dynamic range than the two diode PD, but the AGC
kinda eliminates the advantage of wide dynamic range! I think it was
purely cost saving, and a fancier set of specs couldn't hurt! :-) A
dutch ham did a conversion by removing all the parts associated with the
Version 1 and putting the 1496 on a small piece of perfboard mounted
just above the original board.
<http://home.wanadoo.nl/cmulder/drake.htm#bookmark3>
I'm sure we'll hear other opinions!! :-)
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs
<www.k4oah.com>
David & Chris Drake wrote:
Hi all,
Couple questions: Is there a significant performance difference
between the first and second version 2nd IF/Audio boards?. I believe
Drake changed to the newer version along the time the R7 came out, but
not sure exactly. And: If the answer to the first question is
affirmative, then is there anyone out there who has performed the
upgrade on and early board? Good results?
Thanks,
David
Wd9cmd
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