"David & Chris Drake" <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Garey,
Thanks for the link. My current TR7 has the first gen. board. Its mid
5900's, so your cutoff must be about right. I've 'heard' people say that
the 2nd gen audio is much better, but you know what they say about
perception versus reality. Perception is 90% of reality to many people. So
when drake improved the specs, well, you know what I'm getting at.
Thanks again,
David
Wd9cmd
----- Original Message -----
From: "Garey Barrell" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, April 24, 2008 6:58 PM
Subject: Re: [drakelist] 2nd IF Audio Board in TR7
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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