[Drake] Several Drake questions

[Dave Maples]

All: I have acquired a Drake C line that I'm quite happy with.  I have some
questions, though, about it and the B line that I also have.

1. I'm wondering if there's anyone who knows where the reduction drives used
on the preselector tuning could be obtained.  The Jackson Bros. 6:1
reduction drive seems to be the closest thing, but I doubt that that's what
is being used.  Anyone have a clue here?

2. Anyone have a preferred source for band crystals for the Drakes?  I've
got a bum 40M crystal in the R4C (about 15 kHz off, if you can believe
that).

3. I have recently used a Velleman K4001 audio amplifier in a work-related
project.  This amp delivers 7 watts max to a 4-ohm load (with a 15 VDC
supply).  It's based on the TDA2003 integrated circuit and will operate from
a supply of 8-18 VDC.  It draws 500 MA at 7 watts out.  It has about 40 dB
of gain.  Any reason why I couldn't use this to replace the single
transistor special in the R4C?  I've read about the LM380 replacement; this
seems like an even cleaner approach.  I believe I'll have to replace the
regulators as well, if I read correctly.  Any thoughts on this approach?

All comments welcome!

Thanks,
Dave WB4FUR





-----Original Message-----
From: drake-bounces at mailman.qth.net
[mailto:drake-bounces at mailman.qth.net]On Behalf Of Garey Barrell
Sent: Monday, November 27, 2006 2:54 PM
To: drake at mailman.qth.net
Subject: Re: [Drake] Sub For #47:




Edmund H. Ramm wrote:
> Paul Christensen writes:
>
>
>> Or...eliminate the incandescent lamp altogether and replace it with a
Blue
>> LED mounted in a #47 base
>> [...]
>>
>
>    Eek! Introducing semiconductors to a wonderful 100% valved -and thereby
> EMP-proof- receiver? Buerklin's 33G202 7v/100mA with BA9S socket is my
> favourite #47 replacement.
>
>    73, Eddi ._._.
>

Uhhh, Every R-4/A/B/C & T-4X/B/C has already been "introduced" to
semiconductors..........  :-)

That aside, the 755 IS a great replacement for the 47.  It has an
expected lifetime of almost seven times that of the 47, and the slightly
lower light output is hard to spot unless you have a 47 in one unit and
a 755 in another sitting next to it.  The 755 also reduces the fading of
the original blue-green filter, and more importantly the yellowing of
the diffuser.  It's the yellowing of the diffuser that imparts that
greenish hue rather than fading of the "blue".

Now all we need is for Don, N9OO to put blue AND green LEDs into his
replacement units to more closely match the "real" Drake dial color!!!!!

By the way, I have been using 755 bulbs in MANY Drake units for over 20
years, and have yet to replace one.

73, Garey - K4OAH
Atlanta

Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>


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