[Drake] 4-Line Choices

[Dave Maples]

Lee: I won't try to change your opinion, but having examined both the
current schematic and at least some variations of the modifications for
power supply and audio output, I'm quite confident they are an improvement.

The single-transistor Class-A audio amplifier has much higher distortion and
draws much more power than a properly-matched IC audio amplifier.
Obviously, if the input of the IC amplifier is overdriven, or if it's
oscillating outside the audible range (not hard to do with an LM380) it's
going to sound like junk.

The use of the HV DC for low-voltage operation, vs. rectifying and
regulating the low-voltage AC, is another source of heat and wasted power.

I'm not going to speak for the other mods, but these two are definitely on
my list for my R-4C.  I may or may not follow the Sherwood design in either
case (there's a very small 7-watt audio amplifier from Velleman that I've
used in other designs that I think would be a better  choice, for example),
but correcting these two design issues are high on my list.

To each his own.

73,
Dave WB4FUR


-----Original Message-----
From: drake-bounces at mailman.qth.net
[mailto:drake-bounces at mailman.qth.net]On Behalf Of LEE BAHR
Sent: Wednesday, January 12, 2011 9:20 AM
To: Cecil Acuff; John Barnwell; drake at mailman.qth.net
Subject: Re: [Drake] 4-Line Choices


That is your opinion but not mine.  My experience is they screw up the
radio.

Lee, w0vt


----- Original Message -----
From: "Cecil Acuff" <chacuff at cableone.net>
To: "LEE BAHR" <pulsarxp at embarqmail.com>; "John Barnwell"
<radioniner at yahoo.com>; <drake at mailman.qth.net>
Sent: Wednesday, January 12, 2011 7:56 AM
Subject: Re: [Drake] 4-Line Choices


>I think claiming the Sherwood mods to be BS is a little broad and pretty
>much unfounded.  As nice as the R4C is it has it's problems and all are not
>age related.  The power supply by now needs the filter caps brought up to
>date.  The pesky mixer tube issues and it's bad placement on the chassis
>can be improved upon. (eliminate the tube)  The audio amplifier can be
>improved with cleaner audio and reduced heat and there are a couple of
>other areas that slip my mind at the moment.
>
> Sherwood offers kits to fix the identified shortcomings whether they be
> design or age related.
>
> If you are a purist about these radios and feel the need to make them
> original with their few designed in warts that's fine.  They look nice
> sitting on the shelf pretty and all original.  If you use one regularly
> you will find those upgrades have merit.  They are also very affordable to
> perform.  Those are the Sherwood basic mods..
>
> Sherwood also offers mods to bring the receiver up to modern day
> performance specs on the bands.  Mods that can make the receiver a
> competition grade performer for the contester or DXer on CW.  If you buy
> one of these and want to rag chew on 40 SSB with it you won't like it
> because the roofing filter mods do kill the broad, rich SSB sound these
> radios are known for.  The mods are expensive but do transform the radio
> for tight CW work.  Also check the resale value on these...Sherwood modded
> R4C sell for big bucks relative to a stock receiver.
>
> As I understand it not a week goes by that he doesn't sell R4C related mod
> kits....even after all these years.  He never expected that!
>
>
> Cecil
> K5DL
>

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