[R-390] RE: R-392 Tubes

Fri Jan 6 08:53:01 EST 2006

As long as we are on the subject of R-392's, I have two of these little
beauties sitting next to my R-390A's. For those of you who have 392's
you had better look at the current price and availability of 26C6's.
The last JAN NOS 26C6 that I bought was $10.  I finally decided to try
to solid state the three 26C6's and it was very easy using 2N3819
N-Channel FETs using three Alden tube 7 pin test sockets sold by K5SVC 

http://cgi.ebay.com/ALDEN-7-PIN-TEST-SOCKET_W0QQitemZ5779640770QQcategor
yZ48710QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It took all of a few minutes to complete the conversion and it is
reversible.  I just ordered a few more of the Alden sockets to do the
other radio.

FYI Bill Perry of Wm Perry & Associates still stocks NOS Amphenol
164-4FS 9 pin female power plug for $20.  I also see that there are 6
transistorized audio modules for sales on EPay

http://cgi.ebay.com/Transistorized-Audio-Module-for-R-392-R392-URR_W0QQi
temZ6594628548QQcategoryZ588QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I have one installed in one of my radios and it works great after I had
to remove a feedback resistor in my audio driver (I think it was an 8.2
Meg) It will squeal unless you do.  My radio is a '52 vintage and the
newer ones apparently were changed to accommodate the solid-state audio
module and had the feedback resistor built into the module.

It is a great radio but you definitely need a tube puller. Fortunately
one of mine came with the two finger style tube pullers installed in the
radio.

 Craig W9CLA

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net] On Behalf Of
r-390-request at mailman.qth.net
Sent: Friday, January 06, 2006 3:02 AM
To: r-390 at mailman.qth.net
Subject: R-390 Digest, Vol 21, Issue 17

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Today's Topics:

   1. Re: Beaten Horse Graveyard (Goldberg replacement for  3TF7)
      (Roy Morgan)
   2. RE: Beaten Horse Graveyard (Goldberg replacement for  3TF7)
      (Bruce Hagen)
   3. Re: Beaten Horse Graveyard (Goldberg replacement for 3TF7)
      (Flowertime01 at wmconnect.com)
   4. OT Hammarlund week (Cecil Acuff)
   5. RE: SS replacment for 3TF7 - back-to-back Zeners.
      (Kenneth G. Gordon)
   6. RE: My R-392 Starts Singing (Dan Merz)
   7. Re: My R-392 Starts Singing (Barry Hauser)

----------------------------------------------------------------------

Message: 1
Date: Thu, 05 Jan 2006 16:09:51 -0500
From: Roy Morgan <roy.morgan at nist.gov>
Subject: Re: [R-390] Beaten Horse Graveyard (Goldberg replacement for
	3TF7)
To: Tom Norris <r390a at bellsouth.net>, R-390 at mailman.qth.net
Message-ID: <6.0.0.22.2.20060105154448.06ba5380 at mailserver.nist.gov>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 02:35 PM 1/5/2006, you wrote:

>light bulb ... changes the resistance of a photocell,
>which changes the speed of a motor, which runs a fan, which pushes a
>sailboat across a tub of water,

Egad, Tom! You talked about this on the list???

What will our patent attorney say?  Threaten to quit, no doubt.

I hope no one notices, or if they do, don't take you seriously.

Pssst!
The Guinea Pig at our house recently transitioned to the Great Radio
Room 
in the Sky, but we do still have the two gerbils.  Their 12-year old 
custodian has not noticed that I've installed the potty-and-switch 
mechanisms (PSM) below their cage in the top drawer of her dresser
(TDD). 
She never uses the dresser anyway, so we are safe.  Of course all wires
and 
such are hidden in the walls (HIW) in accordance with the Evidence 
Protection Plan (EPP), so I expect a good long test period before we 
complete the patent application paperwork  (PAP).  I just hope my
soldering 
at midnight doesn't wake her up again (SNIFF)

I had to redesign the gerbil-motion-to-phase shift circuitry (GMTPS) 
because of poor lightening and power line noise immunity (LPLNI), but
it's 
working well now.  Feedback Loop Dynamics Calculations (FLDC) continue
as 
I  optimize the response time, but it's slow because time on the 
multi-processor parallel computer (MPPC) is hard to get just now. Seems
as 
if the Navy folks at the Naval Undersea Warfare Center Carderock (NUWCC)

Hydrotechnology are developing a new Nuclear Submarine Propulsor and the

multi-million point hydrodynamic mesh physics equations in their
modelling 
codes have approached computational limits.  I *wish* they would keep 
things simpler.

Further reports will be sent by carrier pigeon with above abbreviations 
used for the Pidgeon Payload Weight Reduction Effort (PPWRE). I fear
some 
radio nuts might get wind of this and somehow beat us to market.

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Cell 301-928-7794
Work: Voice: 301-975-3254,  Fax: 301-948-6213
roy.morgan at nist.gov --

------------------------------

Message: 2
Date: Thu, 5 Jan 2006 16:48:42 -0500
From: "Bruce Hagen" <b_hagen at sbcglobal.net>
Subject: RE: [R-390] Beaten Horse Graveyard (Goldberg replacement for
	3TF7)
To: "Roy Morgan" <roy.morgan at nist.gov>,	"Tom Norris"
	<r390a at bellsouth.net>, <R-390 at mailman.qth.net>
Message-ID: <HIECIMBMNLCKLMAPHOGHEEEGCKAA.b_hagen at sbcglobal.net>
Content-Type: text/plain;	charset="us-ascii"

Oh, boy!

 Certain member must be under heavy stress. I'm still working on the TV
adapter so we can use the 390 for sound.

Bruce

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On
Behalf Of Roy Morgan
Sent: Thursday, January 05, 2006 4:10 PM
To: Tom Norris; R-390 at mailman.qth.net
Subject: Re: [R-390] Beaten Horse Graveyard (Goldberg replacement for
3TF7)

At 02:35 PM 1/5/2006, you wrote:

>light bulb ... changes the resistance of a photocell,
>which changes the speed of a motor, which runs a fan, which pushes a
>sailboat across a tub of water,

Egad, Tom! You talked about this on the list???

What will our patent attorney say?  Threaten to quit, no doubt.

I hope no one notices, or if they do, don't take you seriously.

Pssst!
The Guinea Pig at our house recently transitioned to the Great Radio
Room
in the Sky, but we do still have the two gerbils.  Their 12-year old
custodian has not noticed that I've installed the potty-and-switch
mechanisms (PSM) below their cage in the top drawer of her dresser
(TDD).
She never uses the dresser anyway, so we are safe.  Of course all wires
and
such are hidden in the walls (HIW) in accordance with the Evidence
Protection Plan (EPP), so I expect a good long test period before we
complete the patent application paperwork  (PAP).  I just hope my
soldering
at midnight doesn't wake her up again (SNIFF)

I had to redesign the gerbil-motion-to-phase shift circuitry (GMTPS)
because of poor lightening and power line noise immunity (LPLNI), but
it's
working well now.  Feedback Loop Dynamics Calculations (FLDC) continue
as
I  optimize the response time, but it's slow because time on the
multi-processor parallel computer (MPPC) is hard to get just now. Seems
as
if the Navy folks at the Naval Undersea Warfare Center Carderock (NUWCC)
Hydrotechnology are developing a new Nuclear Submarine Propulsor and the
multi-million point hydrodynamic mesh physics equations in their
modelling
codes have approached computational limits.  I *wish* they would keep
things simpler.

Further reports will be sent by carrier pigeon with above abbreviations
used for the Pidgeon Payload Weight Reduction Effort (PPWRE). I fear
some
radio nuts might get wind of this and somehow beat us to market.

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Cell 301-928-7794
Work: Voice: 301-975-3254,  Fax: 301-948-6213
roy.morgan at nist.gov --

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------------------------------

Message: 3
Date: Thu, 5 Jan 2006 16:50:14 EST
From: Flowertime01 at wmconnect.com
Subject: Re: [R-390] Beaten Horse Graveyard (Goldberg replacement for
	3TF7)
To: r-390 at mailman.qth.net
Message-ID: <242.4c30983.30eeee96 at wmconnect.com>
Content-Type: text/plain; charset="US-ASCII"

Tom,

How are you going to keep the water level constant under the sail boat?
Won't it evaporate?

Roger AI4NI

------------------------------

Message: 4
Date: Thu, 5 Jan 2006 20:42:47 -0600
From: "Cecil Acuff" <chacuff at cableone.net>
Subject: [R-390] OT Hammarlund week
To: "R390list" <r-390 at mailman.qth.net>
Message-ID: <000f01c6126a$e149c7a0$6401a8c0 at acuff1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original

Well it looks like it a good week for Hammarlund SP-600's on the bay.  A

VLF-31 and a Northern Radio variant.  Both at reasonable prices so far!

I'd love to have the VLF-31.  It ought to be an interesting auction to 
watch.  The last of those I saw sold there went quite high!

Cecil... 

------------------------------

Message: 5
Date: Thu, 05 Jan 2006 18:57:39 -0800
From: "Kenneth G. Gordon" <kgordon at moscow.com>
Subject: RE: [R-390] SS replacment for 3TF7 - back-to-back Zeners.
To: "David Wise" <David_Wise at Phoenix.com>
Cc: R-390 at mailman.qth.net
Message-ID: <43BD6C23.12585.1AC56B38 at localhost>
Content-Type: text/plain; charset=US-ASCII

David Wise wrote:

> There's regulation and then there's regulation.

Absolutely!

>  The shunt clipper
> you describe below is good to, oh I don't know, maybe a few percent,
> which is IIRC slightly inferior to a 3TF7 at the top of its game.

Could be, all right. I haven't compared them too closely. BTW, the 
ballast tube in the SRR-11 isn't a 3TF7, and I can't exactly remember 
which one it is either.

> Why?  Let's say the supply voltage goes up.  The zeners continue to
> lop off the top of the sine wave, but the part they don't, lasts
> longer per cycle and therefore delivers more power to the heaters.

Right. However, in this case, the SUPPLY voltage is 17 VAC.

> An exact answer requires integral calculus.  When ballast tubes
> went out of the mainstream of new instrument design, RCA judged
> the clipper "good enough" for the SRR.

Yup, and it isn't all that stable, either, especially on the upper band 
which includes 32 Mhz.

> 
> There are heavy-duty approaches that can beat this by several orders
> of magnitude.  Will you notice?  Depends, probably not.

As you say, it depends. With the selectivity set at its narrowest, a
little 
drift IS noticeable.

In the case of the SRR-11 Zener regulator, I think it regulates well
down 
on the more "linear" slope of the sine wave, not at the sharply curved 
top. None-the-less, it is pretty crude, IMHO.

As I said above, the supply voltage is 17 VAC for a 6.3 VAC filament.

In any case, I have not yet tested the regulation, but will when I can.

Ken Gordon W7EKB

------------------------------

Message: 6
Date: Thu, 05 Jan 2006 20:47:10 -0800
From: "Dan Merz" <mdmerz at verizon.net>
Subject: RE: [R-390] My R-392 Starts Singing
To: "'Osamu Hazawa'" <pomerol at mocha.ocn.ne.jp>,	"'R390 List'"
	<r-390 at mailman.qth.net>
Message-ID: <000a01c6127c$419c6110$2f01a8c0 at DansDell>
Content-Type: text/plain; charset=us-ascii

Hazama,  as best I remember,  my 392 worked right away like yours after
I
put the power to it.  I then checked all the tubes on a tube tester and
replaced a few weak ones,  as I recall 26A6's.  I never had to do
anything
else to the radio.  It's worked ok since,  now about 13 years later.  I
don't use it very often since I obtained a 390a and then a 390.  The 390
gets the nod nowadays.  When I do turn on the 392,  it never disappoints
me.
The guy that talked me into buying it told me it would go forever with
little service because of the low plate voltages, and he advocated about
24
volts.  I have read that low voltage is a disadvantage,  and is made up
for
in the design with more tubes in the i.f. lineup and moreover that
26A6's
and 26A7 suffer loss of gain,  or tend to be unpredictable in gain,
compared to tubes with higher plate voltages.  It sounds like your radio
is
doing well for no tube checks yet.  I run mine at about 23 volts.  I
suspect
it would operate better at somewhat higher voltage but I followed the
advice
of a veteran military collector and built the unregulated supply that he
recommended with so much capacitance that I have to bring it up to power
gradually to avoid blowing the appropriate line fuse to the power
supply.  I
finally added a delay relay so I didn't forget,  or have to use a
variac.
It has the biggest cap I've ever used in a power supply,  54000 mfd, 30
volts, mostly chosen because it was there at the swapmeet for $1 and it
gets
the voltage up with the transformer we found.  It's mate still is unused
in
my storage cabinet.  I just went down and tried my 392 on 80 meters at
23
volts and 26 volts using a variac to see if I could tell a
difference...yes
more gain at 26 volts (about 1/8 turn on the rf gain control) but band
noise
was high enough and I had enough reserve in rf gain setting that it
didn't
help on the particular station I was listening to.  The 390 was on in
the
background and was much less noisy on the same station. I've got a
Lambda
LMD24 supply that I found recently and I think it can be tweaked to up
to 25
volts which might be a good replacement for my homebuilt supply to get a
little more gain, and maybe I should check my tubes again.  I think I
have a
few spares to exchange in the set. Regards,      Dan 

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]
On Behalf Of Osamu Hazawa
Sent: Thursday, January 05, 2006 4:53 AM
To: R-390 at mailman.qth.net
Subject: [R-390] My R-392 Starts Singing

Hello All,

After a long period of time (more than a half year), I made a set of
power
connector (made with a couple of But Splices) for my R-392 and  I set
the
voltage at a little bit higher than 26V.

I was so excited when I turned on the radio.
At first, nothing was heard....
But I found RF Gain knob was turned all the way to CCW and rotary
switches
for Megacycle have bad electrical contacts.

Yes, it started singing on BC bands!
But unfortunately, ANT Trimmer doesn't do the justice on all bands and
CAL
tone was not heard on higher bands.

What do you out there think should I do first?
Open up the case first?

Any idea would be appreciated.

Osamu Hazawa
 http://www4.ocn.ne.jp/~pomerol/MyPage/menu0.html

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------------------------------

Message: 7
Date: Fri, 06 Jan 2006 01:26:41 -0500
From: Barry Hauser <barry at hausernet.com>
Subject: Re: [R-390] My R-392 Starts Singing
To: Dan Merz <mdmerz at verizon.net>, 'Osamu Hazawa'
	<pomerol at mocha.ocn.ne.jp>,	'R390 List'
<r-390 at mailman.qth.net>
Message-ID: <0d6701c6128a$287a0530$0d0aa8c0 at yourf95424bb04>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
	reply-type=original

Dan, Hazama

IMHO the R-392 is probably one of the most neglected receivers in terms
of 
use and maintenance.  This, I offer, is due to the fact that (a) they're

small, (b) require a DC supply (c) usually operational on delivery or
after 
a bit of tube replacing, (d) are usually unhacked so don't require 
un-hacking, (e) have sealed cases so no corrosion, weathering, dust
inside, 
and a couple of reasons I'm probably forgetting.  Well, one indication
is 
that many of us have them, but they rarely turn up in threads on this 
reflector -- almost as if they're a member of the family who should not
be 
discussed in mixed company ;-).

I have several.  All work.  One day I bothered to do a full -- or mostly

full -- alignment on one of them.  Quite a difference.  Decent
performance 
became very good/excellent performance.  So do take the time to go
through a 
full alignment.  Chances are, the mechanical alignment is good, but the 
coils etc could benefit from a touchup.

When tuned up with good tubes, performance is very close to an
R-390/R-390A. 
There's something on Josh Rovero's web site about detailed comparisons.
One 
limiting factor is the choice of bandwidths vs. the big ones and the AGC

adjustment, but otherwise he found the sensitivity and selectivity to be

nearly identical.

As for voltage, nominally these are 28 volts which represents a 24 volt 
vehicular power source.  These normally vary between 24 and 27.6 (27.8?)

volts depending on generator/battery/engine RPM's.  There are actually
two 
separate pins on the 9 pin connector for filament and B+.  The word is
that 
best performance and tube longevity can be obtained by running the
filaments 
at 24 volts and the B+ as high as 32.  Of course, that means two
separate 
power supplies, so a happy medium might be the 26 vdc.  You could use a 
beefy 24 volt supply and a lower current bench supply to provide the B+
I 
guess.

Due to the relative smallness, but sturdyness, R-392's have a tendency
to 
wind up under the bench or in a closet with stuff piled on them, so
often 
have to be dug out before use.  The big gray ones can't hide in small
spaces 
that well.

Suggest you check out Josh's R-392 web pages if you haven't found them 
already at http://www.roveroresearch.com/r392/r392.html

OK, remembered another possible factor.  To get audio out of these
radios, 
the easiest and most authentic thing to do is use an LS-166 speaker that

already has the UG audio connector, so it's plug 'n play.  However, the 
LS-166 is designed to be concussion-resistent and waterproof.  It has
inner 
and outer protective perforated baskets enveloping the speaker cone and
the 
suspension is very stiff.  They are, in effect, acoustic suspension 
enclosures (no ports) but with the opposite of the high compliance
driver 
that hi-fi acoustic suspension speakers typically incorporate.  As a
result, 
the sound is fairly crummy. Sound quality can be much better if fed to a

normal speaker through a 600-8 ohm transformer.  Or, you can tap into
the 
matching transformer inside the LS-166 and run it to another speaker or
use 
an amplified speaker adapted from a computer speaker package right off
the 
600 ohm output.  One of these days I'm going to slightly modify one of
my 
LS-166's -- install a mini phono jack which will cut out the internal 
speaker when an external one is plugged in.  I just need to get a round 
tuit.  Square ones don't seem to work so good.

enjoy ..
Barry

> Hazama,  as best I remember,  my 392 worked right away like yours
after I
> put the power to it.  I then checked all the tubes on a tube tester
and
> replaced a few weak ones,  as I recall 26A6's.  I never had to do
anything
> else to the radio.  It's worked ok since,  now about 13 years later.
I
> don't use it very often since I obtained a 390a and then a 390.  The
390
> gets the nod nowadays.  When I do turn on the 392,  it never
disappoints 
> me.
> The guy that talked me into buying it told me it would go forever with
> little service because of the low plate voltages, and he advocated
about 
> 24
> volts.  I have read that low voltage is a disadvantage,  and is made
up 
> for
> in the design with more tubes in the i.f. lineup and moreover that
26A6's
> and 26A7 suffer loss of gain,  or tend to be unpredictable in gain,
> compared to tubes with higher plate voltages.  It sounds like your
radio 
> is
> doing well for no tube checks yet.  I run mine at about 23 volts.  I 
> suspect
> it would operate better at somewhat higher voltage but I followed the 
> advice
> of a veteran military collector and built the unregulated supply that
he
> recommended with so much capacitance that I have to bring it up to
power
> gradually to avoid blowing the appropriate line fuse to the power
supply. 
> I
> finally added a delay relay so I didn't forget,  or have to use a
variac.
> It has the biggest cap I've ever used in a power supply,  54000 mfd,
30
> volts, mostly chosen because it was there at the swapmeet for $1 and
it 
> gets
> the voltage up with the transformer we found.  It's mate still is
unused 
> in
> my storage cabinet.  I just went down and tried my 392 on 80 meters at
23
> volts and 26 volts using a variac to see if I could tell a 
> difference...yes
> more gain at 26 volts (about 1/8 turn on the rf gain control) but band

> noise
> was high enough and I had enough reserve in rf gain setting that it
didn't
> help on the particular station I was listening to.  The 390 was on in
the
> background and was much less noisy on the same station. I've got a
Lambda
> LMD24 supply that I found recently and I think it can be tweaked to up
to 
> 25
> volts which might be a good replacement for my homebuilt supply to get
a
> little more gain, and maybe I should check my tubes again.  I think I
have 
> a
> few spares to exchange in the set. Regards,      Dan
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Osamu Hazawa
> Sent: Thursday, January 05, 2006 4:53 AM
> To: R-390 at mailman.qth.net
> Subject: [R-390] My R-392 Starts Singing
>
> Hello All,
>
> After a long period of time (more than a half year), I made a set of
power
> connector (made with a couple of But Splices) for my R-392 and  I set
the
> voltage at a little bit higher than 26V.
>
> I was so excited when I turned on the radio.
> At first, nothing was heard....
> But I found RF Gain knob was turned all the way to CCW and rotary
switches
> for Megacycle have bad electrical contacts.
>
> Yes, it started singing on BC bands!
> But unfortunately, ANT Trimmer doesn't do the justice on all bands and
CAL
> tone was not heard on higher bands.
>
> What do you out there think should I do first?
> Open up the case first?
>
> Any idea would be appreciated.
>
> Osamu Hazawa
> http://www4.ocn.ne.jp/~pomerol/MyPage/menu0.html
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
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>
>
> _____________________________________________________________
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> 

------------------------------

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End of R-390 Digest, Vol 21, Issue 17
*************************************