[R-390] R-390A DB on c/l meter and S signal levels

Sat Apr 6 20:47:47 EDT 2019

Hi Jose,  Welcome to the R-390x forum.  Your English is very good.  Hope
you are enjoying your R-390A.

Yes, the S9 equivalent is 34 db and each additional db on the S scale is an
additional db on the R-390x scale, so you have it right (S9+10 would be 44,
etc.).

Regards, Larry

-----------------------------------------------------------------------------------------------------------------------
On Sat, Apr 6, 2019 at 3:54 PM jm <josemic at gmail.com> wrote:

> Hi everybody. This is my first post and it is about the carrier meter.
> Has somebody made a scale with the equivalent values in terms of S based in
> the carrier meter 0-100 indications?
> I am confused. In some threads of the reflector it is mentioned that S9
> corresponds to a reading of 34  in the scale. But, is it correct that
> S9+10 would be 44 and so on?
> I read every issue and I am very impressed with the technical level.
>
> Sorry for my poor English.
> Jose
> EA8DCP
>
> El sáb., 6 abr. 2019 a las 23:29, <r-390-request at mailman.qth.net>
> escribió:
>
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> > Today's Topics:
> >
> >    1. R 390A Audio Upgrade - Again (Perry Sandeen)
> >    2. 17 MHz AGC pulling problem (Perry Sandeen)
> >    3. Re: knobs- availabiity (Gary I. Biasini)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Sat, 6 Apr 2019 16:41:42 +0000 (UTC)
> > From: Perry Sandeen <sandeenpa at yahoo.com>
> > To: r-390 at mailman.qth.net
> > Subject: [R-390] R 390A Audio Upgrade - Again
> > Message-ID: <1865383702.17702173.1554568902860 at mail.yahoo.com>
> > Content-Type: text/plain; charset=UTF-8
> >
> > Yo Bubba Dudes!
> > There have probably been as many *A* audio upgrades as any other mod.
> Some
> > are more successful than others but most have limitations as they just do
> > some mods to the existing circuit which for long term listening: just
> suck.
> > BTDTGTTS! The Achilles heal of all the mods is that they still used the
> OEM
> > audio output transformer. Although in Chuck Felton's mod he did use some
> > negative feedback.
> >
> > The best mod (and yes it is not reversible so *purists* can stop reading
> > now) is the one done by Bill Kleronomos SK who did them for a side
> business
> > until he passed.
> > What made this the best by far is that it used a Hammond true Hi-Fi P-P
> > output transformer with negative feedback.
> > That said IMNSHO there were seveal shortcomings to his design.
> > First he used a Amperex 6360 9 pin dual heptode(?) mounted in place of
> the
> > last 6AK6 tube used for the local audio output. This tube runs very, very
> > hot.
> >
> > Secondly he changed the line output stage to a 6AH6 as the 1/2 12AU7
> > driver for the 6AK6 tube was removed because of the need for a 6DJ6 phase
> > inverter.? The line audio stage and its associated precision resistors
> are
> > used in the A's calibration.
> > Thirdly, he left unused OEM audio output transformer in place and mounted
> > the new audio transformer where the squelch circuit would be installed.
> > I started to improve on this by relocating the under chassis dropping
> > resistors to the top of the chassis and in their place install new
> > Panasonic electrolytics so that the OEM filter cap sockets would be
> > available to use for P-P 6AQ5 audio tubes.? With a little fitness I was
> > able to remont the OEM filter chokes in the space behind the power
> > tanformer.? An alternate plan was to use the Hammond 1.25 Hy chokes from
> > Triode Electronics and up the filter caps to 330 uF each.? This would
> give
> > the same or better attenuation as the OEM ckt but take far less space. I
> > also planned to do as W. Li did so well was to do a star ground sustem.
> >
> > I added another 9 pin tube so there would be the same 12AU7 driver so the
> > 6AK6 line driver circuit would remain the same.
> > Then I screwed up big time.
> > I felt the 800 narrow filter was useless and cut it out.? That left me
> > with a huge mess of wires that I never got straightened out.? Waiting for
> > *more quality bench time* never happened.
> > I believe that the improvements I started would combine the best on
> > chassis audio with the best reliability.
> > I would be delighted to email all of my circuits, notes, pictures and an
> > unpublished experimental article to all who might want to do this mod.
> > If one leaves in the narrow filter I believe doing the mod is not too
> > difficult.
> > BTW my audio module had the $#^%&^( MFP.? I found that a simple engraving
> > tool was great for removing it from solder terminals.? Wear a mask and
> > don't inhale it.? it's still hazardous even at 60 years old.
> > Regards,
> > Perrier
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Sat, 6 Apr 2019 17:51:12 +0000 (UTC)
> > From: Perry Sandeen <sandeenpa at yahoo.com>
> > To: "r-390 at mailman" <r-390 at mailman.qth.net>
> > Subject: [R-390] 17 MHz AGC pulling problem
> > Message-ID: <959952909.824422.1554573072374 at mail.yahoo.com>
> > Content-Type: text/plain; charset=UTF-8
> >
> > Yo Bubba Dudes!
> > A challenging problem for solving by those with cold logic and a hot
> > soldering iron.
> >
> > One of the puzzling mysteries of the a is the 17 crystal oscillator drift
> > caused by the application of AGC to the first mixer. This can be 300 -
> 450
> > Hz from the findings of Chuck Felton.
> > Collins went to the trouble of putting the crystal in an oven so why not
> > solve this problem.? Best guess.? They knew about it BUT it wasn't in the
> > required stringent spec's so engineering, knowing the cost of solving the
> > problem, just kept quiet.
> > Now for causal AM listening Chuck noted that it probably wouldn't make
> any
> > difference.? However e are interested in listening to the continuous
> sound
> > of the 100 watt station in flea fart from Fiji, or something similar.
> > But for us true believers in getting the ultimate performance from our
> > beloved A's this intolerable technical gaffe must be remedied, if not,
> > we'll become the laughing stock of those heathen rice box lovers.
> >
> > I started to investigating methods for solving the drift.
> > The? major difficulty is that the oscillator is located on the RF chassis
> > making simple access impossible.
> > Also finding a 17 MHz crystal or a harmonically related prove futile
> > except for SMD. Ugh
> >
> > An outboard metal box approach using a SS method led to using a 10 MHz
> and
> > a 27 MHz 1/2 crystal can oscillators feeding a Minicircit passive DBM
> then
> > using a tuned 17 MHz LC circuit.? This would be fed through a very good
> > .01uF/1KV ceramic cap into to pin 5 of the 6AK5 oscillator tube V207
> after
> > removing B+ resistor feed R211.
> > OPS! pin 5 goes to tuned circuit T207.? Square wave into LC circuit, not
> a
> > good idea.
> > Feed the new 17 MHz through P221? Perhaps.
> > Plan two was to remove the 17 MHz crystal, make a new oscillator circuit
> > then feed it into the grid pin 1 of V207 utilizing it as a buffer.
> > Would this work? I don't know.
> > This is just a starting point for others as I will never be able to
> pursue
> > this.? Good luch to any who will even try (and post there results on the
> > list.
> > Regards,
> > Perrier
> >
> >
> >
> >
> >
> >
> > .
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Sat, 6 Apr 2019 14:49:19 -0600
> > From: "Gary I. Biasini" <gary.biasini at shaw.ca>
> > To: "'Lester Veenstra'" <m0ycm at veenstras.com>,  <r-390 at mailman.qth.net>
> > Cc: wb3fau55 at neo.rr.com
> > Subject: Re: [R-390] knobs- availabiity
> > Message-ID: <[email protected]>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > Sorry, it was right beside the last drawing.
> >
> > Here is what I found on the non-tuning knobs - large, small and small
> > without line.
> >
> > Regards,
> >
> > Gary
> >
> > -----Original Message-----
> > From: Lester Veenstra <m0ycm at veenstras.com>
> > Sent: April 6, 2019 8:36 AM
> > To: 'Gary I. Biasini' <gary.biasini at shaw.ca>; r-390 at mailman.qth.net
> > Cc: 'Barry' <n4buq at knology.net>; wb3fau55 at neo.rr.com
> > Subject: RE: [R-390] knobs- availabiity
> >
> > Interesting, and the little knobs?
> > That would be an easier starting point
> > Have to get some bigger Al blanks for the main knobs
> >
> > Lester B Veenstra? K1YCM  M?YCM  W8YCM   6Y6Y
> > lester at veenstras.com
> >
> > Physical and US Postal Addresses
> > 5 Shrine Club Drive (Physical)
> > HC84 452 Stable Ln (RFD USPS Mail)
> > Keyser WV 26726
> > GPS: 39.336826 N? 78.982287 W (Google)
> > GPS: 39.33682 N? 78.9823741 W (GPSDO)
> >
> >
> > Telephones:
> > Home:?????????????????? ? +1-304-289-6057 US cell???????????????????
> > +1-304-790-9192 Jamaica cell:?????????? +1-876-456-8898
> > ?
> >
> > -----Original Message-----
> > From: Gary I. Biasini [mailto:gary.biasini at shaw.ca]
> > Sent: Saturday, April 06, 2019 1:09 AM
> > To: r-390 at mailman.qth.net
> > Cc: 'Lester Veenstra'; 'Barry'; wb3fau55 at neo.rr.com
> > Subject: RE: [R-390] knobs- availabiity
> >
> > Lester,
> >
> > Here is what I found.  I am looking for more.
> >
> > Regards,
> > Gary
> >
> > -----Original Message-----
> > From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> On
> > Behalf Of Lester Veenstra via R-390
> > Sent: April 5, 2019 3:09 PM
> > To: 'Barry' <n4buq at knology.net>; wb3fau55 at neo.rr.com
> > Cc: r-390 at mailman.qth.net
> > Subject: Re: [R-390] knobs- availabiity
> >
> > Anybody got drawings?   I have a cnc mill that should be able
> >
> > Lester B Veenstra? K1YCM  M?YCM  W8YCM   6Y6Y
> > lester at veenstras.com
> >
> > Physical and US Postal Addresses
> > 5 Shrine Club Drive (Physical)
> > HC84 452 Stable Ln (RFD USPS Mail)
> > Keyser WV 26726
> > GPS: 39.336826 N? 78.982287 W (Google)
> > GPS: 39.33682 N? 78.9823741 W (GPSDO)
> >
> >
> > Telephones:
> > Home:?????????????????? ? +1-304-289-6057 US cell???????????????????
> > +1-304-790-9192 Jamaica cell:?????????? +1-876-456-8898
> > ?
> >
> >
> > -----Original Message-----
> > From: r-390-bounces at mailman.qth.net [mailto:
> r-390-bounces at mailman.qth.net]
> > On Behalf Of Barry
> > Sent: Tuesday, April 02, 2019 10:29 AM
> > To: wb3fau55 at neo.rr.com
> > Cc: r-390 at mailman.qth.net
> > Subject: Re: [R-390] knobs- availabiity
> >
> > Yes, Dan is an SK.
> >
> > I think he offered knobs that were machined from solid aluminum and
> > powder-coated.  They were quite nice.
> >
> > Thanks,
> > Barry - N4BUQ
> >
> > ----- Original Message -----
> > > From: wb3fau55 at neo.rr.com
> > > To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> > > Sent: Tuesday, April 2, 2019 9:18:40 AM
> > > Subject: [R-390] knobs- availabiity
> > >
> > > Gang- some time back, i heard Dan Arney had built die-cast molds for
> > > 390 knobs. i guess he is SK? What became of the dies or molds? 73s
> > > Russ wb3fau
> > > ______________________________________________________________
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