[R-390] R-390A DB on c/l meter and S signal levels
Larry H
larry41gm at gmail.com
Sat Apr 6 23:55:43 EDT 2019
Jose, I found this chart I made up about the relation of S signal levels
to db. It's attached. Note the difference between the kwm2 and the R-390A.
Regards, Larry
On Sat, Apr 6, 2019 at 5:47 PM Larry H <larry41gm at gmail.com> wrote:
> 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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>> > End of R-390 Digest, Vol 180, Issue 5
>> > *************************************
>> >
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