[Phono-L] Scott AW23 volume expander
Douglas Houston
cdh041 at earthlink.net
Sat Jun 27 21:42:51 PDT 2009
Well, that answers a lot. My AW23 is in (I believe,) the Wellington
cabinet, and it don't got no expander! Little wonder I didn't know about
it! I wonder if anything was in "Silver Ghodts" about it. I believe that
the tweeters were available on all of those sets, as accessories. I have
some of the tweets laying around, and should check if hey're the right ones
for that set. Thanks for the info!
> [Original Message]
> From: Andrew Baron <andy at popyrus.com>
> To: Antique Phonograph List <phono-l at oldcrank.org>
> Date: 6/27/2009 11:53:49 PM
> Subject: [Phono-L] Scott AW23 volume expander
>
> Hi Doug ~
>
> The volume expander on the Scott AW-23 was an outboard unit, contained
> in a small, rectangular, chrome plated box that mounted outboard of
> the main chassis on rubber vibration absorbing pads. The box
> contained four tubes although I don't know off hand what the tube
> numbers are.
>
> It has three umbilical cords: One that went to the receiver chassis
> and brances off to interface with two of the tubes that are near one
> another (with substitute grid clips and caps for each of these two
> receiver chassis tubes, so the components in the chrome box were put
> in series with these tubes grid circuits). A second cord goes to the
> expander control knob, which had its own appropriately stamped
> escutcheon to match the stock ones. The third cord goes to the
> dynamic speaker and terminates in a female-male plug that sandwiches
> between the stock speaker plug and the amplifier/PS chassis, if I
> recall correctly. I assume this is for filament and plate supply
> voltages.
>
> On the Tasman cabinet, the metal box mounted directly behind the
> chassis on the left side of the same shelf, and the expander control
> knob was mounted toward the back of the left side of the cabinet, not
> far from the top. I don't know if all the expander equipped AW-23s
> had the (also optional) tweeters, but I should think that most of them
> would have had them.
>
> Thanks for your various accounts and reminiscences. I always read
> them when you post here and on Levnet as well.
>
> Best,
> Andy Baron
> Santa Fe
>
>
> On Jun 27, 2009, at 9:15 PM, Douglas Houston wrote:
>
> > As usual, greg, nice take. I wasn't aware that Scott had an expander
> > on his
> > AW23. I have one, and never knew it! The expander control tube would
> > have
> > had to be a 6A7 in that set. He certainly did have it on the
> > Philharmonic!
> >
> > By the way, the 6A7, while a pentagrid tube, doesn't actually have
> > five
> > grids! The second "grid" is two rods, serving as an anode for the
> > oscillator. Withe the intro of metal tubes, the 6A7 became the 6A8.
> >
> > The tube that really opened up as the ideal control tube for
> > expanders was
> > the 6L7, introduced in 1935, as one of the original 9 metal tubes.
> > It, and
> > the 6H6, dual diode, were the duet that made expanders easy to
> > happen. I
> > have both the D22 and the R99, as well as the U 109: the 1938
> > version of
> > the D22. On those big RCA combos, the expander operated only on the
> > phonograph, and not on radio reception. The D22 has a little "dynamic
> > amplifier", with three tubes ( I believe), and they feed the amplifier
> > directly. :Likewise, it's similarly done on the U-109. Those big RCA
> > hunkers really roar!
> >
> > It sounds amusing, I suppose, but Midwest incorporated a volume
> > expander on
> > its model 20-38, which was their masterpiece for 1938. I once had
> > one, but
> > didn't yet understand the expander, so I swapped off the set to a
> > friend.
> > I'd like to have that monster now!
> >
> > In the fifties, when microgroove recording was becoming more
> > sophisticated
> > as time passed, Mercury, for one, used what was called: Reeves-
> > Fairchild
> > Margin Control. High level passages automatically widened the groove
> > pitch,
> > so that dynamic range could be preserved, without using compression. A
> > microscope shows it easily.
> >
> >
> >> [Original Message]
> >> From: Greg Bogantz <gbogantz1 at charter.net>
> >> To: Antique Phonograph List <phono-l at oldcrank.org>
> >> Date: 6/27/2009 3:51:11 PM
> >> Subject: Re: [SPAM] Re: [Phono-L] Young collectors
> >>
> >> An interesting thing about dynamic volume expanders/compressors for
> > readers
> >> of this antique phonograph forum is that they date back to the early
> > 1930s.
> >> dbx didn't invent them by any means. The earliest appearance of this
> >> circuit in consumer products was in models by E.H. Scott in the
> >> Allwave
> > 23
> >> (a massive 23-tube radio divided into two or more chrome-plated
> >> chassis -
> >> the volume expander was yet a separate chassis sold as an option),
> >> and
> > the
> >> RCA R-99 record player and D-22 radio/phonograph, both of which
> >> included
> > the
> >> volume expander as standard equipment. These models appeared about
> >> 1935.
> >> Professional compressor circuits were being used a little earlier,
> >> mostly
> > to
> >> compress the signals for AM radio broadcasting (FM wasn't available
> >> yet).
> >> These circuits really weren't technologically feasable until the
> > invention
> >> of the pentagrid tube (it had FIVE grids!) which was originally
> >> designed
> > for
> >> the purpose of providing the oscillator and mixer functions in a
> >> single
> > tube
> >> in superheterodyne radio circuits. But the extra grids allowed
> >> this tube
> > to
> >> be used as a DC-controlled transconductance amplifier - the
> >> variable gain
> >> element necessary to accomplish dynamic volume control. Pentagrid
> >> tubes
> >> were used for this purpose for many years until the development of
> >> solid
> >> state technologies that could do the same thing. Curiously,
> >> though, the
> >> most popular DC-controlled amplifiers used in recording studios
> >> then and
> >> even NOW are a simpler technology employing light-dependent resistor
> > (LDR)
> >> elements. Even though this technology is 50 years old, modern
> >> recording
> >> engineers still prefer the sound of LDR compressors over the more
> >> modern
> >> circuits.
> >>
> >> Greg Bogantz
> >>
> >>
> >>
> >> ----- Original Message -----
> >> From: <Zonophone2006 at aol.com>
> >> To: <phono-l at oldcrank.org>
> >> Sent: Saturday, June 27, 2009 5:46 AM
> >> Subject: Re: [SPAM] Re: [Phono-L] Young collectors
> >>
> >>
> >>> does anyone remember the expanders of dbx fame
> >>> i have and had used a lot of them back in the 70's for expanding and
> >>> constricting the music
> >>>
> >>>
> >>>
> >>> In a message dated 6/26/2009 11:47:39 P.M. Eastern Daylight Time,
> >>> phonographs at charter.net writes:
> >>>
> >>> I used to work at a hi-fi stereo shop in Madison, WI about 2
> >>> years ago
> >>> and
> >>> found that many young people were into turntables and vinyl. They
> > tended
> >>> to
> >>> be high school and college age students. The biggest reason why
> >>> they
> >>> liked
> >>> vinyl was because it was cheap. They could buy used records at
> >>> used
> >>> record/CD stores and at garage sales for 99 cents or less, while
> >>> the
> >>> average
> >>> used priced CD for popular music was $8.99.
> >>>
> >>> Even though these vinyl enthusiasts understood records and were
> > familiar
> >>> with them, they had little to no knowledge of 78s or cylinder
> >>> records.
> >>> When
> >>> I would share this technology with them, they thought it was the
> > coolest
> >>> thing.
> >>>
> >>> Records have been making a comeback now for several years and new
> > vinyl
> >>> is
> >>> being produced, although expensive at nearly $30 or more for an
> >>> album.
> >>> Just
> >>> a few years ago there were high-resolution formats of digital music
> >>> called
> >>> SACD and DVD Audio. These formats were near record quality, but
> >>> never
> >>> really caught on as they needed special players to play these
> >>> discs.
> >>> Records actually began to overtake these formats and within a few
> >>> years
> >>> SACD
> >>> and DVD-Audio was dead.
> >>>
> >>> When CDs came out around 1983-84, it was thought they would be
> >>> record
> >>> killers and records would go the way of the cassette tape. While
> > there
> >>> was
> >>> a huge decline in record and turntable sales, the market never
> >>> died.
> > It
> >>> faded away for a few years, but is coming back. There are many
> >>> young
> >>> people
> >>> who appreciate the quality of high-end turntables and stereo
> >>> systems to
> >>> give
> >>> these records the respect they deserve. A good stereo system
> >>> will make
> >>> records sound better than a CD. Records have an ambiance that CDs
> > lack
> >>> and
> >>> can produce a 3D audio effect, while CDs have a monodimensional
> >>> sound.
> >>>
> >>> Online music, including MP3, MP4, WMAs, etc have become very
> >>> popular in
> >>> recent years by people of all ages. It is a matter of convenience.
> >>> Convenience always wins over quality. Take disc records to
> >>> cylinders
> > for
> >>> example. Discs were more compact and soon provided two songs on
> >>> one
> >>> disc,
> >>> even though they didn't sound quite as good as cylinders at the
> >>> turn
> > of
> >>> the
> >>> century. Online music also allows you to buy only the songs you
> >>> want,
> >>> eliminating the waste of a full album and is more cost effective.
> > This
> >>> is
> >>> proving to be the demise of the CD. Many stores have reduced the
> >>> space
> >>> used
> >>> to carry the once mighty CD. Perhaps the CD will one day go away
> >>> as
> >>> well.
> >>> This awaits to be seen.
> >>>
> >>> Many of the younger people who are a product of the iPOD generation
> > may
> >>> not
> >>> have heard records and probably have never heard a good sounding
> >>> stereo
> >>> system. That is a shame because it is an experience to behold.
> >>> All
> > we
> >>> can
> >>> do is educate and share this information with these younger
> > generations
> >>> in
> >>> order to keep the analog recording alive and well.
> >>>
> >>>
> >>>
> >>>
> >>> -----Original Message-----
> >>> From: phono-l-bounces at oldcrank.org
> >>> [mailto:phono-l-bounces at oldcrank.org]On Behalf Of Robert Wright
> >>> Sent: Friday, June 26, 2009 4:31 PM
> >>> To: Antique Phonograph List
> >>> Subject: [SPAM] Re: [Phono-L] Young collectors
> >>>
> >>>
> >>> But because DJ'ing is 'cool', some of that mentality rubs off on
> > (young)
> >>> consumers. We have a more phono-conscious youth culture now than
> >>> in
> > the
> >>> last 20 years because of it. Meanwhile, analog (vinyl, strictly
> >>> speaking)
> >>> has been strengthening its foothold in the audiophile market (and
> >>> publications) VERY solidly since '97 or so, and there are more
> >>> record
> >>> labels
> >>> (both large-scale that release on vinyl AND indie labels dedicated
> >>> strictly
> >>> to audiophile pressings) today than ever. Someone else on the list
> > said
> >>> it
> >>> already -- it comes and goes in cycles, as it always has --
> >>> remember
> > the
> >>> pre-war blues 78 market back when Gayle Dean Wardlow risked his
> >>> life
> >>> canvassing for them in the 60's?
> >>>
> >>> The truth is, we only know the state of things as we can see
> >>> them, and
> >>> none
> >>> of us ever really has an accurate idea of the overall picture
> >>> (thankfully).
> >>>
> >>> Best to all,
> >>> Robert
> >>>
> >>>
> >>>
> >>> ----- Original Message -----
> >>> From: "John Maeder" <appywander at hotmail.com>
> >>> To: "Antique Phonograph List" <phono-l at oldcrank.org>
> >>> Sent: Friday, June 26, 2009 3:30 PM
> >>> Subject: RE: [Phono-L] Young collectors
> >>>
> >>>
> >>>
> >>> Yes, that was my line of thinking exactly what with club DJs
> > scratching,
> >>> etc., when I planned my talk. I think, perhaps, that club DJ's
> >>> are the
> >>> primary consumer of vinyl and 'civilians' simply aren't exposed
> >>> to it
> > in
> >>> a
> >>> hands-on home environment anymore. Having said that, I recently
> >>> read
> >>> that
> >>> vinyl record production is at its highest level in a couple of
> >>> decades
> >>> right
> >>> now, although still just a very small fraction of unit sales. I
> >>> guess
> >>> just
> >>> music 'geeks' buy vinyl nowadays? Even CDs and DVDs are in sales
> > decline
> >>> now because of MP3 and MP4.
> >>>
> >>> John M
> >>>
> >>>> From: jay.horenstein at gmail.com
> >>>> To: phono-l at oldcrank.org
> >>>> Subject: RE: [Phono-L] Young collectors
> >>>> Date: Fri, 26 Jun 2009 13:18:34 -0700
> >>>>
> >>>> Vinyl isn't a thing of the past. It's still used in clubs.
> >>>> Turntables
> >>> are
> >>>> used as instruments in Rap, Hip Hop, R&B. Classes on how to use
> >>>> them
> >>>> as instruments are given to aspiring DJ's. Stereos are still
> >>>> sold in
> >>>> almost
> >>>> every large store, and new artists are still recording on vinyl.
> > It's
> >>>> my
> >>>> guess that the young people ignorant of the record player, download
> > all
> >>>> their music from the internet, and are probably just as clueless
> >>>> to
> > the
> >>>> CD.
> >>>
> >>> _______________________________________________
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> >>>
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> >>>
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