Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Oct Thu 23, 2014 8:56 am


All times are UTC [ DST ]



Post New Topic Post Reply  [ 14 posts ] 
Author Message
 Post subject: Rumble and Contour
PostPosted: Feb Fri 26, 2010 12:51 pm 
New Member

Joined: Jan Thu 22, 2009 5:25 am
Posts: 17
Location: Canada
My vintage amp has a dedicated switch for each of these functions. They are selected as either on or off. Can anyone describe what these are used for?


Top
 Profile  
 
 Post subject:
PostPosted: Feb Fri 26, 2010 1:17 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 164
Location: Park City, Kansas, USA
Rumble is a filter to remove very low audio frequencies created by the turn-table platter and motor, etc. It's an electronic patch used to compensate for less expensive turntables.

_________________
trader_vic


Top
 Profile  
 
 Post subject:
PostPosted: Feb Fri 26, 2010 1:31 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 6552
Location: Raleigh NC USA
The contour switch is actually a "loudness" contour switch.

A "loudness" control differs from an ordinary "volume" control. It is set up in a special frequency-compensating circuit. As the loudness control is adjusted, the bass and treble response is varied. This is done to compensate for the human ear's frequency response, which changes in step with the loudness of a sound.

Some "loudness contour" switches cut the frequency compensating circuitry out altogether. With others, there may be multiple "loudness contours" that may be selected. This allows for differing room acoustics etc.

Some of the older hi-fi systems had an altogether different kind of compensator switch, with selections such as "RIAA," "AES," "Angel," "London," "Col" (Columbia) etc.

In the days before RIAA became the accepted frequency compensation standard for disc recordings, many record companies used their own frequency compensation curves. This selector switch allowed you to set up your system for proper frequency response, depending on the record brand you were playing.

Larry

_________________
It don't make a go if it ain't got that GLOW!


Top
 Profile  
 
 Post subject:
PostPosted: Feb Fri 26, 2010 2:27 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 11737
Location: Warner Robins, GA
Also don't forget Yamaha's use of a separate variable loudness contour control.


Top
 Profile  
 
 Post subject:
PostPosted: Feb Fri 26, 2010 7:29 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 10771
Location: Baltimore, MD, USA
Tube Radio wrote:
Also don't forget Yamaha's use of a separate variable loudness contour control.


And so did Allied Radio Knight-Kit. I have several amps that use the continuously variable loudness as well as a volume control. An example would be the KG-870 transistor amp, 56 Watts RMS but advertised as a 70 Watt amp. A victim of the BS power wars in the 60s until the settled back down to RMS...

_________________
Don


Top
 Profile  
 
 Post subject:
PostPosted: Feb Sun 28, 2010 7:04 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 11737
Location: Warner Robins, GA
Oh I did not know that. Personally I don't use loudness controls. They color the sound too much for my liking.


Top
 Profile  
 
 Post subject:
PostPosted: Feb Sun 28, 2010 3:17 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 6552
Location: Raleigh NC USA
And for me, it's the other way around.

It all depends on what you're used to.

:wink: Larry

_________________
It don't make a go if it ain't got that GLOW!


Top
 Profile  
 
 Post subject:
PostPosted: Feb Sun 28, 2010 4:16 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 10771
Location: Baltimore, MD, USA
BigBandsMan wrote:
And for me, it's the other way around.

It all depends on what you're used to.

:wink: Larry


For sure. I know that some will remove/bypass tone controls. And that is fine. It is what makes the world go around, freedom of choice. But I like to contour the sound to my liking. I like to listen to music at a low volume (Just sometimes :wink: ) with the contour such that it has crisp highs and solid but not boomy bass. I know that bass reflex cabinets often will be highly efficient allowing very low power amplifiers. However, I prefer what I would call sealed acoustic reflex cabinets that often require more power but sound, to me, to have a tighter bass. I know that RCA made a lot of the New Orthophonic phonographs in the 50s that had two 12" woofers and a PP 6V6GT amplifier of about 10 watts that would shake the room. But it sounds boomy to me...

_________________
Don


Top
 Profile  
 
 Post subject:
PostPosted: Feb Sun 28, 2010 6:28 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 6552
Location: Raleigh NC USA
Don, you should get hold of a pair of EV S-80 professional studio monitors. They have only 8" woofers and piezo tweeters, but they are tough, and they're small and light enough to work well as bookshelf speakers. Their performance should surprise you.

I've been using my pair with my Fisher 400 since the early 1990's. They have clear full-fidelity sound, they spread it out well, and you don't get a sense that they are coloring the sound. And they're anything but boomy.

:wink: Larry

_________________
It don't make a go if it ain't got that GLOW!


Top
 Profile  
 
 Post subject:
PostPosted: Feb Sun 28, 2010 10:52 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 10771
Location: Baltimore, MD, USA
Larry what I have right now is my Sansui 1000A connected to a pair of Klipsch Heresy II speakers. I also have several pairs of Bang & Olufsen S45 and S75 speakers. I have a pair of the S45-2 speakers in this room too and switch to them from the Klipsch.

_________________
Don


Top
 Profile  
 
 Post subject:
PostPosted: Mar Mon 01, 2010 2:27 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 6552
Location: Raleigh NC USA
Excellent units, all those. I take nothing away from them. But if a pair of those 80's ever fall into your hands, I won't be surprised if you find a place for them.

When my 400 was down last fall, I cranked Big Bertha through my pair for a few days. I'd never done that before.

Except for it being a mono signal going through to both units, I could have sworn that the Fisher was still driving them. They sure made Bertha sound different than that big Peavey system I usually use with her.

:wink: Larry

_________________
It don't make a go if it ain't got that GLOW!


Top
 Profile  
 
 Post subject:
PostPosted: Mar Mon 01, 2010 3:08 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 11737
Location: Warner Robins, GA
Yea I used to have the bass and treble controls set full CW and loudness control set to on, but working with the sound system at church has changed the way I listen to music. Now loudjness controls are off and tone controls are set to flat.

Since I have a pair of four way DIY speakers with one amp on the subs (one for right channel and one for left channel) that's where I adjust my tone. I adjust the midrange L-pad and tweeter L-pad to where they are both balanced with the midbass. Then I adjust the level on the subwoofer amp till the bass is set to my liking. I use this setup for picnics at work and even far away the sound is still just as clear as it is up close. I will never buy speakers again, but will rather build my own. What I have built cost about as much as pro audio speakers do, but I get much better sound.

Now admittently I will play with the tone controls and loudness control on an amp that sounds too flat or when driving speakers that are lacking a bit in sound quality.


Top
 Profile  
 
 Post subject:
PostPosted: Mar Mon 01, 2010 11:15 pm 
Member

Joined: Apr Mon 24, 2006 1:05 am
Posts: 1711
Location: Ellington CT
The McIntosh C-20 has a variable "loudness" control called "aural comp(ensator)". Heathkit SP-2A's also have them, as do others, most likely. The C-20's helps in my listening room MUCH. Nice feature.
Kevin

_________________
"There Is Nothing Finer Than A Stromberg-Carlson"


Top
 Profile  
 
 Post subject:
PostPosted: Mar Mon 01, 2010 11:34 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 6552
Location: Raleigh NC USA
Right, Kevin. You always need provision to tune the unit to the room. No two rooms are alike, and each has resonances and nulls to deal with, at the very least.

And that aural compensator control is Mac all the way, doing the job right from the get-go. It's always best to get a first-class unit for first-class pay. Settling for anything else is never ultimately satisfying (or wise).

:wink: Larry

_________________
It don't make a go if it ain't got that GLOW!


Top
 Profile  
 
Post New Topic Post Reply  [ 14 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests



Search for:
Jump to:  




















Privacy Policy :: Powered by phpBB