-
Please note that there are a few updates and clarifications made in the Audiokarma Rules, mostly relating to advertising and the addition of the new "Paying it Forward" & "Giving back" forums in the AudioKarma Audio Marketplace section.
Magnavox Concert Grand Score
- Thread starter Horn Head
- Start date
Horn Head
Super Member
Note that the 1960 model's TT was dead center of the cabinet. And the sealed speaker chamber is the same for both left and right arrays (not different enclosures).
The theory for different woofers seems sound. But it doesn't appear to apply to the CG. Maybe just hold-over technology available at the time?.....
markus
Master Procrastinator
My '58 Concert Grande does the same thing - two different woofers, and they are essentially 'free air' as there is no real enclosure.
I'm sure it sounded like a good idea at the time
different horns from one side to the other also . . .
Awesome thread folks!
I haveread through the entire thread. I didn't see anyone post the specified frequency response for nthe unit. Does anyone know how these amps perform? Are they built for a 4, 8, or 16 ohm load?
Most magnavox units I have seen were built with a 4 ohm load in mind. I have had a couple of the 182-ba units. These wera a stereo little brother version of the CG's.
Cool find to say the least.:thmbsp:
I haveread through the entire thread. I didn't see anyone post the specified frequency response for nthe unit. Does anyone know how these amps perform? Are they built for a 4, 8, or 16 ohm load?
Most magnavox units I have seen were built with a 4 ohm load in mind. I have had a couple of the 182-ba units. These wera a stereo little brother version of the CG's.
Cool find to say the least.:thmbsp:
Horn Head
Super Member
Not sure of the speaker impedences in the CG....can check though.
I ran the amps through some big EVs. 35W at 1100hz and below to the EV 15B, and 15W at above crossover to EV 1824 mids and T35 highs (using a passive X36 crossover between the HF horns).
I was blown away after dialing them in. But I'm a simple guy. The sound went from very delicate at low volumes to brutishly powerful and controlled at high volume (that's where that discussion about the 1812 canons started).
No real tests done on frequency response but to my ears they seemed to cover as much of the range as most would want - and have all that reserve power.
Glad you enjoyed the thread. Lots of helpful info from many kind folks who posted.
I ran the amps through some big EVs. 35W at 1100hz and below to the EV 15B, and 15W at above crossover to EV 1824 mids and T35 highs (using a passive X36 crossover between the HF horns).
I was blown away after dialing them in. But I'm a simple guy. The sound went from very delicate at low volumes to brutishly powerful and controlled at high volume (that's where that discussion about the 1812 canons started).
No real tests done on frequency response but to my ears they seemed to cover as much of the range as most would want - and have all that reserve power.
Glad you enjoyed the thread. Lots of helpful info from many kind folks who posted.
jeffhamman
Active Member
Concert Grand score
First- Happy New years to all AK members,Im sad to say I parted with my 1960 concert grand,the good news get this.. is that I traded it to a fellow ak and Magnavox Friend that lives here in Tulsa. I now have a 1958 concert grand. I never thought I would get rid of the 1960 one but he made me an offer I really could not refuse-no money exchanged hands,along with the 58 I also got a nice 1964 hybrid fisher console,it too is unique. He's happy and Im happy. One or the other will have to live in the garage. We plan to recapp his new concert grand.
First- Happy New years to all AK members,Im sad to say I parted with my 1960 concert grand,the good news get this.. is that I traded it to a fellow ak and Magnavox Friend that lives here in Tulsa. I now have a 1958 concert grand. I never thought I would get rid of the 1960 one but he made me an offer I really could not refuse-no money exchanged hands,along with the 58 I also got a nice 1964 hybrid fisher console,it too is unique. He's happy and Im happy. One or the other will have to live in the garage. We plan to recapp his new concert grand.
advilian
Active Member
Nice!!!! In the early 1960s my parents had a monstrous monaural Magnavox the size of a Dumpster that I eventually cannibalized in my foolish youth. It was a little scary and all tubes and heat and had two 12-inch woofers. I learned a little about hifi on that machine. It had a magically rich, thick, globular sound that I can only barely remember, but I'm not sure I have ever heard anything quite like it since. When I was 12 and desperate for a stereo I used the Magnavox for one channel and my mom's old Wollensak tape recorder monitor for the other. I remember reading somewhere that Richard Rodgers' wife said he never felt he needed stereo sound.
The full text of US Patent 3102605, inventors Freimann and Graef, both of
Magnavox, which was filed July 5, 1960 and issued Sept 3, 1963, can be found
at
http://www.google.com/patents/US3102605?printsec=drawing#v=onepage&q&f=false
It makes for very interesting reading, giving a full description of the
tunnel and advantages thereof, and the benefit of using woofers with different
resonance frequencies in the same enclosure.
Magnavox, which was filed July 5, 1960 and issued Sept 3, 1963, can be found
at
http://www.google.com/patents/US3102605?printsec=drawing#v=onepage&q&f=false
It makes for very interesting reading, giving a full description of the
tunnel and advantages thereof, and the benefit of using woofers with different
resonance frequencies in the same enclosure.
jeffhamman
Active Member
Magnavox concert grand
Thanks this is very good magnavox info. I always wondered about the 2 different woofer theory. now I know!
Thanks this is very good magnavox info. I always wondered about the 2 different woofer theory. now I know!
63bird
New Member
wow!
this thread has been a wealth of info for me. i have a 58 and 59 model both recapped.
Horn Head do you still have yours or the amps? if so im curious as to how you like them after all this time for them break in again?
also what is your favorite speakers to run them on?
i have some extra amps "amp148" and a set of "amp150" and was thinking about finding if there is some kind of 5.1 preamp that can run all the maggies for home theatre?
i welcome all comments or concerns. thanks guys
this thread has been a wealth of info for me. i have a 58 and 59 model both recapped.
Horn Head do you still have yours or the amps? if so im curious as to how you like them after all this time for them break in again?
also what is your favorite speakers to run them on?
i have some extra amps "amp148" and a set of "amp150" and was thinking about finding if there is some kind of 5.1 preamp that can run all the maggies for home theatre?
i welcome all comments or concerns. thanks guys
markus
Master Procrastinator
Hey I know that handle! Btw.....any surround receiver with preouts *should* work.....
Nice to see you in ak dave
63bird
New Member
cool
im usually a lurker reading and learning.
but i thought it would be cool to use my spare amps as channels in a surround sound setup.
i might get a plate amp 300 -500 watt. To run 2 15" subwoofers since it drives me nuts with one powered sub and how some parts of the room it slams and others it dont. so i think 2 subs will be better.
but im picking up a sealed box to try my different 15" speakers with the concert grand amps and see how tight of a punch it has.
i will look for a reciever with preouts i wasnt sure they exist. thanks
im usually a lurker reading and learning.
but i thought it would be cool to use my spare amps as channels in a surround sound setup.
i might get a plate amp 300 -500 watt. To run 2 15" subwoofers since it drives me nuts with one powered sub and how some parts of the room it slams and others it dont. so i think 2 subs will be better.
but im picking up a sealed box to try my different 15" speakers with the concert grand amps and see how tight of a punch it has.
i will look for a reciever with preouts i wasnt sure they exist. thanks
jeffhamman
Active Member
original Magnavox to start
Open cabinet for sure. I like the sound of the cabinets using 2@12inch with a high freq horn. Sort of reminds me of wharfedale w90's.
Open cabinet for sure. I like the sound of the cabinets using 2@12inch with a high freq horn. Sort of reminds me of wharfedale w90's.
InPhaseAudio
New Member
Barn Fresh 58 Concert Grand
Just bought this from a local thrift store. I am on call, anytime they get vintage audio. I pick it up tomorrow. I will go over it and see what needs done. I may try to sell it whole - tough these days. If not, I will salvage the amps and speakers. I have a recording studio and would love to biamp one of my sets of monitors. I wish I could keep it whole, for myself.
It may have been mentioned - but what is the crossover point? If I keep it, I may try to dig in an modify the crossover.
It has the optional remote receiver; alas, no remote..... Got so excited, when I opened the back, that I forgot to take pics of the front. LOL
Cheers, TJ
Just bought this from a local thrift store. I am on call, anytime they get vintage audio. I pick it up tomorrow. I will go over it and see what needs done. I may try to sell it whole - tough these days. If not, I will salvage the amps and speakers. I have a recording studio and would love to biamp one of my sets of monitors. I wish I could keep it whole, for myself.
It may have been mentioned - but what is the crossover point? If I keep it, I may try to dig in an modify the crossover.
It has the optional remote receiver; alas, no remote..... Got so excited, when I opened the back, that I forgot to take pics of the front. LOL
Cheers, TJ
Attachments
InPhaseAudio
New Member
Garage Fresh '59 Mag Concert Grand
I just picked this up, from a local thrift store. I am on their speed dial, whenever they get old electronics. I help them price items. Sometimes, I get first crack at a nice unit.
This provincial model sat in the original owner's garage for 22 years.
I tested all of the tubes on a BK 500. I had to swap in a few tubes; 2 preamp and 1 amp. I dialed it up slowly, over a 2 hour period. The tuner is stuck at one end. Being as such, I have not been able to test the radio. If I have time tomorrow, I will dig into it.
I plugged in an outside source into the tape inputs. It sounds good. This thing rocks! Left channel has some AC hum, so the PS filter caps need to be replaced. The right side is quiet. Pots on the front of the tuner are a lil scratchy. Nothing that a bit of cleaner won't address.
I have a recording studio, and would LOVE to have the amplifiers. That said, I am also a historian. I would love to see this go, whole, to a good home.
I have included a few pics. I will post a picture of the guts, tomorrow.
Cheers,
Tomas Jones
InPhase Audio
I just picked this up, from a local thrift store. I am on their speed dial, whenever they get old electronics. I help them price items. Sometimes, I get first crack at a nice unit.
This provincial model sat in the original owner's garage for 22 years.
I tested all of the tubes on a BK 500. I had to swap in a few tubes; 2 preamp and 1 amp. I dialed it up slowly, over a 2 hour period. The tuner is stuck at one end. Being as such, I have not been able to test the radio. If I have time tomorrow, I will dig into it.
I plugged in an outside source into the tape inputs. It sounds good. This thing rocks! Left channel has some AC hum, so the PS filter caps need to be replaced. The right side is quiet. Pots on the front of the tuner are a lil scratchy. Nothing that a bit of cleaner won't address.
I have a recording studio, and would LOVE to have the amplifiers. That said, I am also a historian. I would love to see this go, whole, to a good home.
I have included a few pics. I will post a picture of the guts, tomorrow.
Cheers,
Tomas Jones
InPhase Audio
Attachments
InPhaseAudio
New Member
59-60 Concert Grand
Had a few minutes to look at the Grand. Turntable turns and mechanism works properly. I don't have a piece of vinyl I am willing to sacrifice. Tuner is stuck at one end of the dial. I really don't want to pull it out. Here is a pic of the guts, minus the dust.
I hope to let this go; whole. If there is no interest, I will keep the amps for my recording studio.
Had a few minutes to look at the Grand. Turntable turns and mechanism works properly. I don't have a piece of vinyl I am willing to sacrifice. Tuner is stuck at one end of the dial. I really don't want to pull it out. Here is a pic of the guts, minus the dust.
I hope to let this go; whole. If there is no interest, I will keep the amps for my recording studio.
Attachments
brunjenkins
New Member
I have a CG 1960 with remote. The volume control motor didn't work and I took it out years ago. Finally took it apart and cleaned the armature and it fired up again. Problem is when you adjust the volume up or down with the remote it goes quite fast. Is this normal? Or was their a resistor or something coming off the motor which I lost?
If they all have the same crossover that's in the AMP150 and AMP172, then by the calculations based on my measurements of the inductance and capacitance, they're around 1100 Hz.
IIRC, the coils in those should be about .6H. Yes, .6 Henry. That's how you get a reasonably low crossover point, with high-impedance signal lines.
Regards,
Gordon.