Author Topic: My 1958 Concert Grand Restoration Project  (Read 12352 times)

Pat L

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Re: My 1958 Concert Grand Restoration Project
« Reply #45 on: November 13, 2014, 07:24:19 PM »
A couple more pics.

I want to give a very special thanks to our fellow member Dave (AMP82-01-00), he not only traded me the original amps back, he also gave me the ultra rare horn adapter you see above the left channel amplifier. Without his help this console would not be playing for quite some time yet. Also, thanks go out to Modernman61 as I was able to purchase the tuner, faceplate, and selector switch from him.

Guys, this thing sounds so good that my wife told me it was "magical"  :D

Harbourmaster

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Re: My 1958 Concert Grand Restoration Project
« Reply #46 on: November 13, 2014, 08:34:28 PM »
Magical??? Are there unicorns lurking about your CG??

How about some pics of the undersides of those chassis??
-- Aloha, Ken

No Console Left Behind!

Pat L

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Re: My 1958 Concert Grand Restoration Project
« Reply #47 on: November 13, 2014, 09:29:48 PM »
Pics of the underside of the amps.

Harbourmaster

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Re: My 1958 Concert Grand Restoration Project
« Reply #48 on: November 13, 2014, 09:48:10 PM »
Gotta love the simplicity of these Maggies compared to some of the other stuff out there!
-- Aloha, Ken

No Console Left Behind!

Larry H

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Re: My 1958 Concert Grand Restoration Project
« Reply #49 on: November 13, 2014, 10:04:56 PM »
Pat, those CG amplifiers sure don't have many capacitors to change in them.  But, I've noticed the same thing with RCA amps...the bigger the amp case, the fewer the number of capacitors it has.  I wonder why that is?
--Larry

vintage cltr

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Re: My 1958 Concert Grand Restoration Project
« Reply #50 on: November 14, 2014, 07:22:12 AM »
wow!

that is all I can say. I remember you buying the shell and seeing it in your garage.

to see that unit finished and brought back from assured death, makes me happy  ;D
Loud and Vintage.... any questions?

Pat L

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Re: My 1958 Concert Grand Restoration Project
« Reply #51 on: November 14, 2014, 07:32:35 AM »
In regards to the number of capacitors, I have made the same observation myself. Some amps seem to have many, some have few. I'm not qualified to judge circuit design professionally, but I do have an opinion. I think it's apparent that some designs are simply more elegant, they accomplish their task in the simplest and most efficient way.

If you look at these two amps they are huge for their power output. The transformers are obviously conservatively designed. In fact each output transformer has multi ohm windings that aren't even used. Perhaps others more knowledgeable than I will weigh in.


Consoleman

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Re: My 1958 Concert Grand Restoration Project
« Reply #52 on: November 14, 2014, 08:29:52 AM »
REALLY nice Pat. Can you explain the amp configuration? That looks like an AMP-150 with 4x 6V6 driving the woofers, like my Berkshire.
Mark

Pat L

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Re: My 1958 Concert Grand Restoration Project
« Reply #53 on: November 14, 2014, 09:39:32 AM »
Each amp is two amps on one chassis. The low frequency drivers are powered by 4 6V6's in a parallel push pull configuration providing 20 watts of power to it's respective speaker. The high frequency horns are powered by a single ended single tube 6V6 amplifier supplying 5 watts of power to each. From a power and tube layout perspective the amps are identical.

The amps differ from the typical AMP-150's in two important areas. The crossover network on these amps is set at 1000 hz, and on the more typical amps it is set at 2000 hz. The other key difference is the pin out configurations on the speaker sockets are completely different. The plugs are not interchangeable and must be reconfigured. There are also minor capacitor and resistor value differences to support the different crossover frequency.   

Consoleman

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Re: My 1958 Concert Grand Restoration Project
« Reply #54 on: November 14, 2014, 10:20:14 AM »
OK so basically 2 AMP-150s with a different crossover. When did they go to the monster amps with 6 6V6s for the woofer and 2 6V6s for the horn?
Mark

Pat L

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Re: My 1958 Concert Grand Restoration Project
« Reply #55 on: November 14, 2014, 10:53:19 AM »
The next model after mine, the Concert Grand's that debuted in October of 1959. But check out the AMP-148, it's an earlier variant or precursor to the later AMP82-01-00's found in the 1959 CG's.

AMP82-01-00

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Re: My 1958 Concert Grand Restoration Project
« Reply #56 on: November 16, 2014, 06:41:19 PM »
Hey Pat I'm glad to help it come back from stripped!!!
David        "If it ain't interesting, its really just boring"

Curtis W

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Re: My 1958 Concert Grand Restoration Project
« Reply #57 on: November 17, 2014, 12:37:59 PM »
Yep. My 1956 Imerial Symphony has the amp 148 with eight 6v6 gt tubes. In one mono speaker cabinet

AMP82-01-00

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Re: My 1958 Concert Grand Restoration Project
« Reply #58 on: November 17, 2014, 02:36:32 PM »
To me the amp148 is the best looking one of all the Maggie's. However I like most all of them. I've converted speakers to run on the bi-amped setup or swap a molex connector and you can run them as  regular stereo speakers. Soon as its complete I'll post it. I did a set for a good friend of mine. Now I'm doing a set for me.
David        "If it ain't interesting, its really just boring"