View Full Version : Magnavox Concert Grand 300H stereo mod


Stevel
07-03-2011, 11:46 AM
Hello,
I recently purchased a Magnavox Concert Grand model 300H. I was hoping it was the model with the dual amps (AMP148), however, this must be an early model as it has one AMP148, albeit beefy with dual 5U4 rectifiers and 8 6V6GT's in PP configuration.

I was removing the record changer for service, and noticed it was wired for stereo! So I started tracing things and found a little amplifier, AMP177 mounted under the tape player. It has a single 12AX7, which is being powered by one of the output tubes. There is an adapter under one of the 6V6GT tubes.
The little amp has a couple pots on it, and it appears that there is a volume control mounted inside the record storage area... it must be for the second channel

I wonder if the modification creates stereo for the internal speakers, or (most likely) stereo for a separate speaker tapped off the little AMP177?

There is also an AMP151 in the cabinet, but it seems to be a 2nd channel amp for the tape deck only.

Any info would be appreciated regarding this "stereo" mod.

Steve
http://mysite.ncnetwork.net/jaimzb11/radios/maggiecg1.jpg
http://mysite.ncnetwork.net/jaimzb11/radios/300hb.jpg

wildone
07-03-2011, 11:49 AM
Wow

Again Wow!

The wife looked at he pic and said " Nice but it has been gutted"

???

I show her the reflection of the plate in the panel.


WoW,

I would love to have that. Very cool.

WO

Augjer
07-03-2011, 12:00 PM
I'd say you have options, options, options!

Good score, I'd take lots of picture so you know where everything hooks up if you let it sit for a month... does it have a diagram on the back panel?

bobabode
07-03-2011, 03:24 PM
More pics, please. There's a yahoo group 'magnavox friends' that has a lot info. You'll need to register to access the files section. That's a great one! Congrats!

gguillot
07-03-2011, 03:30 PM
That has to be one of the best looking consoles I have ever seen! Is the glass area just open storage? Where are the controls mounted? And the phonograph player? Can't tell with the reflections on the glass...

JBL GUY
07-03-2011, 03:46 PM
Congratulations on your new console.

Very nice.

gadget73
07-03-2011, 05:08 PM
The AMP177 is a phono pre-amp of sorts. An umbilical cable would plug into the side of it and go to an external cabinet which would have contained another amplifier similar to whats in the main cabinet.

Stevel
07-04-2011, 01:16 AM
That has to be one of the best looking consoles I have ever seen! Is the glass area just open storage? Where are the controls mounted? And the phonograph player? Can't tell with the reflections on the glass...
The glass areas are just decorative, except for the middle panel which hides the tuner and main controls.
In the top, sliding glass panels cover the record changer and reel-to-reel player.

This one was well used, so the tuner faceplate is quite worn (knobs removed to show this in the picture), but I have an old donor unit (Magnavox 295HM) that has a nice looking tuner faceplate.

While the capacitors are on order, I will service the record changer and detail the cabinet.

Steve
http://mysite.ncnetwork.net/jaimzb11/radios/maggiecg2.jpg
http://mysite.ncnetwork.net/jaimzb11/radios/maggiecg5.jpg

hammondcrazy
07-04-2011, 01:50 AM
Can you still find these at a reasonable price??? and where would be the best place to locate a concert grand? I would love one mono stereo I dont care. Are there a lot of them around?? I never seen one in real life. But hpe God has one for me. as I been praying for one. Thanks Mike

cubby01
07-04-2011, 02:05 AM
Can you still find these at a reasonable price??? and where would be the best place to locate a concert grand? I would love one mono stereo I dont care. Are there a lot of them around?? I never seen one in real life. But hpe God has one for me. as I been praying for one. Thanks Mike

A lot depends on where you are I think. Odds increase through haunting craigslist and estate sales/auctions in areas of nicer home developments or townships that went through a building boom in the 50s and 60s. Thrifts and garage sales as well but less likely imo.

Stevel
07-04-2011, 02:44 AM
Can you still find these at a reasonable price??? and where would be the best place to locate a concert grand? I would love one mono stereo I dont care. Are there a lot of them around?? I never seen one in real life. But hpe God has one for me. as I been praying for one. Thanks Mike
These were very high-end consoles, pretty much for the wealthy crowd. Some of the dual-amp models sold for $1500 in the early 1960's. That would be over $11,000 in modern times.

They do pop up occasionally, but you have to be lucky. I did get lucky on this Concert Grand. I paid $50 for it, plus gas for the 200 mile round trip.

Steve

tylerparrott
07-04-2011, 08:20 AM
Wow, that thing is a serious beauty.

Serious beauty.

TheRed1
07-04-2011, 09:55 AM
Hello, I recently purchased a Magnavox Concert Grand model 300H. I was hoping it was the model with the dual amps (AMP148), however, this must be an early model as it has one AMP148, albeit beefy with dual 5U4 rectifiers and 8 6V6GT's in PP configuration.Bill has the '58 Magnavox catalog (which has a very similar Concert Grand) on his Shed Radios website:

http://www.shedradios.com/cat3.html

Congratulations on your Concert Grand, a truly magnificent Magnavox!

DaLarry
07-04-2011, 01:02 PM
My Gawd! What a wonderful piece! I love old consoles and have two Grundigs which I cherish. I'm only a computer geek and envy all of your electronic chops!

hammondcrazy
07-04-2011, 01:36 PM
My Gawd! What a wonderful piece! I love old consoles and have two Grundigs which I cherish. I'm only a computer geek and envy all of your electronic chops!

I wish I was a computer geek. That is a hard gig. Patience is the biggest key to success in that field!! HOWEVER. I merged a console with a nice P4 SFF compaq and a old monitor and so I have it wired into the tape aux input and I have a jukebox thing going on. I love merging the old with the new. If God allows me to ever find a concert grand that would one that I would NEVER modify!! but I have a 1966 magnavox that I put the screen where the record storage was and it looks almost factory done and it is awesome!! I think computers hooked up built in the old consoles is a neat way to bring them into the 21st century.

DaLarry
07-04-2011, 08:51 PM
I wish I was a computer geek. That is a hard gig. Patience is the biggest key to success in that field!! HOWEVER. I merged a console with a nice P4 SFF compaq and a old monitor and so I have it wired into the tape aux input and I have a jukebox thing going on. I love merging the old with the new. If God allows me to ever find a concert grand that would one that I would NEVER modify!! but I have a 1966 magnavox that I put the screen where the record storage was and it looks almost factory done and it is awesome!! I think computers hooked up built in the old consoles is a neat way to bring them into the 21st century.

You forced me to do it! I finally posted some info and pics on The Elder Geeks Digital-Analog Man Cave (http://www.audiokarma.org/forums/showthread.php?p=4785471#post4785471). Check it out and let me know what you think.

Horn Head
07-06-2011, 11:03 PM
Nice CG. Hope to see more posts with pics of it. Good luck on the resto (sorry, no info on that model here).

jeffhamman
11-24-2011, 08:12 PM
This would be a 1957 model,the 58 model is called the 205st.which does not use the glass panels on each side of the tuner like yours.the 58 which uses 2 amps similar to the one you have but they are rated at 25 watts ea. instead of the 40 watts your amp148 has, I suppose the 300 would be considered mono. but does have the smaller 151 amp used for ?.It was not until 59 when the cg was redesigned for 2 50 watt amps similar to the amp148. but no reel to reel option on these newer ones. you either got a mpx stereo adaptor or a remote control option.

markus
11-24-2011, 10:00 PM
VERY NICE !!

this must be the prior year to mine . . . your's is BEAUTIFUL. . .. mine needs a little work (cabinet is not perfect .. .)

mine does not have the tape deck, but is 'all stereo' amp 148 and 150 IIRC

woofer arrangement is the same .. . do you have a Jensen RP109 on one side and a EV 8HD on the other ? that's how mine is set up . ..

again . .. VERY NICE !!!!!

jeffhamman
11-27-2011, 08:57 PM
tDO you happen to know the model # of yours, I have both 57,58 catalogs.the 57 is the 300h.with 1 40 watt 148 style amp, im not sure what the smaller amp was used for or if it was added latter. in my 58 catalog shows using 2 25 watt 150 style amps,the 2nd amp might be the amp179 but essentially the same.This could be considered stereo. but no reel2reel option,is yours original?

hammondcrazy
01-14-2013, 07:31 PM
I know thiis is an old thread. I was in Kentucky and saw a 300 H on craigslist in Lima Ohio Called the guy and he still had it. I drove 600 mile round trip and got it. it has two horns and two amps. two woofers. I was wondering how that console could be so shiney. I never knew they made glass sliders on the top. I just got home and will unload it later. I can't beleive how tall this thing is. He told me 37 inches I could have sworn that he measured it wrong. It is the tallest console I ever seen.

bobabode
01-14-2013, 10:04 PM
Fortune smiles on those who wait and keep their eyes open! Can't wait to see pics, HC. Lots of them!:yes:

hammondcrazy
01-15-2013, 01:01 AM
tomorrow I will start taking pictures and get it recapped. It looks so stately in my living room. It is the king of consoles. I love the height of it. Being 6' 4 it is nice to not have to stoop. I love my Royal electra Fisher but too low.