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9304-20 (Not Standing Alone)

A

auxtech66

Active Member
Well, I guess I missed something fairly important while attempting to make this a standalone amp. I found several threads here discussing the Molex plug removal and adding resistors to the balance circuit(resistors not added yet). I also saw that the addition of a power switch should have been pretty straight forward. This is what Ive done: I followed one side of the A/C line to one side of the transformer the Molex connector. Then found the !$@#%#^@&^. Never mind I just figured out where I went wrong. I'll post results later tonight.
 
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I am not at Stand Alone yet

Please do post your results and- any pictures of how you traced this and wired your switch would be great for me...

I just bought a Magnavox console with a similar amp A9304-00 and I am going to guess at how to wire the switch and remove the umbilical cord...

If you had a photo or two it would sure help -

Thanks:thmbsp:
 
Now it's putting

I've installed the power switch and new rca's. No caps or resistors to this point. When a speaker is connected to either channel it sounds like a small motor putting along. Any idea's? Thanks
 
The coupling caps and resistors have been replaced. The putting sound is gone and the amp is dead silent. I have only attempted to play an mp3 player through it with very small cheapo speakers to this point. It does play but volume is a little low. Keep in mind I only had 330ohm resistors on hand. Will the 390's provide more gain?
 
Not sure about the 390 Ohm resistor - but a preamp would more than likely give the sound a boost...

I had a little RCA amp about 8 watts that was not real loud when using an Mp3... but the preamp brought out a beautiful sound on very efficient speakers...
 
See this thread. It's for a different Magnavox amp version, but the same thing applies to your amp, most likely:

http://www.audiokarma.org/forums/showthread.php?t=161146

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Your resistors and such may need to be located in a slightly different place (as I mentioned, you have a different model), but they will be somewhere in that same area...

As for 330 vs. 390 ohms- in fact, using 330 ohms will give slightly more gain than the 390s. I've done this before, to up the gain just a tad... works fine.

Regards,
Gordon.
 
Thanks Gordon, I did in fact hook up my preamp and try it out just briefly, all seems good. I'll have a chance for an extended play test later today. Here's hoping it sings...
 
Here are the Picts

Everything is working great. I'm listening to FM stereo through my Kenwood C1 Pre Amp,the 9304-20 and a pair of Altec 890C's. This amp sounds terrific.:music:
 

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Original Preamp?

In the second photo above it looks like you are still using the original preamp?

Did you strip out the reciever section and make the preamp a standalone?

How does it sound?
 
billyunderhi said:
In the second photo above it looks like you are still using the original preamp?

Did you strip out the reciever section and make the preamp a standalone?

How does it sound?
Click to expand...

The pre amp was combined with the tuner section of the console. This is only the power amp section. The Amp was modified to act as a standalone power amp and cannot be used without the use of a seperate pre amp.
 
Pic # 2 on the right... where the amp sits on top of the turntable plastic cover... just to the right in the pic it looks like an old chasis with cables coming out of it...

I thought maybe it was the original tube pre-amp and I windered how or if you had disconnected the tuner portion to make a stand alone.

I am guessing thats another amp or seperate piece of equipment...:scratch2:
 
billyunderhi said:
Pic # 2 on the right... where the amp sits on top of the turntable plastic cover... just to the right in the pic it looks like an old chasis with cables coming out of it...

I thought maybe it was the original tube pre-amp and I windered how or if you had disconnected the tuner portion to make a stand alone.

I am guessing thats another amp or seperate piece of equipment...:scratch2:
Click to expand...

Your right that is another amp. I've considered adding a separate power supply to a tuner in order to use it stand alone but havnt attempted it yet.
 
auxtech66 said:
Your right that is another amp.
Click to expand...

I see a Stromberg! Either an ASR333 or ASR433...

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Have you compared the sound of these two EL84 amps (the Maggie vs. the Stromberg) back-to-back? I know the preamp is an ancillary affector, but it would be interesting to see a comparison of character aspects (bass response, etc)...

Regards,
Gordon.
 
GordonW said:
I see a Stromberg! Either an ASR333 or ASR433...

attachment.php


Have you compared the sound of these two EL84 amps (the Maggie vs. the Stromberg) back-to-back? I know the preamp is an ancillary affector, but it would be interesting to see a comparison of character aspects (bass response, etc)...

Regards,
Gordon.
Click to expand...
That's very observant of you Gordon. The other is an ASR433. As of yet I have not compared the two. I've just finished the recap of the maggie and I'm trying to give it a little run time before a comparison. As it stands now I do like the sound of the maggie but I am very partial to the Stromberg. The ASR is outfitted with a full compliment of Bugle Boys and has a wonderfully wide sound stage.

Best Regards,
Don
 
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