organ amp

rmunson

Well-Known Member
Not sure what to do with this beast -

It came with a nice home organ we purchased - we decided to just use the internal speakers because they sound fine and takes up less space w/o the external speakers and amp --

Does anyone have insights into what this amp could do? The original owner had the speakers installed up in his walls above the organ - what have I got there? The smaller speaker has 2 pairs of connectors and the larger just one pair -- 2 channels of high and 1 channel of low? Is this a type of bi-amping?

It powers up off the organ power switch -
I bypassed the relay and put it on a power strip to power up.

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well, you can use the sub, maybe integrate with different mains, you wont know the mystery of the two inputs on the mains until you take the mains apart and see how they are wired. if you have a preamp to use withit, it might sound neat. the unit probably works exactly as you say.
 
It looks like a three channel amp. Older three channel tube amps ran the midrange and treble stereo, (two channels), and the third channel ran a single woofer for bass. Summing both channels into a mono signal for the bass. Yours could be different though. Maybe two channels for music and one for a microphone? Look at all three amp boards. Are the parts on all three identical? One may be different? If all three are the same I'm guessing one channel was connected to a mic out from a preamp for a microphone. Being an organ amp it could be like the old three channel amps. If at leased two of the amps boards are the same you should be able to turn it into a stereo amp. Maybe add a low pass filter for the third if needed and run a sub from it.
 
Hi guys -
yeah - this is an interesting amp - 3 identical amps sending output to 2 mids and one combined low pass -- but still essentially mono --

the speaker arrangement seems awkward - we had one cab on either side of the organ it was ok -- but for use for anything else, I guess you would want them stacked, right? Because there isn't really any Left/Right distinction...

I guess I could try wiring in 2 standard Left Right front speakers and put the low pass speaker in the middle...

I'm just trying to find a use for this.... maybe a 2 channel amp for an entertainment center?

rigging up new input cables for this is a unique challenge as well -- essentially 2 channels merge into the inputs on the amp -- but how would I wire it for the source side?

let's say the preamp source has the standard L/R rca jacks... that's 4 wires.... L signal, R signal and 2 grounds ---- combine the grounds into one spade and one spade each for L and R -- so I have 2 rcas on the source side and 3 spades on the amp side -- woudl that work?

Thanks for the brainstorming help!
Reed
 
If the speaker grounds are tied together at some point inside you should be ok. It looks easy enough to seperate the channels. If they are the same you have a Stereo amp with an extra channel. there are cheap sub low pass filter preamp kits that combine both channels into one with gain and frequency control. I bought one for around $12. A cheap wall wart drives it. look up the number on those STK power pack outputs and you should get an idea of the output wattage.
 
If the speaker grounds are tied together at some point inside you should be ok. It looks easy enough to seperate the channels. If they are the same you have a Stereo amp with an extra channel. there are cheap sub low pass filter preamp kits that combine both channels into one with gain and frequency control. I bought one for around $12. A cheap wall wart drives it. look up the number on those STK power pack outputs and you should get an idea of the output wattage.
it says 100w @0.4% distortion. Totally useful, make sure power supply is in good shape, and the STK's don't get smoked, cause you may not find another.
 
so if I wanted to send signal into this from a standard receiver via tape out how would I do that?

The way it was connected up to the organ was via two aux out 1/4" mono plugs where the signal went into L and R and the ground for each plug each shared a single ground on the amp ---

So how would I substitute and RCA coming off tape out for the 2 monos coming from the Organ's aux out? The amp is looking for a L and R and a ground...
on an RCA, would I just carefully strip away ground on each side of the cable, combine them and then give each shielded signal strands their own lug?

Thanks!
Reed
 
would I just carefully strip away ground on each side of the cable, combine them and then give each shielded signal strands their own lug?

Yes. I have made many cables this way. Saves money from buying them.

L & R ground (stranded) together goes to "G", and left and right + wires go to the L & R inputs.
 
ok - cables are ready to go - going to test today -
question about the speakers --

on the amp they are labled M1 and M2 - (mid 1, mid 2)
and low pass -- is a low pass the same as a sub woofer?
 
so if I wanted to send signal into this from a standard receiver via tape out how would I do that?

The way it was connected up to the organ was via two aux out 1/4" mono plugs where the signal went into L and R and the ground for each plug each shared a single ground on the amp ---

So how would I substitute and RCA coming off tape out for the 2 monos coming from the Organ's aux out? The amp is looking for a L and R and a ground...
on an RCA, would I just carefully strip away ground on each side of the cable, combine them and then give each shielded signal strands their own lug?

Thanks!
Reed
Not the tape outs, those output at full volume. You need a pre-out, variable signal. Do you have a preamp or a reciever with pre outs?
 
ah - thanks -
yes - my 727 (avatar pic) does have preouts... as well as my little Denon BS system --
Thanks for the heads up - that would have been a painful experience --
 
I do see one thing which suggests this amplifier is not going to be great, and was cost cut. Those STK modules inside. The SX 727 is itself superb, one of Pioneer's better receivers. Try it and play with it, but don't be surprised if the SX 727 is the sound which grabs you.
 
yep my 727 is my main rig -- I'm just looking to do some testing with this - hoping to see if I can drive this subwoofer
 
Some STK modules sounded not bad at all. Pioneer and Technics (and others) used them in a few amplifiers. I've herd some good ones. You may get not bad sound which will sound better once you recap those amplifier boards inside that unit
 
yeah... tested it with my denon and a cd --
the organ amp sounds does not sound very good as a normal stereo... guess it's only good for one thing.
 
yeah... tested it with my denon and a cd --
the organ amp sounds does not sound very good as a normal stereo... guess it's only good for one thing.

Maybe try it using the pre outs from you Pioneer and see if the sound is any better? Most of the sound character of any unit l believe is achieved in the pre amp stages.
 
yeah... tested it with my denon and a cd --
the organ amp sounds does not sound very good as a normal stereo... guess it's only good for one thing.

If the gain stage is properly set, one reason might be some eq built into the amp if it was designed to drive a bigger driver with no tweeter. Does it sound overly bright?
 
yeah... tested it with my denon and a cd --
the organ amp sounds does not sound very good as a normal stereo... guess it's only good for one thing.

There isn't any technical reason it should sound bad. While specs themselves aren't necessarily the final say-so in sound quality, those STKs should perform pretty well. I'd suspect settings/configuration/connections could be more the issue.
 
Hi guys -
OK, so I revisited the organ amp again and I have set it up as a center channel in our TV system - I'm very happy with how it sounds -
some questions on how to manage the input into this rig:

I'm using our AV receiver to send signal out a tape out to a bookshelf receiver's source in. The bookshelf receiver has a PRE OUT -- the bookshelf receiver sends signal to the organ amp --

so far so good.... here's my question for the group:

Is there a way I could send all of my sources from the AV receiver? at this time, I can only send the DVD/VHS tape ins down to the 2nd amp -- - I have a mac mini coming in on AUX but in order to send sound to both the AV receiver and the organ amp I need to remove one of the tape ins and plug the AUX in on that input --

Am I basically limited by my AV receiver only have the 2 pairs of tape in/out?
 
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