Allen 100-C: bypass original amps to new external sound system?

[Will Wilkin]

I finally got a home practice organ for my son, who is a student of pipe organ. I think it is an Allen 100-C, and thus made in 1970, according to the list posted here:

https://organforum.com/forums/forum/...847#post341847

All the keys and pedals work, all the stops seem to work. But it is not very loud.

The seller tells me the organ has 2 amplifiers but one is blown so an Allen-competent technician bypassed one of the 2 amps, running both speakers from a single original amp.

Would it be feasible for me to take the wires inputting to those 2 original amps and run them instead into some aftermarket external preamplifier or processor from which I could send line inputs to various external amplifiers and speaker systems, and/or to external powered home stereo speakers or keyboard amplifiers resembling electric guitar amplifiers?

[John Vanderlee]

The audio level out of a MOS1 organ is not high enough to drive a standard "home" audio amplifier. It would also need a preamp stage like a mixer. Why bother with all that extra stuff if it is just the Allen amp? They're (used) cheaply available on Ebay, probably for less than you pay the technician. If it is the 50(40?) watt model I could send you one just for the shipping. I love to help students out, it's part of our mission.

[myorgan]

I believe I may have one of those amps as well. I could even deliver it depending on where in New England you are located.

Michael

[jbird604]

If interested, take a look at my post just now on my thread, see post #13 where I talk about putting a modern amp on an old MOS organ quite similar to yours:

https://organforum.com/forums/forum/...res#post729346

[Will Wilkin]

Thank you John Vanderlee and "myorgan", I gratefully accept an Allen amp to bring this organ back to original power. I am in Oxford CT and would enjoy a reasonable ride with my son to get it, or ship if too far.

Meanwhile jbird, I read your report on the amp swap and quickly imagine sound possibilities if I can just also get a "line out" compatible with a preamp allowing me multiple amps and speakers throughout the house.

[myorgan]

I am in Oxford CT and would enjoy a reasonable ride with my son to get it, or ship if too far.

In that case, you're about 1-2 hours from John, and about 5-6 hours from me. John, let me know if yours is unavailable, and I can make arrangements for mine.

Michael

[John Vanderlee]

Sure, I am going into the shop this afternoon. I have a collection of them. I'll verify a working pair and Will may have them both. We can arrange pickup at mutual convenience.
John

[Will Wilkin]

Thanks John, do I read you as if amps should be replaced in pairs? I imagine I should find the model number on the existing bad amp and compare it to the pair you are offering?

[myorgan]

That couldn't hurt. However, MOS-1 organs generally only used 1-2 styles of amplifiers. They look different, but work the same.

Michael

[John Vanderlee]

I just need to get rid of some stuff. It helps me out.

[John Vanderlee]

I checked my "stock" and found a bunch of them. There are different input jack configurations on the chassis. Actually any type of that can easily be changed to the other. So just to be sure I give you(Will Wilkins) the right ones - or fix one so they are - please post or send some pictures of the ones you have. We can continue this on PM if you like, and make the arrangements. For general knowledge and to the Forum, I did notice that earlier ones used discrete components for the preamp stage in those amps. For curiosity's sake, when did that hangover to an IC design occur?

[John Vanderlee]

Not "hangover" but CHANGEOVER. I was sober.. honest! ;-)

[myorgan]

You expect us to believe that?!!! Sorry, I couldn't resist.

Michael

[Will Wilkin]

Thanks again John, I will pull the organ away from the wall and open it up to view the amps and their terminal style. Then I'll post a pic here.