Improving the sound of Allen MOS organs.

[BaconByte]

I'm looking to improve the sound of the MOS-II I have. I know fun stuff like reverb and good speakers make a vast improvement but how can one make it sound less.... electronic... if that is even possible. I have been told that if I replace all the tantalum caps with film caps on the DAC board that the organs sound will vastly improve. Any info on this and any other tips to make it sound better?

[arie v]

Hi,

Maybe I'm mistaken, but I always thought the model 301 was a MOS I organ, not MOS II.

Remember a pig with lipstick is still a pig.

There is little you can do, as there is very little data that defines a stop. When additional stops are added, Allen just made there computers do a mathematical summation so one gets even less definition. At some point Allen added a frequency separation, which added some chorus effect. Basically no voicing is available to the end user other than volume and brightness.

Some folk have tried adding some kind of reverberation to try to cover up the electronic nature of the tone. It can help if setup right.

The later DAC boards (DAC-4), was cleaner sounding than earlier ones.

But the basic tone remains the same.

Any quality improvement you try will cost you more than say buying a used MDS organ of equivalent size.

You can try to do the Hauptwerk thing.............will sound a lot less electronic.

AV

[BaconByte]

Hi,

Maybe I'm mistaken, but I always thought the model 301 was a MOS I organ, not MOS II.

Woops. You're not mistaking. I actually have the 305 which is MOS-II. Typo on my part. But generally I assume they are all very similar compared to the later ADC and MDS series.

There is little you can do, as there is very little data that defines a stop. When additional stops are added, Allen just made there computers do a mathematical summation so one gets even less definition. At some point Allen added a frequency separation, which added some chorus effect. Basically no voicing is available to the end user other than volume and brightness.

Some folk have tried adding some kind of reverberation to try to cover up the electronic nature of the tone. It can help if setup right.

The later DAC boards (DAC-4), was cleaner sounding than earlier ones.

But the basic tone remains the same.

Any quality improvement you try will cost you more than say buying a used MDS organ of equivalent size.

You can try to do the Hauptwerk thing.............will sound a lot less electronic.

AV

I am planning to go for reverb, some rather nice reverb units are floating around craigslist near me for very little. As for buying an MDS or going Hauptwerk I know going virtual will get too expensive too quickly and an MDS would be nice to own but in all likelyhood before the end of summer I want to acquire some sort of AGO theater organ. A Conn 645 or even 650 or a Rodgers Trio is what I really want. I just want to see if I can make this Allen a little nicer for the time being because it unfortunately wont stay because it doesn't fit in my front door.

[indianajo]

Personally I detest the sound of the 301 I have access to due to volunteer work. I refreshed the power amps to get it over the finish line, it went silent in October. I'm helping install a pipe organ at the church. I really prefer the sound of my 1968 analog Hammond organ to the 301.
I'd start looking at the door frame seriously, if you are shopping. 30" opening is the minimum to play the used organ game. A few 2x6"s, a packaged frame and door, there you are. I changed mine out in 1986 because the door kept blowing open. I put 6 each 2x6 in there behind it to stiffen it up. I also put a metal door in with double key locks, in and out. That was 24 years before I got into picking up bargain organs. Now thieves break open a window and carry the VCR out through the window, whoopie****. No gold jewelry here.
Used AGO pedal organs are so expensive here, I bought a 1970? Schober, which has 30 tabs all with the same sound. Arie apparently lives in used organ central on Newfoundland, but the seminaries around here are full of organ majors with rich parents who want an allen or rodgers. I won't decend to a Rodgers 50x, rubber for keyboards does not a good used organ make. Hauptwerk is expensive, but jorgan is not. There is even a $30 program it yourself midi encoder available over on the vitual organ threads. Kinkennon.com was it? Any used computer after Pentium II should work. People won't steal those or CRT displays, either. I use the free linux operating system ubuntu, which is compatible with jorgan apparently.
A 305 has great key precious metal contacts, as does my Schober. That is the main thing. The 301 downtown has great amps, the S100, after all the e-caps were replaced. But the speakers downtown are ****. allen designed speakers to suppress the high frequencies, since the MOS era produced such vile digital artifacts. The speakers at the church rattle if power gets too high, probably the surrounds are rotted, like all old Allens. There was a used Peavey PV15 for $100 on CL last week, look for a bargain like that. I love my Peavey SP2-XT's I paid about $600 the pair for in 2010. They won't do 32' stops, but then the small Allen speakers won't either. I really don't even like 32' much: I discovered JS Bach on a radio with a 5" speaker. Those 1964 Colombia LP's don't have the 32' anyway.
Certainly replacing tantalum caps that are 30 years old is a sure shot, but may not improve sound. If film won't fit (the smallest grade newark stocks is 63 v) then aluminum electrolytics are much tinier than they were in 1980. However, I didn't like the sound of the new Allen computer organ I tried on the sales floor in Foley's in 197?.
There is something weird about using reverb on old MOS organs, the loud pedal is not line level compatible. (1.6 v or 2 v max) see this thread http://www.organforum.com/forums/sho...OS-2-Reference
Good luck.

[JoeyB3]

You can try to do the Hauptwerk thing.............will sound a lot less electronic.

AV

I am in the middle of re-doing a Rodgers console that was very poorly converted over to a Hauptwerk design. I must admit that in test driving it before dismantling, the HW concept is an amazing ride and you should certainly consider it. It's a 100% guarantee the sound will be superior to whatever you will do with the analog sound you're working with now. I've been able to play 3 different organs in my living room...all quite different from each other: a Baroque style, a Romantic style, and a huge Symphonic style.

If you're content with only playing one organ, you could easily rename the tabs on your 305 to match an organ with a similar stop listing. Or, for a few $$ more, you could set up 2 touch screens on either side (digital drawknob jambs) and you could have a party! Currently the console I have has its knobs set up to mimic the Skinner at Our Lady of Mount Carmel in Chicago.

[radagast]

I'm looking to improve the sound of the MOS-II I have. I know fun stuff like reverb and good speakers make a vast improvement but how can one make it sound less.... electronic... if that is even possible. I have been told that if I replace all the tantalum caps with film caps on the DAC board that the organs sound will vastly improve. Any info on this and any other tips to make it sound better?

I used to have an Allen 203 MOS organ. I wanted to experiment with it to see if I could fatten the sound up. What I was thinking of doing was this: get a multi-effects box like an Alesis where I could do two or more things at once. One channel would have a slight delay and a slight pitch shift. Then both channels would have reverb. If that wasn't enough than one channel of the organ would also have a slight chorus.

There is a company that I think is called Harrison Labs. They had a unit designed for MOS organs that was supposed to fatten the sound. I think the unit was called a Travelling Wave Generator.

[jbird604]

The Allen 305 is not such a bad organ. Before doing any extreme tinkering or spending money on add-ons, I'd first make sure everything is working properly and do all the routine maintenance -- checking power supplies and amps, key contacts, interconnects, good speaker drivers for both channels, etc. Make sure the celeste rank is correctly tuned and regulated for volume. All these things will bring the most satisfactory sound out of this model.

MOS-II organs incorporated a lot of nice features that Allen had offered only as expensive options during the original MOS period. So your 305 has frequency separation (a slight pitch offset between the two channels that eliminates the dead sterility of the original MOS tuning). It has "dash three" voicing, which separates some of the stops of a given chorus, such as the great principal chorus, between the two channels for a more interesting ensemble.

As to tinkering, there are in fact features built into the MOS-II system that were never used in any of the stock models. We have a great big MOS-II (system 1105 with four computer systems driving 10 audio channels) that we installed and now maintain here on which we modified the tremulants by moving some jumpers on the Keyboard Array (KBA board). We added tabs that say "Theatrical Trem" and these turn on the biggest, boldest, sweetest trems you'll ever hear on a digital organ without the need for any external trem generators or devices. We also modified the celeste tuning settings so that various degrees of celeste can be chosen, but that is something you can only do on the multiple computer models.

Just saying all this to say that the 305 is actually a decent organ for what it is. You may find it worthwhile to add a digital reverb (using the Harrison Labs isolators so you won't mess up the expression circuitry) to make it sound more modern. And you won't ever get the voicing capabilities of a modern digital because, as someone noted above, adding stops just makes the computer add the samples together, eventually obscuring the details of each stop. But in spite of the limitations, which I know well, I often hear a MOS organ in a beautiful acoustic space that sounds very good indeed. Allen had the "basics" of digital tone production figured out way back then, and today's digitals of every brand just build on the same principles, with more channels, more DACs, more voicing control.

[myorgan]

I'm looking to improve the sound of the MOS-II I have.

Bacon,

What's throwing everyone off is your signature. You have the Allen listed as a 301-B MOS-II, when it is actually a 305B.

Current Organs:
Conn 621, Allen 301-B MOS-II, Hammond M-100, Hammond M-3, Hammond L-100 with Leslie 247, Hammond Model E and another Hammond T-582
Former Organs: (I miss them all)
Hammond Piper, Hammond T-582, Hammond Caddet, Yamaha Clavinova, Rodgers 22D and the Hammond H-100

If you correct your signature, you'll probably get better quality input.

Michael

P.S. Personally, I like the sound of my 505B at church. The Flutes, String Celestes, and Alterable Reeds are especially nice!

[BaconByte]

I am in the middle of re-doing a Rodgers console that was very poorly converted over to a Hauptwerk design. I must admit that in test driving it before dismantling, the HW concept is an amazing ride and you should certainly consider it. It's a 100% guarantee the sound will be superior to whatever you will do with the analog sound you're working with now. I've been able to play 3 different organs in my living room...all quite different from each other: a Baroque style, a Romantic style, and a huge Symphonic style.

If you're content with only playing one organ, you could easily rename the tabs on your 305 to match an organ with a similar stop listing. Or, for a few $$ more, you could set up 2 touch screens on either side (digital drawknob jambs) and you could have a party! Currently the console I have has its knobs set up to mimic the Skinner at Our Lady of Mount Carmel in Chicago.

Thats what I might do during Winter time. Each day I see or hear them I become more and more interested in building a virtual organ. I probably would have by now if I didn't have the E. It'd be nice to have any organ I want at my disposal. But I do really want that nice theater organ console! Normally I am not too picky on details but that I am! Be it I pick up an old Rodgers or Conn or get so fed up and build my own.

As to tinkering, there are in fact features built into the MOS-II system that were never used in any of the stock models. We have a great big MOS-II (system 1105 with four computer systems driving 10 audio channels) that we installed and now maintain here on which we modified the tremulants by moving some jumpers on the Keyboard Array (KBA board). We added tabs that say "Theatrical Trem" and these turn on the biggest, boldest, sweetest trems you'll ever hear on a digital organ without the need for any external trem generators or devices. We also modified the celeste tuning settings so that various degrees of celeste can be chosen, but that is something you can only do on the multiple computer models.

Just saying all this to say that the 305 is actually a decent organ for what it is. You may find it worthwhile to add a digital reverb (using the Harrison Labs isolators so you won't mess up the expression circuitry) to make it sound more modern. And you won't ever get the voicing capabilities of a modern digital because, as someone noted above, adding stops just makes the computer add the samples together, eventually obscuring the details of each stop. But in spite of the limitations, which I know well, I often hear a MOS organ in a beautiful acoustic space that sounds very good indeed. Allen had the "basics" of digital tone production figured out way back then, and today's digitals of every brand just build on the same principles, with more channels, more DACs, more voicing control.

This intrigues me! I shall have to experiment with the KBA board to see what kind of trems I can get out of it! And for the digital reverb am I correct in assuming the "isolators" are just 22k resistors? I read that somewhere.

Bacon,
What's throwing everyone off is your signature. You have the Allen listed as a 301-B MOS-II, when it is actually a 305B. If you correct your signature, you'll probably get better quality input.

Done and done. Typed it up in haste when I first got it.

[jbird604]

The Harrison Labs isolators are just resistors. I can't testify as to the value, but they are a "plug and play" solution, being built right into the adapters. The only thing you have to do is to put some resistance between the output of the reverb unit and the input of the Allen amp so that the expression will continue to work. I've added reverb to a couple of MOS organs over the years, and in both cases I just added some resistors in series with the reverb output. Can't even tell you what value I used, just tried different ones until it worked. I would've guessed somewhat higher than 22K though, maybe more like 100K, as you have a line level output from the reverb, and the amps have very sensitive inputs, normally working with signals in the millivolt range.

[cantornikolaos]

I'm looking to improve the sound of the MOS-II I have. I know fun stuff like reverb and good speakers make a vast improvement but how can one make it sound less.... electronic... if that is even possible. I have been told that if I replace all the tantalum caps with film caps on the DAC board that the organs sound will vastly improve. Any info on this and any other tips to make it sound better?

There is a guy on Youtube, RetroChad, or something like that, who has an Allen 301. He did a lot of work on it himself. He replaced one of the MOS boards. He re-capped it. that alone made a huge improvement. It may still have some intermittant issues, but it does sound better. It is in a somewhat live room and I'm sure that helps. It IS one of those situation where it sounds pretty decent, the further away you get. :)

Even new Allen organs sound electronic. Just cruise on over to the "AOCVideo" channel on Youtube and give it a listen. It sounds like organ noise coming out of speakers. It is vastly improved over the older sound, but it still betrays itself. I'm going to have to second Arie V's statement about pigs wearing lipstick.

Things like a good reverb processor and good speakers can go a long way to help trick it into sound less harsh and unnatural, but those older models has so little information to begin with, and information is lost every time more stops are added. My church's MDS doesn't sound any better than and MOS I've ever heard. It's pretty bad. It's dull and muddy. It's very homogeneous. I think the best thing we could do to improve the sound is reenact that famous scene from "Office Space" and look for a redundant pipe organ that needs to be relocated.

[Menschenstimme]

" I think the best thing we could do to improve the sound is reenact that famous scene from "Office Space" and look for a redundant pipe organ that needs to be relocated."

WTF?!

[BaconByte]

And where exactly would I put a pipe organ in my house? I already have a handful of Hammond's and Conn's that take up my entire basement as it is. Plus the Concert E is finally going into the basement. I barely have room for myself let alone some dying pipe organ that will sound awful in a dead acoustic space.

Also did we watch the same Office Space? I don't think so.

[cantornikolaos]

Dude, I'm sorry I ever bothered you. It's clear that what works for me doesn't work for you, and vise-versa. I am going to have to second the remarks about adding reverb and beefing-up the sound. That should go a long way towards improving things. One thinng I wanted to do with an old Allen 705 is make it into a MIDI console with a PC inside it running HW, or something similar.

P.S. I was suggesting that reenacting the scene from "Office Space" would be a solution for my situation, not necessarily yours.

[myorgan]

One thinng[sic] I wanted to do with an old Allen 705 is make it into a MIDI console with a PC inside it running HW, or something similar.

Nikolaos,

If you're looking for an Allen 705 console, our friendly Florida Flipper has a 705 console (w/o the innards) priced the same as a fully-functional 705 should run on *Bay. Who knows, it might be what you need? Hopefully, you at least don't mind Allen's build quality.

Hope that helps.

Michael