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Thursday, January 6, 2011

Wurlitzer 625t - A theater organ without tabs? How to move a 625t

The Wurlitzer 625t is a very well designed organ overall and the tone is spectacular. I have owned and played mine for several months now and it seems to be a versatile organ for many styles. The keys are the fastest known to man. This helps make up for the fact that this theater organ has no theater tabs! The 950 had tabs, and I've heard about the 630t and wonder if maybe it had theater tabs?
For playing theater styles it has the 16',8',4',2',and 1' TIBIA 'ranks' (tabs) directly attached through the separate amplifier to the two speed internal Leslie. It's very easy to get the low 16' plus 1'  high pitch skating rink tones associated only with external Leslie cabinets with horns. The DIAPSON ranks are necessary when playing church music and filling out the sound in theater style music. There are 16', 8', 4', and 2' Diapson tabs. Other upper manual tabs include Clarinet, trumpet, strings, wah, 4 different key percussion including Harp, Piano, Hawaiian guitar- there is also a slide control for repeat percussion on these tabs. Hawaiian guitar playing can be further accentuated by the lever on the volume pedal that lowers the upper and lower manuals by 1/2 step in pitch.


WATCH VIDEOS ON YOUTUBE FOR THE 625t just put Wurlitzer 625t in the search bar. Jimmy Smith UK ( not the famous American B3 player) played the 625t ( exactly like your BTW) on a record and it's got 4 songs on youtube with pics of the organ. I wrote to Jimmy recently and he responded saying it was a very fun and satisfying organ to tour with. He played it 100% stock through an external Leslie cabinet. There is no multi-plug outlet on the organ, but there is an adapter to the internal Leslie which is simple to hook a multi-pin standard female socket to.
   Please feel free to include this info in your ad and have prospective buyers give me a call. PAUL 614-257-0266

 I would be happy to explain what I know about this organ. I've had mine for several months and couldn't be happier. One thing I did to really improve the tone going to the internal Leslie speaker was to get rid of the limiting resistors that are connected to the outside of the RCA plug on the amplifier. ( the amp is located on the inner wall of the right side of the organ). There are two RCA plugs e large aluminum finned power amp input jacks going into this amp. One is for the Tibia 'ranks' (tabs) to the power amp for the Leslie and the other is for the Drums and Bass pedals to the super heavy duty 12 inch speaker. There are also two 6"x9" speakers in this organ. Of the two RCA plugs,the plug closest to the back of the organ is the one for the Leslie. I disconnected the two resistors that are soldered together- one end going the RCA plug's outer sleeve and the other end down to the circuit board. This really opens up the tone of the Tibias. It restores the full frequency range of the Leslie. I honestly have no reason why they put these resistors here, it's not like it is limiting the output to save the speaker or anything. There is also a resistor pair in series going to the other RCA plug's sleeve and down to the circuit board as well. This might or might not have a limiting effect on the bass and drum sounds, but I never unhooked it to see because these sounds are excellent even with the resistors.
Although the power amp is no where near the fragile parts of the organ which can be harmed by static read the warning below.


WARNING!! NEVER TOUCH THE LONG MULTI-PIN IC's OR ANY OTHER CIRCUIT GOING TO THEM UNLESS YOU ARE GROUNDED TO THE ORGAN CHASSIS. SIMPLY TOUCH A METAL SURFACE ON THE ORGAN first.

WHEN TRANSPORTING ORGAN IT IS POSSIBLE TO LIGHTEN THE ORGAN BY ABOUT 100 POUNDS BY REMOVING ORGAN BACK COVER, TOP MUSIC HOLDER, ORGAN TOP ( UNPLUG THE LIGHT CONNECTION ON THE RIGHT SIDE) DISCONNECT ALL OF THE THE CONNECTOR PLUGS ON THE LEFT SIDE, REMOVE THE TWO PIVOT PINS WHICH CONNECT THE UPPER ROW OF SWITCHES AND THE CHASSIS WHICH HOLDS THEM. YOU CAN ALSO REMOVE THE POWER AMP IF YOU REMOVE THE THREE NUTS ALONG THE BACK AND THE PLUGS ON TOP AND THE TWO RCA PLUGS. GET A 'WIRE LABELING KIT' FROM RADIO-SHACK.

5 comments:

  1. Oh' and to get the top of the organ off remove the lights are the screws from where the lights are at- I think one screw midway on each side.
    Now LIFT TOP STRAIGHT UP. It helps to have one person on each side lifting at the same time.

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  2. Hello, any scematics for Wurlitzer 625.. I was trying to bypass the oscillator stage on a switch with an external oscillator in.. Any ideas on how to locate the oscillator stage ?

    Thanks in advance,

    chris-

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    1. If you still need a schematic for the 625 I do have any part you want scanned and I do have a scanner now. I am curious about which part of the 625 you are introducing and external oscillator to? It would almost seem more plausible to mess with the Orbit synth part of the organ since the organs tibia,diapason,horn,and reed sections are mostly created using Top Order Synthesis...but perhaps this is exactly what you are after? I get a little confused about the TOS master oscillator tone generators. Is it possible to introduce a more robust signal in place of the TOS stock chips? What sort of post-TOS filtering takes place? Another area of confusion for me. I know that in the transistor divider organs and vacuum tube oscillator organs there were always transformers or inductors used to voice the various tibia,reed,string,horn,diapason, but this does not exist on master oscillator TOS organs.
      I would love if someone did a series on electronic organs in video form, where each organ type is disassembled and explained in detail. The North Suburban Hammond Organ Society has done their excellent articles on the Hammond X-66 and Wurlitzer 4600 electrostatic reed organs and they are very easy to understand. Following this as a guide would be perfect. The analog electronic organ is the perfect candidate to be emulated as we see more and more digital processor development.

      Finally we are at a point where analog emulation can be done with accuracy. I look for the random properties of analog electronics to be translated into digital to the point where it will be possible for analog chip fabrication to become a possibility. In fact it is already a possibility with FPGA's. Check out Hammond HOAX on Youtube. These organs are amazing and they are built on a generic industry standard $200 FPGA board. FPGA is a platform where any number of processors can be designed to carry out a function. In the case of a HOAX Hammond organ they use the FPGA to make tone wheel generators in real time. The process is all that this part of the FPGA is dedicated to. It makes 91 individual tones just like a real Hammond tone wheel organ. The tones are always ON. This allows the keys to have 9 contacts just like a real Hammond tone wheel organ. A key click generator is also possible. My hammond Elegante had a key click generator that was random and was very believable. There is even a Start Switch and tone wheel 'noise' circuit someone made for the HOAX.
      These HOAX FPGA's can be purchased and installed in any organ. In fact many have installed them in their older Hammond 'clone wheel' organs.

      If it is possible for them to emulate a Hammond tone wheel organ this way then it is also possible to recreate other analog organs using FPGA's.

      That is just one example. These days anything is possible, but in terms of recreating analog electronic organs it's more a matter of finding those who desire the sounds of analog. I know I'm in!

      Of course the mid 70's brought us the LSI chips like what is in the Wurlitzer 625, Hammond Elegante, Thomas Trianon, Kimball Fantasia, and many others. Ironically these organs have a sound which would be very easy to duplicate digitally and essentially sound the same as their analog LSI versions. It is the tonal characteristics of LSI that seem to be prevalent in digital organs.

      One would think that an organ with a minimum of components would sound thin, but our analogs of yesteryear prove quite the opposite. The Hammond tone wheel organ and Wurlitzer electrostatic reed organs have very few components, yet they sound powerful and have wonderful ensemble qualities. Each note produces many audible sounds that mesh and sound very natural. The vacuum tube oscillator organs share these characteristics as well. Transistor oscillator organs also can sound quite full when they are designed well. Of course it is the analog factor that makes these organs stand out.

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  3. Hello, I recently acquired a 625T mostly for it's appearance and physical condition and price. It is presently in need of some repair,how much I'm not sure of but you got to start somewhere... It makes a loud buzzing hum when turned on which fades down to a low humming noise but also low output on most functions (of which I know nothing about)the orbit synth seems dead also. I was able to obtain at the same time a Lowery Genie 44 which does work for the most part may need some cleaning up with contact cleaner. Anyway back to the 625T, the packing behind the Leslie has been taped over which I will gingerly look at. I am in need of a manual, owners to start with and then a full service manual, any idea where I might find these, I emailed Greehill in the UK but the price with shipping is almost $100 for the service manual. Well it's down to the workshop to see what we can find out... Thanks
    Bob

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  4. Well I must say I have been a bad blogger and nearly abandon this one. Actually I sort of forgot about it, but seeing how Bob has left a comment it seems like maybe a worthy cause to add an update or two.. If I had a scanner I would load my entire service manual to the 625t. I bought a full factory technicians copy of the Wurlitzer 625t/630 for $8 from Jan Giradot (AKA the writer of the proverbial master list for organs- the Organ List > http://www.lowreyforum.com/notes/Eorgan_list_v4.pdf
    You can contact Jan at:
    For the time being I can help anyone who has any questions about issues they are having with their 625t,950,4500,4300, or any other transistor organ from the 1960's. I'm also able to help with the all electronic Swingin' Rhythm, the Wurlitzer Combo Organ, I have several amplifier schematics including the 7100,7200, 7300, and so on. I can send you copies of any of my schematics as I have a large service manual covering several models. Look on the Organ Forum and search the following on the site: The OFFICIAL ORGAN SCHEMATIC THREAD
    From there you can send me a PM ( personal message)and I can assist with any schematic page you might need. It might be a photo image of a page I can upload to you. BTW if you have certain tabs that don't work this is usually associated with bad 4016be chips, they can switch two different signals electronically. You can look up the pin-out for a 4016be, then just trace your tabs that are out to the associated 4016be then bypass the path through the chip to hear if the failed tab works. If so then it is the chip. I suggest buying a dozen or so of these 4016be's and taping the extra's inside. Note too that you should always ground yourself to the aluminum trim on the upper manual so that your body static does not short out any CMOS components like the long multi-pin tone generators. Also handle the 4016's with care. I'd suggest installing chip sockets so that future replacement is easy.- Good luck!
    Oh', I'm hooking my 625t up to a Leslie 705 and a pair of 540's this week and might post the results.

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