Wurlitzer 1100 - Speaker

I need an advice about my Wurlitzer 1100.

Originally Wurlitzer 1100 has the old type of speaker which needs 300 V for an extra field coil. In my Wurlitzer somebody has replaced the originally speaker with one who don’t needs 300 V for an extra field coil.

I have recently found the original speaker for my Wurlitzer 1100 and I have two questions.

I suppose my amplifier is modified in some way when they replaced the original speaker which one who don’t need 300 V for the field coil. Could anybody tell me what kind of modification they can have done with my amplifier and how to modify it to original again?

The second question is about the sound quality. Today the sound quality is very good and I wonder if anybody has an idea about the original speaker. Could I expect any big difference in sound quality? Perhaps somebody who has a Wurlitzer 1100 with original speaker could tell me what you think about the sound quality.

Regards

Bo Korposoff
Sweden

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Bo Korposoff

Stockholm / Sweden

Hello Bo Korposoff

If your amplifier has been modified, you'll see a large resistor (25 or 50W) connected on the speaker socket from pin 8 to ground. To convert it back to original, just remove this resistor and plug in the speaker.

Hope, this helps.



Erwin

Thank you for the information. I am actually not sure if I have seen any big resistor in the amplifier but I suppose the amplifier must be modified to work with a speaker without any field coil.

Do you have any idea about the sound quality for the original speaker? My dilemma is if I should install the original speaker or not. The sound is ok today but of course it would be nice to install the original speaker but on the other hand I don’t want to be disappointed over the sound.

Regards

Bo



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Bo Korposoff

Stockholm / Sweden

I think, the speaker field coil in this amplifier is also used as a choke, filtering the rectified plate-voltage. If your amp is modified by a resistor, you have a filter-resistor instead of a filter-choke. I dont know how this circumstance affects sound quality or power. Maybe some of the power is gone in resistor loss-heat, on the other hand - maybe you need less power to drive a permanent-magnet-speaker.
I think, you can find out the really difference only by trial and error!

regards
Helmut


Gruss
Helmut



1 mal bearbeitet. Zuletzt am 21.12.06 09:41.

I have now tried with the original jukebox speaker but the sound is poor and distorded. When I turn up the volyme the sound gets even more distorded.

I have found out that my amplifier is not modified by the person who change to a speaker without any feild coil. He simply just cut the wires for the feild coil. Perhaps the amplifier has been damage by this. However it works well when I use the new speaker without a field coil.

Do anybody have any idea why it doesn't work with the original speaker?

I am grateful for all advice.


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Bo Korposoff

Stockholm / Sweden

Hallo Bo,

Is it possible there is later Amplifier in your 1100? Original there is the 506 type. I think this typ cannot work without modification with a permanent-magnet speaker. If it still does - maybe, someone has put a choke in the circuit and removed the field coil lugs from the speakers plug. Now you have no voltage for the origin. field coil. This could explain the poor sound and distortion.

regards
Helmut





Gruss
Helmut

It is the original amplifier 506 for Wurlitzer 1100 in my jukebox.

I have messure and I have around 330 V on the wires to the field coil so it looks normal but when I turn up the volyme a bit the sound is going to be more and more distorded. I don't understand what the problem could be.

Hallo Bo,

measure the plate voltage on both 6L6 using the original and then measure with the "new" Speaker. Is there any difference? Do you have correct value (look at the schematic) by using the original field coil speaker? Do you measure noticeable higher values by using the "new" speaker?

regards
Helmut



Gruss
Helmut

Ok,

I shall do the measure in the weekend. Could you please tell me exactly how I should measure the plate load? I am not so good on electronic works unfortunately.

Regards

Bo

Hallo Bo,

I hope you have a schematic for the Wurlitzer 506 amp. I have none but I think the plate voltage ist written on this paper and also the pin where you have to measure the values to ground. On the oc 33 socket of the 6L6 the plate is pin 3 looking from the bottom and start to count clockwise left from the "nose".
Watch your fingers doing this measure-job - life-dangerous voltages are all around!

good luck and a happy New Year!

regards
Helmut

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Helmut

Thank you for the information!

Will do the messure job the following days. I will also check the original speaker by connect it to the field coil wires and then connect the speaker to my stereo. The distortation when I turn up the volyme have made me a little suspicious. Could it be some problem speaker cone?

Many greetings and Happy New Year!

Regards

Bo

Hi,

I have at least got some time to continue the job to find out what my problem could be.

I made a test of my original speaker. I measured the resistance and got around 5100 Ohm for the field coil and around 7 Ohm for the speaker coil so that was ok. But when I borrow the field voltage from the jukebox speaker and connected the speaker to my stereo I got the same distorted sound. I measured the field voltage and that was 320 V that seems ok so what I understand it must be some problem with the speaker.

When I look at the speaker it looks perfect but perhaps it could be some problem with the speaker cone position perhaps. What do you think? Do you have any idea what it could be?

Regards
Bo

Hallo Bo,

So you have a problem with the speaker itsself. I´m not a professional in speaker-Problems, but one time I had troubles with a distorted Seeburg-sound. If I touch the speakers membrane there was a low scratching noise to hear. The speakers coil touched the surrounding area. This problem ist difficult to fix, you must try to center the speakers coil exactly. I hope there are any screws to make this adjustment.

good luck

Helmut

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Helmut

I think it's problem with the in and out postion och the speaker cone (not the position in sideways). When the cone move rear I trhink it touch the bottom of the speaker base. I think I have read somewhere that you could use water to moisten the cone and then let it dry in a new position. I have never touch this. Could it be a solution perhaps to test?

Regards
Bo

Hallo Bo,

Maybe it´s a solution, but a risky one! If anything goes wrong, the speakers cone is unrecoverable lost. Take care and look for someone, who has experience in such speaker repairs. I haven´t!

regards
Helmut

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Helmut

I have found a solution on my problem.

I found a company who can do speaker re-coning. They will fix the speaker for just 60 euro and I can pickup my re-coned speaker tomorrow afternoon. It will be great to put back the original speaker.

Thanks for all help I got!

Bo