Wurlitzer Model 4150 Organ (paging Enzo)

[Don Moose]

I'm apparently collecting organs now - a Hammond L120 last week, a Wurlitzer 4150 this week. I've been looking for cheap source material to build a guitar amp into a mid-30's RCA Victrola/Radio cabinet, so any old organs and radios in local thrift shops get their backs popped off.

[I know Enzo has a ton of background in the Wurlitzer jukeboxes (if what's left of my memory serves), and hope the odd organ crossed his bench.]

The Hammond is a tone-wheel model, so I'm gonna restore it. This Wurlitzer, however appears to have a market value of roughly $60 (what I paid for it) and contains upward of 30 tubes. Since it has so many, I need someone familiar with the product line to tell me if the heaters are parallel or some series/parallel combination - strings of 10 or 20 to get to 120VAC.

The power transformer looks to be about the size of a cinder block ... well, half a cinder block, and the OT is a whole bunch smaller.

Any (informed) insight welcome!
Supposition, so labeled welcome, too!

[Enzo]

Oh no, don;t be draggin me into organ-land.

The closest I came to organ service was dispatching the organ repair guy at a large music store. I also provided support for him in ordering parts and such. he didn't need my help technically at all.

The jukes were not really related to the organs. And yes I have done a lot of jukebox work. I have an old Seeburg in here right now. In fact I need to finish it up.

As far as I know no organ would have multiple strings of series tubes. That would be a relaibility nightmare. But that is an opinion. SImple enough to pop the tubes and read the numbers. You see a lot of 6's and they are parallel.

Unlike the tone wheels where the note spacing is built in, the other organs like the Wurlys rely on oscillators and dividers. DEpending on the organ there could be a master oscillator and subsequent division to get the notes of the scale and then the octaves from those. Other organs had 12 oscillators for the notes ofhte scale and then octave dividers. In any case, the oscillators had to be tunes for pitch. Parts drift,a dn adjustment brings the freqs back to pitch. Until you run out of adjustment room... Then you had the job the organ guy hated. You have to replace aging caps in the oscillator circuits and THEN retune to pitch.

So the PT will be large because it has to support all those tube heaters and power all those oscillator circuits as well as the amplifiers. Your OT will be whatever is suited to the power output and power tube complement.

[Don Moose]

Yup 12 tunable oscillators and dividers made of 28 12FQ8s. 5 12AX7 and another FQ8 in the top of the box for something or other and a power amp with 2 12AX7 and 2 6L6. The rectifier is a 5U4.

Wife got to play with it a little and wants to keep it because it has that 1-button chord feature. I guess the hunt continues.

Lower manual is weak and a couple of B keys are dead, but this shouldn't be too tough.

Thanks, Enzo!

[Enzo]

Looks like a bunch of 12v tubes then.


Make a deal with the wife. You get to gut the organ for parts. Tell her organ doning is currently popular. Then go get her a little Yamaha PSR series personal keyboard to play. Those have the one key chord accompaniment along with rhythm accompaniment. Best Buy sells them.

If she just MUST have the furniture, yank the guts from the Wurly and set the PSR on the empty keyboard shelf. I know keyboardists who set up an empty baby grand shell to set their synth/MIDI controller in on stage - looks nicer than a stand in a supper club.

Win-win.

And that PSR will play rings around the old Wurly.

My fave is to play Little Drummer Boy to a samba beat in pipe organ voice. Then shift it to minor key. Evil Drummer Boy.

[Don Moose]

I like the idea, but the Wurly's paid for; and appears to need very little work.

Her hope is that the one-key chords can get the boy engaged in putting down the guitar hero and actually learning a real instrument.

All I really need is to find another $60 tube keyboard or $20 stereo.

[Enzo]

Check for dirty or oxidized key contacts for the dead notes. If multiple of same note, like from a certain octave and lower, look for a dead divider stage.

[Don Moose]

Originally Posted by Enzo

If multiple of same note, like from a certain octave and lower, look for a dead divider stage.

That's where I am. Tried a little tube swappy (same position, different divider string) but that made it worse.
Probably need to get in there with a strong light and a magnifier and check the solders.

BTW, the divider tubes are 12FQ8s - a dual triode, each with dual plates. Cathode is common and it requires a 12.6V heater (no 6.3V option). Would these be useful as a PI (LTPI) in a mixed tube/mode output section? (bearing in mind that they're not current production)