6v & 90v DC Power supply
 

Hello Spehro,

In case of a Hammond organ it might since it has a speaker. Of course,
it's a tube amp but that is a whole other matter which alone could make
this thread balloon.

Don't some of them have rotating speakers?


That was an accessory item, a Leslie speaker. A huge cabinet with a
rotating speaker on slide contacts, motors, gears. We don't have one and
we wouldn't know where to put it anyway. The amp under the organ is only
20W AFAIK with a huge speaker. That's real watts, not PMPS or whatever
kids call "power" these days. Meaning it can make the sound of a large
pipe organ and not lose steam after holding the bass chord for more than
a hundred milliseconds.


Sure, but can you flip a switch and be playing the flute or er-hu?


Actually you could. Ours doesn't have the flute presets but drawbars.
With these you can set the ratio of all the harmonics and the manual
shows the settings for a lot of common instruments. Some sound real,
some don't. But we also have a small environmentally friendly (zero
electric power, made from wood) flute. Not that I can play it but my
wife can.

Regards, Joerg

http://www.analogconsultants.com

6v & 90v DC Power supply
 

Hello Michael,

That is a "Leslie" speaker. I have to service the one at my church.
The bearings are shot.


If you get stuck or need a rare part talk to Bob:
http://www.tonewheel.com/services.htm

That's where I got my Hammond oil. Very friendly and helpful. His dog
was very friendly as well, he greeted me first.

Regards, Joerg

http://www.analogconsultants.com

6v & 90v DC Power supply
 

"Joerg" wrote in message
...
Hello Spehro,

In case of a Hammond organ it might since it has a speaker. Of course,
it's a tube amp but that is a whole other matter which alone could make
this thread balloon.

Don't some of them have rotating speakers?

That was an accessory item, a Leslie speaker. A huge cabinet with a
rotating speaker on slide contacts, motors, gears. We don't have one and
we wouldn't know where to put it anyway. The amp under the organ is only
20W AFAIK with a huge speaker. That's real watts, not PMPS or whatever
kids call "power" these days. Meaning it can make the sound of a large
pipe organ and not lose steam after holding the bass chord for more than a
hundred milliseconds.


Sure, but can you flip a switch and be playing the flute or er-hu?

Actually you could. Ours doesn't have the flute presets but drawbars. With
these you can set the ratio of all the harmonics and the manual shows the
settings for a lot of common instruments. Some sound real, some don't. But
we also have a small environmentally friendly (zero electric power, made
from wood) flute. Not that I can play it but my wife can.

Regards, Joerg

http://www.analogconsultants.com

The Wurlitzer down at Roaring 20s Pizza and Pipes
http://www.roaring20spizza.com/ actually plays instruments like horns and
drums.

6v & 90v DC Power supply
 

what kind of bearings? - ball bearings are like tubes - thay have
numbers and substitutes. Bronze bearings are routinely made by
machinists. Babbit is hardest as it is poured in place but you might
be better off replacing them with something else like bronze. Bearing
technology is not all that complicated if you poke into the right
group of folks.


More like bronze bearings. But it ain't that easy. When you take it
apart you end up with hundreds of pieces. It is the most complicated
concoction of moving mechanical parts I ever encountered. The photo at
near bottom show just a small part of it:
http://www.myplanet.net/x77dude/photos.html

Regards, Joerg

http://www.analogconsultants.com

6v & 90v DC Power supply
 

Joerg wrote:

More like bronze bearings. But it ain't that easy. When you take it
apart you end up with hundreds of pieces. It is the most complicated
concoction of moving mechanical parts I ever encountered. The photo at
near bottom show just a small part of it:
http://www.myplanet.net/x77dude/photos.html

Regards, Joerg

http://www.analogconsultants.com


Stay away from early jukeboxes and old NCR cassh registers, too! :-)

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

6v & 90v DC Power supply
 

Hello James,

The Wurlitzer down at Roaring 20s Pizza and Pipes
http://www.roaring20spizza.com/ actually plays instruments like horns and
drums.


Thanks! That is one big organ. The 20HP blower motor alone speaks
volumes. I wish we had one of these somewhere in California.

Regards, Joerg

http://www.analogconsultants.com

6v & 90v DC Power supply
 

"Joerg" wrote in message
om...
Hello James,

The Wurlitzer down at Roaring 20s Pizza and Pipes
http://www.roaring20spizza.com/ actually plays instruments like horns and
drums.

Thanks! That is one big organ.

It is built into the whole building.


The 20HP blower motor alone speaks
volumes. I wish we had one of these somewhere in California.


It was in the Paramont Theater in Oakland California back in 1932.

Regards, Joerg

http://www.analogconsultants.com

6v & 90v DC Power supply
 

On Thu, 29 Dec 2005 22:12:04 +0000, James F. Mayer wrote:
"Joerg" wrote in message
om...
Hello James,

The Wurlitzer down at Roaring 20s Pizza and Pipes
http://www.roaring20spizza.com/ actually plays instruments like horns and
drums.

Thanks! That is one big organ.

It is built into the whole building.

The 20HP blower motor alone speaks
volumes. I wish we had one of these somewhere in California.

It was in the Paramont Theater in Oakland California back in 1932.

"Installed in 1931 at a price of $20,000 this Mighty Wurlitzer enjoyed
only a brief period of glory before the theatre closed in 1932. By the
late 1950's, the organ was sold and placed in storage."
-- http://www.roaring20spizza.com/history.htm

But, wasn't $20K in 1931 dollars equivalent to about two mil nowadays?
=:-O

Thanks,
Rich

6v & 90v DC Power supply
 

"Joerg" bravely wrote to "All" (29 Dec 05 18:54:44)
--- on the heady topic of " 6v & 90v DC Power supply"

Jo From: Joerg
Jo Xref: core-easynews rec.radio.amateur.homebrew:90375
Jo sci.electronics.design:535390


Jo Hello Spehro,

In case of a Hammond organ it might since it has a speaker. Of course,
it's a tube amp but that is a whole other matter which alone could make
this thread balloon.

Don't some of them have rotating speakers?


Jo That was an accessory item, a Leslie speaker. A huge cabinet with a
Jo rotating speaker on slide contacts, motors, gears.

Later on the speaker didn't rotate. The speaker was mounted face up.
Covering the speaker was a rotating funnel with 2 output horns at the
apex. The dual rotating horns gave a strong Doppler Effect that was
hard to duplicate electronically. A belt turned the rotating funnel
which was driven by a variable speed motor under user control.

A*s*i*m*o*v

6v & 90v DC Power supply
 

On Tue, 27 Dec 2005 02:02:15 +0000, James F. Mayer wrote:

I need to generate 6v DC and 90v DC from a 12v DC automotive electrical
system to power an RT-70A/GRC surplus military radio. I need about 250 mA
at +6 volts and about 75 mA at +90 volts. I was thinking about using the
guts from an old battery back up but it would be a bit of a kluge. Are
there any 90 volt regulators in the 78xx series? How do I get the voltage
up to where I can get something that I can get the 90 volts from.

Probably the easiest is to obtain one of the original power supplies.

Most installations using the RT-70 were in conjunction with an RT-66/RT-67
or RT-68 and an audio distribution amplifier. A separate vibrator power
supply was supplied those cases where the RT-70 was used 'stand alone'.
One approach to homebrewing a vehicular power supply is to mimic the
original vibrator supply. Provide the heater supply through dropping
resistors and emulate the vibrator supply by building an inverter using a
pair of switching transistors and a junk 60 Hz power transformer.
Regulation isn't necessary if you get the right transformer. The only
thing the least bit tricky with this approach is properly snubbing the
primary leakage inductance to prevent destroying the switching transistors.

Probably the most compact approach is to build a flyback supply with both
a six and 90 volt output. Regulate the 6 volt output and let the 90 volt
output track. The advantage of the flyback supply is that it can be
designed to operate over a wide range of input voltages while maintaining
a regulated output. In addition, the overall size will be much smaller due
to the high switching frequencies (300 kHz typical) used by modern flyback
controller chips.

Getting
the 6 volts doesn't seem to be a problem. A 7806 off the battery should
work for that unless any of you can see a problem doing that. Maybe the
common common would be a problem. Right now I'm running it off of an HP6299A
and an HP6236B with commons jumpered. I'd like to be able to go portable
with it.