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.

6v & 90v DC Power supply
 

"Bart Rowlett" wrote in message
g...
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.


Here's a reference to 'Silicon Chip' magazine, who ran some articles about
these devices.
http://www.siliconchip.com.au/cms/A_30674/article.html

I recall seeing a commercial unit which was a semiconductor equivalent of
the vibrator, two AC132 transistors (IIRC) as a multivibrator running into a
transformer. The article above gives enough hints to be useful though.

Here's some other useful links:
http://www.radios.freeserve.co.uk/vibrators/vib.htm

Woops, here we go, found the one I was after:
http://www.vmarsmanuals.co.uk/newsle...s/vibrator.pdf
Circuit for the solid-state vibrator.

Cheers.

Ken

6v & 90v DC Power supply
 

On Wed, 28 Dec 2005 16:29:14 -0600, clifto
wrote:

Rich Grise, but drunk wrote:
"... Accurate imitation of the Hammond sound with simple electronic
circuitry was difficult, because the subtly-changing phase relationships
between tonewheels could not be easily replicated...."

OK, fair enough. :-)

I guess a piano is even harder - they don't even reproduce well from a
live recording! :-)

I heard a decently accurate electronic piano sound long before I heard
anything remotely resembling the timber of a B3.

---
Oak, was it, or maple?


--
John Fields
Professional Circuit Designer

6v & 90v DC Power supply
 

John Fields wrote:
On Wed, 28 Dec 2005 16:29:14 -0600, clifto
wrote:
Rich Grise, but drunk wrote:
"... Accurate imitation of the Hammond sound with simple electronic
circuitry was difficult, because the subtly-changing phase relationships
between tonewheels could not be easily replicated...."

OK, fair enough. :-)

I guess a piano is even harder - they don't even reproduce well from a
live recording! :-)

I heard a decently accurate electronic piano sound long before I heard
anything remotely resembling the timber of a B3.

---
Oak, was it, or maple?

Not that I would be one to pass up a good straight line, but just in case...

Main Entry: tim·bre
Variant: also tim·ber /'tam-b&r, 'tim-; 'tam(br&)/
Function: noun
: the quality given to a sound by its overtones: as
a : the resonance by which the ear recognizes and identifies a voiced
speech sound
b : the quality of tone distinctive of a particular singing voice or
musical instrument
?tim·bral /'tam-br&l, 'tim-/ adjective

Source: Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.

--
If John McCain gets the 2008 Republican Presidential nomination,
my vote for President will be a write-in for Jiang Zemin.

6v & 90v DC Power supply
 

I assume that you do not have the companion AM-65 audio amplifier?
Shame, because internal to that unit is a power supply (don't remember the
numbers now) that allowed you to operate the AM-65/RT-70 combo from 6, 12 or
24 volts depending on the power supply used. The usually supplied unit used
24 volts (Korean War American military standard elec system). If you can't
get the 12 volt version, modification instructions can be found in a 73
Magazine article called
"New Orders for the R-108" which was a companion receiver for the big
brother of the RT-70, the RT-68. R-108 used the same series of plug in
internal power supplies that the AM-65 did.
There was also a magazine article in the now defunct as well Ham Radio
mag titled "Get on Six Meters-The Easy Way". It dealt with a manpack 6
channel radio of Canadian ancestry that also needed 90 Volts. I have the
entire run of that magazine from 1969 to 1990 on cd. If I can figure out how
to extract the stuff off the disk, I'll email it to you. Now, the fee for
such information.....
You will regale me with tales of operation and modification of
aforementioned Olive Drab garbed electronic equipment!!! I'll email you
later from my own account so that you will get my real email address, or you
can use the arrl reflector. 73

Chris



"James F. Mayer" wrote in message
nk.net...
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. 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.