6v & 90v DC Power supply

Buy a DC-DC converter that includes other protection features (ie overvoltage and overcurrent protection) and outputs known parameters (ie ripple voltage). I doubt you will find a single DC-DC converter for both voltages. But a small converter for each voltage should work. Many sources including this one that just arrived on my desk -

.

BTW, power from automotive systems should also worry about load dump. Technically load dump can be a transient as much as 270 volts on a 12 volt system. In reality, such events may only be 50 volts or less. Transients that would not damage other automotive electronics already designed for this rare and so destructive event.

That is a problem with some regulators such as 78xx series. Maximum voltage is typically not sufficient for automotive purposes - would require additi> Probably good enough for his measly 32 volts. I need to

Hello Rich,

Even with complicated electronics it wasn't. IIRC it was Suzuki-Hammond which came out with the XK2 and then the XK3. Those are pretty elaborate synthesizer organs. But according to the experts it just ain't the same.

Regards, Joerg

It seems like, no matter how closely you try to mimic the waveform of a real instrument, there's always something that says, "This is electronic." Or, maybe more accurately, "This is not real." ;-)

Cheers! Rich

On Wed, 28 Dec 2005 02:20:02 -0500, w_tom top-posted: ...

This is what transzorbs

and hash chokes are for.

I'm not affiliated with Vishay, formerly General Semiconductor, just a satisfied customer. I've used them to protect circuits against the transients caused by a 5 KV arc in an ion gun. :-)

Cheers! Rich

You will find a number of solutions (e.g. battery radios) in the Usenet group: rec.antiques.radio_phono

gb

Actually SGS Thompson that specifically makes protectors for automobiles and load dump (do what 'too small' transzorb would also do) acknowledge in their app notes that:

This would explain why an 'up to 270 volt' transient is not routinely observed. Still, automotive electronics typically should withstand about 50 volts ballpark without damage. Transzorb could be but one part of that protection system. Or a DC to DC converter that specifically has such protection could be obtained. A weakness of Transzorbs are their low power abilities. The advantage - those avalanche diodes can handle so much more power than conventional zeners. My first design that used Transzorb was maybe 20 years ago. GS was selling Transzorbs even long before then.

Load dump does not occur frequently. But that > This is what transzorbs

I heard a decently accurate electronic piano sound long before I heard anything remotely resembling the timber of a B3. Still haven't heard anything that sounds exactly like a B3 (other than an A100 or another B3).

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

I'm going to build a modified Lythall but I need to determine what the wattage of the 330 Ohm resisters would be. I'm thinking they should be fairly high.

Yabbut, how many gyrators and phase shifters and stuff does it take to model, for example, a bowed string? ;-)

Thanks! Rich

Whatever it is, if it has to come out of speakers it isn't going to sound quite right.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Don't some of them have rotating speakers?

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

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Hello Rich,

I have a feeling that this is exactly the problem. Engineers try to mimic the output waveform instead of looking how the real instrument is built. If they did that, they'd try to emulate all the individual parts and pieces.

Regards, Joerg

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.

It'll take a lot of gyrators and filters but considering that one can buy a 400MHz DSP for less than a crate of beer these days it should be feasible. In case of our piano the DSP still couldn't win. The piano doesn't need power. Not even light since it has its own candles.

Regards, Joerg

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.

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

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Member of DAV #85.

Michael A. Terrell
Central Florida

Hello Spehro,

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.

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

Hello Michael,

If you get stuck or need a rare part talk to Bob:

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

The Wurlitzer down at Roaring 20s Pizza and Pipes

actually plays instruments like horns and drums.

"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." --

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

Thanks, Rich