søndag den 25. november 2018 kl. 07.35.52 UTC+1 skrev David Lesher:
> Jeff Liebermann <jeffl@cruzio.com> writes:
> 
> >On Sat, 10 Nov 2018 22:39:37 -0600, guitar-lead@myband.com wrote:
> 
> >>Need schematic for a 100 megawatt audio amplifier using vacuum tubes.
> 
> >No problem and no vacuum tubes required.  A few diesel train engines
> >driving air compressors feeding a big Wagnerian horn should do the
> >trick.  Modulation would be by pneumatic valve control, fluidics, or
> >hydraulic modulators.  
> 
> An old prof told of working on a WWII airborne PA system to
> warn civilians about a pending attack. They ended up with a
> compressed air driven horn modulated with a slotted plate for a
> valve, modulated.

here mechanical sirens were in use until 1993 and to make sure they 
worked they were tested every Wednesday at noon, now they are electronic
and only tested with sound once a year  

Jeff Liebermann <jeffl@cruzio.com> writes:

>On Sat, 10 Nov 2018 22:39:37 -0600, guitar-lead@myband.com wrote:

>>Need schematic for a 100 megawatt audio amplifier using vacuum tubes.

>No problem and no vacuum tubes required.  A few diesel train engines
>driving air compressors feeding a big Wagnerian horn should do the
>trick.  Modulation would be by pneumatic valve control, fluidics, or
>hydraulic modulators.  

An old prof told of working on a WWII airborne PA system to
warn civilians about a pending attack. They ended up with a
compressed air driven horn modulated with a slotted plate for a
valve, modulated.

-- 
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Sun, 18 Nov 2018 18:28:09 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

>On Thu, 15 Nov 2018 21:27:43 -0500, Phil Hobbs wrote:
>
>> (Who used to stand down in the mosh pits of prog rock concerts in the
>> mid-70s wearing ear plugs and taking photos.
>
>You'd need military grade ear-defenders for this band:
>
>https://www.youtube.com/watch?v=-bgJC4YSNF4

I used to work for a company that made the headphones football coaches
wear on the sidelines.  To make sure the devices worked, we needed
ambient noise measurements where the devices were to be used.  The
ambient noise on the sidelines of an Auburn/Alabama game exceeded
120dB, which can cause instant hearing loss.  We also sold equipment
to train the players to function in that environment. <boggle>

On Thu, 15 Nov 2018 21:27:43 -0500, Phil Hobbs wrote:

> (Who used to stand down in the mosh pits of prog rock concerts in the
> mid-70s wearing ear plugs and taking photos.

You'd need military grade ear-defenders for this band:

https://www.youtube.com/watch?v=-bgJC4YSNF4




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On Fri, 16 Nov 2018 06:31:33 +0200, upsidedown@downunder.com wrote:

>On Thu, 15 Nov 2018 07:31:20 -0800, John Larkin
><jjlarkin@highlandtechnology.com> wrote:
>
>>On Wed, 14 Nov 2018 23:14:59 -0800 (PST), tabbypurr@gmail.com wrote:
>>
>>>On Wednesday, 14 November 2018 21:04:51 UTC, John Larkin  wrote:
>>>> On Sun, 11 Nov 2018 10:51:34 -0800 (PST), tabbypurr wrote:
>>>> >On Sunday, 11 November 2018 04:39:41 UTC, guita...@myband.com  wrote:
>>>> >
>>>> >> Need schematic for a 100 megawatt audio amplifier using vacuum tubes.
>>>> >
>>>> >Mount the control rods on large long throw speaker coils, use the valve amp to drive those. No, won't work, steam doesn't have much frequency response. Maybe use the generators of a nuke plant in amplidyne mode. You'd need to make some custom ones to cover the higher frequencies if this is for audio - I hope it's not.
>>>> 
>>>> There are some thousands-of-PSI multi-horsepower hydraulic servo
>>>> valves that get into the hundreds of Hz. Hydraulic bass drivers?
>>>
>>>hydraulics are just control & gearing, but it's a way to use a cheap high power drive, the compressor.
>>>
>>>> I'm always impressed by big hydraulics. They move mountains, usually
>>>> with reversed mechanical advantage. But my knees work with reversed
>>>> mechanical advantage; if I lift a hundred pounds, my muscles must be
>>>> pulling tons.
>>>> 
>>>> I wonder why so many guys fanticize about being rock stars. Sounds
>>>> dreadful to me.
>>>
>>>Sounds great to people with no other opportunities. Not stuck in an office all day, saying yes sir yes sir for a bit above minimum wage. Most buy into the money wasted on superficial junk thing. I prefer to do something useful.
>>>
>>>
>>>NT
>>
>>The fraction of people with enough musical talent to be stars is in
>>the parts-per-million.
>>
>>What's the SPL where air goes nonlinear, where the negative peaks hit
>>vacuum? That 100 megawatts wouldn't work on any rock-concert
>>soundstage.
>
>At about 180 dB, the positive peaks are at 2 bar and negative at 0
>bar..

Correction: It is 194 dB
https://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level

>
>Some speakers claim 100 dB/W sensitivity at 1 m, thus 100 MW would be
>80 dB higher so 180 dB would be possible, but since multiple speakers
>would be needed, how would you measure the pressure at 1 m from _all_
>, so not practical due to the geometry.

Thus 100 MW is not quite enough.

On Thu, 15 Nov 2018 07:31:20 -0800, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

>On Wed, 14 Nov 2018 23:14:59 -0800 (PST), tabbypurr@gmail.com wrote:
>
>>On Wednesday, 14 November 2018 21:04:51 UTC, John Larkin  wrote:
>>> On Sun, 11 Nov 2018 10:51:34 -0800 (PST), tabbypurr wrote:
>>> >On Sunday, 11 November 2018 04:39:41 UTC, guita...@myband.com  wrote:
>>> >
>>> >> Need schematic for a 100 megawatt audio amplifier using vacuum tubes.
>>> >
>>> >Mount the control rods on large long throw speaker coils, use the valve amp to drive those. No, won't work, steam doesn't have much frequency response. Maybe use the generators of a nuke plant in amplidyne mode. You'd need to make some custom ones to cover the higher frequencies if this is for audio - I hope it's not.
>>> 
>>> There are some thousands-of-PSI multi-horsepower hydraulic servo
>>> valves that get into the hundreds of Hz. Hydraulic bass drivers?
>>
>>hydraulics are just control & gearing, but it's a way to use a cheap high power drive, the compressor.
>>
>>> I'm always impressed by big hydraulics. They move mountains, usually
>>> with reversed mechanical advantage. But my knees work with reversed
>>> mechanical advantage; if I lift a hundred pounds, my muscles must be
>>> pulling tons.
>>> 
>>> I wonder why so many guys fanticize about being rock stars. Sounds
>>> dreadful to me.
>>
>>Sounds great to people with no other opportunities. Not stuck in an office all day, saying yes sir yes sir for a bit above minimum wage. Most buy into the money wasted on superficial junk thing. I prefer to do something useful.
>>
>>
>>NT
>
>The fraction of people with enough musical talent to be stars is in
>the parts-per-million.
>
>What's the SPL where air goes nonlinear, where the negative peaks hit
>vacuum? That 100 megawatts wouldn't work on any rock-concert
>soundstage.

At about 180 dB, the positive peaks are at 2 bar and negative at 0
bar..

Some speakers claim 100 dB/W sensitivity at 1 m, thus 100 MW would be
80 dB higher so 180 dB would be possible, but since multiple speakers
would be needed, how would you measure the pressure at 1 m from _all_
, so not practical due to the geometry.

On 11/15/18 2:44 PM, John Larkin wrote:
> On Thu, 15 Nov 2018 10:44:41 -0500, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
> 
>> On 11/15/18 10:31 AM, John Larkin wrote:
>>> On Wed, 14 Nov 2018 23:14:59 -0800 (PST), tabbypurr@gmail.com wrote:
>>>
>>>> On Wednesday, 14 November 2018 21:04:51 UTC, John Larkin  wrote:
>>>>> On Sun, 11 Nov 2018 10:51:34 -0800 (PST), tabbypurr wrote:
>>>>>> On Sunday, 11 November 2018 04:39:41 UTC, guita...@myband.com  wrote:
>>>>>>
>>>>>>> Need schematic for a 100 megawatt audio amplifier using vacuum tubes.
>>>>>>
>>>>>> Mount the control rods on large long throw speaker coils, use the valve amp to drive those. No, won't work, steam doesn't have much frequency response. Maybe use the generators of a nuke plant in amplidyne mode. You'd need to make some custom ones to cover the higher frequencies if this is for audio - I hope it's not.
>>>>>
>>>>> There are some thousands-of-PSI multi-horsepower hydraulic servo
>>>>> valves that get into the hundreds of Hz. Hydraulic bass drivers?
>>>>
>>>> hydraulics are just control & gearing, but it's a way to use a cheap high power drive, the compressor.
>>>>
>>>>> I'm always impressed by big hydraulics. They move mountains, usually
>>>>> with reversed mechanical advantage. But my knees work with reversed
>>>>> mechanical advantage; if I lift a hundred pounds, my muscles must be
>>>>> pulling tons.
>>>>>
>>>>> I wonder why so many guys fanticize about being rock stars. Sounds
>>>>> dreadful to me.
>>>>
>>>> Sounds great to people with no other opportunities. Not stuck in an office all day, saying yes sir yes sir for a bit above minimum wage. Most buy into the money wasted on superficial junk thing. I prefer to do something useful.
>>>>
>>>>
>>>> NT
>>>
>>> The fraction of people with enough musical talent to be stars is in
>>> the parts-per-million.
>>>
>>> What's the SPL where air goes nonlinear, where the negative peaks hit
>>> vacuum? That 100 megawatts wouldn't work on any rock-concert
>>> soundstage.
>>
>> Air goes nonlinear way before you get there.  Sound is basically
>> adiabatic, so near the positive pressure peaks the air is hotter and the
>> speed of sound correspondingly faster.  Thus the positive peaks get
>> steeper and steeper as the wave propagates.  Doesn't take long to build
>> up shock waves, or very nearly.
>>
>> Cheers
>>
>> Phil Hobbs
> 
> Sounds like a shock line, NLTL. Fast samplers use them.

Same idea, yeah.
> 
> Superheated shock waves would impress the crowd at the concert.

The first one would blow out their ear drums, at which point they'd have 
other things on their minds besides music, like whether it would also 
homogenize their internal organs.

The kids dancing in front of the speaker stacks would have a poor prognosis.

Cheers

Phil Hobbs

(Who used to stand down in the mosh pits of prog rock concerts in the 
mid-70s wearing ear plugs and taking photos.  He still has several 
hundred slides to prove it, not that he wants to.) :)


-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On Thu, 15 Nov 2018 12:25:21 -0500, Neon John <no@never.com> wrote:

>On Sun, 11 Nov 2018 23:35:55 -0800, Jeff Liebermann <jeffl@cruzio.com>
>wrote:
>
>>There might be a PCB in the low
>>level part of the amplifier, but stages operating at over 1000 watts
>>need big fat conductors, physically large capacitors, heavy duty
>>transformers, oil bath capacitors, and high current knife switches.
>
>Really?  The last induction heater I designed before I retired is
>rated at 5kW.  Everything is on a 4oz, 4 layer board.  My IR camera
>shows about 25 deg C rise at full power.  My PFC/boost universal boost
>controller boosts incoming line to 385 volts.  5kW is only about 13
>amps.  The current in the tank runs around 80 amps at 80kHz.
>
>I have a 10kW unit on my bench that I will test after the Thanksgiving
>holiday.  Same board and SiC FETs.  There are two differences.  One is
>the resonating capacitor is split into 2 smaller capacitance units.
>The second is that I've applied vertical bus bars on the power traces.
>
>John
>
>

The OP can maybe live with peak music power, or Chinese watts, which
is easier to manage on PC boards.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Thu, 15 Nov 2018 10:44:41 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 11/15/18 10:31 AM, John Larkin wrote:
>> On Wed, 14 Nov 2018 23:14:59 -0800 (PST), tabbypurr@gmail.com wrote:
>> 
>>> On Wednesday, 14 November 2018 21:04:51 UTC, John Larkin  wrote:
>>>> On Sun, 11 Nov 2018 10:51:34 -0800 (PST), tabbypurr wrote:
>>>>> On Sunday, 11 November 2018 04:39:41 UTC, guita...@myband.com  wrote:
>>>>>
>>>>>> Need schematic for a 100 megawatt audio amplifier using vacuum tubes.
>>>>>
>>>>> Mount the control rods on large long throw speaker coils, use the valve amp to drive those. No, won't work, steam doesn't have much frequency response. Maybe use the generators of a nuke plant in amplidyne mode. You'd need to make some custom ones to cover the higher frequencies if this is for audio - I hope it's not.
>>>>
>>>> There are some thousands-of-PSI multi-horsepower hydraulic servo
>>>> valves that get into the hundreds of Hz. Hydraulic bass drivers?
>>>
>>> hydraulics are just control & gearing, but it's a way to use a cheap high power drive, the compressor.
>>>
>>>> I'm always impressed by big hydraulics. They move mountains, usually
>>>> with reversed mechanical advantage. But my knees work with reversed
>>>> mechanical advantage; if I lift a hundred pounds, my muscles must be
>>>> pulling tons.
>>>>
>>>> I wonder why so many guys fanticize about being rock stars. Sounds
>>>> dreadful to me.
>>>
>>> Sounds great to people with no other opportunities. Not stuck in an office all day, saying yes sir yes sir for a bit above minimum wage. Most buy into the money wasted on superficial junk thing. I prefer to do something useful.
>>>
>>>
>>> NT
>> 
>> The fraction of people with enough musical talent to be stars is in
>> the parts-per-million.
>> 
>> What's the SPL where air goes nonlinear, where the negative peaks hit
>> vacuum? That 100 megawatts wouldn't work on any rock-concert
>> soundstage.
>
>Air goes nonlinear way before you get there.  Sound is basically 
>adiabatic, so near the positive pressure peaks the air is hotter and the 
>speed of sound correspondingly faster.  Thus the positive peaks get 
>steeper and steeper as the wave propagates.  Doesn't take long to build 
>up shock waves, or very nearly.
>
>Cheers
>
>Phil Hobbs

Sounds like a shock line, NLTL. Fast samplers use them.

Superheated shock waves would impress the crowd at the concert.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Sun, 11 Nov 2018 23:35:55 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>There might be a PCB in the low
>level part of the amplifier, but stages operating at over 1000 watts
>need big fat conductors, physically large capacitors, heavy duty
>transformers, oil bath capacitors, and high current knife switches.

Really?  The last induction heater I designed before I retired is
rated at 5kW.  Everything is on a 4oz, 4 layer board.  My IR camera
shows about 25 deg C rise at full power.  My PFC/boost universal boost
controller boosts incoming line to 385 volts.  5kW is only about 13
amps.  The current in the tank runs around 80 amps at 80kHz.

I have a 10kW unit on my bench that I will test after the Thanksgiving
holiday.  Same board and SiC FETs.  There are two differences.  One is
the resonating capacitor is split into 2 smaller capacitance units.
The second is that I've applied vertical bus bars on the power traces.

John

John DeArmond
http://www.neon-john.com
http://www.tnduction.com 
Tellico Plains, Occupied TN
See website for email address