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What is the most powerful audio output tube?



 
 
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  #11  
Old December 8th 16, 07:55 PM posted to sci.electronics.design,rec.audio.tubes
Dave Platt[_2_]
external usenet poster
 
Posts: 7
Default What is the most powerful audio output tube?

In article >,
Tim Wescott > wrote:

>If you're serious about this, get this book. It'll provide hours of
>drooling entertainment if you're just a fanboy, so it'll still be worth
>it:
>
>https://www.tubesandmore.com/product...be-manual-tt-5


Scan available for free at http://w5jgv.com/downloads/RCA-TT-5.PDF
(although the price of the Tubes And More reprint is an excellent one!)

The application tables for AF power amplifier and modulator service
start on page 88. The 7650 and 833A seem to be the brutes of the lot.


Ads
  #12  
Old December 8th 16, 08:18 PM posted to sci.electronics.design,rec.audio.tubes
Bitrex
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Posts: 19
Default What is the most powerful audio output tube?

On 12/08/2016 11:59 AM, John Larkin wrote:
> On Thu, 8 Dec 2016 10:39:35 -0500, bitrex
> > wrote:
>
>> On 12/08/2016 10:19 AM, wrote:
>>> What is the most powerful audio output tube, as far as RMS wattage
>>> output?
>>>
>>> I have gotten some powerful sound from four 6L6 tubes in push-pull
>>> parallel. but I want more. I know it's possible to use eight 6L6 tubes,
>>> which I believe is called " push-pull parallel - parallel", but I'm
>>> looking into other possible tubes.
>>>
>>> At one time, I thought the 807 tube was more powerful than the 6L6, but
>>> after careful research, it's almost identical, but with a different
>>> envelope (plate on the top cap).
>>>
>>> I'm looking to get a full 500W RMS (or more) output (per channel), from
>>> all tubes, .... With four 6L6 tubes in PPP, I can only get around 120W
>>> RMS (per channel).
>>>

>>
>> The output tranny required for 500 watts RMS is going to be a huge piece
>> of ****-off iron that will probably set you back the better part of a
>> grand, at least.
>>
>> 500 watts RMS from four tubes will require you to step up way beyond
>> 6L6es and 807s, I think. You're probably going to want to look at
>> something like RF power triodes or tetrodes, 813s or the GU-13 if you're
>> okay with going ex-Soviet.
>>
>> I am not a pro tube guy though so that's just my guess.

>
> The transformer is the problem, especially if you go with a giant
> transmitting tube that runs at high plate voltages.


Yeah, not to mention the "instant death" ~1.5kV supply and cap bank that
would be required to feed such a beast.

> There have been transformerless audio power amps, using that beast
> low-mu triode tube, the one Tek used in their B+ regulators.


I think that's the 6080/6AS7. I saw a 50 watt OTL amp that used
something like 8 or 12 of 'em in push pull parallel to hit that.

I can't even imagine what you'd have to throw at that topology to get 500.

> Why not use mosfets? Toobs are silly.


An OTL headphone amp using say a single 6N7 power triode for each
channel and something like a 12AU7 used as a diff-pair gain stage would
be a nice weekend project for maybe half a watt per channel - way more
than required.

You can drive MOSFETs or tubes of the same polarity stacked totem-pole
from a tube diff pair, but the driver design has to be a little clever
to equalize output impedance and gain between the stages:

http://www.tubecad.com/2010/12/29/Low-Voltage%20OTL.png

I'd question my sanity if I started thinking about a 500 RMS watt
all-tube amp though. Well, this guy actually did do something rather crazy:

http://www.chambonino.com/construct/const9.html

Output transformer looks like it weighs about as much as I do.
  #13  
Old December 8th 16, 08:19 PM posted to sci.electronics.design,rec.audio.tubes
Tauno Voipio
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Posts: 3
Default What is the most powerful audio output tube?

On 8.12.16 19:44, Tim Wescott wrote:
> On Thu, 08 Dec 2016 09:19:23 -0600, boomer#6877250 wrote:
>
>> What is the most powerful audio output tube, as far as RMS wattage
>> output?
>>
>> I have gotten some powerful sound from four 6L6 tubes in push-pull
>> parallel. but I want more. I know it's possible to use eight 6L6 tubes,
>> which I believe is called " push-pull parallel - parallel", but I'm
>> looking into other possible tubes.
>>
>> At one time, I thought the 807 tube was more powerful than the 6L6, but
>> after careful research, it's almost identical, but with a different
>> envelope (plate on the top cap).
>>
>> I'm looking to get a full 500W RMS (or more) output (per channel), from
>> all tubes, .... With four 6L6 tubes in PPP, I can only get around 120W
>> RMS (per channel).

>
> AM Radio stations used some that would do 50,000W, I believe. Is that
> sufficient?
>
> You don't want the "most powerful" tube -- you just want one that fits
> your wimpy (relative to "big radio") requirements.
>
> If you're serious about this, get this book. It'll provide hours of
> drooling entertainment if you're just a fanboy, so it'll still be worth
> it:
>
> https://www.tubesandmore.com/product...be-manual-tt-5
>


Eimac's 'The Care and Feeding of Power-grid Tubes' is also very good,
if it is somewhere to be found.

> A pair of 4-1000A tubes would be dandy, but I don't know where to find
> them (I'm a fanboy, not an expert).


For Class-B push-pull a pair of zero-bias triodes is much easier
to handle, e.g. 3-500Z or 3-1000Z. The kilowatt tubes are a bit
of overkill for 500 W output.

> Note that ALL of the tubes I'm mentioning here are radio tubes, not
> audiophile tubes -- if you judge an amplifier by more than how hot it
> gets and how much it costs, you may not be happy with the sound.


Right - the big tubes are classified as transmitting tubes even when
they are used in high-level AM modulators (where IMHO the biggest
audio outputs are used).

--

-TV

  #14  
Old December 8th 16, 08:28 PM posted to sci.electronics.design,rec.audio.tubes
Bitrex
external usenet poster
 
Posts: 19
Default What is the most powerful audio output tube?

On 12/08/2016 02:18 PM, bitrex wrote:

> I'd question my sanity if I started thinking about a 500 RMS watt
> all-tube amp though. Well, this guy actually did do something rather crazy:
>
> http://www.chambonino.com/construct/const9.html
>
> Output transformer looks like it weighs about as much as I do.


There's not nearly enough protection on that monster for my liking,
either. If I were crazy enough to build something like that I'd probably
have a dedicated uP on every output tube monitoring all the
voltages/currents of interest and shutting everything down quickly if
something looked amiss.

Those transformers don't look cheap.
  #15  
Old December 8th 16, 08:49 PM posted to sci.electronics.design,rec.audio.tubes
Cursitor Doom
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Posts: 1
Default What is the most powerful audio output tube?

On Thu, 08 Dec 2016 15:51:54 +0000, Ralph Barone wrote:

> Go big or go home. http://www.g8wrb.org/tetrodes/


The last toob in that list (1MW) has the comment "the ultimate tube for
QRP" so I'm guessing this person doesn't know his Ps for his Os. Unless
he's aiming for ultimate sarcasm.

  #16  
Old December 8th 16, 09:56 PM posted to sci.electronics.design,rec.audio.tubes
boB
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Posts: 1
Default What is the most powerful audio output tube?

On Thu, 08 Dec 2016 09:19:23 -0600, wrote:

>What is the most powerful audio output tube, as far as RMS wattage
>output?
>
>I have gotten some powerful sound from four 6L6 tubes in push-pull
>parallel. but I want more. I know it's possible to use eight 6L6 tubes,
>which I believe is called " push-pull parallel - parallel", but I'm
>looking into other possible tubes.
>
>At one time, I thought the 807 tube was more powerful than the 6L6, but
>after careful research, it's almost identical, but with a different
>envelope (plate on the top cap).
>
>I'm looking to get a full 500W RMS (or more) output (per channel), from
>all tubes, .... With four 6L6 tubes in PPP, I can only get around 120W
>RMS (per channel).



How about a high AVERAGE output wattage ?



boB
  #17  
Old December 8th 16, 10:08 PM posted to sci.electronics.design,rec.audio.tubes
Bitrex
external usenet poster
 
Posts: 19
Default What is the most powerful audio output tube?

On 12/08/2016 11:55 AM, John Larkin wrote:
> On Thu, 08 Dec 2016 09:19:23 -0600, wrote:
>
>> What is the most powerful audio output tube, as far as RMS wattage
>> output?
>>
>> I have gotten some powerful sound from four 6L6 tubes in push-pull
>> parallel. but I want more. I know it's possible to use eight 6L6 tubes,
>> which I believe is called " push-pull parallel - parallel", but I'm
>> looking into other possible tubes.
>>
>> At one time, I thought the 807 tube was more powerful than the 6L6, but
>> after careful research, it's almost identical, but with a different
>> envelope (plate on the top cap).
>>
>> I'm looking to get a full 500W RMS (or more) output (per channel), from
>> all tubes, .... With four 6L6 tubes in PPP, I can only get around 120W
>> RMS (per channel).

>
> https://dl.dropboxusercontent.com/u/.../Tubes/833.jpg
>
>


The ex-Soviet version GU-48 are pretty cheap on eBay...
  #18  
Old December 8th 16, 10:19 PM posted to sci.electronics.design,rec.audio.tubes
Tim Wescott
external usenet poster
 
Posts: 8
Default What is the most powerful audio output tube?

On Thu, 08 Dec 2016 21:19:52 +0200, Tauno Voipio wrote:

> On 8.12.16 19:44, Tim Wescott wrote:
>> On Thu, 08 Dec 2016 09:19:23 -0600, boomer#6877250 wrote:
>>
>>> What is the most powerful audio output tube, as far as RMS wattage
>>> output?
>>>
>>> I have gotten some powerful sound from four 6L6 tubes in push-pull
>>> parallel. but I want more. I know it's possible to use eight 6L6
>>> tubes,
>>> which I believe is called " push-pull parallel - parallel", but I'm
>>> looking into other possible tubes.
>>>
>>> At one time, I thought the 807 tube was more powerful than the 6L6,
>>> but after careful research, it's almost identical, but with a
>>> different envelope (plate on the top cap).
>>>
>>> I'm looking to get a full 500W RMS (or more) output (per channel),
>>> from all tubes, .... With four 6L6 tubes in PPP, I can only get around
>>> 120W RMS (per channel).

>>
>> AM Radio stations used some that would do 50,000W, I believe. Is that
>> sufficient?
>>
>> You don't want the "most powerful" tube -- you just want one that fits
>> your wimpy (relative to "big radio") requirements.
>>
>> If you're serious about this, get this book. It'll provide hours of
>> drooling entertainment if you're just a fanboy, so it'll still be worth
>> it:
>>
>> https://www.tubesandmore.com/product...be-manual-tt-5
>>
>>

> Eimac's 'The Care and Feeding of Power-grid Tubes' is also very good,
> if it is somewhere to be found.
>
>> A pair of 4-1000A tubes would be dandy, but I don't know where to find
>> them (I'm a fanboy, not an expert).

>
> For Class-B push-pull a pair of zero-bias triodes is much easier to
> handle, e.g. 3-500Z or 3-1000Z. The kilowatt tubes are a bit of overkill
> for 500 W output.


May not be the best sounding result if you're going for audiophoolery.
Low-mu triodes with the grid voltages negative would be best then, or AB1
beam tubes, maybe.

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com
  #19  
Old December 9th 16, 12:29 PM
John L Stewart John L Stewart is offline
Senior Member
 
First recorded activity by AudioBanter: Jan 2011
Location: Toronto
Posts: 301
Smile

Here Ya Are! Add a couple more KT88s & you are there.

John L Stewart
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  #20  
Old December 9th 16, 07:45 PM posted to sci.electronics.design,rec.audio.tubes
piglet
external usenet poster
 
Posts: 1
Default What is the most powerful audio output tube?

On 08/12/2016 15:19, wrote:
> What is the most powerful audio output tube, as far as RMS wattage
> output?
>
> I have gotten some powerful sound from four 6L6 tubes in push-pull
> parallel. but I want more. I know it's possible to use eight 6L6 tubes,
> which I believe is called " push-pull parallel - parallel", but I'm
> looking into other possible tubes.
>
> At one time, I thought the 807 tube was more powerful than the 6L6, but
> after careful research, it's almost identical, but with a different
> envelope (plate on the top cap).
>
> I'm looking to get a full 500W RMS (or more) output (per channel), from
> all tubes, .... With four 6L6 tubes in PPP, I can only get around 120W
> RMS (per channel).
>


I had one of these in my collection:

<http://r-type.org/exhib/aaa1098.htm>

sold it on ebay to some audio guy for lot of money

The heater alone consumes 90 watts.

piglet

 




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