What is the most powerful audio output tube?

On Thu, 08 Dec 2016 09:19:23 -0600, boomer#6877250@none.com 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/53724080/Tubes/833.jpg


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

On Thu, 8 Dec 2016 10:39:35 -0500, bitrex
<bitrex@de.lete.earthlink.net> wrote:

>On 12/08/2016 10:19 AM, boomer#6877250@none.com 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 fuck-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.

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

Why not use mosfets? Toobs are silly.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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/products/rca-transmitting-tube-manual-tt-5

There are a lot of tubes that will do your job that are both in that book 
and available.

The 1625 is basically an 807 with a different base and a 12V filament -- 
all other ratings are the same.  It's much cheaper than the 807 from 
tubesandmore.com.  Eight of them (enough to do 500W) is cheaper than a 
pair of 813's, and they'll run at a much less lethal plate voltage.

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).

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.  

-- 
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

In article <hcSdnRvDjfWQAdTFnZ2dnUU7-b-dnZ2d@giganews.com>,
Tim Wescott  <tim@seemywebsite.com> 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/products/rca-transmitting-tube-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.

On 8.12.16 18:53, Jim Thompson wrote:
> On Thu, 8 Dec 2016 18:43:02 +0200, Tauno Voipio
> <tauno.voipio@notused.fi.invalid> wrote:
>
>> On 8.12.16 18:10, Lasse Langwadt Christensen wrote:
>>> Den torsdag den 8. december 2016 kl. 16.49.20 UTC+1 skrev Tauno Voipio:
>>>> On 8.12.16 17:19, boomer#6877250@none.com 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).
>>>>
>>>>
>>>> 807 is the transmitting version of 6L6, so it's no wonder that it looks
>>>> similar.
>>>>
>>>> For the power level you're after, you may need real transmitting tubes,
>>>> e.g. a pair of 3-500Z's. Please understand that the voltages and
>>>> currents encountered at those power levels will be lethal in careless
>>>> hands.
>>>>
>>>
>>> first hit on google for 500w tube amp
>>>
>>> http://www.chambonino.com/construct/const9.html
>>>
>>
>> The maximum plate dissipation of a 813 is 100 W, which is a bit too
>> little for continuous 500 W out. 4 * 813 will stand 400 W on plate,
>> but 2 * 3-500Z will stand 1 kW.
>
> <http://www.radiowrench.com/sonic/so02017.html>
> 		
>                                         ...Jim Thompson


4CX1000A and friends are more fussy to handle than the glass-envelope
toobs, and an audio amplifier does not need the minimal-RF-impedance
structures of the external-anode ceramic tubes.

-- 

-TV

On 12/08/2016 11:59 AM, John Larkin wrote:
> On Thu, 8 Dec 2016 10:39:35 -0500, bitrex
> <bitrex@de.lete.earthlink.net> wrote:
>
>> On 12/08/2016 10:19 AM, boomer#6877250@none.com 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 fuck-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.

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/products/rca-transmitting-tube-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

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.

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.

On Thursday, December 8, 2016 at 2:19:56 PM UTC-5, 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/products/rca-transmitting-tube-manual-tt-5
> >
> 
> Eimac's 'The Care and Feeding of Power-grid Tubes' is also very good,
> if it is somewhere to be found.

http://www.g8wrb.org/data/Eimac/care_and_feeding_of_power_grid_tubes.pdf

Cheers,
James Arthur