As PP Power Tube wich is the most powerful 9 pin twin triode tube ?

[kagliostro]

As to be used for PP output in a small amp

which is/are the most powerful twin triode 9 pin tube/s ?

Many Thanks

K

[VMS]

Hi K,

I don't know but my guess is ECC99.

http://www.jj-electronic.com/pdf/ECC99.pdf


V

[HotBluePlates]

ECC99 is probably a good guess.

You probably want to look for a tube with the highest plate dissipation rating, while having the lowest Mu.

Low Mu implies a bigger input signal will be needed for full power, but also that plate current will likely also be higher for the same plate voltage swing.

[kagliostro]

Thanks to All

@ VMS

good tube 5W plate dissipation

@ HotBluePlates

You probably want to look for a tube with the highest plate dissipation rating, while having the lowest Mu

what you say has sense, I agree

@ Drgonzonm

thanks for the 8 pin tube indication, but I'm looking for 9 pin tubes (at the moment  )

I think that among 8 pin tubes there are also other triodes rated for much more plate W (I've in stock a pair of NOS JAN-5998 TUNG-SOL - this tubes are rated 13W plate - despite that seems they aren't so friendly to be used as final tubes in a guitar amp)

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=5998

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I've find 3 other 9 pin interesting tubes, also if a bit less powerful than ecc99

the 6CG7 - 5687 - 6840

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=6CG7

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=5687

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=6840

and may be also the russian 6n6p

http://www.mif.pg.gda.pl/homepages/frank/sheets/113/6/6N6P.pdf

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The ecc99 seems really interesting, for the spec and because there is also a current production of this tube

http://www.tube-town.net/info/datenblaetter/tubes/jj/jjecc99.pdf

the datasheet say 4 x ecc99 in PP can give 10W, so a pair will be enough for a little amp

---

if someone has other ideas he is welcome  

Thanks again

K

[jazbo8]

This might be of interest, Tiny Croaker aka MiniAmp 2.0.

Jaz

[kagliostro]

Thanks Jazbo8

that is an interesting link on the matter

lot of links with interesting stuff  there

K

[jojokeo]

12BH7A is close but the ECC99 beats it for sure. Just bias it properly w/ the correct OT & voltage to get the most out of it. It's a very good sounding tube.

[jojokeo]

Just a quick suggestion - don't overthink it. Just decide how much output power you're looking for. Then decide which tube(s) you want to use and how you want to run them. Then look at their max plate & screen voltages/currents/dissipation factors and ballpark an output impedance for the OT. Getting it perfect is not likely or needed. These factors will change depending on certain factors and as long as you're in the ballpark you'll be fine and will need to fine tune voltages & dissipation in the end anyway as it's hard to make exact what the final load and B+ voltage drops will be until you get there. Then you have part tolerances which is only around +/- 20% anyway which is also another reason to ballpark everything first. When the amp is up and running you can fine tune cathode & screen resistors to get as close as you want to max Pdiss or anything else you want that's needed and it'll sound great (or as good as it's going to get anyway).

[kagliostro]

Thanks Jojokeo & Drgonzonm

Now I've some tube to look for at the next Radio Amateur flea market

(11/05/2013 in Marzaglia (MO) Italy - it's a very big international flea market  )

K

[darryl]

...it's a very big international flea market

Even fleas can profit from membership of the EU?  



Back to the topic: The three equivalent types GU-17 or QQE03/12 or 6360 are a twin tetrode in a 9-pin bottle. One of these would fit the specification of push-pull output from a single 9-pin valve. If triode operation was also a critical part of the spec. they could possibly be triode strapped.

http://tubedata.milbert.com/sheets/018/g/GU17.pdf

http://tubezone.net/pdf/6360.pdf

[kagliostro]

Thanks Darryl

Even fleas can profit from membership of the EU ?

There will be someone who has a profit from the EU and the euro  

---

the question was about 9 pin triodes (and relatively low output power)

but to find an usable small tetrode is always interesting

QQE03/12 6360 ...... yes .......... am I correct if I remember you used it in one of your amps ?

Push Pull Class AB2 Amplifier
Plate Voltage .................................         300 V
Grid No. 2 Voltage ............................        250 V
Grid No. 1 Voltage ............................      -21.5 V
Grid No. 1 Current ............................        64 mA
Plate Current (Zero Signal) ...................     30 mA
Plate Current (Maximum Signal) ................  100 mA
Grid No. 2 Current (Zero Signal) ..............    1 mA
Grid No. 2 Current (Maximum Signal) ........... 11.4 mA
Driving Power .................................         0.04 W
Load Resistance ...............................        6.5K Ω
Power Output (approx) .........................     17.5 W

WOW 17.5W from a single very small tube,that is a respectable data

can it be drive from a conventional PI ?

If you used it I'd like to know which B+ and OT primary impedance you used

Thanks

K

[PRR]

> I've in stock a pair of NOS JAN-5998 TUNG-SOL - this tubes are rated 13W plate - despite that seems they aren't so friendly to be used as final tubes in a guitar amp

Pretty rare.

Could make a *good* audio amp. Probably not enough "bark and bite" for a guitar amp. HUGE drive requirement. Assume 325V supply, 50V dropped in 500 ohm common cathode resistor, 8Kpp loading. About 10 Watts but you need *50V* peak grid drive. This can maybe be done with 250V on the driver, but everything has to be just-right, and still driver distortion may exceed final stage distortion.

Twin-tube on 8 pins can be twin-triode or twin-pentode with common cathode and screens.

Triodes: for no grid current (like nearly all audio amps), if Mu is 5 or less, the drive requirements is too large; if 10 or more, it won't pass enough current to be interesting. 6080 Mu=2 is too hard to drive. 6BL7 Mu=15 won't make much power unless you go very high plate voltage and very high load impedance.

There is another mode: drive grids positive, which means large grid current, asymmetric, which means capacitor-coupling won't work. Driver transformers can work; now you want a higher Mu, over 20. But this is pretty heroic stuff, mostly used above 200 watts per pair.

6N7/6A6 is an exception. Before power pentodes, the zero-bias push-pull class B was terrific in the 10 Watt range when power was limited (such as cars). Frank's has 6N7 data with class-A info. This might be an interesting guitar amp, but you need a specialized driver transformer. An AX7 and 6V6-pair will make the same power lighter and cheaper.

> 6360 ... could possibly be triode strapped.

No. G2 is common to both halves.

> WOW 17.5W from a single very small tube,that is a respectable data
> can it be drive from a conventional PI ?

No. The sheet shows 12W out in AB1 (no grid current, conventional driver).

That's under "CCS" rating, broadcast transmitter with long hours of un-interrupted service. Stage amps could run the ICAS rating, but that only allows a little more dissipation. Even if this can all be used, the increase would not be "wow".

Also heat will be a problem.

[DummyLoad]

There will be someone who has a profit from the EU and the euro   

spain and greece!   

--pete

[kagliostro]

Thanks PRR

I always learn something from you

May be, one day, I'll feel me enough skilled to try to use the 5998 tubes for an amp, but I have yet to read many, many posts here in the forum to have enough know-how before I felt ready

---

I swapped the readings on the datasheet and in my previous post I wrote QQE03/12 but posted the data from the 6360 (I corrected the post)

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I've understand what you expained, so it is an usable tube but not so far in output from other 9 pin tubes

Just a curiosity, if I can ask, (odd tube madness  )

one of this QQE03/12 can be used as PI as to drive a QQE04/20 and/or QQE06/40 ?

I know a conventional 12ax7 can be used for this purpose, I'm thinking to an old Italian Davoli amp who used ell80 tube as a Concertina PI or LTPI (in that case triode strapped - I've just read QQE03/12 can't be triode strapped, so I refer at it used as tetrode)


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@ Pete

spain and greece!

you missed Italy  

  In these parts every 15-20 days an unemployed person or a small businessman hangs himself, last one two days ago  

K

[darryl]

> 6360 ... could possibly be triode strapped.

No. G2 is common to both halves.

Oops! I should have considered that... 

Thanks PRR.

...to find an usable small tetrode is always interesting

If you used it I'd like to know which B+ and OT primary impedance you used

I used the GU-17 version of the valve. The B+ was 212 volts, the OT primary was 8kΩ plate-to-plate and the power output was about 4 watts.

The details are here:  http://www.el34world.com/Forum/index.php?topic=12647.0

[kagliostro]

Thanks Darryl

it seemed to me you used something like it or similar tube in the past

Ciao

Franco

[DummyLoad]

you missed Italy 

  In these parts every 15-20 days an unemployed person or a small businessman hangs himself, last one two days ago 

K

that is sad. i did not think things were as bad in italy. my best wishes to to you and your family k.

--pete

[kagliostro]

I'm lucky (but of course I want to see only the half full glass), my wife has a demanding job but safe and my old father receives his pension

in two months from now I would have been entitled to a pension and next year at july I would have to be payed for it, but because of the past caretaker government, the pension will be paid to me only between seven years (and reduced)

since the begin of 2012 I'm one of the 250,000 esodati here in Italy

esodato is a person who the firm where he worked as an employee didn't want to keep more (they want young employee) and with whom he made an agreement as this person remain at home, as not much time is needed to wait for their retirement

in good or bad, this is my fate

Franco

[PRR]

> Doesn't operating these tubes in Class A mode kind of defeat the purpose of push pull?

Cancels much distortion.

[HotBluePlates]

> Doesn't operating these tubes in Class A mode kind of defeat the purpose of push pull?

Cancels much distortion.

And in that process, more than twice the SE power is developed. In some cases, with some tubes, it can even approach 5 times the power of the single-ended condition.

[kagliostro]

Doesn't operating these tubes in Class A mode kind of defeat the purpose of push pull?

Please due to translation problem I'm not able to exactly understand what the phrase  really want to say

can someone repeat the concept with other worlds ?

I apologize for misunderstand

Thanks

K

[DummyLoad]

http://tubedata.milbert.com/sheets/019/6/6158.pdf

http://tubedata.milbert.com/sheets/127/6/6900.pdf

the above seem interesting...

--pete

[kagliostro]

Two interesting tubes Pete

the missile tube has a 4.25W per plate dissipation, notable in his small envelope

Franco

[kagliostro]

A Compactron, you can find other interesting tubes among them

but those are 12 pin tubes not 9 pin tubes

K

[jazbo8]

5687 is a remote cutoff pentode not dual triode. Great preamp tube though...

[kagliostro]

Thanks Drgonzonm

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Jazbo8

May be you confuse the numbers

http://www.r-type.org/exhib/aaa0436.htm

http://www.nj7p.info/Common/Tube/SQL/Tube_query.php?Type=5687

K

[jazbo8]

Yes I did 

[HotBluePlates]

Oops... nevermind.

[kagliostro]

Interesting tube, but, unluckily, very expensive

K

[PRR]

> 13d3 tube 5 watts per triode. 

5W dissipation, but very high plate resistance. I don't see much more than 3 Watt audio output even at absurd conditions.

[kagliostro]

Thanks for the clarification PRR

K