iron from an ECLL800 amp

[birt]

I've been looking to reuse the iron of a PP ECL800 amp. (a single tube with triode PI and 2 pentodes for about 9W PP)
the datasheet of the tube tells me it uses a 11K OT but i'm not sure if that is for 1 pentode or for 2.
it's probably very obvious but i'm a bit confused here.


what output tube options do i have when i use my transformers in a new project? (and maybe some extra heater juice)
i was thinking maybe ECL80 in PP?

[Ed_Chambley]

I read on the Lorenz data sheet Ra-a is 10K at 250VDC.  I would think if you are running voltages ~300VDC, this would open up lots of possible tubes.  It was common for Hammond (Organ Company) to use 6v6 with 10K to  the 8ohms.  Also Zenith used EL84's with a 10K primary for their consumer console amps.  I am not 100% sure. but I think the tube is the same as ECL80 with a internal driver.

Compactron tube with a driver and 2 Output Pentodes. I believe you would have plenty of options.  Check out page 42 of this: http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1964-07.pdf

I believe it will give you all the info you would want to know about the use of the ECLL800 since it is a build using the tube and you can get all the specs.

[kagliostro]

You can use the OT with a pair of EL95 tubes in PP


the EL95 is the single pentode vorsion of ELL80 (2 x pentode tube), the ECLL80, if I remember correctly, is an ELL80 plus a triode


Franco

[birt]

You can use the OT with a pair of EL95 tubes in PP


the EL95 is the single pentode vorsion of ELL80 (2 x pentode tube), the ECLL80, if I remember correctly, is an ELL80 plus a triode


Franco

well i thought so as well but i can't find confirmation anywhere that the pentodes of ELL80 and ECLL800 are the same.

[kagliostro]

On this datasheet you can see the ECLL800 tube in PP at 250v class AB need a 11k aa OT for 8.5W output

http://tdsl.duncanamps.com/link.php?target=C8259F25

On this datasheet you can see the ELL80 tube  in PP at 250v class AB need a 11k aa OT for 8.5W output

http://tdsl.duncanamps.com/link.php?target=0025A2EE

On this datasheet you can see the ECLL80 tube in PP at 250v class AB need a 11k aa OT for 8.5W output

http://tdsl.duncanamps.com/link.php?target=C8259F25

On this datasheet you can see the EL95 tube in PP at 250v class AB need a 10k aa OT for 7W output

http://tdsl.duncanamps.com/link.php?target=2C259BDC

Not exactly the same performance and OT request but very similar to the ELL80 & ECLL80

Also a pair of 6AQ5 tubes can be used with that OT

http://tdsl.duncanamps.com/link.php?target=09259DBB

Franco


p.s.: I forgot, give a control to the OT you recovered to define the effective primary impedance

[PRR]

ECLL800 makes no sense except as a push-pull amp.

The sheet suggests 250V at 10K or 11K load.

Since ECLL800 is unobtainable now, but the iron survives, you want a tube(s) to suit. 6V6, EL84 are suitable. Bigger than you need for 9 Watts/pair, but readily available and won't be strained.

> confirmation anywhere that the pentodes of ELL80 and ECLL800 are the same.

They are probably very similar. Philips rang-up multiple variants on the same guts with different gain factors. But the main thing is: tubes is tubes. If it is generally "the same size of a dog", it can be made to work. Sending a beagle to do a corgi's work, that's more dog than you need, but a beagle can turn a corgi's dog-wheel.

6V6 has a sheet condition for about 250V and 10K load; 10K, 11K, who can tell?

EL84 does not bother with 250V 10K, but suggests 8K. Worked into 10K-11K it will give 72%-80% of sheet power, and you can run the bias 20% colder to save heat.

[DummyLoad]

ECLL80 is close to 6BM8/ECL82. i'd use those. ECLL80 is 6W plate diss. 6BM8/ECL82 is 7W.

something else to consider: what wire gauge was used in those transformers? will they handle current of P-P 6V6/EL84 at 300V?

just my 2cents...

--pete

[birt]

ECL82 looks like a good choice. i'll have to add some more heater current but that's ok.
i looked at a datasheet and it seems ok with 10K as well.

[birt]

still looking at the ECL80 as well since i have a bunch of those and the heater current is just 300mA.
i can get about 3W PP and it should work well with the OT i have. this will make it a very low watt amp though.

[DummyLoad]

another suggestion:
use a pair of EL95/6DL5: they're still relatively inexpensive and available NOS. a pair come in at 400mA heater draw and within required total heater budget of a single ECLL800 which is 600mA. for the driver, use a sub-miniature 5719 or a 7 pin miniature 6AB4 single triode for phase inverter and you're total system heater draw is under budget by 50mA.

spec-wise the EL95 are about a very close match to the ECLL800 power pentodes. S is 5mA/V on EL95 and is 6 mA/V for ECLL80; Pdiss is 6W for both.

if you look at the spec sheet for the ECLL800, the triode has a very low mu: 1.2. i think the triode was meant to be used as a split-load (cathodyne/concertina) phase inverter.

--pete

[kagliostro]

I agree with Pete

a tube you can use as pre is a 6ak5 (filament 175mA) or an ef86 (filament 200mA) or a 5879 only 150mA for filament

if you have not enough current for the heaters to supply a PI you can think to build a PP section without PI if you are comfortable with a low power output

(give a look to the link)

https://www.ampbooks.com/mobile/amp-technology/6L6-phase-inverter/

Franco


p.s.: I assumed you have 600 mA of current available for the heaters ..... but ... is so or you have more ??

[birt]

the amp has an ECLL800, 12AX7 and EZ81. but heater current is no problem at all, i can add a little 6V transformer.


the reason i wasn't looking at the EL93 (which is the logical first option) is because i don't have any.
i do have loads of ecl80 and some ecl82. for the preamp i'll try something with another tube i have in abundance, like ECF83 or ECF80 for example :-)

[DummyLoad]

>>> p.s.: I assumed you have 600 mA of current available for the heaters ..... but ... is so or you have more ??

i assumed he wanted to replace the same number of components with available parts and remain within the allotted 600mA heater draw for the three components. i had a hunch there were more gain stages since the one bottle is not necessarily a complete amplifier.

>>> the reason i wasn't looking at the EL93...

is there such a tube? i can't seem to find data on an EL93.... link?

--pete

[kagliostro]

I think he mean EL95 ....

With the ecl82 you have many options

Gibson GA8T


Univox U45B


Watkins Westmister


And others

Franco

[birt]

>>> p.s.: I assumed you have 600 mA of current available for the heaters ..... but ... is so or you have more ??

i assumed he wanted to replace the same number of components with available parts and remain within the allotted 600mA heater draw for the three components. i had a hunch there were more gain stages since the one bottle is not necessarily a complete amplifier.

>>> the reason i wasn't looking at the EL93...

is there such a tube? i can't seem to find data on an EL93.... link?

--pete

sorry EL95 :-)

[PRR]

> ECLL800, the triode has a very low mu: 1.2. i think the triode was meant to be used as a split-load (cathodyne/concertina) phase inverter.

No, that would give significantly unbalanced outputs.

If you just wire it as a "voltage amplifier", the mu of 1.2 degrades to effective gain very close to ONE. Negative one counting polarity. So if you have a driver and one power pentode, want a PP output, this tacks-in, taps the existing drive, inverts it, and drives the second power pentode.
http://www.radiomuseum.org/images/tubeenvdiag_klein/ecll800.png

In fact, Tg1 is hard wired to P1g1. And all three cathodes are common. And triode Gm is very tiny. There's hardly any choice. (Nor any reason you should know this; it is a very odd obscure duck.)

But all moot because ECLL800 is too valuable to play with.

And if you are not up-marketing your 1958 Radio 500 into a new/improved for 1959 Radio 600, you can find better ways to do a push-pull output.

[kagliostro]

I've just find this Hagstrom mod 310 schematic


an ECLL800 guitar amp, I post it just for connoissance






 
Hangtrom has build also other amps for guitar and bass with the ECLL800 tube







Franco