KT 44 anyone tried these

[exurbia]

Has anyone out in DIY land used the KT44 for an amp ? I have come across quite a few of them and their kin.

Are they of any use or should i dump them on ebay.

[Trout]

The KT44 beam tetrode on a B7 base is described for both audio use and television line output service. In the television role the valve can withstand a positive anode surge of 8,000 volts. The KT series are mainly known, however, as audio devices.
The classic envelope is 52 mm in diameter, and excluding the B7 base pins is 130 mm tall.
equivalents ARP26 - CV1340 - CV1437 - CV1576 - VT73 - VT75A


One interesting looking tube!

[anatech]

Hey Gene,
Didn't even know that existed. Cool looking tube.

What's the plate dissipation rated at?

-Chris

[exurbia]

Anode dissipation is ten Watts, this for the 11e3 which is the KT44 equivalent. I have plenty of the 11e3, they are gorgeous and look really lovely when they are lit up.

[exurbia]

P.S The anode structure is open at the sides and allows the aligned grids to be seen.
i will post some pics when i dig the valves out of the box.

They are similar looking to the 12e1 which i use as a triode in a williamson derivative.

[Trout]

The Chart I found has these specs,

Here Is a quad on Ebay,KT44 On Ebay


Web Chart

Absolute Maximum Operating Conditions

Vh......... (4.0)
Ah..........(2.0)
Va..........(250)
VS..........(250)
VG..........(-25)
mAa.......(85)
mAs........(20)
gm..........(6.3)
Pout ......(7.5W)
D............(9%)

Vh =Voltage applied to heater.

Ah =Current rating of heater measured in Amps

Va = Voltage applied to anode. Referenced to cathode regarded as at 0V

Vs =Voltage applied to screen grid. With respect to cathode

Vg =Voltage applied to control grid. With respect to cathode

Vosc =Voltage applied to second control grid in frequency changers

mAa =Current rating of anode circuit measured in milliamps. 1000mA = 1A

mAs =Current rating of screen grid

mAg =Current rating of control grid. This is normally very low.

ra = Anode AC resistance

gm =Mutual conductance. The change of mA of anode current that flows for a 1 volt alteration in g1 volts

rk =Cathode bias resistor

rl =Optimum output load resistance

Pdriv =The input power in Watts required to drive the valve to maximum output

Pout =The number of Watts of output power

Pdiss =The power in Watts that the anode can dissipate

D =Percentage distortion of amplified signal. Audio output valves

freq = The highest frequency in MHz that can be used at maximum output

f.max = The highest frequency in MHz at which that the valve will produce useful power

Gene

[rcavictim]

Dump 'em on ebay and use thr dough to get some common tubes that are easy to get that will sound just as good. Sockets will be a pain to get I suspect.

If you like that look, go with ST bottle vintage 6BG6 (also has a top plate cap). Basically an 807 or 6L6. The 6BG6 also used in early TV horizontal line sweep and audio use..

[Trout]

Originally posted by rcavictim
Dump 'em on ebay and use thr dough to get some common tubes that are easy to get that will sound just as good. Sockets will be a pain to get I suspect.

If you like that look, go with ST bottle vintage 6BG6 (also has a top plate cap). Basically an 807 or 6L6. The 6BG6 also used in early TV horizontal line sweep and audio use..

There are some Pro's & Cons to dumping them on ebay. Chances are they sound fairly good, He has access to them very cheap, And though fairly rare, They do not fetch much on the aftermarket. Common of less know output tubes.

On the other hand,

If you have them, It could make for a couple of generations of listening pleasure without much investing in "Popular" Nos Valves like KT77's,EL34's which can cost 10X these valves.

Then there is the conversation factor on such unusual equipment. Lots of guys head in some way off the beaten path projects and end up with incredible sounding amps.

I personally find it odd that more guys do not use 807's at the current nos price. Pairs for $10.00US on ebay? Compared to some output tubes, Thats a great Price!

AES has sockets for almost every tube made, I have not looked for the sockets, But those could not be the only tubes that used the 7pin base.

OOOooooor,
haha, What he said, Sell Them or trade them, or even better, send them to me for proper disposal.
Trout

[speaker]

Originally posted by Trout
I personally find it odd that more guys do not use 807's at the current nos price. Pairs for $10.00US on ebay? Compared to some output tubes, Thats a great Price!

Yes, that one amazes me too.

The 807 is a great tube by any standard.

So, Shhhhhhhhhhhhhhhhhhhhhhhhh already!

[exurbia]

For sure the 807 is a top item. Sounds good too

The 12e1 is also a little ripper, the 11e3 looks very similar but it has one of those obscure 7 pin pain in the **** BVA bases.

my Williamson derivative originally used 807's and sounded rather nice. I changed to the 12e1 and the sound is even better although the power output has dropped considerably. Now a paltry 16 Watts

This is a great sounding valve, i hope that the 11e3 can be of use as well. It would be nice if such a pretty valve sounded as good as it looked.