That was well worth telling and the substitutes are fascinating.
That rises and interesting point. If DC heaters are to be used a constant current PSU and series connection is an option. If L317 that is one resistor to do the job. It also would allow the LM317 to run cool as long as enough voltage is available for power fluctuations. If sufficient valves are of this type worth a though? I suspect it is as often these valves are cheaper.
I met a man driving a steam locomotive. When I asked had he done it in real life he said yes and no. He trained on steam and past his tests on steam, he never drove steam after that. I am just the same. Studied valves and never touched them in real life. Like him it is now I try my hand at it.
EL & UL 84 if anyone wants to look.
UL84 @ The National Valve Museum
EL84 @ The National Valve Museum
That rises and interesting point. If DC heaters are to be used a constant current PSU and series connection is an option. If L317 that is one resistor to do the job. It also would allow the LM317 to run cool as long as enough voltage is available for power fluctuations. If sufficient valves are of this type worth a though? I suspect it is as often these valves are cheaper.
I met a man driving a steam locomotive. When I asked had he done it in real life he said yes and no. He trained on steam and past his tests on steam, he never drove steam after that. I am just the same. Studied valves and never touched them in real life. Like him it is now I try my hand at it.
EL & UL 84 if anyone wants to look.
UL84 @ The National Valve Museum
EL84 @ The National Valve Museum
Yes, the LM317 works very well as a current regulator in a series heater chain. In my own diy preamp there are four PCC88's per channel in the RIAA phono preamp and also two PCC88's in each of both line stages. I've provided three series heater chains for four valves each, fed from a rough DC voltage of about 32 volts, going into the input pins of three LM317's, whose adjust and output pins are connected by two 8R2 resistors in parallel. No caps are needed. Thus I can draw exactly 0.3 amps of heater current from each of the three adj pins. Take into account that heating up time is enormous (about one minute), but the tubes do benefit from the lack of surge current while powering up the device.
Best regards!
Best regards!
Guys,
I have come into possession of a sh#tload of TV tubes, including the following:
24LQ6/24JE6C
3A3C
10GF7A
5GH8A
12CL3
3CB6
11HM7
2DS4
6CL3
6KD6
1B3/1G3GT
6JQ6/6JE6
6BK4C
...and probably a few other types (I'm too lazy to dig to the bottom of the box).
These are NOS still in the original orange RCA boxes.
Does anyone have any use for these?
I have come into possession of a sh#tload of TV tubes, including the following:
24LQ6/24JE6C
3A3C
10GF7A
5GH8A
12CL3
3CB6
11HM7
2DS4
6CL3
6KD6
1B3/1G3GT
6JQ6/6JE6
6BK4C
...and probably a few other types (I'm too lazy to dig to the bottom of the box).
These are NOS still in the original orange RCA boxes.
Does anyone have any use for these?
Some of those tubes are useless, but some have become quite valuable. The 24LQ6/24JE6C were used in radio frequency linear amplifiers that used as many as 10 or 12 of them and tube life was short. This used up the worlds supply of the tubes driving the prices into the $40+ range. The 6KD6 and 6LQ6/6JE6 also were used in some of these amps, AND make AWESOME audio amps in the 150+ WPC range.
In the US we had primarily 115 volts AC and DC power usually 60 Hz AC but 20 Hz was used in some places. The lower line voltage required higher current tubes. All of the series string line powered radios used 150 mA heaters until the very end of tube radios when a set of 100 mA heaters was introduced.
Common 150 mA octals are 12SA7, 12SJ7, 12SK7, 12SQ7, 35L6, 50L6, 35Z5.
Common 150 mA 7 pin miniatures are 12BE6, 12BA6 12AU6, 12AV6, 12AT6, 35C5, 50C5, 50B5, 35W4
The 100 mA tubes are 18FW6, 18FX6, 18FY6, 32ET5, 36AM3
Early TV tubes were 300 mA, often 12 volt versions of popular 6 volt tubes 12SN7, 12SL7, 12V6....
As TV's got bigger, the power demands went up, so 450 mA heaters were introduced. Color TV's required more tubes, and more power, so 600 mA heaters came out.
I have used the UL84 in a 100 mA series string guitar amp, paired with some American 100 mA tubes. There IS a 100 mA 12AX7. It is the 20EZ7, rather hard to find. The EL84 is a 6BQ5. The EL86 is a 6CW5. Similar tubes, but the 6CW5 has a fine pitch screen grid. Don't feed it more than 200 volts or so.
There is a similar contradiction on our side of the ocean. The 12L6, 17L6, 25L6, 35L6, and 50L6 have no relation to the 6L6. All except the 35L6 are odd voltage versions of the 6W6. The 35L6 is unique.
In the US we had primarily 115 volts AC and DC power usually 60 Hz AC but 20 Hz was used in some places. The lower line voltage required higher current tubes. All of the series string line powered radios used 150 mA heaters until the very end of tube radios when a set of 100 mA heaters was introduced.
Common 150 mA octals are 12SA7, 12SJ7, 12SK7, 12SQ7, 35L6, 50L6, 35Z5.
Common 150 mA 7 pin miniatures are 12BE6, 12BA6 12AU6, 12AV6, 12AT6, 35C5, 50C5, 50B5, 35W4
The 100 mA tubes are 18FW6, 18FX6, 18FY6, 32ET5, 36AM3
Early TV tubes were 300 mA, often 12 volt versions of popular 6 volt tubes 12SN7, 12SL7, 12V6....
As TV's got bigger, the power demands went up, so 450 mA heaters were introduced. Color TV's required more tubes, and more power, so 600 mA heaters came out.
I have used the UL84 in a 100 mA series string guitar amp, paired with some American 100 mA tubes. There IS a 100 mA 12AX7. It is the 20EZ7, rather hard to find. The EL84 is a 6BQ5. The EL86 is a 6CW5. Similar tubes, but the 6CW5 has a fine pitch screen grid. Don't feed it more than 200 volts or so.
There is a similar contradiction on our side of the ocean. The 12L6, 17L6, 25L6, 35L6, and 50L6 have no relation to the 6L6. All except the 35L6 are odd voltage versions of the 6W6. The 35L6 is unique.
Hi poynt99,
these tubes are of some interest to me. What's your quantities? Would you like to ship them to Germany? Please send me PM, including your price. Thanks!
Quite right! EL86/6CW5/PL84/15CW5/UL84 are rather interesting little AF power tubes. Due to their less screen/grid amplifcation factor, one can draw much more AF power from one pair, compared to EL84/6BQ5's. The Mullard datasheet reads 25 watts well within the specs. Now remember that in Europe the PL84 was used also as a b-w TV frame deflection amp with plate voltage spikes up to 1.5 kV, so I wouldn't mind to feed the plates from 350 - 400 volts. Suddenly nearly 50 watts are possible, without stressing all the other maximum specs. But don't ever exceed 200 volts screen voltage!
Best regards!
30FL1 @ The National Valve Museum
Was this device ever used as an audio device? My brother supplied the data here.
Was this device ever used as an audio device? My brother supplied the data here.
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A typical AB1 push pull amp runs about 60% efficiency. The maximum plate dissipation for a pair of 6CW5's is 24 watts. That would put the rated maximum output power at about 36 watts. You should be able to get more power for brief peaks, but I haven't seen over 35 watts in G1 drive. Screen drive experiments are coming.
I have obtained about 32 watts at clipping in a Tubelab SPP board with 420 volts plate, 175 volts screen, and a 3300 ohm load using cathode bias. That amp is still alive after about 5 years of intermittent guitar amp use with the same set of tubes....which were pulled out of a scrap Hewlett Packard audio oscillator.
The isolation transformer powered guitar amp I built uses UL84's running from a 320 volt plate supply and a 160 volt screen supply. The OPT is a surplus mains toroid which should give a load of about 3000 ohms. I get 25 watts from this amp.
The real surprise is the 13GB5/XL500. I can get 150 watts for short periods of time, and 100 watts continuously from these tubes.
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I like the 12cl3 and 6cl3 both fine diodes about 250ma for the 6cl3 . How many of each do you have ?
About 15 years ago Antique marked their 42KN6's down to $1.50 each. I called them up and bought all 200 of them. Peak Cathode Current 1500 mA. Basically no need for tapped secondary on the output transformer; solid state amplifier convenenience because of that huge current capacity. And in Enhanced Triode Mode these are fierce. A pair will do 150 watts with 400 volts on the plates. They love the voltage doubler type of power supply; the screens want to be at half the plate voltage. They have that tight bass like solid state amps; again that current capacity is able to handle the lower impedance that the output xfmr primary has at lower frequency. So with good Acrosound iron running with the 16-ohm tap into 8-Ohm speakers the 42kn6's have that tight flat solid state sound. Nevertheless the 42KN6's let you know that they are indeed thermionic devices.
There are two kinds of "KN6's. There is the version with one large sweep tube inside. They are the only kind that works in RF amplifier applications, so they have become rare and expensive.
The other kind has TWO small sweep tubes inside the envelope that are wired in parallel. I have found these cheap if the seller knows the difference. I think that these may have the best peak current and saturation voltage characteristics in audio applications. I have tried both kinds of 6KN6's in the same amp.
The dynamic characteristics you speak of are common to all of the big sweep tubes that have high peak current capability, 6LR6, 6LW6, 6KD6, 6KN6, 6LX6....
650 volts and 3300 ohms gets you almost 200 watts.
650 volts and 2500 ohms gets you 250 watts.
650 volts, 4 tubes and 1250 ohms gets you 500 watts of woofer thumping tube amp power.
The other kind has TWO small sweep tubes inside the envelope that are wired in parallel. I have found these cheap if the seller knows the difference. I think that these may have the best peak current and saturation voltage characteristics in audio applications. I have tried both kinds of 6KN6's in the same amp.
The dynamic characteristics you speak of are common to all of the big sweep tubes that have high peak current capability, 6LR6, 6LW6, 6KD6, 6KN6, 6LX6....
650 volts and 3300 ohms gets you almost 200 watts.
650 volts and 2500 ohms gets you 250 watts.
650 volts, 4 tubes and 1250 ohms gets you 500 watts of woofer thumping tube amp power.
The pentode guts in the 12HE7 appears to be the half of the doubled up -KN6 tube. (it's wattage is reduced to 10 Watts due to the damper diode in the same bottle, should be good for 15 Watts without the damper operating)
An RCA memo later says to replace the doubled -KN6 guts with a single 6KD6.
The 12HE7 pentode also appears to be a cut down (smaller plate size) version of the 6HB5/21HB5 (18 Watt). The 6HB5/21HB5 have an unusually big plate though for an 18 Watt tube, same size as some of the 24 Watt tubes.
An RCA memo later says to replace the doubled -KN6 guts with a single 6KD6.
The 12HE7 pentode also appears to be a cut down (smaller plate size) version of the 6HB5/21HB5 (18 Watt). The 6HB5/21HB5 have an unusually big plate though for an 18 Watt tube, same size as some of the 24 Watt tubes.
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I got BOTH kinds (double and singles) The doubles are OG Transylvania; I have lots of the RCA and GE sleeves; as well as Sylvania; some of those are singles tho. I also have a pair of Cincinatti amps that I upgraded to MC75 topology; currently a quad of 6550s reside in it. Dual output secondaries but 16 Ohms when paralleled. Hmmm...
12EN6 looks to be very similar to 12L6 or 12W6 tubes.
http://www.diyaudio.com/forums/tube...nificent-television-tubes-17.html#post3861718
http://frank.pocnet.net/sheets/127/1/12EN6.pdf
http://frank.pocnet.net/sheets/127/1/12W6GT.pdf
http://frank.pocnet.net/sheets/127/1/12L6GT.pdf
http://frank.pocnet.net/sheets/093/2/25L6GT.pdf
http://frank.pocnet.net/sheets/093/6/6W6GT.pdf
http://www.diyaudio.com/forums/tube...nificent-television-tubes-17.html#post3861718
http://frank.pocnet.net/sheets/127/1/12EN6.pdf
http://frank.pocnet.net/sheets/127/1/12W6GT.pdf
http://frank.pocnet.net/sheets/127/1/12L6GT.pdf
http://frank.pocnet.net/sheets/093/2/25L6GT.pdf
http://frank.pocnet.net/sheets/093/6/6W6GT.pdf
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Thanks Smoking-amp...
So OPT should have 4K for PP and maybe 2k for PP parallel...At 250V B+ /60 ma bias PPP what max audio power I can squeeze from these sleepers?
I know that sweep tubes are mostly underrated, so they can deliver more power than specified..
I also have those 12L6GT but only 4 pcs....and seem operate in lower B+.
It seems that octals or other big bottles sound better to me...
So OPT should have 4K for PP and maybe 2k for PP parallel...At 250V B+ /60 ma bias PPP what max audio power I can squeeze from these sleepers?
I know that sweep tubes are mostly underrated, so they can deliver more power than specified..
I also have those 12L6GT but only 4 pcs....and seem operate in lower B+.
It seems that octals or other big bottles sound better to me...