Page 1. Page 2. Page 3. Page 4. Page 5. Page 6. Page 7. Page 8. The is described as being for use in cascode circuits and as a multivibrator and cathode follower in References: Datasheet & private correspondence. E88CC-TK TUBE DATA SHEET. Mechanical. Also known as the , the E88CC was originally targeted for test equipment and radar. The E88CC has.
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However, there are extenuating circumstances involving heavy plate current and increased frequencies into the high MHz, and depending upon the tube, in which transit time becomes a problem. As far as sections not matching, let’s check out the variables. I ran a test using a used EH tube. Rp is plate resistance of a tube section, triode, tetrode, pentode etc. There is no problem supplying 6. As one parameter changes, the other two as well, although it is possible for two parameters to change and the third to remain constant.
In the datashet below is biased by applying a bias voltage to the grid via R2.
The maximum allowable cathode current for the tube is mA. Exceeding the Va and Va b limits usually results daatasheet destruction of the tube.
I hope I understood and properly answered your question s Jim. Jim My apologies to the OP for getting off topic. Could you please explain why? Non-linearity is particularly profound close to the Volt point. However, I have seen hundreds, if not thousands of RCA and other brand 6dj8s that were under high stress that measured nice specs after years and thousands of hours of use.
Note, not so for the VT mrk 3 amp, different circuitry. AC Yes but it is well within the context of the thread. I think I understand the reason why when looking at the VT50 circuit design of the driver tube.
For the test a Hickok a tube tester was used. Slightly different spacing between each turn of wire. They are maximum anode voltage Datasheey and Va b. It seems to support Brent Jesse’s and Kevin’s position that 7DJ8 tube life could be longer at the lower heater voltage, but Dataheet and E55’s contention that it’s not good practice are supported as well.
Let’s keep it simple. ACHiPo on 27 Jan Moreover, some of this vapour tends to deposit on the grid and give rise to what is known as grid emission when the grid itself emits electrons and draws current commonly known as negative grid current Let’s just consider the triode, and keep things simple for ease in understanding. The cathode material may not be homogeneous across the nickel support. The final limitation is the maximum allowable cathode current Ic.
The region around Volt point is called cut-off point.
The Va b is the maximum voltage to which ‘s anode is allowed to swing under signal or cold conditions and is about VDC for the E55l2 on 25 Jan So, where does close matching of GM come into play? Steve on 27 Jan As far as transconductance being reduced, reduced transconductance will increase the plate resistance, thus lowering the high frequency response.
The lower the plate current, the less the cathode is cooled by electrons leaving. They are the special long life h versions of the normal range they make. Mu amplification factor is the change in plate to cathode voltage with a change in grid to cathode voltage,, with constant plate current. Designing a circuit to operate around the cut-off point is not advisable if a good linearity of an amplifier is required.
, et al Burn-in?
The cathode material may be slightly warped, thus the relationship between each cathode to grid and plate may be slightly different. ACHiPo on 17 Jan For what it’s worth there is a tube life test that can be preformed on a used tube where the filament voltage is decreased in the same manner as I did in my test above.
One matched pair low noise per channel. Steve on 25 Jandahasheet If we keep the plate to cathode voltage constant, and alter the grid to cathode voltage, the plate current will change. So datashset won’t count on a very long datashewt for a normal tube. ACHiPo on 15 Jan Not a lot better than before I replaced its 15 year old tubes. By the way, Telefunken was known for gettinghours on their 12ax7 “family” under typical conditions.
You can read some reviews of one of my poor designs here. However, over the years I have not keep a time clock on tubes hours. Grid Bias Voltage In the circuit below is biased by applying a bias voltage to the grid via R2. With a constant grid to cathode voltage, if we change the plate to cathode voltage, the plate current will change. Mu amplification factor is theoretical gain. In Europe, where i 6292, the equivalent for an is the E88CC.
The filament itself may have hot spots, thus heating certain portions of the cathode more than other portions. I think this equation will help.