I found this this article fascinating. Didn’t know the C3G was the first to use a clamping grid and was the first in a series of great tubes. Translated to English.
https://www-jogis--roehrenbude-de.t...milie.htm?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en
https://www-jogis--roehrenbude-de.t...milie.htm?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en
Need to visit this site later when at home again. But what I know for sure from an article in the German magazine FUNKSCHAU #4, 1957, is the PCC88 was introduced that year to replace the SQ tube E88CC which had appeared in TV frontends the year before. PCC88 can be regarded as successor of the E88CC, aimed at the consumer market. In fact and besides the SQ properties and heater power requirements, E88CC and PCC88 are the same tubes.
Best regards!
Best regards!
Perhaps they "flashed" a bit too bright when first turned on, in a series arrangement
I have many PCC88 (Tungsram) and E88CC (various: Tungsram, Mullard, Telefunken, Valvo, etc.). I tested them for noise and distortion in the line stage of my preamplifier, actually an SRPP stage. Then I shortlisted the E88CC tubes as generally lower noise and THD.
I have the ones with blue/ red box
Two shape of internal elements
Need some selection but are fine
So did I: my proof is that the Philips datasheet for the ECC88 has the curves designated as PCC88. So they sid not mind to make a new set, it is the same tube (safe for the filament current).
I have a question. The ECC88 is always defined as being designed for cascode use.
So one section has a higher Vfk.
And one section is the designated input.
Now i once read that the output section has a sort of beam forming plate, or a slight bend in some metal near the anode. - due to the fact that the top section sees more voltage (swing) ?
Can anyone corroborate or invalidate this?
If true, it must have had to do with some initial use case, where the ECC88 provides better service (Noise? Distortion?) than for example the EF86 at very high frequencies.
So one section has a higher Vfk.
And one section is the designated input.
Now i once read that the output section has a sort of beam forming plate, or a slight bend in some metal near the anode. - due to the fact that the top section sees more voltage (swing) ?
Can anyone corroborate or invalidate this?
If true, it must have had to do with some initial use case, where the ECC88 provides better service (Noise? Distortion?) than for example the EF86 at very high frequencies.
I don't see that difference in Vfk rating in this E88CC datasheet http://www.r-type.org/pdfs/e88cc.pdf Then again, the E88CC was meant for more than just cascode circuits in televisions. Besides, it's a datasheet from 1968, so not the original from the late 1950's. The two parts sometimes have 0.1 pF different capacitances.
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@triode_al: Besides the heaters, ECC88 and PCC88 are the same tube. Their »mother«, the E88CC, is another, a SQ one.
Wrt beam forming plates: Perhaps you're confusing with ECC2000? The xx88's don't feature them.
Best regards!
Wrt beam forming plates: Perhaps you're confusing with ECC2000? The xx88's don't feature them.
Best regards!
And another thought.
A “constant voltage”, Vfil tube (=6.3) is in structure of the filament in the heating tube of the cathode quite different from one with a “constant current” drive, Ifil. (=300mA). They will heat up differently for sure.
I like to add that the Philips repeater tubes have a constant current drive, where for longlivety the current may not deviate less than some percent or so.
Take the E180F, the deviation of this 300mA tube is max 15mA; I have a Philips repeater tube where the allowed deviation is less if one wants to get 20 years of continous !!! use with only a 8% loss in transmission S.
A “constant voltage”, Vfil tube (=6.3) is in structure of the filament in the heating tube of the cathode quite different from one with a “constant current” drive, Ifil. (=300mA). They will heat up differently for sure.
I like to add that the Philips repeater tubes have a constant current drive, where for longlivety the current may not deviate less than some percent or so.
Take the E180F, the deviation of this 300mA tube is max 15mA; I have a Philips repeater tube where the allowed deviation is less if one wants to get 20 years of continous !!! use with only a 8% loss in transmission S.