It looks to be a solid state replacement of the original vacuum tube. “Heater” current specified at 0.7 mA DC with mandatory polarity. I wonder what the internal circuit may be.
LND150? I have played around with this transistor as it approximates a 12AX7...but in a guitar ahmp...never played much with it on a home amp...
Imagine if someone could do it. How in the heck is a small company even going to make the grids for this spec. Refer to vinyl savor. I think he said 1 tenth a human hair, 20 perfect turns per mm.
The meaning of "a substitute" is stretched to the max. From the site:
"The Phædrus Audio EC8020-pH electronic Supertube™ is designed to fulfil the role of very low-noise preamplifier tube and may be regarded as a substitute for any of the tubes given in the table; although the pinout and transconductance value follow the EC8020."
The anode dissipation of the tubes in the table range from 4.2 to 8 Watt. The 'anode' dissipation of the EC8020-ph is only 1 Watt. Ofcourse 1 Watt is enough for many preamp applications, but that doesn't make it 'a substitute' yet.
"The Phædrus Audio EC8020-pH electronic Supertube™ is designed to fulfil the role of very low-noise preamplifier tube and may be regarded as a substitute for any of the tubes given in the table; although the pinout and transconductance value follow the EC8020."
The anode dissipation of the tubes in the table range from 4.2 to 8 Watt. The 'anode' dissipation of the EC8020-ph is only 1 Watt. Ofcourse 1 Watt is enough for many preamp applications, but that doesn't make it 'a substitute' yet.
The part about noise completely neglects 1/f noise, which is usually far from negligible for valves at audio frequencies, and for a given valve type, tends to get worse at higher anode currents.
They claim that their device, whatever it may be, has a subsonic 1/f corner frequency and a very small anode to grid capacitance. Very low noise JFET with a cascode on top? Then again, JFETs usually have 1/f corners in the audible range. Built-in gate stopper resistor that increases the white noise a bit and thereby lowers the 1/f corner frequency?
They claim that their device, whatever it may be, has a subsonic 1/f corner frequency and a very small anode to grid capacitance. Very low noise JFET with a cascode on top? Then again, JFETs usually have 1/f corners in the audible range. Built-in gate stopper resistor that increases the white noise a bit and thereby lowers the 1/f corner frequency?
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I find it VERY misleading and in bad faith calling it EC8020 and all that chatter about 12A*7 tubes, grid spacing, etc. when it´s OBVIOUSLY a SS device.
They should show it as-is and compete on their own merit , not stolen one.
IF there is any sealed in vacuum glass bottle there, and glowing red hot filaments inside that , then show it.
Of course, nothing of the kind and their repeated use of the word "Tubes" is a fraud, plain and simple.
Not minor detail: NO CURVES in the so called "datasheet".
They even show a GLASS miniature tube in the "dimensions" statement.😡 😡 😡
7788 E810F
The 7788 (50 mA/V) was used in all the HP 1402A plug ins used in the 140 Series scopes. 20 MHz Dual Channel in a small (?) scope circa 1968. They were very popular.
http://hparchive.com/Brochures/HP-140A-Brochure.pdf
The 7788 (50 mA/V) was used in all the HP 1402A plug ins used in the 140 Series scopes. 20 MHz Dual Channel in a small (?) scope circa 1968. They were very popular.
http://hparchive.com/Brochures/HP-140A-Brochure.pdf