Hi,
New member here. Just a quick thread to see if any members had TV7 tube testers. I specifically need the data setting for a TV7 for a EC88/6DL4/6522/8255/E88C triode tube. The EC88/DL4 is not related in any way to a ECC88/6DJ8. I just acquired a quad of these made in the early 1960's by Amperex and they need to be tested. I've downloaded all the addendum updates for the TV7 series including Nolan Lee's and this tube is not listed in any of the documentation under all 5 of these tube type designations.
Would greatly appreciate any members feedback,
thank you in advance!
jim
New member here. Just a quick thread to see if any members had TV7 tube testers. I specifically need the data setting for a TV7 for a EC88/6DL4/6522/8255/E88C triode tube. The EC88/DL4 is not related in any way to a ECC88/6DJ8. I just acquired a quad of these made in the early 1960's by Amperex and they need to be tested. I've downloaded all the addendum updates for the TV7 series including Nolan Lee's and this tube is not listed in any of the documentation under all 5 of these tube type designations.
Would greatly appreciate any members feedback,
thank you in advance!
jim
I have no experience with a TV7 (only with AVO testers) but looking at the datasheets for the EC88 and the EC86, I think they are very close to each other electrically, just other pinout (and differences in interelectrode capacitances but those are not important when tube testing).
But there must be other forum members who faced to same problem as you now do.
But there must be other forum members who faced to same problem as you now do.
EC88 was used in UK TV,s in the RF tuner section ---I have changed plenty of them its interchangeable ( for testing ) with the E88C but the 8255 is not pin identical ( for testing ) .
I would agree with PCL200 in cases like this small capacitance variations wont matter when testing in a tube tester .
The tube wasn't meant for audio and you can get a much lower noise factor from others of the same type it is also meant for UHF and the multiple grid connections were specially connected together and required a different layout to normal ( like a ground plane ) so the that HF oscillation was avoided as the Frame-Grid tube had a very high Mu ---not ideal for general audio use----IMO.
I just remembered even if the grids were all connected together each required its own small value ceramic capacitor for stability.
I would agree with PCL200 in cases like this small capacitance variations wont matter when testing in a tube tester .
The tube wasn't meant for audio and you can get a much lower noise factor from others of the same type it is also meant for UHF and the multiple grid connections were specially connected together and required a different layout to normal ( like a ground plane ) so the that HF oscillation was avoided as the Frame-Grid tube had a very high Mu ---not ideal for general audio use----IMO.
I just remembered even if the grids were all connected together each required its own small value ceramic capacitor for stability.
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Hi new member,
This is the 6 V version of the PC88. It is an UHF preamplifier used in grounded grid configuration. I concur with duncan2 that its use in audio is not optimal. I actually tried it as grounded grid amplifier for MC elements but found it much noisier than its mixer cousin PC86. Both were much noisier than solid state amps.
This is the 6 V version of the PC88. It is an UHF preamplifier used in grounded grid configuration. I concur with duncan2 that its use in audio is not optimal. I actually tried it as grounded grid amplifier for MC elements but found it much noisier than its mixer cousin PC86. Both were much noisier than solid state amps.
EC88 has a 6.3V heater and the PC88 has a 3.8V heater but is identical otherwise. The TV-7 settings for the PC88 are:
SELECTOR: ET1-8020
BIAS: 15
RANGE: D
MIN VALUE: 50
REMARKS: Set line test = 54
The closest heater voltage on the TV-7 is 4.3 volts. Setting the line test to 54 reduces the heater voltage nearer to 3.8 volts that the PC88 requires. To test a EC88, set the heater voltage to 6.3 volts and do not set the line test to 54 but set it as normal.
SELECTOR: ET1-8020
BIAS: 15
RANGE: D
MIN VALUE: 50
REMARKS: Set line test = 54
The closest heater voltage on the TV-7 is 4.3 volts. Setting the line test to 54 reduces the heater voltage nearer to 3.8 volts that the PC88 requires. To test a EC88, set the heater voltage to 6.3 volts and do not set the line test to 54 but set it as normal.
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After thinking about the data I posted in the previous message, I am not sure the selector setting is correct. The data came from Nolan Lee's spreadsheet. The first two letters set the filament connection. ET is often correct for 7 pin tubes but 9 pin tubes are more often EV instead.
Set the selector to ET0-0000 and see if the filament lights up. If not try EV0-0000. If that works, then use EV1-8020 to test the tube.
Set the selector to ET0-0000 and see if the filament lights up. If not try EV0-0000. If that works, then use EV1-8020 to test the tube.
Thank you all (Robert PCL200, Duncan2 & Regenpak ) for your kind replies and Time!
Quality observations taken - "not the best tube/valve choice for audio consideration"...
Thank you Bill_P !.. I will try the setting now and let you know....
kindest regards to all, Jim
Quality observations taken - "not the best tube/valve choice for audio consideration"...
Thank you Bill_P !.. I will try the setting now and let you know....
kindest regards to all, Jim
Thank you Bill_P and members for your kind replies and time!,
Bill_P your 2nd post (observation) is correct and worked,
>"Set the selector to ET0-0000 and see if the filament lights up. " (It doesn't)
>"If not try EV0-0000." (It does!)
So The correct TV7 setting for an EC88/6DL4(Vf 6.3 Volts/If 0.165 Ampere/ and also for I believe the (E88C/8562=Vf 6.3 Volts / If 0.155 Ampere) Tube/Valve.
Correct TV7 settings are:
SELECTOR: EV1-8020
BIAS: 15
RANGE: D
MIN VALUE: 50
REMARKS: Set line test to normal setting (i.e. straight up 12 O'clock to 60)
So issue solved!
fyi, All 4 Amperex EC88/6DL4's tested excellent gM & mA with these settings.
thank you again, kindest regards, Jim
Bill_P your 2nd post (observation) is correct and worked,
>"Set the selector to ET0-0000 and see if the filament lights up. " (It doesn't)
>"If not try EV0-0000." (It does!)
So The correct TV7 setting for an EC88/6DL4(Vf 6.3 Volts/If 0.165 Ampere/ and also for I believe the (E88C/8562=Vf 6.3 Volts / If 0.155 Ampere) Tube/Valve.
Correct TV7 settings are:
SELECTOR: EV1-8020
BIAS: 15
RANGE: D
MIN VALUE: 50
REMARKS: Set line test to normal setting (i.e. straight up 12 O'clock to 60)
So issue solved!
fyi, All 4 Amperex EC88/6DL4's tested excellent gM & mA with these settings.
thank you again, kindest regards, Jim