Higher line voltage will cause plate & screen to also be more. Over time tubes lose some emission and draw less current. This will also cause voltage to be higher.
Not a problem unless you exceed tube or cap ratings. A 6F6 can operate on higher voltage but you might check that others don't exceed a tube manual?
Norm
:Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
:
:Hi Brian
:
: Higher line voltage will cause plate & screen to also be more. Over time tubes lose some emission and draw less current. This will also cause voltage to be higher.
:
: Not a problem unless you exceed tube or cap ratings. A 6F6 can operate on higher voltage but you might check that others don't exceed a tube manual?
:
:Norm
:
::Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
::
:
:
Not a problem with 6SQ7 or 5Y3. For 6SA7 and 6SK7 check with a tube manual and mesure actual voltage. These tubes have an operating plate rating of 250 volts. Up to 300 volts is allowed. See manual:
http://frank.pocnet.net/sheets/127/6/6SK7.pdf
Norm
:The other tubes are 6SK7 (RF), 6SA7, 6SK7, 6SQ7, and the 5Y3. These tubes should handle the higher voltage OK?
:
::Hi Brian
::
:: Higher line voltage will cause plate & screen to also be more. Over time tubes lose some emission and draw less current. This will also cause voltage to be higher.
::
:: Not a problem unless you exceed tube or cap ratings. A 6F6 can operate on higher voltage but you might check that others don't exceed a tube manual?
::
::Norm
::
:::Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
:::
::
::
:
:
:Brian
:
: Not a problem with 6SQ7 or 5Y3. For 6SA7 and 6SK7 check with a tube manual and mesure actual voltage. These tubes have an operating plate rating of 250 volts. Up to 300 volts is allowed. See manual:
:
:http://frank.pocnet.net/sheets/127/6/6SK7.pdf
:
:Norm
:
::The other tubes are 6SK7 (RF), 6SA7, 6SK7, 6SQ7, and the 5Y3. These tubes should handle the higher voltage OK?
::
:::Hi Brian
:::
::: Higher line voltage will cause plate & screen to also be more. Over time tubes lose some emission and draw less current. This will also cause voltage to be higher.
:::
::: Not a problem unless you exceed tube or cap ratings. A 6F6 can operate on higher voltage but you might check that others don't exceed a tube manual?
:::
:::Norm
:::
::::Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
::::
:::
:::
::
::
:
:
That is confusing. Screen voltage is actual seen at the tube. Screen supply will be through a resistor dropping voltage to the screen. If possible keep actual screen voltage 100 or less. A lot higher and the screen could start glowing red.
Norm
:thanks Norm.
:In some manuals there is a distinction under Maximum Ratings referring to screen supply voltage - 300 and screen voltage - 100. How does this apply to my case?
:
::Brian
::
:: Not a problem with 6SQ7 or 5Y3. For 6SA7 and 6SK7 check with a tube manual and mesure actual voltage. These tubes have an operating plate rating of 250 volts. Up to 300 volts is allowed. See manual:
::
::http://frank.pocnet.net/sheets/127/6/6SK7.pdf
::
::Norm
::
:::The other tubes are 6SK7 (RF), 6SA7, 6SK7, 6SQ7, and the 5Y3. These tubes should handle the higher voltage OK?
:::
::::Hi Brian
::::
:::: Higher line voltage will cause plate & screen to also be more. Over time tubes lose some emission and draw less current. This will also cause voltage to be higher.
::::
:::: Not a problem unless you exceed tube or cap ratings. A 6F6 can operate on higher voltage but you might check that others don't exceed a tube manual?
::::
::::Norm
::::
:::::Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
:::::
::::
::::
:::
:::
::
::
:
:
:Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
:
Using a modern voltmeter to measure plate and screen voltages will probably always show higher voltages than those indicated in an antique schematic. Reason: The older voltmeters were around 1000 ohms/volt and loaded the circuit more, thus showing lower voltages. Using a modern 20,000 ohms/volt meter results in more accurate readings.
Lou
:Finally putting my Canadian RCA A24 back together, noticing the voltages are running about 40 volts higher, particularly on the screen and plate of the 6F6G output tube. All other tubes running a bit higher as well. With all new capacitors and higher line voltage, and using a digital multimeter, is this acceptable? Schematic calls for 232 and 250 on plate and screen respectively.
: