ECC802S 12AU7 ECC82 heater question

korabetsni · 12th October 2011, 11:48 AM

hello,
i wanna ask how to connect the ecc82s heater.The pins 4, 5 and 9 are the heaters. The pin 9 is the common pin. If i want to use 6.3vdc i must connect in parallel the two heaters?(4,5 together and 9 the second pin).
and if i want to use 12,6vdc i must use only the pin 4 and 5?(connected in series)
What is the difference of those two modes? (exept the different supply)

MrCurwen · 12th October 2011, 11:55 AM

There is no audible difference.

DF96 · 12th October 2011, 12:15 PM

There might be a small difference in hum with an AC supply, depending on how the heaters are wired and how the triodes are used. Some data sheets may suggest which triode to use first for low hum. This will not be an issue for a line stage, and ECC82 is probably not a suitable valve for a phono input so probably of no practical significance.

korabetsni · 12th October 2011, 02:14 PM

the heater must be connected in one of those two ways (parallel or serial)? can i use only the one heater?

DF96 · 12th October 2011, 02:23 PM

You can use one heater if you only want to use one triode. In that case, an alternative is EC90/6C4 which is half an ECC82 on a B7G base.

century tek · 13th October 2011, 07:58 AM

Just a side note, the 12AU7/12AX7 tube types were designed with the option of using 6.3 or 12 volt taps depending on the circuit topology. The 6.3 volt tap was usually used in all power transformer applications where as the 12 volt tap was usually used in the power transformerless or hot chassis designs.

korabetsni · 14th October 2011, 09:42 AM

The polarity of the heaters supply matters? I mean if i connect the two heaters (12AU7) in parallel, the + of the 6,3 Vdc power supply must be connected to pin 9 or 4,5? or it does not matter?

DF96 · 14th October 2011, 09:46 AM

Does not matter.

carageae · 3rd July 2012, 12:03 PM

In this case I should connect the 9 pin to GND and 4,5 to +6,3V.
In the eventuality of change for example to ECC88 we can keep the 9 pin to GND and use the 4,5 pins for heater supply - useful especially for PCB designs, it's easier to modify the heater supply.

12th October 2011, 11:48 AM	#1
korabetsni diyAudio Member Join Date: Mar 2011	ECC802S 12AU7 ECC82 heater question hello, i wanna ask how to connect the ecc82s heater.The pins 4, 5 and 9 are the heaters. The pin 9 is the common pin. If i want to use 6.3vdc i must connect in parallel the two heaters?(4,5 together and 9 the second pin). and if i want to use 12,6vdc i must use only the pin 4 and 5?(connected in series) What is the difference of those two modes? (exept the different supply)

3rd July 2012, 12:03 PM	#9
carageae diyAudio Member Join Date: Apr 2008	ECC82 heater in DC In this case I should connect the 9 pin to GND and 4,5 to +6,3V. In the eventuality of change for example to ECC88 we can keep the 9 pin to GND and use the 4,5 pins for heater supply - useful especially for PCB designs, it's easier to modify the heater supply.

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12th October 2011, 11:55 AM	#2
MrCurwen diyAudio Member Join Date: Feb 2010 Location: Helsinki	There is no audible difference.

12th October 2011, 12:15 PM	#3
DF96 diyAudio Member Join Date: May 2007	There might be a small difference in hum with an AC supply, depending on how the heaters are wired and how the triodes are used. Some data sheets may suggest which triode to use first for low hum. This will not be an issue for a line stage, and ECC82 is probably not a suitable valve for a phono input so probably of no practical significance.

12th October 2011, 02:14 PM	#4
korabetsni diyAudio Member Join Date: Mar 2011	the heater must be connected in one of those two ways (parallel or serial)? can i use only the one heater?

12th October 2011, 02:23 PM	#5
DF96 diyAudio Member Join Date: May 2007	You can use one heater if you only want to use one triode. In that case, an alternative is EC90/6C4 which is half an ECC82 on a B7G base.

13th October 2011, 07:58 AM	#6
century tek diyAudio Member Join Date: Nov 2010	Just a side note, the 12AU7/12AX7 tube types were designed with the option of using 6.3 or 12 volt taps depending on the circuit topology. The 6.3 volt tap was usually used in all power transformer applications where as the 12 volt tap was usually used in the power transformerless or hot chassis designs.

14th October 2011, 09:42 AM	#7
korabetsni diyAudio Member Join Date: Mar 2011	The polarity of the heaters supply matters? I mean if i connect the two heaters (12AU7) in parallel, the + of the 6,3 Vdc power supply must be connected to pin 9 or 4,5? or it does not matter?

14th October 2011, 09:46 AM	#8
DF96 diyAudio Member Join Date: May 2007	Does not matter.