ecc802s SRPP preamplifier

korabetsni · 17th November 2011, 11:01 AM

hello,
i have finished a preamplifier with the ECC802S Tesla tubes. The circuit diagram is here: DIY ECC802S (12AU7 / ECC82) Vacuum Tube SRPP Preamplifier
The schematics shows on the tubes pins 6 about 215volts. I have only 205volts and i am using the same power supply but with larger capacitors.(not 3x100uf but 3x470uF). Maybe my tubes draws a little more current. Is this voltage ok? Also i have a problem with the heater voltage. I am using the LM317 to supply 6,3vdc. Without the tubes i have 6,3v but when i put the tubes on the heater voltage drops to 5,8v possibly because the transformer cannot supply the current needed.(the transformer voltage drops from 8 to 7Vac with the load) Is this ok or i must rewind the transformer? (i made the transformer by myself).
Thank you
george

radiostar · 17th November 2011, 04:49 PM

205V is ok, you need more input voltage on LM317, 7 volts is not enough ...

Good luck!

17th November 2011, 11:01 AM	#1
korabetsni diyAudio Member Join Date: Mar 2011	ecc802s SRPP preamplifier hello, i have finished a preamplifier with the ECC802S Tesla tubes. The circuit diagram is here: DIY ECC802S (12AU7 / ECC82) Vacuum Tube SRPP Preamplifier The schematics shows on the tubes pins 6 about 215volts. I have only 205volts and i am using the same power supply but with larger capacitors.(not 3x100uf but 3x470uF). Maybe my tubes draws a little more current. Is this voltage ok? Also i have a problem with the heater voltage. I am using the LM317 to supply 6,3vdc. Without the tubes i have 6,3v but when i put the tubes on the heater voltage drops to 5,8v possibly because the transformer cannot supply the current needed.(the transformer voltage drops from 8 to 7Vac with the load) Is this ok or i must rewind the transformer? (i made the transformer by myself). Thank you george

17th November 2011, 04:49 PM	#2
radiostar diyAudio Member Join Date: Apr 2009	205V is ok, you need more input voltage on LM317, 7 volts is not enough ... Good luck! __________________ tubes.rs facebook.com/tubes.rs

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