6X4 Tube rectifier.

SINGLEENDED · 17th March 2007, 06:12 PM

6X4 Tube rectifier:

Need some answer to the above.
What is the life span for the tube, if I were to use it daily for 8 hours.

sawreyrw · 17th March 2007, 06:34 PM

I think it should last thousands of hours, if you operate it within its ratings. It is a relatively low current tube.

Eli Duttman · 17th March 2007, 06:56 PM

Quote:

Originally posted by SINGLEENDED
6X4 Tube rectifier: Need some answer to the above.
What is the life span for the tube, if I were to use it daily for 8 hours.

Well made vacuum rectifiers have long service lives. 10+ years is not an unrealistic expectation. Who made your 6X4?

sorenj07 · 17th March 2007, 09:21 PM

also, what does the current load, idle and max, look like on your (pre)amp?

ulibub · 18th March 2007, 01:35 PM

Hi!

I use the 6X4 as a rectifier in a hybrid bridge (with two BY 127 Si-diodes) in the power supply of my preamp, who takes about 50 mA at 300V. Rectifier input voltage is 450 V AC. From the tube's cathode, there goes a NTC resistor (ca. 300 Ohm cold, a few ohms hot, to reduce startup current) to a 50 uf electrolytic, a 5 H choke, another 50 uf cap, and then into the first regulator tube, a PL 84. Voltage reference is a TAA 550 temperature-compensated precision zener voltage source (33 V).

I built this amp in the late 80's, and at the moment where I am writing this posting, it has run 22,869 hours.... (I have a counter in the PSU....

), always with the same tubes.... This also applies to the PL 84 / PL 95 / PCF 802 in the 2-stage regulated power supply....

So far I don't see any signs of weakening of the tube(s)....

Don't know how much you'd charge the tube, but with the above data you easily could expect about 8 years of 8 h daily service.... (23,000 : 8 : 365)

Uli

SINGLEENDED · 18th March 2007, 02:02 PM

6X4 Made by GE 60' NOS.
I run it this way. 220 CT . to 6X4 . First oil caps. at 15uf non polar.next comes the choke @ 8H 100mA , another caps @ 68uf. next another choke 8H 100 mA last caps 68uf. So its CLCLC.

ulibub · 18th March 2007, 02:11 PM

how much current do you draw out of the power supply? My 6X4 is a NOS made by Tungsram.

Geek · 19th March 2007, 01:40 AM

6X4 is a good tough little tube. Used it for hundreds of hours in a headphone amp feeding into a cap twice the recommended size. Zero failures

SINGLEENDED · 19th March 2007, 01:46 PM

The pre amp. consume 250vdc @ 100ma.

Eli Duttman · 19th March 2007, 10:44 PM

Quote:

The pre amp. consume 250vdc @ 100ma.

IMO, that's too much for a 6X4. 70 mA. is "normal". Look at the data sheet. While I wouldn't worry if the draw is 75 mA., a switch to the 6CA4/EZ81 is indicated, if 100 mA. of B+ are really needed.

17th March 2007, 06:12 PM	#1
SINGLEENDED diyAudio Member Join Date: Feb 2006 Location: Kuala Lumpur	6X4 Tube rectifier. 6X4 Tube rectifier: Need some answer to the above. What is the life span for the tube, if I were to use it daily for 8 hours. __________________ etl

18th March 2007, 02:02 PM	#6
SINGLEENDED diyAudio Member Join Date: Feb 2006 Location: Kuala Lumpur	Thank You Guys. 6X4 Made by GE 60' NOS. I run it this way. 220 CT . to 6X4 . First oil caps. at 15uf non polar.next comes the choke @ 8H 100mA , another caps @ 68uf. next another choke 8H 100 mA last caps 68uf. So its CLCLC. __________________ etl

19th March 2007, 01:46 PM	#9
SINGLEENDED diyAudio Member Join Date: Feb 2006 Location: Kuala Lumpur	How much current The pre amp. consume 250vdc @ 100ma. __________________ etl

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17th March 2007, 06:34 PM	#2
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	I think it should last thousands of hours, if you operate it within its ratings. It is a relatively low current tube.

17th March 2007, 09:21 PM	#4
sorenj07 diyAudio Member Join Date: May 2006	also, what does the current load, idle and max, look like on your (pre)amp?

18th March 2007, 01:35 PM	#5
ulibub diyAudio Member Join Date: Nov 2006 Location: Lorraine	Hi! I use the 6X4 as a rectifier in a hybrid bridge (with two BY 127 Si-diodes) in the power supply of my preamp, who takes about 50 mA at 300V. Rectifier input voltage is 450 V AC. From the tube's cathode, there goes a NTC resistor (ca. 300 Ohm cold, a few ohms hot, to reduce startup current) to a 50 uf electrolytic, a 5 H choke, another 50 uf cap, and then into the first regulator tube, a PL 84. Voltage reference is a TAA 550 temperature-compensated precision zener voltage source (33 V). I built this amp in the late 80's, and at the moment where I am writing this posting, it has run 22,869 hours.... (I have a counter in the PSU.... ), always with the same tubes.... This also applies to the PL 84 / PL 95 / PCF 802 in the 2-stage regulated power supply.... So far I don't see any signs of weakening of the tube(s).... Don't know how much you'd charge the tube, but with the above data you easily could expect about 8 years of 8 h daily service.... (23,000 : 8 : 365) Uli

18th March 2007, 02:11 PM	#7
ulibub diyAudio Member Join Date: Nov 2006 Location: Lorraine	how much current do you draw out of the power supply? My 6X4 is a NOS made by Tungsram.

19th March 2007, 01:40 AM	#8
Geek diyAudio Member Join Date: Sep 2004	6X4 is a good tough little tube. Used it for hundreds of hours in a headphone amp feeding into a cap twice the recommended size. Zero failures

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