6DJ8 Linestage

DoomPixie · 15th December 2005, 05:53 PM

Hey all, I have been experimenting with my 6DJ8 linestage and have changed a few component values and came up with the following, It sounds better than it did originally, anyone got any suggestions for me to improve it further?
Owen

Zen Mod · 15th December 2005, 10:38 PM

Quote:

Originally posted by DoomPixie
Hey all, I have been experimenting with my 6DJ8 linestage and have changed a few component values and came up with the following, It sounds better than it did originally, anyone got any suggestions for me to improve it further?
Owen

is it 0,2uF enough for your power amp?

suggestions?

toss that SRPP ,wire both halves in para,then use some nice choke in parafeed ,mebbe even in WE config, burn them on some 90V and 20mA
and enjoy

after that -you can use some other tube in WOT style

DoomPixie · 16th December 2005, 08:59 AM

i built 3 6DJ8 pre's last year and this one sounded best out of the three (to my ears at the time anyway)
Since then i have changed the value of the output capacitor from 0.6uF to 0.2uF and it sounds better BUT i was useing some really cheap 0.2uF caps to get 0.6uF and now i am useing some nice 0.1uF caps i got out of an old osciloscope that was going to the scrappers. so mabey the change for the better has to do more with the quality of the cap's than with the value?
Owen

DoomPixie · 26th January 2006, 01:37 PM

ok, just thought i would revive this thread, i have just replaced the output cap's with some nice 2.2uF cap's i bought... yet to test it with the new cap's in.. anyone have any sugestions how to improve this further?
Owen

hacknet · 26th January 2006, 03:46 PM

whats the kinda current running through those babies? it might be a good idea to float the heaters so the top valve's heater insulation doesnt give problems.

DoomPixie · 26th January 2006, 05:20 PM

i'll measure the current tommorow. not sure what it is of the top of my head. might ad another RC stage to the power supply aswell to get rid of the remaining hum (only just noticable with volume maxed out and no input signal) and tweak it a little so the B+ is closer to 200V..
Owen

Original Burnedfingers · 27th January 2006, 11:34 AM

Why don't you convert it to the Aikido circuit? This will get rid of any noise and from a performance aspect the Aikido will smoke it.

DoomPixie · 27th January 2006, 05:31 PM

to be honest, i dont think there will be any noise problems atall when i have sorted the power supply out properly. have you got any schematics for the Aikido? how many tubes does it use?
Owen

lt cdr data · 29th January 2006, 07:39 PM

turn it into a mu stage, definately improves the srpp no matter what some say.

a 10k or 20 k resistor above the top resistor, a 1MEG also and a coupling cap is all you need.

Original Burnedfingers · 29th January 2006, 07:45 PM

Tube count increases

I will try to post a schematic

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16th December 2005, 08:59 AM	#3
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	i built 3 6DJ8 pre's last year and this one sounded best out of the three (to my ears at the time anyway) Since then i have changed the value of the output capacitor from 0.6uF to 0.2uF and it sounds better BUT i was useing some really cheap 0.2uF caps to get 0.6uF and now i am useing some nice 0.1uF caps i got out of an old osciloscope that was going to the scrappers. so mabey the change for the better has to do more with the quality of the cap's than with the value? Owen

26th January 2006, 01:37 PM	#4
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	ok, just thought i would revive this thread, i have just replaced the output cap's with some nice 2.2uF cap's i bought... yet to test it with the new cap's in.. anyone have any sugestions how to improve this further? Owen

26th January 2006, 03:46 PM	#5
hacknet diyAudio Member Join Date: Nov 2002 Location: sg	whats the kinda current running through those babies? it might be a good idea to float the heaters so the top valve's heater insulation doesnt give problems.

26th January 2006, 05:20 PM	#6
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	i'll measure the current tommorow. not sure what it is of the top of my head. might ad another RC stage to the power supply aswell to get rid of the remaining hum (only just noticable with volume maxed out and no input signal) and tweak it a little so the B+ is closer to 200V.. Owen

27th January 2006, 11:34 AM	#7
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Why don't you convert it to the Aikido circuit? This will get rid of any noise and from a performance aspect the Aikido will smoke it.

27th January 2006, 05:31 PM	#8
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	to be honest, i dont think there will be any noise problems atall when i have sorted the power supply out properly. have you got any schematics for the Aikido? how many tubes does it use? Owen

29th January 2006, 07:39 PM	#9
lt cdr data diyAudio Member Join Date: Dec 2003 Location: earth	turn it into a mu stage, definately improves the srpp no matter what some say. a 10k or 20 k resistor above the top resistor, a 1MEG also and a coupling cap is all you need.

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