tube based CCS

GAK · 8th February 2004, 09:48 PM

Hi
Any good source for tube based CCS?
Thanks

EC8010 · 8th February 2004, 11:10 PM

Just use a pentode with an undecoupled cathode resistor. If you make the control grid positive, you can use a larger cathode resistor, which is then multiplied by the pentode's enormous mu.

ray_moth · 10th February 2004, 12:56 AM

I'm about to try this, in the tail of an LTP 6SL7 phase-splitter, using a 6AU6 (petode). It seems to be straightforward enough, except that a tube CCS needs quite a high voltage compared with solid state. Hopefully it sounds better, though!

planet10 · 10th February 2004, 02:19 AM

Quote:

Originally posted by EC8010
Just use a pentode with an undecoupled cathode resistor. If you make the control grid positive, you can use a larger cathode resistor, which is then multiplied by the pentode's enormous mu.

I just finished reading the triode/pentode CCS section in Morgan Jones book -- his description seemed a bit more involved....

dave

Sch3mat1c · 10th February 2004, 03:16 AM

Probably striving for perfection then. Ain't needed. The same approach works fine in SS, biasing the "grid" (gate or base) positive (negative for P type) to account for the positive (on NPN and depletion-mode transistors) "grid"-"cathode" potential with a pair of diodes or (for really high quality) a zener.

Tim

GAK · 11th February 2004, 02:47 PM

I think Morgan Jones reffers on a CCS for a PSU.I need a CCS for anode load for a triode line stage.
Like Gary Pimm's CCS.But Gary Pimm has more information about SS CCS.I love tubes and I like a tubed CCS.But I need more information.
The new issue of audioXpress has a nice article!!A triode preamp with EL34 for CCS.
But any new information is acceptable!

Ray_moth:can you post a schematic?

EC8010 · 11th February 2004, 03:29 PM

Using a pentode as a CCS is easy enough, but you need to give some clues as to how much current it must sink, and how many volts are available for its operation. EF91/6AM6 is a possibility, as is EF184/6EJ7.

GAK · 11th February 2004, 03:41 PM

EC8010 : You have right for this.
I need it for an anode load for a 12B4A line stage.With
Vg -12.5V
Rk 410R bypassed
Ia 30mA
rp 950R
u 6.4
The anode voltage is as much as I need.I haven't order the power transformer yet.

If you want more details let me know.

EC8010 · 11th February 2004, 06:00 PM

Well, it is possible to use a pentode as an anode load, but it's not usually worth it - a high-mu triode is simpler and lower distortion. I'm guessing that Va is about 100V. Your best option is to turn the stage into a mu-follower using a 6C45 triode as the upper valve.

runeight · 12th February 2004, 04:58 AM

may i ask, out of curiosity, why so much idle current? it would seem for most linestage type applications, you could get away with 10mA or even less depending on what your load looks like.

I agree with EC. I think a hi mu triode is practially as good a a pentode and easier to do.

In fact, if you were hanging around in 6922 territory, I think you could make a very respectable mu-follower with two 6922s.

8th February 2004, 09:48 PM	#1
GAK diyAudio Member Join Date: Apr 2001 Location: Greece	tube based CCS Hi Any good source for tube based CCS? Thanks __________________ let's boom chitty boom

8th February 2004, 11:10 PM	#2
EC8010 diyAudio Moderator Emeritus Join Date: Jan 2003 Location: Near London. UK	Just use a pentode with an undecoupled cathode resistor. If you make the control grid positive, you can use a larger cathode resistor, which is then multiplied by the pentode's enormous mu. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...

10th February 2004, 03:16 AM	#5
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Probably striving for perfection then. Ain't needed. The same approach works fine in SS, biasing the "grid" (gate or base) positive (negative for P type) to account for the positive (on NPN and depletion-mode transistors) "grid"-"cathode" potential with a pair of diodes or (for really high quality) a zener. Tim __________________ Seven Transistor Labs Projects and Resources

11th February 2004, 02:47 PM	#6
GAK diyAudio Member Join Date: Apr 2001 Location: Greece	I think Morgan Jones reffers on a CCS for a PSU.I need a CCS for anode load for a triode line stage. Like Gary Pimm's CCS.But Gary Pimm has more information about SS CCS.I love tubes and I like a tubed CCS.But I need more information. The new issue of audioXpress has a nice article!!A triode preamp with EL34 for CCS. But any new information is acceptable! Ray_moth:can you post a schematic? __________________ let's boom chitty boom

11th February 2004, 03:29 PM	#7
EC8010 diyAudio Moderator Emeritus Join Date: Jan 2003 Location: Near London. UK	Details, details... Using a pentode as a CCS is easy enough, but you need to give some clues as to how much current it must sink, and how many volts are available for its operation. EF91/6AM6 is a possibility, as is EF184/6EJ7. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...


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10th February 2004, 12:56 AM	#3
ray_moth diyAudio Moderator Emeritus Join Date: Jan 2004 Location: Jakarta	I'm about to try this, in the tail of an LTP 6SL7 phase-splitter, using a 6AU6 (petode). It seems to be straightforward enough, except that a tube CCS needs quite a high voltage compared with solid state. Hopefully it sounds better, though!

11th February 2004, 03:41 PM	#8
GAK diyAudio Member Join Date: Apr 2001 Location: Greece	EC8010 : You have right for this. I need it for an anode load for a 12B4A line stage.With Vg -12.5V Rk 410R bypassed Ia 30mA rp 950R u 6.4 The anode voltage is as much as I need.I haven't order the power transformer yet. If you want more details let me know. __________________ let's boom chitty boom

12th February 2004, 04:58 AM	#10
runeight diyAudio Member Join Date: Sep 2003 Location: Texas	may i ask, out of curiosity, why so much idle current? it would seem for most linestage type applications, you could get away with 10mA or even less depending on what your load looks like. I agree with EC. I think a hi mu triode is practially as good a a pentode and easier to do. In fact, if you were hanging around in 6922 territory, I think you could make a very respectable mu-follower with two 6922s.

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