working out Z out for tube with IXYS IXP10M45S plate load

duderduderini · 16th January 2008, 08:26 PM

Hi There
I would like some guidance as to how to work out Z out of a tube with its plate load being supplied by the IXP10M45S.
I have read the article at maarten@platenspieler.com and I figure It probably should be MU follower formulas given the output is taken from the anode of the driven tube.
Given the Current regulator does not have the plethora of caps and resistors though, I am wondering if it may be accurate.
I would appreciate any help
Thanks
Nick

EC8010 · 16th January 2008, 08:30 PM

It's just r_a (at the operating point). As simple as that.

duderduderini · 16th January 2008, 09:07 PM

Hi Ec
Hope your xmas woas good and that 2008 is fine for all.
The datasheet for the e180f seems to only provide data in pentode op.
I will look for more info
At this point i have the setip working at 5.5 mA and 153V so is it as simple as V/I?
Thanks

EC8010 · 16th January 2008, 09:11 PM

If you look on the E180F data sheet, you should find it gives a value for mu(g₁-g₂). This is the same as the triode mu. You can find gm at your operating current using the pentode data, and from that use r_a(triode) = gm x mu(g₁-g₂).

dsavitsk · 16th January 2008, 09:51 PM

Quote:

Originally posted by duderduderini
e180f ... working at 5.5 mA and 153V

Probably a little low on the current. More like 12-16mA is probably a good point to shoot for.

http://www.triodeguy.com/Triodeguy%2...asurements.pdf

duderduderini · 16th January 2008, 09:56 PM

Hi Again
Ok mu=50
Gm.. is that transconductance or is it derived by operating point (150V @ 5.1mA) ?
Thanks

duderduderini · 16th January 2008, 10:28 PM

I will try increasing current.. i find with other tubes that they can sound a bit unpleasant at higher anode currents.. Is that my imagination?
The 180F at 5.1 doesnt sound objectionable at this point but i will double the current and see for myself
Once agin thanks for the datasheet.
Nick

duderduderini · 17th January 2008, 01:39 AM

Hi
using Ec's formula ra(triode) = gm x mu(g1-g2).
refering to the triode sheet for the 180F
mu=60
gm =17.6 so rA=1056
on the triode data sheete refered to in this post a valus for Rp is given of 3.4k
Ra is not the same as rp i take it?
Thanks

EC8010 · 17th January 2008, 07:15 AM

Quote:

Originally posted by duderduderini
using Ec's formula ra(triode) = gm x mu(g1-g2).

That's because the twit EC had his brains out of gear. He meant to say ra = u/gm. If he had spent less time on formatting and more on thinking, he wouldn't have confused you. My apologies.

duderduderini · 18th January 2008, 07:13 AM

Hi EC
dont worry.. i sppend much of my life in a confused state these days as I find it helps with the vagaries of modern life. Thanks to all for your help.
I plan to construct an riaa stage based on the e180f in triode mode and the ixys current regulator..
Will see how it works.
Thanks
Nick

16th January 2008, 08:26 PM	#1
duderduderini diyAudio Member Join Date: Mar 2004 Location: Albury NSW Australia	working out Z out for tube with IXYS IXP10M45S plate load Hi There I would like some guidance as to how to work out Z out of a tube with its plate load being supplied by the IXP10M45S. I have read the article at maarten@platenspieler.com and I figure It probably should be MU follower formulas given the output is taken from the anode of the driven tube. Given the Current regulator does not have the plethora of caps and resistors though, I am wondering if it may be accurate. I would appreciate any help Thanks Nick __________________ "Better to say nothing and keep them guessing than to speak and remove all doubt."

16th January 2008, 08:30 PM	#2
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	It's just r_a (at the operating point). As simple as that. __________________ 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...

16th January 2008, 09:07 PM	#3
duderduderini diyAudio Member Join Date: Mar 2004 Location: Albury NSW Australia	so if we use e180f as triode Hi Ec Hope your xmas woas good and that 2008 is fine for all. The datasheet for the e180f seems to only provide data in pentode op. I will look for more info At this point i have the setip working at 5.5 mA and 153V so is it as simple as V/I? Thanks __________________ "Better to say nothing and keep them guessing than to speak and remove all doubt."

16th January 2008, 09:11 PM	#4
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	If you look on the E180F data sheet, you should find it gives a value for mu(g₁-g₂). This is the same as the triode mu. You can find gm at your operating current using the pentode data, and from that use r_a(triode) = gm x mu(g₁-g₂). __________________ 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...

16th January 2008, 09:56 PM	#6
duderduderini diyAudio Member Join Date: Mar 2004 Location: Albury NSW Australia	At the risk of sounding completely stupid Hi Again Ok mu=50 Gm.. is that transconductance or is it derived by operating point (150V @ 5.1mA) ? Thanks __________________ "Better to say nothing and keep them guessing than to speak and remove all doubt."

16th January 2008, 10:28 PM	#7
duderduderini diyAudio Member Join Date: Mar 2004 Location: Albury NSW Australia	Thanks for the triode datasheet I will try increasing current.. i find with other tubes that they can sound a bit unpleasant at higher anode currents.. Is that my imagination? The 180F at 5.1 doesnt sound objectionable at this point but i will double the current and see for myself Once agin thanks for the datasheet. Nick __________________ "Better to say nothing and keep them guessing than to speak and remove all doubt."

17th January 2008, 01:39 AM	#8
duderduderini diyAudio Member Join Date: Mar 2004 Location: Albury NSW Australia	So is this the Ra Hi using Ec's formula ra(triode) = gm x mu(g1-g2). refering to the triode sheet for the 180F mu=60 gm =17.6 so rA=1056 on the triode data sheete refered to in this post a valus for Rp is given of 3.4k Ra is not the same as rp i take it? Thanks __________________ "Better to say nothing and keep them guessing than to speak and remove all doubt."

18th January 2008, 07:13 AM	#10
duderduderini diyAudio Member Join Date: Mar 2004 Location: Albury NSW Australia	I am always confused Hi EC dont worry.. i sppend much of my life in a confused state these days as I find it helps with the vagaries of modern life. Thanks to all for your help. I plan to construct an riaa stage based on the e180f in triode mode and the ixys current regulator.. Will see how it works. Thanks Nick __________________ "Better to say nothing and keep them guessing than to speak and remove all doubt."

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