PL 519 electrical characteristics

Seraph · 11th October 2008, 06:34 PM

I have been testing some PL519's and getting some different results. I have been setting Vg1=-37V, Va=150V, Vg2=100V. Under these conditions for most samples Ia is anywhere between 25 ma to 35 ma, for one tube it was more than 70 ma. Tester is an AVO 163.

Could any recommend test setup parameters for a new PL 519?

Thanks

Fuling · 11th October 2008, 06:49 PM

IIRC these tubes are known for being quite inconcistent.
http://www.tubes.mynetcologne.de/roe..._triode_e.html

EC8010 · 11th October 2008, 09:11 PM

25mA to 35mA sounds pretty good to me. As the other respondent said, PL519 is not expected to be consistent - it's a TV line scan valve. The best test parameters are those you intend to apply in your amplifier...

Seraph · 11th October 2008, 11:06 PM

<The best test parameters are those you intend to apply in your amplifier...>

And 40 ma is the design bias current for each PL519 in this amp. I'm finding of the 2 rows of 5, PL519's in each OTL mono block, only a few are operating near 40 ma. Most are biased between 18-25 ma and a couple between 70 to 80 ma. Replacing a single high or low conducting tube to match its mirror mate is hit-or-miss and buying 10 matched PL519's per amp is pricey at the moment. I have been wondering about the feasibility of a simple servo bias control to keep the bias point fixed.

Any ideas?

EC8010 · 12th October 2008, 09:32 AM

I', guessing this is an OTL amplifier? Would it be possible to modify the design to bias valves individually? I take your point that obtaining that many matched valves would be expensive.

Seraph · 12th October 2008, 01:46 PM

Yes these are OTL. Setting the bias points for each tube individually might be the easiest route. I will investigate that. Cathode resistors in this amp are 1.2 Ohm. So I will be needing some fine adjustment around this value possibly using a pot and a resistor in parallel. However, I have found that the PL519 cathode current can increase with age hence the need for a scheme to regulate the bias current rather than having to constantly monitor and adjust the bias current. A bad PL519 might be one that has its bias current increase with aging while at the same time its grid negative supply has remained fixed.

carolus · 24th December 2008, 05:23 PM

A bit late, i give my test results about PL519.
Project OTL T8 (upgraded to T12) ...(this is not a "product placement")
Test 47 x PL519 ("second hand" for a apple & egg) ..and 4 new tubes (never used).
Set points: Va=160Vdc, Vg=-40dc,Ufil=40Vac, Rcat=1ohm (1%),
G1 with 10k (stop), G2 with 100ohm to Va, G3 to cat
mV meter acros Rc
Scoop on Cathode (check oscilations & microinterruption)
Important: Test reading after 25min (temp-) stabilitation
Results: Ia between 26,8mA and ....92mA (one at 166mA) with approx a delta plus/min 2mA.
I think & prudent: it's difficult (unreal) to loock (and buy) after paired (identical caracteristques) PL519 (PL509)....even "new one" ....
I have no experience with "individual grid bias".
I hope that this can help (a little).
Allez, salukes.

To all, My best wishes for a good and fine Christmas and a great and safe end/new year .....let us hope ...

okk · 10th July 2010, 07:36 AM

Quote:

Originally Posted by carolus

A bit late, i give my test results about PL519.
Project OTL T8 (upgraded to T12) ...(this is not a "product placement")
Test 47 x PL519 ("second hand" for a apple & egg) ..and 4 new tubes (never used).
Set points: Va=160Vdc, Vg=-40dc,Ufil=40Vac, Rcat=1ohm (1%),
G1 with 10k (stop), G2 with 100ohm to Va, G3 to cat
mV meter acros Rc
Scoop on Cathode (check oscilations & microinterruption)
Important: Test reading after 25min (temp-) stabilitation
Results: Ia between 26,8mA and ....92mA (one at 166mA) with approx a delta plus/min 2mA.
I think & prudent: it's difficult (unreal) to loock (and buy) after paired (identical caracteristques) PL519 (PL509)....even "new one" ....
I have no experience with "individual grid bias".
I hope that this can help (a little).
...

good experience

okk · 24th October 2010, 03:54 AM

i have measured about 10 pl519 or pl509. the source were different, NOS or used.
most of them, Ia were 90mA - 100mA.
but only one "NOS" pl509 from Japan was 60mA.

carolus · 24th October 2010, 06:43 AM

Quote:

Originally Posted by okk

.....i have measured about 10 pl519 or pl509. the source were different, NOS or used ......

Hi Okk, good work & to know the (your) results (& deviations) ...
(results after minimum 20minutes warming up ?)
Fyi, my OTL (PL519) is nice in the musical-audio-running (and heat) ... and no problem (10Hr/day/365d) ...
Have a good time in China audio,
Allez, salukes & best regards,

11th October 2008, 06:34 PM	#1
Seraph diyAudio Member Join Date: Mar 2007	PL 519 Electrical Characterstics I have been testing some PL519's and getting some different results. I have been setting Vg1=-37V, Va=150V, Vg2=100V. Under these conditions for most samples Ia is anywhere between 25 ma to 35 ma, for one tube it was more than 70 ma. Tester is an AVO 163. Could any recommend test setup parameters for a new PL 519? Thanks

11th October 2008, 09:11 PM	#3
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	25mA to 35mA sounds pretty good to me. As the other respondent said, PL519 is not expected to be consistent - it's a TV line scan valve. The best test parameters are those you intend to apply in your amplifier... __________________ 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...

12th October 2008, 09:32 AM	#5
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	I', guessing this is an OTL amplifier? Would it be possible to modify the design to bias valves individually? I take your point that obtaining that many matched valves would be expensive. __________________ 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...

24th October 2010, 03:54 AM	#9
okk diyAudio Member Join Date: Sep 2003 Location: Beijing	i have measured about 10 pl519 or pl509. the source were different, NOS or used. most of them, Ia were 90mA - 100mA. but only one "NOS" pl509 from Japan was 60mA. __________________ make it better.

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11th October 2008, 06:49 PM	#2
Fuling diyAudio Member Join Date: Aug 2001 Location: Sweden (Mora)	IIRC these tubes are known for being quite inconcistent. http://www.tubes.mynetcologne.de/roe..._triode_e.html

11th October 2008, 11:06 PM	#4
Seraph diyAudio Member Join Date: Mar 2007	<The best test parameters are those you intend to apply in your amplifier...> And 40 ma is the design bias current for each PL519 in this amp. I'm finding of the 2 rows of 5, PL519's in each OTL mono block, only a few are operating near 40 ma. Most are biased between 18-25 ma and a couple between 70 to 80 ma. Replacing a single high or low conducting tube to match its mirror mate is hit-or-miss and buying 10 matched PL519's per amp is pricey at the moment. I have been wondering about the feasibility of a simple servo bias control to keep the bias point fixed. Any ideas?

12th October 2008, 01:46 PM	#6
Seraph diyAudio Member Join Date: Mar 2007	Yes these are OTL. Setting the bias points for each tube individually might be the easiest route. I will investigate that. Cathode resistors in this amp are 1.2 Ohm. So I will be needing some fine adjustment around this value possibly using a pot and a resistor in parallel. However, I have found that the PL519 cathode current can increase with age hence the need for a scheme to regulate the bias current rather than having to constantly monitor and adjust the bias current. A bad PL519 might be one that has its bias current increase with aging while at the same time its grid negative supply has remained fixed.

24th December 2008, 05:23 PM	#7
carolus diyAudio Member Join Date: Jan 2005 Location: Brussel	A bit late, i give my test results about PL519. Project OTL T8 (upgraded to T12) ...(this is not a "product placement") Test 47 x PL519 ("second hand" for a apple & egg) ..and 4 new tubes (never used). Set points: Va=160Vdc, Vg=-40dc,Ufil=40Vac, Rcat=1ohm (1%), G1 with 10k (stop), G2 with 100ohm to Va, G3 to cat mV meter acros Rc Scoop on Cathode (check oscilations & microinterruption) Important: Test reading after 25min (temp-) stabilitation Results: Ia between 26,8mA and ....92mA (one at 166mA) with approx a delta plus/min 2mA. I think & prudent: it's difficult (unreal) to loock (and buy) after paired (identical caracteristques) PL519 (PL509)....even "new one" .... I have no experience with "individual grid bias". I hope that this can help (a little). Allez, salukes. To all, My best wishes for a good and fine Christmas and a great and safe end/new year .....let us hope ...

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