864 / VT-24 DHT curves

This is one of the other great DHTs I received from Vegard Winge for tracing.

Here are the curves and the SPICE model: 864 DHT Composite

The SPICE composite model based on Dmitry’s:

**** 864 VT-24 DHT Composite ******************************************
* Created on 03/16/2013 19:30 using paint_kit.jar 
* www.bartola.co.uk/valves
* Curves image file: 864 SMALL.jpg
* Data source link: 864 SMALL.jpg
* Created by Ale Moglia valves@bartola.co.uk
*----------------------------------------------------------------------------------
.SUBCKT TRIODE_864-Composite 1 2 3 4 ; Plate Grid K1 K2
+ PARAMS: CCG=2.3P CGP=5.3P CCP=1.3P 
+ MU=7.14 KG1=13560 KP=98 
+ KVB=1.88 VCT=-0.07 EX=1.41 RGI=2000
* Vp_MAX=200 Ip_MAX=0.008 
* Vg_step=2 Vg_start=0 Vg_count=11
* END PARAMS -----------------------------------------------------------------------
* cathode resistor is 4.4 ohm, the pins K1 and K2 are 1.1 ohms from the ends of it
RFIL_LEFT 3 31 1.1
RFIL_RIGHT 4 41 1.1
RFIL_MIDDLE 31 41 2.2
E11 32 0 VALUE={V(1,31)/KP*LOG(1+EXP(KP*(1/MU+V(2,31)/SQRT(KVB+V(1,31)*V(1,31)))))}
E12 42 0 VALUE={V(1,41)/KP*LOG(1+EXP(KP*(1/MU+V(2,41)/SQRT(KVB+V(1,41)*V(1,41)))))}
RE11 32 0 1G
RE12 42 0 1G
G11 1 31 VALUE={(PWR(V(32),EX)+PWRS(V(32),EX))/(2*KG1)}
G12 1 41 VALUE={(PWR(V(42),EX)+PWRS(V(42),EX))/(2*KG1)}
RCP1 1 3 1G
RCP2 1 4 1G
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
D4 6 4 DX ; FOR GRID CURRENT
RG1 2 5 {RGI} ; FOR GRID CURRENT
RG2 2 6 {RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$

Hope this is useful…

Ale

307a DHT in triode and Schade feedback

Vegard Winge kindly sent me some great DHTs for tracing including the 307a directly heated pentode. The sample traced is not an original Western Electric but a lovely Raytheon RK 75 307a NOS. There is limited information of this valve in triode mode and the folks at DIYaudio are looking at potentially using it for a DHT headphone amp.

This valve has a filament of 5.5V and 1A and an anode dissipation of 21W in class A (including screen dissipation) when triode-connected.

Let’s see how this valve performs in triode-mode:

How well can we match a triode model for this valve?

Continue reading “307a DHT in triode and Schade feedback”

Russian pentodes in triode mode

After some proper time tracing the curves, here are a set of Russian high-frequency pentodes in triode-mode for comparison. I was looking at closer ones to D3a and these are the ones I had at hand and wanted to include in the tests:

	6Z5P	6Z9P	6Z11P	6Z49P-D	6Z51P	6P15P	6E5P	6E6P-E	D3a
Vf [V]	6.3	6.3	6.3	6.3	6.3	6.3	6.3	6.3	6.3
If [ma]	450	300	440	300	300	760	600	610	315
Pa [W]	4	3.75	6	3.4	3.5	13.5	10.6	8.8	4.5
Gm [ma/V]	7	35	33	17.75	29	16	32	25	34
μ	44	36	40	44.3	79.5	22	30	34	68
Ra [Ω]	6K2	1k	1K2	2K5	2K7	1K6	960	1K3	2K
Ia [ma]	16	29	40	15.7	23	52	50	30	22
Va [V]	252	125	150	200	150	250	200	200	200

Well, as you can see in the table above, the 6e5p and 6e6p-e (both tetrodes) were included in the list. Some interesting points to highlight:

Continue reading “Russian pentodes in triode mode”

6E5P/6Э5П and 6E6P-E/6Э6П-E in triode mode

One of the first valves I traced with my curve tracer was the 6E5P/6Э5П. It has a very good reputation when triode-strapped. I did many tests and found this one being a superb driver given is one of the most linear valves out there. Many use them as a 300B driver. I will probably implement Rod Coleman’s shunt cascode topology in my 45 SE or in a 6C4C/4P1L PSE design.

Over the weekend I traced many valves as managed to recalibrate the oscilloscope and tracer and wanted to play with some samples I had around.

Here is the 6E5P/6Э5П in triode mode:

And here are the updated SPICE model parameters:

Now, let’s have a look at it’s close brother the 6E6P-E/6Э6П-E in triode mode. It has a long life (10,000 hours against only 500hours):

Many praise the 6e6p-DR tetrode over these two, I haven’t tried it yet myself but here are the minor differences between 6E5P/6Э5П and 6E6P-E/6Э6П-E to highlight:

Both 6E5P/6Э5П and 6E6P-E/6Э6П-E have very linear curves!
6E5P/6Э5П: less anode resistance and higher transconductance compared to 6E6P-E/6Э6П-E which seems to have a tad more of gain

6P36S / 6П36С beam tetrode in triode mode

My friend Vyacheslav sent me for testing an 6P36S / 6П36С output beam tetrode which was used for TV horizontal deflection circuits in the old days. Here are the nice curves in triode mode:

Low anode resistance and high current capability with its 12W of anode dissipation make this cheap indirectly heated tetrode an interesting candidate for an amplifier. Let’s have a look at the triode model:

Happy to complete the triode SPICE model if someone can translate the Russian datasheet and provide me with the electrode capacitances.

Well, how will this triode perform in a simple SE configuration? With a low Ra, a 5K anode impedance OT will work well:

With just 55Vpp we can drive this valve to produce 2W @ THD=1.6% (without considering the driver distortion cancellation). The valve can be biased nicely at 55mA and 220V.

3A5 DHT (Continued)

Lars requested the paralleled triode curves. Here they are:

And the SPICE model which is more accurate than my previous version:

* Created on Sat Jan 19 15:50:19 GMT 2013 using tube.model.finder.PaintKIT
* model URL: http://www.bartola.co.uk/valves/
* Created by Ale Moglia 2013 valves@bartola.co.uk
*————————————————–
.SUBCKT TRIODE_3A5-2 SMALL 1 2 3 ; P G K ;
+ PARAMS: CCG=.9P CGP=3.2P CCP=1.0P RGI=2000
+ MU=12.46 EX=1.3857 KG1=1965.0 KP=132.0 KVB=1.875 VCT=-1.6 ; Vp_MAX=200.0 Ip_MAX=0.032 Vg_step=2.0
*————————————————–
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
R1 2 5 {RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$

Looking at distortion, as expected the pair of paralleled triodes performs better than a single triode:

C3g and D3a triode SPICE models

Using my C3g and D3a triode curves, I developed the following SPICE models:

** D3A TRIODE ************************************************************
* Created on Sat Jan 12 09:17:53 GMT 2013 using tube.model.finder.PaintKIT
* model URL: http://www.bartola.co.uk/valves/valve-curves/d3a-triode/
* Created by Ale Moglia valves@bartola.co.uk
*--------------------------------------------------
.SUBCKT TRIODE_D3A 1 2 3 ; P G K ; 
+ PARAMS: CCG=6.7P CGP=3.3P CCP=1P RGI=2000
+ MU=72.1 EX=1.456 KG1=65.625 KP=534.0 KVB=300.0 VCT=0.0557 ; Vp_MAX=500.0 Ip_MAX=0.07 Vg_step=0.5
*--------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))} 
RE1 7 0 1G 
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1} 
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID 
C2 2 1 {CGP} ; GRID=PLATE 
C3 1 3 {CCP} ; CATHODE-PLATE 
D3 5 3 DX ; FOR GRID CURRENT 
R1 2 5 {RGI} ; FOR GRID CURRENT 
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N) 
.ENDS 
*$

C3G triode SPICE model

** C3G TRIODE ************************************************************
* Created on Sat Jan 12 09:40:08 GMT 2013 using tube.model.finder.PaintKIT
* model URL: http://www.bartola.co.uk/valves/valve-curves/c3g-pentodetriode/
* Created by Ale Moglia valves@bartola.co.uk
*--------------------------------------------------
.SUBCKT TRIODE_C3G 1 2 3 ; P G K ; 
+ PARAMS: CCG=7P CGP=2.7P CCP=6P RGI=2000
+ MU=50.4 EX=1.428 KG1=199.6875 KP=426.0 KVB=204.0 VCT=0.5760 ; Vp_MAX=500.0 Ip_MAX=0.07 Vg_step=1.0
*--------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))} 
RE1 7 0 1G 
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1} 
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID 
C2 2 1 {CGP} ; GRID=PLATE 
C3 1 3 {CCP} ; CATHODE-PLATE 
D3 5 3 DX ; FOR GRID CURRENT 
R1 2 5 {RGI} ; FOR GRID CURRENT 
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N) 
.ENDS

Tracing German Pentodes

Had the opportunity today to trace some great Siemens pentodes in both pentode and triode modes:

4P1L SPICE model updated

Dmitry Nizh kindly worked out the 4P1L triode SPICE model using his great tool:

Here is Dimtry’s model:

** 4P1L_TRIODE ************************************************************

* Created on Mon Jan 07 07:31:48 PST 2013 using tube.model.finder.PaintKIT
* URL: http://www.bartola.co.uk/valves/valve-curves/4p1l/
*————————————————–
.SUBCKT TRIODE_4P1L_TRIODE 1 2 3 ; P G K ;
+ PARAMS: CCG=8P CGP=7P CCP=9P RGI=2000
+ MU=8.232 EX=1.3719 KG1=851.25 KP=108.0 KVB=528.0 VCT=-1.0 ; Vp_MAX=450.0 Ip_MAX=0.08 Vg_step=5.0
*————————————————–
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
R1 2 5 {RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$

4P1L Pentode Spice Model

Inspired by Rajko’s model, I tried creating my own Spice model of the 4P1L pentode:

Dmitry’s tool for pentode is difficult to fit to the pentode curves, not as the triode tool which is very accurate. Here’s Dmitry’s explanation:

“The pentode model equations, as defined by Koren, have one very, very important property: they reduce to a pretty accurate triode model of the same device if the screen moves together with the plate (I have a parameter UL for that and for ultra-linear arrangement, UL=1 is triode – try it! – then ul=0.4 or so is for UL connection, UL>1 is so called supertriode connection). That’s the good news, a really good one but that is the end of the good news. The bad news is that pentode and tetrode fitting can be at best very approximate – that is, the knee region and the slopes are not right for most tetrodes and pentodes, with the exception for some small-signal pentodes.”

Here is my model. Hopefully someone can try it and report some results:

** 4P1L PENTODE ************************************************************
* Created on Sun Jan 06 18:21:28 GMT 2013 using tube.model.finder.PaintKIP
* model URL:
*————————————————–
.SUBCKT PENT_4P1L PENTODE 1 2 3 4 ; P G K G2
+ PARAMS: CCG=9P CGP=0.1P CCP=9.5P RGI=2000
+ MU=9.27 EX=1.4139 KG1=1658.84 KG2=3528.0 KP=469.2 KVB=40.504 ; Vp_MAX=450.0 Ip_MAX=0.07 Vg_step=1.0
*————————————————–
RE1 7 0 1MEG ; DUMMY SO NODE 7 HAS 2 CONNECTIONS
E1 7 0 VALUE= ; E1 BREAKS UP LONG EQUATION FOR G1.
+{V(4,3)/KP*LOG(1+EXP((1/MU+V(2,3)/V(4,3))*KP))}
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1*ATAN(V(1,3)/KVB)}
G2 4 3 VALUE={(EXP(EX*(LOG((V(4,3)/MU)+V(2,3)))))/KG2}
RCP 1 3 1G ; FOR CONVERGENCE
C1 2 3 {CCG} ; CATHODE-GRID 1
C2 1 2 {CPG1} ; GRID 1-PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
R1 2 5 {RGI} ; FOR GRID CURRENT
D3 5 3 DX ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS