OUTPUT PENTODE Output pentode rated for 25W anode dissipation, ntended for use in a.c. mains operated equipment. PRELIMINARY DATA HEATER Vh Ih 6.3 1.5 v A CAPACITANCES 7.2 15.5 <1.1 <1.0 11 pF pF pF pF pF Cout Cln C&-gl Cgl-h Ck-h CHARACTERISTICS Va v go Vgs la Igo Vgl gm ra (.I.gl-gO 250 250 0 100 14.9 -13.5 11 15 11 v v v mA mA V mA/V kil OPERATING CONDITIONS AS SINGLE VALVE CLASS "A" AMPLIFIER Pentode connection Va 250 V Vg2 250 V Vga 0 V Vg1 -13.5 V Rk 120 (1 la 100 mA Ig2 14.9 mA R. 2.0 k(1 V1n (r.m.B.) (Pout=50mW) 0.5 V *Pout 11 W V1n (r.m.B.) 8.7 V *Dtot 10 % *Pout and Dtot are measured at fixed bias and therefore represent the power output available during the reproduction of speech and music. When a sustained sine wave is applied to the control grid the bias across the cathode resistor will readjust itself as a result of the increased anode and screen-grid currents. This will result in approximately 10% reduction in power output. ISSUE 2 EL34 256-1
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OUTPUT PENTODE
Output pentode rated for 25W anode dissipation,
ntended for use in a.c. mains operated equipment.
PRELIMINARY DATA
HEATERVh
Ih
6.31.5
vA
CAPACITANCES7.2
15.5<1.1<1.0
11
pFpFpFpFpF
Cout
Cln
C&-gl
Cgl-hCk-h
CHARACTERISTICSVa
v go
Vgs
la
Igo
Vgl
gm
ra
(.I.gl-gO
250250
0100
14.9-13.5
111511
vvv
mAmA
VmA/V
kil
OPERATING CONDITIONS AS SINGLE VALVE CLASS "A"AMPLIFIER
Pentode connection
Va 250 VVg2 250 VVga 0 VVg1 -13.5 VRk 120 (1la 100 mAIg2 14.9 mAR. 2.0 k(1V1n (r.m.B.) (Pout=50mW) 0.5 V
*Pout 11 WV1n (r.m.B.) 8.7 V
*Dtot 10 %
*Pout and Dtot are measured at fixed bias and therefore represent thepower output available during the reproduction of speech and music.When a sustained sine wave is applied to the control grid the biasacross the cathode resistor will readjust itself as a result of theincreased anode and screen-grid currents. This will result inapproximately 10% reduction in power output.
ISSUE 2 EL34 256-1
OUTPUT PENTODE
Output pentode roted for 2SW onode dissipotion,
intended for use in a.c. mains operated equiPment.
OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL
Distributed load conditions with screen-grid tapping at 43% ofprimary turns
4301
4252 x 62.5
2x652x5.02x5.1
470326.6
200.8
430
1
425
2 x 62.5
2x70
2x5.0
2x7.5
470
52
6.6
37
1.3
vkO
VmAmAmAmA
OV
kOW
%
V"J-VRk
Rg2 (per valve)
Vg2+VRk
18(0)
18 (max. sig.)
Ig2(0)
Ig2 (max. sig.)
Rk (per valve)
V1n(gl-gl) r.m...
R8-8
Pout
Dtot
OPERATING CONDITIONS FOR TWO VALVES IN PUSH.PULL
Fixed bias
4251000
0
2x30
2x120
2x4.4
2x25
-38
3.4
54
55
5.0
375470
0
2x35
2x120
2x4.7
2x25
-32
2.8
45
44
5.0
yOy
mAmAmAmA
ykO
yW%
Vb
"Rg2
Vg2
18(0)
la (max. sig.)
Ig2 (0)
Ig2 (max. sig.)
Vg1
R8-a
V1n (gi-g 11 r.m.8.
Pout
Dtot
*Screen-grid resistor common to both valves,
These operating conditions apply with a stabilised line voltage andallow for a 25V drop in the primary winding of the output trans-former at maximum signal. If there is an additional drop of 25Vin the h.t. line voltage at maximum signal Pout=45W and 36W.The optimum anode-to-anode load under these conditions are4.0kD. and 3.8kD. respectively.
These operating conditions apply with stabilised line voltages andallow for a 2SV drop in the primary winding of the output trans-former at maximum signal. If there is an additional drop of 25Vin the line voltages at maximum signal Pout=58W and 90W. Theoptimum anode-to-anode load under these conditions are 5.0k!1and 11 kO respectively.
OPERATING CONDITIONS FOR TWO VALVES IN PUSH.PULL
Cathode biasVb 375 V
*Rg. 470 OtRk 130 OVg. O Vla(ol 2x75 mAla(max.sig.) 2x95 mAIg.(ol 2x11.5 mAIn (max.c5jgr) ! 2 x 22.5 mARa_a 3.4 kOV1n(gl-gl) r.m.8. 42 VPout 35 WDtot 5.0 %
*Screen-grid resistor common tO both valves.
tCommon cathode bias resistor.
These operating conditions allow for a 20V drop in the primarywinding of the output transformer and a 5V drop in the h.t. linevoltage at maximum signal.
ISSUE 2 EL34 1056.3
OUTPUT PENTODE
Output pentode rated far 25W anode dissipation,
intended for use in a.c. mains operated equipment.
"A"OPERATING CONDITIONS AS SINGLE VALVE CLASSAMPLIFIER