EML 320B-XLS Data Sheet
Replaces also 842 tube

Last Update:

Description

This tube is the same as 300B-XLS, apart from the heater current, which is higher. For this reason we point out only the differences, and for all other information we refer to the 300B-XLS data sheet.

Front view


Side View

 

The intention of 320B-XLS vs 300B-XLS

With tubes, when increasing the heater power, the tube gets more suited for harder conditions. For this reason we recommend the 320B in situations where 300B-XLS would be used near the end of it's possibilities. Such as biased close to maximum, and for Push-Pull amplifiers. Though Push Pull can be made with any 300B, it is known to be harder on the tubes than a Single Ended design.

Sound Character of the EML 320B-XLS

Generally the even higher heater power of the 320B-XLS will give the tube a fraction more impulsiveness if used at high output power. So for designers who want to get the upmost in terms of output power, but are reluctant to stress the 300B-XLS very hard, 320B-XLS is the choice.

For use in Push Pull amplifiers, this tube is also a natural choice, because this type of amplifier is hard on the tubes by definition. The 320B-XLS is made to deal with such conditions, and will allow the amplifier to play gently at low sound level, as well as reproduce higher sound level with the detail and precision you expect from a push pull amplifier.

EML 320B-XLS heater Ratings
heater Voltage 
= 5 Volt (AC or DC) 
Tolerance on heater voltage
5%
heater Current

~ 1.7 Ampere
.
EML 320B-XLS Maximum Conditions 
(Voltage and current not possible simultaneously - not a recommended operating point)
Anode Voltage 
550Volt 
Anode Current 
160mA 
Power Output in Class A 
22Watt 
Peak Anode Dissipation 65 Watt, one minute

Highest possible Grid to ground resistor, Single Ended.
150kOhm 

Highest possible Grid to ground resistor, Push-Pull.
50kOhm 

 

320B-XLS Recommended Single Ended operating points
(This is just a selection, other choices are possible)

Anode Voltage

(Against Heater)

Control Grid Voltage

(Against Heater)
Anode Current (ma)
Anode Rp (Ohm)
Load
(Ohm)

Anode Dissi-pation

(Watt)

Power
Output (Watt)
2nd harm.
(dB)
.
450
-97
80
700
2000
36
18
22
450
-97
80
700
3000
36
15
26
450
-97
80
700
4500
36
12
31
.
475
-97
90
670
1900
43
21
23
475
-97
90
670
2800
43
17
27
475
-97
90
670
4200
43
14
32
.
500
-98
110
630
1800
55
27
23
500
-98
110
630
2700
55
22
27
500
-98
110
630
4000
55
17
32

Choice of output transformer impedance: For each working point, a wide range of primary impedance is possible. When using a transformer of another value, you can estimate the output power and distortion by averaging between two rows of this table. Example: 500V, 110mA. Use of Lundahl LL1623-120mA (3k type). This will give you appr. 20 Watt @ 28dB 2nd harmonics. (28dB distance of signal to 2nd harmonics.

 

EMISSION LABS 300B-XLS tube curves

Curves of 320B-XLS apply

 

Anode Curves Print Version (full size pdf)


Download these curves as PTE file


What is a PTE file?

Some recommended Lundahl transformers
  Primary
 Secondary
 Anode Current
LL1623-090mA
11Hz @1.5dB 		3000Ω Alt.B = 4Ω
Alt.C = 8Ω
Alt.D = 16Ω 		90mA

LL1623-120mA
13Hz @1.5dB

 3000Ω Alt.B = 4Ω
Alt.C = 8Ω
Alt.D = 16Ω 		120mA
Alternative:
Use transformer Impedance Boards for LL1623 by JACMUSIC.
EE16 switches between 4 and 8Ohms at 3k.
EE18 switches between 8 and 16Ohms at 3k.

LL1664-80mA
13Hz @1.5dB

 3000Ω 8Ω 80mA

Complete list of recommendations here

 

320B-XLS Mechanical Data

Size including Socket (but excluding pins): 175 x 63mm
Weight of one tube: 140 Gram
Shipment weight for pair in gift box: 750 Gram

Standard UX4 Base

 

Pin 1: Heater1
Pin 4: Heater2
Pin2: Anode
Pin3: Grid