SOWTER AUDIO TRANSFORMERS
PRE/LINE AMP SUMMARY

LINE OUTPUT TRANSFORMERS are available for the various types of amplifier commonly used. These are push-pull, single ended, and ac coupled either taking the output from a cathode follower or SSRP or as a parafeed arangement from the anode. In the case of the PP or SE transformers a step down ratio is used to lower the output impedance as a trade off with the output voltage level. It is always a good idea to have a low output impedance to drive the line capacitance and Miller capacitance of the power amplifier.

"600 OHM" BALANCED LINES are used almost universally in recording, broadcasting and most large installations where analogue signals need to be fed from one piece of equipment to the next. The balancing virtually eliminates ground noise and unwanted signals which can be induced into cables. Transformers are a very effective means for converting unbalanced signals to balanced as well as providing almost complete isolation from ground noise. A further benefit of using balanced lines is the elimination of unwanted "pops" and "bangs" when signals are switched. Many HiFi enthusiasts are now using 600 ohm lines as their equipment becomes more complex.

PRE AMP AND LINE AMP PRODUCTS

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world wide

TYPE
click for spec
Descr.

Application/

Primary inductance

Voltage
ratio
Nominal
Z ratio
Total DC res ref secy ohms Max level at 50 Hz (dBu) Max level at 50 Hz (V rms) Package /core size/style
Buy 9041

PUSH-PULL
Line Output

 

PP triode 125H
0.5 mA unbalance
5CT:1 15k / 600 39 +23
(output)
11 j open 70% Mumetal
Buy 8650 PP triode 250H
0.5 mA unbalance
9CT:1 15k / 185 14 +28 (output) 19 A open 50% Mumetal
Buy 9050 As 8650 250H
0.5 mA unbalance
6CT:1 15k / 417 31 +32
(output)
30 A open 50% Mumetal
Buy 9900 PP triode 100H 8CT:1+1 10K/
150+150
65 +36
(output)
49 D 100% M6 Shrouded or open frame
Buy 1161

PP triode 120H
Geometric balance

11.5:1+1 20K/
150+150
54 +40
(output)
77 D 100% M6 Shrouded or open frame
Buy 9745 PP triode
73H
10CT:1+1

15K/
150+150

77 +36
(output)
49 A 100% M6 Shrouded or open frame
Buy 1160 SINGLE ENDED
Line Output
30 mA 40H 10:1
or 5:1
15K/
150+150
76 +30
(output)
  D Shrouded
100% M6
Buy 9705 30 mA 40H 4:1 10k / 600 95 +24
(output)
12 D Shrouded
100% M6
Buy 9040 40 mA 50H 5:1 15k / 600 65 +30 (output) 24 H Shrouded 100% M6
Buy 9560 3.75:1 8K / 600 93 +26
(output)
18
Buy 9042 AC Coupled Line Output AC coupled Cathode follower 3CT:1 5k / 600 39 +23
(output)
11 j open 70% Mumetal
Buy 1010 AC Coupled Cathode follower 5:1 15K/600 30 +30 25 A open 50% Mumetal
Buy 8940 AC Coupled Cathode follower 3:1 5k / 600 17 +28 (output) 19 A open 50% Mumetal
Buy 9111 Parafeed Line Output 6.4 :1
3.2 : 1
1.62 : 1
22K / 600
6K / 600
1k5 / 600
20 +20
+26
+32
8.4
16
33
A (Mumetal can)
Buy 3575 Input Isolating, Unbal/Bal conversion Amp or PC card to bal input 1:1CT 10k / 10k 1300 +26 15 e (Mumetal can)
Buy 8920 Input phase splitter. 1:1+1 Full geometric balance 10K/
10K+10K
3200 +28 19

f (Mumetal can)

Buy 1125 Input phase splitter. 1:0.5+0.5 Full geometric balance 10K/
2.5K+2.5K
1468 +28 19 f (Mumetal can)
Buy 3603 PC card or CD player to bal output 1:1CT 600/600 150 +17 5.5 e (Mumetal can)
Buy 8540 Line and mic etc input     600 ohm input phase splitter 1:4CT 600/10k
47k load ok
112
ref pry
+16 (Input) 4.9 e (Mumetal can)
Buy 4383 600 ohm to grid 1CT:4 600/10k
47k load ok
112
ref pry
+16 (Input) 4.9 e (Mumetal can)
Buy 4935 200 ohm to grid 1CT:7 200/10k
47k load ok
50
ref pry
+12 (Input) 3.1 e (Mumetal can)
Buy 9045 50/200 ohm to grid(s) geometric balance 1+1:5CT 200/25k 45
ref pry
+18 (Input) 6.2 j(Mumetal can)
Buy 9062 Very High level 600 ohm to grid(s) geometric balance 1CT:4+4 600/40k 103 ref pry +24 (Input) 100 j(Mumetal can)
Buy 9063 Very High level 600 ohm to grid(s) geometric balance 1CT:2+2 600/10k 102 ref pry +24 (Input) 50 j(Mumetal can)
Buy 9762 DAC to tube amplifier interface I/V transformer for CD player 1:6.4+6.6 200 Ohm I/V resistor   n/a n/a j (Mumetal can)