Tube Output Transformers
All OPTs are built to order in our dual coil single C-core style and can be ordered with a choice of core air-gap for Push-Pull or Single-Ended applications. Most of our OPTs can be configured for different primary and secondary impedances. For the comprehensive list of sub-types, please click here.
The use of C-cores with well-defined air-gap results in an almost constant inductance throughout the whole operating voltage range. For SE transformers, the primary inductance variation due to signal level is less than 7%.
Most of the transformers below are available with amorphous iron C-cores. The amorphous cores are considered to have sonic advantages, but the signal level capability with amorphous core is about 30% less than with a conventional silicon-iron C-core.



Tube output transformers, sorted in Primary Impedance
Model
Primary Impedance
Secondary impedance
Max power at 30Hz Push Pull
Max power at 30Hz Single Ended
Weight KG
Configuration
see data sheet
Price
USD
Suitable for tubes
600Ω
700W
140W
4.5
C
361.00
650Ω
250W
50W
2.5
C
241.00
680Ω
4Ω, 8Ω,16Ω
700W
140W
4.6
C,D,E
357.00
1K
360W
70W
4.5
B
361.00
1.2K
4Ω, 8Ω, 16Ω
125W
25W
2.5
B,C,D
241.00
1.2K
4Ω, 8Ω, 16Ω
360W
70W
4.6
B,C,D
387.00
1.2K
4Ω, 8Ω
180W
36W
2.5
C,D
available in AM & Ag, call for pricing
241.00
1.6K
4Ω, 8Ω, 16Ω
250W
50W
2.5
C,D,E
241.00
2K
4Ω, 8Ω, 16Ω
105W
21W
2.5
B,C,D
available in AM & Ag, call for pricing
241.00
2.3K
8Ω, 16Ω
180W
35W
4.5
B,C
361.00
KT66 
2.3K
8Ω, 16Ω
62W
13W
2.5
B,C
241.00
KT66
2.6K
4Ω, 8Ω, 16Ω
188W
36W
2.5
C,D,E
243.00
2.6K
8Ω, 16Ω
180W
35W
4.6
B,C
387.00
3K
4Ω, 8Ω, 16Ω
125W
25W
2.5
B,C,D
241.00
300B
3K
8Ω, 16Ω
112W
2.2W
0.74
B,C
132.00
300B
3k
8Ω, 16Ω
112w
2.2W
0.74
B,C
Nanocrystalline core
301.00
300B
3K
55W
10W
1.4
150.00
300B
3K
5Ω tap
N/A
16W
2.5
288.00
300B
3K
8Ω tap
N/A
16W
2.5
288.00
300B
3.1K
105W
21W
2.5
3.1K : 5
241.00
300B
3.2K
100W
20W
2.5
3.1K : 8
241.00
300B
3.3K
4Ω, 8Ω, 16Ω
250W
50W
2.5
C,D,E
241.00
300B
4.3K
4Ω & 8Ω
160W
N/A
2.5
Multi tap secondary OPT
289.00
KT88, KT120
4.5K
4Ω, 8Ω, 16Ω
105W
20W
2.5
B,C,D
243.00
KT88, KT120
4.6K
8Ω, 16Ω
45W
10W
2.5
B,C
available in AM & Ag, call for pricing
241.00
EL34,KT88
4.7K
5Ω & 8Ω
100W
20W
2.5
5+8 Elekit
241.00
EL34,KT88,
KT120
4.7K
5Ω, 8Ω
100W
20W
2.5
5Ω,8Ω
241.00
EL34,KT88,
KT120 
5K
40W
8W
1.4
150.00
LL1663AM

5K
40W
8W
1.4
Amorphous core
330.00
LL1663Ag

5K
40W
8W
1.4
Silver wire
4098.00
LL1663AgAM

5K
40W
8W
1.4
Silver wire and amorphous core
4365.00
5.5K
4Ω, 8Ω, 16Ω
320W
60W
4.0
C,D,E
361.00
5.5K
40W
8W
1.4
150.00
LL1682AM

5.5K
40W
8W
1.4
Amorphous core
330.00
LL1682AgAM

5.5K
40W
8W
1.4
Silver wire and amorphous core
4098.00
5.6K
8Ω, 16Ω
62W
13W
2.5
B,C
241.00
6K
4Ω, 8Ω, 16Ω
125W
25W
2.5
B,C,D
241.00
6K
4Ω, 8Ω, 16Ω
24W
4W
0.75
B,C,D
132.00
6K
N/A
5W
1.35
198.00
6.5K
4Ω, 8Ω, 16Ω
250W
50W
2.5
C,D,E
241.00
9K
160W
30W
4.6
361.00
300B
9.2K
4Ω, 8Ω, 16Ω
160W
30W
4.0
B,C,D
361.00
9.7K
8Ω, 16Ω
45W
9W
2.5
B,C`
243.00
10K
4Ω, 16Ω
160W
30W
4.6
361.00
845
11K
4Ω, 8Ω, 16Ω
125W
25W
2.5
B,C,D
241.00
11K
95W
18W
4.6
361.00
11.5K
8Ω, 16Ω
62W
13W
2.5
B,C
241.00
16K
4Ω, 16Ω
N/A
5W
1.4
150.00
10Y, 801A
EML20B
16K
N/A
5W
1.4
150.00
10Y, 801A
EML20B
20K
4Ω, 16Ω
160W
30W
4.6
362.00
211
20K
160W
30W
4.6
362.00
211
LL1691BAg
20K
160W
30W
4.6
Silver wire
10513.00
211
23K
8Ω, 16Ω
62W
13W
2.5
B,C
241.00
To place an order, please click here