Power Transformers
We manufacture a limited range of C-core mains transformers, primarily for tube amplifiers. Our transformers are best used with bridge rectifier circuits (four diodes), but some transformers can also be used with full wave rectifier circuits. ‎
The hybrid power supply principle provides a bridge rectifier circuit using classical tube rectifier tubes in combination with modern diodes.
The transformer primaries are connected in series for 210 – 250V and in parallel for 105 – 125V. Secondary voltages are calculated for 230V / 115V primary voltage.
 
The secondary voltage listed are no-load voltage. Voltage drop because of load can be calculated from transformer copper resistance and load current. For optimal use, about 75% of power should be taken from secondary 1.
 
In our mains transformers, a small deliberate C-core air-gap is used to prevent from core saturation caused by any DC unbalance in the mains outlet.
 
 
 
 
 
Power Transformers
 Model
Secondary 1
Secondary 2 3
Secondary 4 5
Secondary 6
 Weight kg / Rating
Price
USD
350V/0.63A
5.9V/3.1A
6.6V/3.1A
  
2.5 / 250VA
192.00
230V/1.0A
6.6V/3.1A
6.6V/3.1A
  
2.5 / 250VA
192.00
350V/0.63A
6.6V/3.1A
6.6V/3.1A
  
2.5 / 250VA
192.00
500V/0.43A
6.6V/3.1A
6.6V/3.1A
  
2.5 / 250VA
192.00
530-0-530
6.6V/3.1A
6.6V/3.1A
  
2.5 / 250VA
192.00
340V/0.55A
6.3V/3.1A
6.3V/3.1A
110V/40mA
2.5 /250VA
203.00
250-0-250/0.16A
6.6V/3A
5.2V/3A
48V/0.1A
1.4 / 120VA
192.00
110V/0.1A
6.6V/3A
 
  
2.5 / 250VA
192.00
350V/0.63A
6.6V/3A
5.9V/3A
48V/0.1A
2.5 / 250VA
195.00
290V/0.55A
6.3V/3.1A
6.3V/3.1A
  
2.5 / 250VA
192.00
443V/0.3A
5.4V/4A
6.7V/2A
  
2.5 / 250VA
192.00
21V/2.5A x 2
21V/2.5A x 2
 
  
250VA
162.00
250-0-250/0.13A x2
6V/2A
6V/2A
30V/0.1A
1.4 / 100VA
192.00
115V/0.9A
115V/0.9A
 
  
2.5 / 200VA
185.00
350-0-350/0.2A
6.1V/2A + 4.7V/3A
4.7V/3A
150V/0.1A
2.5 / 250VA
212.00
Mains Isolation Transformers
 Model
Secondary 1
Secondary 2 3
Secondary 4 5
Secondary 6
 Weight kg / Rating
Price
USD
115V + 115V
 
 
  
2.5 / 300VA
192.00
115V + 115V
 
 
  
1.3 / 100VA
136.00
115V + 115V
10V + 10V
 
  
2.5 / 300VA
192.00
To place an order, please send your inquiry with your complete shipping address to erhardaudio@gmail.com, thank you.