Universal Single Ended Output Transformers for Tube Amps
Author: Kevin M Date Posted:3 November 2017
Universal Single Ended Tube Output Transformers
General purpose and Hi-Fi output transformers for single ended amps
- 125SE Series for general purpose and replacement use, from 3 W to 25 W.
- 1626–1642 Series Hi-Fi transformers from 25 W to 75 W, with recommended triode and pentode tubes.
- Click any part number to see price, stock and dimensions in our shop.
If you cannot find the item you wish to purchase on our website, email us at info@evatco.com.au.
No matching parts. Email info@evatco.com.au and we will help find one.
125SE Series: General Purpose Single Ended
- Designed for general purpose or replacement use (not Hi-Fi) in single ended tube output circuits.
- Frequency response: 100 Hz – 15 kHz at full rated power (±1 dB max, ref. 1 kHz).
- Open style with minimum 12" long primary and secondary leads.
- All sizes use butt stacked cores (29M6 steel) with an air gap, to reduce D.C. core saturation.
- Primary impedance from 2,500 to 10,000 Ω. Secondary impedance from 4 to 32 Ω.
- Need full frequency response (20 Hz – 20 kHz)? See the 1627–1642 Series. For push-pull use, see the 125 Series.
| Part No. | Minimum Inductance | DC Resistance (±20%) |
|---|---|---|
| 125ESE | 9.58 H | 90.6 Ω |
Single Ended Hi-Fi Tube Output: 25–75 Watts
Recommended tubes for each transformer are listed in the table below.
- Designed for high fidelity, single ended, Class-A tube output circuits (triode, tetrode or pentode tubes).
- Enclosed (shielded) construction with four slot, chassis Type "X" mounting.
- Frequency response at least 20 Hz – 20 kHz at full rated power (±1 dB max, ref. 1 kHz).
- Insulated flexible leads, 8" minimum.
- Every unit except the 1642SE and 1638SEA includes a 40% screen tap for Ultra-Linear tetrode/pentode operation. The 1642SE and 1638SEA have no screen tap as they are designed mainly for high impedance triode tubes.
- High quality grain oriented silicon steel laminations (M6), gapped to reduce core saturation in Class-A circuits.
- Can't see an amp in our website? We may not range it day to day. Let us know and we can special order it for you.
| Part No. | Audio Watts | Primary Impedance (Ω) | Primary Max DC Bias | Inductance | Ultra-Linear 40% Tap | Secondary Impedance (Ω) | Hipot Test (VRMS) |
|---|---|---|---|---|---|---|---|
| 1626SEA | 25 | 600 | 200 mA | 2.9 H | Yes | 4 - 8 - 16 | 2000 |
| 1640SEA | 30 | 1,250 | 200 mA | 14 H | Yes | 4 - 8 - 16 | 2000 |
| 1627SEA | 30 | 2,500 | 160 mA | 20 H | Yes | 4 - 8 - 16 | 2000 |
| 1630SEA | 30 | 3,500 | 135 mA | 42 H | Yes | 4 - 8 - 16 | 2000 |
| 1628SEA | 30 | 5,000 | 120 mA | 48 H | Yes | 4 - 8 - 16 | 2000 |
| 1642SE | 75 | 5,000 | 300 mA | 53 H | No | 4 - 8 - 16 | 3500 |
| 1629SEA | 30 | 6,500 | 100 mA | 55 H | Yes | 4 - 8 - 16 | 2000 |
| 1638SEA | 30 | 10,000 | 90 mA | 88 H | No | 4 - 8 - 16 | 2000 |
Recommended Tubes
"Parallel" means the listed tubes are run in parallel to share the load.
| Part No. | Triodes | Pentodes |
|---|---|---|
| 1626SEA | 6C33 | — |
| 1640SEA | Parallel:2A36A36B4G300B572B811A | Parallel:65506CA7 |
| 1627SEA | 2A36A36B4G300B | 6CA76L680758816550Parallel:6AQ56V6EL84 |
| 1630SEA | 2A36A36B4G300B | 6CA76L680758816550Parallel:6AQ56V6EL84 |
| 1628SEA | 211300B572B811A | 6AQ56V66L680758816550EL84 |
| 1642SE | Parallel:211572811A845 | — |
| 1629SEA | 211811A572B845 | 6AQ56V66L680758816550EL84 |
| 1638SEA | 211845 | — |
Need dimensions, mounting details or help matching a transformer to your build? Search the part number in our shop or email info@evatco.com.au.
