Hammond 125E 15 W Universal Push-Pull Tube Output Transformer
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Create Free Business AccountKey Features
- 15 W push-pull output, the largest in the 125A-125E range
- 1,200 to 25,000 ohm CT primary with 1.5 to 15 ohm speakers
- 60 mA max DC bias per side; 2.99 H primary inductance
- Secondary solder lugs 1-6 for convenient speaker connection
- 1500 Vrms dielectric strength; up to 105C temperature range
- Open style, 3.69 x 2.00 x 2.31 in, 1.5 lbs
- RoHS and REACH compliant, made in Canada
The 125E is the highest-power model in the 125A-125E universal push-pull "classic" tube output family, rated at 15 audio watts. It is intended for general purpose or replacement use (not Hi-Fi) in push-pull tube output circuits, giving repair shops and amplifier builders one part that can stand in for many different output transformers.
Solder lugs 1 to 6 on the secondary let you set the reflected primary impedance, blue wire to brown wire, from 1,200 to 25,000 ohms with 1.5 to 15 ohm voice coils. As examples from the hook-up table, an 8 ohm speaker across lugs 1&4 reflects 11,600 ohms, and a 15 ohm speaker across lugs 2&6 reflects 8,000 ohms.
The 125E is rated for a maximum of 60 mA DC bias per side, with 2.99 H primary inductance listed in the ordering table. Typical drawing values are 162 ohms primary DCR (blue - brown), 6.40 H primary inductance and 38.4 kOhm primary impedance at 1 kHz, 1 V. Dielectric strength is 1500 Vrms, the temperature range is up to 105C, and typical response is 1.0 dB from 100 Hz to 15 kHz; the label is marked 100Hz - 30kHz, 15 WATTS.
It is an open style transformer with minimum 5 inch primary leads (BLU plate, RED B+, BRN plate). Overall dimensions are A 3.69 in (94 mm), B 2.00 in (51 mm), C 2.31 in (59 mm) and D 3.13 in (80 mm), with 0.19 in (5 mm) mounting holes, and it weighs 1.5 lbs (0.68 kg). The part is made in Canada and RoHS and REACH compliant. For single ended amplifiers, the 125SE Series is recommended.
Ideal For
- Replacement output transformer for 15 W push-pull tube amplifiers
- Push-pull tube audio and guitar amp output stages
- Matching tube outputs to 1.5-15 ohm speakers
Overview
| Series | 125A-125E Series Universal Push-Pull Tube Output |
| Application | General purpose or replacement use (not Hi-Fi) in push-pull tube output circuits |
| Description | Audio transformer, universal push-pull tube output, 15 watts |
| Part Number | 125E |
| Short Description | AUDIO TX OUTPUT SE OR PP |
| Single-Ended Alternative | For single ended use, see the 125SE Series |
Dimensions
| A (Overall) | 3.69 in (94 mm) |
| B (Overall) | 2.00 in (51 mm) |
| C (Overall) | 2.31 in (59 mm) |
| D (Overall) | 3.13 in (80 mm) |
| Weight (Table) | 1.5 lbs |
| G - Mounting Hole | 0.19 in (5 mm) |
Electrical
| Audio Watts | 15 |
| Label Marking | PRI: BLU - RED - BRN 1200 - 25000 OHM CT; 100Hz - 30kHz; 15 WATTS |
| Secondary DCR 1-2 | 111 mΩ |
| Secondary DCR 1-3 | 248 mΩ |
| Secondary DCR 1-4 | 392 mΩ |
| Secondary DCR 1-5 | 582 mΩ |
| Secondary DCR 1-6 | 790 mΩ |
| Dielectric Strength | 1500 Vrms |
| Primary Connections | BLU (plate), RED (B+ centre tap), BRN (plate) |
| Output Power (Typical) | 15 Watts |
| Max. DC Bias Per Side | 60 mA |
| Primary Impedance Range | 1,200 to 25,000 ohms |
| Secondary Impedance 1-2 | 2.77 Ω @ 1.0 kHz, 1.0 V OC |
| Secondary Impedance 1-3 | 16.2 Ω @ 1.0 kHz, 1.0 V OC |
| Secondary Impedance 1-4 | 42.8 Ω @ 1.0 kHz, 1.0 V OC |
| Secondary Impedance 1-5 | 99.6 Ω @ 1.0 kHz, 1.0 V OC |
| Secondary Impedance 1-6 | 169 Ω @ 1.0 kHz, 1.0 V OC |
| Secondary Inductance 1-2 | 0.36 mH @ 1.0 kHz, 1.0 V OC |
| Secondary Inductance 1-3 | 1.92 mH @ 1.0 kHz, 1.0 V OC |
| Secondary Inductance 1-4 | 4.90 mH @ 1.0 kHz, 1.0 V OC |
| Secondary Inductance 1-5 | 10.6 mH @ 1.0 kHz, 1.0 V OC |
| Secondary Inductance 1-6 | 38.0 mH @ 1.0 kHz, 1.0 V OC |
| Input Impedance (Typical) | 1200 - 25000 Ω |
| Primary DCR, Blue - Brown | 162 Ω |
| Secondary Impedance Range | 1.5 to 15 ohms |
| Output Impedance (Typical) | 1.5 - 15 Ω |
| Primary Inductance (Table) | 2.99 H |
| Frequency Response (Series) | 150 Hz - 15 kHz at full rated power (+/- 1 dB max, ref. 1 kHz) |
| Frequency Response (Typical) | Typ. 1.0 dB from 100 Hz to 15 kHz |
| Primary Impedance Blue - Brown | 38.4 kΩ @ 1.0 kHz, 1.0 V OC |
| Primary Inductance Blue - Brown | 6.40 Hy @ 1.0 kHz, 1.0 V OC |
Identifiers
| UPC | 623980189000 |
| UNSPSC | 39121301 |
Hook-Up Data
| Speaker On Secondary Lugs 1&2 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 27000 Ω |
| Speaker On Secondary Lugs 1&3 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 5400 Ω; 2 Ω speaker: 7200 Ω; 3.2 Ω speaker: 11500 Ω; 4 Ω speaker: 15000 Ω; 6 Ω speaker: 21600 Ω |
| Speaker On Secondary Lugs 1&4 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 2150 Ω; 2 Ω speaker: 2900 Ω; 3.2 Ω speaker: 4600 Ω; 4 Ω speaker: 5800 Ω; 6 Ω speaker: 8700 Ω; 8 Ω speaker: 11600 Ω; 12 Ω speaker: 17400 Ω; 15 Ω speaker: 21500 Ω |
| Speaker On Secondary Lugs 1&5 - Resulting Primary Impedance (BLU To BRN) | 2 Ω speaker: 1400 Ω; 3.2 Ω speaker: 2200 Ω; 4 Ω speaker: 2800 Ω; 6 Ω speaker: 4200 Ω; 8 Ω speaker: 5600 Ω; 12 Ω speaker: 8400 Ω; 15 Ω speaker: 10200 Ω |
| Speaker On Secondary Lugs 1&6 - Resulting Primary Impedance (BLU To BRN) | 3.2 Ω speaker: 1200 Ω; 4 Ω speaker: 1500 Ω; 6 Ω speaker: 2300 Ω; 8 Ω speaker: 3000 Ω; 12 Ω speaker: 4500 Ω; 15 Ω speaker: 5600 Ω |
| Speaker On Secondary Lugs 2&3 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 18000 Ω; 2 Ω speaker: 24000 Ω |
| Speaker On Secondary Lugs 2&4 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 4200 Ω; 2 Ω speaker: 5600 Ω; 3.2 Ω speaker: 9000 Ω; 4 Ω speaker: 11200 Ω; 6 Ω speaker: 16800 Ω; 8 Ω speaker: 22500 Ω |
| Speaker On Secondary Lugs 2&5 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 1550 Ω; 2 Ω speaker: 2050 Ω; 3.2 Ω speaker: 3300 Ω; 4 Ω speaker: 4100 Ω; 6 Ω speaker: 6150 Ω; 8 Ω speaker: 8200 Ω; 12 Ω speaker: 12300 Ω; 15 Ω speaker: 15500 Ω |
| Speaker On Secondary Lugs 2&6 - Resulting Primary Impedance (BLU To BRN) | 3.2 Ω speaker: 1700 Ω; 4 Ω speaker: 2100 Ω; 6 Ω speaker: 3150 Ω; 8 Ω speaker: 4200 Ω; 12 Ω speaker: 6300 Ω; 15 Ω speaker: 8000 Ω |
| Speaker On Secondary Lugs 3&4 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 16500 Ω; 2 Ω speaker: 22000 Ω |
| Speaker On Secondary Lugs 3&5 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 3300 Ω; 2 Ω speaker: 4400 Ω; 3.2 Ω speaker: 7000 Ω; 4 Ω speaker: 8800 Ω; 6 Ω speaker: 13200 Ω; 8 Ω speaker: 17600 Ω; 12 Ω speaker: 26400 Ω |
| Speaker On Secondary Lugs 3&6 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 1300 Ω; 2 Ω speaker: 1700 Ω; 3.2 Ω speaker: 2700 Ω; 4 Ω speaker: 3400 Ω; 6 Ω speaker: 5100 Ω; 8 Ω speaker: 6800 Ω; 12 Ω speaker: 10200 Ω; 15 Ω speaker: 12800 Ω |
| Speaker On Secondary Lugs 4&5 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 10000 Ω; 2 Ω speaker: 13500 Ω; 3.2 Ω speaker: 21600 Ω; 4 Ω speaker: 27000 Ω |
| Speaker On Secondary Lugs 4&6 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 2400 Ω; 2 Ω speaker: 3200 Ω; 3.2 Ω speaker: 5100 Ω; 4 Ω speaker: 6400 Ω; 6 Ω speaker: 9600 Ω; 8 Ω speaker: 12800 Ω; 12 Ω speaker: 19200 Ω; 15 Ω speaker: 24000 Ω |
| Speaker On Secondary Lugs 5&6 - Resulting Primary Impedance (BLU To BRN) | 1.5 Ω speaker: 8500 Ω; 2 Ω speaker: 11000 Ω; 3.2 Ω speaker: 18000 Ω; 4 Ω speaker: 22000 Ω |
Packaging & Shipping
| Shipping Weight | 1.5 lbs (0.68 kg) |
Construction & Finish
| Style | Open style |
| Primary Leads | Minimum 5" long |
| Country Of Origin | Made in Canada |
| Secondary Connections | Solder lugs 1-6 |
Environmental & Protection
| Temperature Range | Up to 105C |
Compliance & Certifications
| RoHS Compliant | Yes |
| REACH Compliant | Yes |
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Frequently Asked Questions
What is the 125E rated for?▾
15 audio watts with up to 60 mA DC bias per side.
What impedances can it match?▾
Primary impedances from 1,200 to 25,000 ohms (blue to brown) with speakers of 1.5 to 15 ohms, set by the choice of secondary lugs.
What primary DC resistance does it have?▾
Typically 162 ohms, blue to brown.
Can I use it in a single ended amp?▾
It is designed for push-pull output; the 125SE Series is for single ended use.
What are its dimensions and weight?▾
A 3.69 in (94 mm), B 2.00 in (51 mm), C 2.31 in (59 mm), D 3.13 in (80 mm), 0.19 in (5 mm) mounting holes, 1.5 lbs.
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