Hammond 1750WR 135W Push-Pull Guitar Amp Output Transformer
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Create Free Business AccountKey Features
- 135 W push-pull output transformer for tube guitar amplifiers
- 2,000 ohm C.T. primary with 4 and 8 ohm secondary taps
- Includes 20% linear taps for added versatility
- Drop in replacement referenced to Fender 13691 (Bassman 135, Super Six 135, Vibrosonic Reverb 100)
- Frequency response 40Hz - 15KHz (0/-1.0dB ref. 1KHz), distortion under 1% at 40Hz
- Open style with minimum 10 in primary and secondary leads
- 2000VRMS dielectric strength, -40 to 105 degC temperature range
- RoHS and REACH compliant
The 1750WR is a 135 watt push-pull output transformer for tube guitar amplifiers, built as a drop in replacement for original Fender units. It is aimed at amp technicians, restorers and builders servicing high-power Fender designs such as the Bassman 135, Super Six 135 and Vibrosonic Reverb 100, and it is referenced against Fender part number 13691. The drawing lists a typical application of Fender 013691 for the Bassman 135, Twin Reverb and Vibrosonic Reverb.
Electrically, the 1750WR matches a 2,000 ohm center-tapped primary to 4 and 8 ohm speaker loads and includes 20% linear taps for added versatility. Typical frequency response is 40Hz to 15KHz (0/-1.0dB referenced at 1KHz) with distortion below 1% at 40Hz. Measured primary DC resistance is 65.70 ohms (brown-red) and 66.30 ohms (red-blue); primary inductance is 12.64H (76.18K ohm impedance) at 1.0 kHz, 1.0 V, with 2.28mH leakage inductance. Dielectric strength is 2000VRMS and the rated temperature range is -40 to 105 degC.
Construction follows the original part as closely as possible in material and design specifications to preserve the stock tone, and the unit is made to look similar to the factory transformer where possible. It is an open style transformer with primary and secondary leads at least 10 inches long. The manufacturer's part page lists a bobbin winding, while the series ordering table lists paper, so check the variant you need before ordering.
Drawing dimensions include A 4.050 in, B 3.715 in, C 3.500 in, D 3.500 in, E 2.500 in and F 3.020 in, with 0.187 x 0.300 in mounting slots. Shipping weight is 6.5 lbs (2.95 kg), and the 1750WR is RoHS and REACH compliant.
Ideal For
- Replacing the output transformer in a Fender Bassman 135
- Servicing Super Six 135 and Vibrosonic Reverb 100 amplifiers
- 135 W push-pull tube amplifier repair and restoration
- Upgrading high-power amp builds that need 4 and 8 ohm outputs
Overview
| Series | 1750 Series (Tube Guitar Amplifier - Output Transformers) |
| Product Type | Tube guitar amplifier output transformer |
| Manufacturer Description | Output transformer, guitar amp, 2,000 C.T ohm pri., 4, 8 ohm sec., 135W |
| Manufacturer Short Description | CUSTOM TRANSFORMER 135W FENDER |
Dimensions
| Dimension A | 4.050 in ±0.063 |
| Dimension B | 3.715 in ±0.125 |
| Dimension C | 3.500 in ±0.063 |
| Dimension D | 3.500 in ±0.063 |
| Dimension E | 2.500 in ±0.063 |
| Dimension F | 3.020 in ±0.063 |
| Mounting Slot G | 0.187 in x 0.300 in ±0.015 |
Electrical
| Distortion | Less than 1% @ 40Hz |
| Linear Taps | Includes 20% linear taps |
| Power Rating | 135 W |
| Amplifier Type | Push-Pull |
| Primary Impedance | 2,000 ohms C.T. |
| Frequency Response | 40Hz - 15KHz (0/-1.0dB reference @ 1KHz) |
| Dielectric Strength | 2000VRMS |
| Secondary Impedance | 4, 8 ohms |
| DCR Primary Red-Blue | 66.30 ohms |
| DCR Primary Brown-Red | 65.70 ohms |
| DCR Secondary Black-Green | 0.220 ohm |
| DCR Secondary Black-Grn/Yel | 0.156 ohm |
| Leakage Inductance (Brown-Blue, @ 1.0 KHz, 1.0 V SC) | 2.28mH |
| Primary Inductance / Impedance (Brown-Blue, @ 1.0 KHz, 1.0 V OC) | 12.64H / 76.18K ohm |
Identifiers
| UPC | 623980298443 |
| UNSPSC | 39121301 |
Compatibility
| Fender Amp Models (Ref.) | Bassman 135, Super Six 135, Vibrosonic Reverb 100 |
| Original Amp Manufacturer | Fender |
| Similar Fender P/N (Ref.) | 13691 |
| Typical Application (Drawing) | Fender 013691 for Bassman 135, Twin Reverb, Vibrosonic Reverb |
Packaging & Shipping
| Shipping Weight | 6.5 lbs (2.95 kg) |
Construction & Finish
| Leads | Minimum 10 in long primary and secondary leads |
| Style | Open style |
| Appearance | Constructed to look similar to original factory units (where possible) |
| Design Intent | Designed for drop in replacement of original units |
| Materials & Design | Material used and design specifications kept as close as possible to the original part to preserve the stock "tone" |
| Winding Type (Part Page) | Bobbin |
| Winding (Series Ordering Table) | Paper |
Environmental & Protection
| Temperature Range | -40 to 105 degC |
Compliance & Certifications
| RoHS Compliant | Yes |
| REACH Compliant | Yes |
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Frequently Asked Questions
Which amplifiers is the 1750WR intended for?▾
The series table lists the Fender Bassman 135, Super Six 135 and Vibrosonic Reverb 100, similar to Fender part number 13691. The drawing gives a typical application of Fender 013691 for the Bassman 135, Twin Reverb and Vibrosonic Reverb.
What impedances does the 1750WR provide?▾
It has a 2,000 ohm center-tapped primary and 4 and 8 ohm secondaries, rated 135 W in push-pull service.
Is the 1750WR paper or bobbin wound?▾
The manufacturer's part page lists the winding type as bobbin, while the series ordering table lists paper.
What is the frequency response?▾
40Hz to 15KHz, 0/-1.0dB referenced at 1KHz, with distortion under 1% at 40Hz.
How long are the leads?▾
It is an open style transformer with primary and secondary leads at least 10 in long.
