Transformers & Chokes

One Electron

One Electron chokes and transformers are designed by John Atwood, to fill the need for high-quality yet affordable audio transformers and chokes that are not normally available elsewhere.

Hammond

Hammond Manufacturing offers a full range of transformers, chokes and enclosures.
P-T298DT Transformer - Hammond, Line Step Up Isolation, Toroidal, 500 VA
Capacity: 500 VA
Dimensions: 9" long by 6" wide by 4" height
Features:
  • Primary 120VAC, 50/60 Hz., Secondary 240VAC.
  • Provides circuit isolation.
  • Toroidal transformer for high isolation, low noise, light weight cool operation and low profile.
  • 50 or 60 Hz.
$270.24
P-T1182-40 Transformer- Hammond, Toroidal Power, 40V / 80V secondary
Dual 117/234 VAC primary, 50/60 Hz. operation. 80 V series, 40 V parallel secondary.
$225.18
P-TBFT-1B Transformer - One Electron, BFT-1B, Power
The BFT-1B from One Electron was designed to power a stereo amplifier using UBT-1's in each channel but will also power an 80 watt push-pull tube amplifier. The BFT-1B is slightly larger than earlier versions of the BFT-1, allowing lower flux density and cooler operation. The tapped high-voltage windings and three filament windings provide flexibility in design. An electrostatic shield between the primaries and secondaries reduces power-line noise coupling. The primary arrangements allows use on virtually any power grid in the world.
$225.00
P-T162XSEA Transformer - Hammond, Output, Single-Ended, 30 W
  • Over designed for single ended tube output circuits (triode, tetrode or pentode tubes).
  • Enclosed (shielded), 4 slot, above chassis Type 'X' mounting.
  • Frequency response at least 20 Hz. to 20 Khz. at full rated power (± 1 db max. ref.
$159.23
P-T176D Transformer - Hammond, Step-Up, 500VA
Capacity: 500VA Features:
  • Single winding does not provide isolation, for use where equipment is already isolated and only voltage change is required.
  • World wide applications, 50 or 60 Hz.
$132.86
P-TUBT-2 Transformer - One Electron, Output, 4800 Ω to 16/8/4 Ω
The UBT-2 from One Electron is the same size and power (15 watts) as the UBT-1, but has a higher primary impedance suitable for single tubes running at B+ voltages of 400 to 500 volts, such as: 50, WE 300B,etc.
$129.95
P-TUBT-1 Transformer - One Electron, Output, 1600 Ω to 16/8/4 Ω
The UBT-1 from One Electron is a low-impedance single-ended output transformer intended for parallel combinations of tubes running a B+ voltages of 250 to 325 volts, such as: two or three EL34s (triode connected), three 2A3s, two 300Bs, two 6AS7s, etc., as well as single sweep tubes run in 'enhanced-triode' mode, resulting in 10 to 15 watts of output power.
$125.00
P-T850-X Transformer - Hammond, Audio Broadcast Quality, 850A Series
Deep-drawn steel case with tin plated finish, with two convenient 6-32 mounting studs with mounting hardware. Sealed case and wax potted core internally for stable characteristics and long life. Wide frequency response +/- 0.5 db max. from 20 Hz. to 20 Khz. (except units over 5K ohms impedance, may be down 1 db @ 20 Khz.) Insertion loss of apx. 1 db.
$120.63
P-T300-Z Transformer - Hammond, High Voltage Universal Plate & Filament, Horizontal mount
  • Primary: Universal - 100, 110, 120, 200, 220,230, 240 VAC 50/60 Hz.
    • NOTE: units are designed to operate with BOTH primary windings engaged.
    • See primary wiring information under resources.
  • Bias Tap: 50 VAC tap from high voltage secondary C.T.
Starting at $111.62
P-TUBT-3 Transformer - One Electron, Output, 3000 Ω to 16/8/4 Ω
The UBT-3 from One Electron is the same size and power (15 watts) as the UBT-1, but has a primary impedance suitable for single or paralleled tubes running at B+ voltages of 300 to 400 volts, such as: 2A3, WE 300B, 50, etc.
$109.95
P-T800-X Transformer - Hammond, Audio Broadcast Quality, 800A Series
Deep-drawn steel case with tin plated finish, with two convenient 6-32 mounting studs with hardware. Includes wire leads (minimum length of 4"). Frequency response +/- 0.5 db max. from 50 Hz. to 15 Khz. Insertion loss of apx. 1 db. Maximum power level +15 dbm. (except 841A, 842A & 844A which are +20 dbm) with specified characteristics, or higher levels with reduced low frequency performance.
$106.28
P-T143 Transformer - Hammond, Power, 350-0-350V, 70-90 mA
Custom manufactured to replace most 6 and 7 tube sets of the early 1930s. Supplied with vertical mounting shells. Provides a seperate filament winding for audio output stages.
Specifications
Rating: 350-0-350 V, 70 or 90 mA (if 5 V winding is used with 2 A rectifier)
Windings: 5 V, 3 A; 2.5 V, 7.5 A; 2.5 VCT, 3.5 A
Mounting Centers:2 x 2.625"
Weight: 4.2 lbs.
Overall Height: 3.12"
$105.95
P-T1182-24 Transformer- Hammond, Toroidal Power, 24V / 48V secondary
Dual 117/234 VAC primary, 50/60 Hz. operation. 48 V series, 24 V parallel secondary.
Starting at $104.55
P-T1650XA Transformer - Hammond, Tube Output, Easy Wire Secondary
  • Designed for push-pull tube output circuits.
  • Enclosed (shielded), 4 slot, above chassis Type 'X' mounting.
  • Frequency response 30 Hz. to 30 Khz. at full rated power (± 1 db max. - ref.
Starting at $96.51
P-T290-MARSHALL Transformer - Hammond, Guitar Amplifier, replacement for Marshall
  • Replacements for Marshall amps
  • Designed for drop in replacement of original units.
  • Physically, parts were designed to look similar to original factory units (where possible).
  • Material used & design specs. were kept as close as possible to the original part to preserve the stock "tone".
Starting at $96.50
P-T1750X-VOX Transformer - Hammond, Output, replacement for Vox
  • Replacements for Vox Amps
  • Designed for drop in replacement of original units.
  • Physically, parts were designed to look similar to original factory units (where possible).
  • Material used & design specs. were kept as close as possible to the original part to preserve the stock "tone".
Starting at $95.44
P-T171X Transformer - Hammond, Isolation / plug & receptacle
  • Primary 115VAC, 50 / 60 Hz., Secondary 115VAC
  • Provides complete circuit isolation.
  • Electrostatic shield between primary & secondary to greatly attenuate surges and noise.
  • Hi-pot tested to 2 KV RMS.
  • Circuit breaker in primary.
  • Standard 3-wire, grounded plug & receptacle.
  • Input (primary) connected to 5 foot long cord & standard North American plug (NEMA 5-15P).
  • Output (secondary) connected to 1 foot long "pig tail" cord, 3-wire, standard North American grounded receptacle (NEMA 5-15R).
  • North American Mark of Safety - C UL & UL listed (File #E211544)
  • Indoor use only
  • Remember - These units do NOT convert line frequency
Starting at $87.42
P-T1650X Transformer - Hammond, Tube Output, Push-Pull
  • Designed for push-pull tube output circuits.
  • Enclosed (shielded), 4 slot, above chassis Type 'X' mounting.
  • Frequency response 30 Hz. to 30 Khz. at full rated power (± 1 db max. - ref.
Starting at $85.25
P-RC-1 Choke - One Electron, Audio, PRC-1, for Shunt Feed SE Output
The PRC-1 audio choke from One Electron was designed for shunt-feed single-ended output applications, but is also useful where quality inductive loads are needed or as high-quality filter chokes.
$85.00
P-T290-FENDER-120-UP Transformer - Hammond, Guitar Amplifier, replacement for Fender, 120 V upgrade
  • Designed for drop in replacement of original units. Upgraded units with variable voltage.
  • Physically, parts were designed to look similar to original factory units (where possible).
  • Material used & design specs. were kept as close as possible to the original part to preserve the stock "tone".
  • See P-T290-FENDER-120 for 120 V basic transformers, P-T290-FENDER-240 for 240 V transformers

Warning: Not all amplifier models of the same name use the same transformer model.
Starting at $84.18
P-T126B Transformer - Hammond, Tube Driver Interstage
Audio watts: 4
Impedance: 5k ohms
D.C. Resistance: 178 ohms
Inductance: 44 henries
Rated D.C. Bias Current: 30 mA
Features:
  • Designed for driver use ONLY in single ended tube output amplifiers. These units replace coupling capacitor circuits for improved sound.
  • Closed style with minimum 8" long leads.
  • All models use bifilar wound windings for exceptional coupling and bandwidth.
  • Minimum frequency response 20 Hz. - 20 Khz (± 1db max. ref. 1 Khz.).
  • The core is gapped to support the specified D.C.
$83.64
P-T1182-60 Transformer- Hammond, Toroidal Power, 60V / 120V secondary
Dual 117/234 VAC primary, 50/60 Hz. operation. 120 V series, 60 V parallel secondary.
Starting at $80.42
P-T710-X Transformer - Hammond, High Voltage Plate, 115 VAC, 50 / 60 Hz
  • Primary 115 VAC, 50 / 60 Hz.
  • At 2,000 VAC and above, secondary leads are through rubber bushings
  • Units can be run full wave bridge or full wave C.T.
  • V.A. is a C.C.S. rating
  • Current ratings are CCS (Continuous Commercial Service) & ICAS ratings (Intermittent Commercial or Amateur Service).
  • Enclosed, 4 hole chassis mount.
  • Minimum 6" long leads.
  • Class A insulation (105 degrees C).
  • Hi-Pot test at a minimum of twice secondary voltage
  • Conservative designs - CSA certified (209651).
Starting at $78.99
P-T290-YORKVILLE Transformer - Hammond, Guitar Amplifier, replacement for Yorkville / Traynor
  • Replacement for Yorkville/Traynor amplifiers
  • Designed for drop in replacement of original units.
  • Physically, parts were designed to look similar to original factory units (where possible).
  • Material used & design specs. were kept as close as possible to the original part to preserve the stock "tone".

Part No. Primary Secondary 1 Secondary 2 Secondary 3 Yorkville / Traynor Amp Yorkville / Traynor Part No VAC Hz. P-T290TRA 120 V 60 Hz. 320 V @ 600 mA 60 V @ 50 mA 6.3 V.C.T. @ 9 A 100 Watt Bass A-1380 P-T290TRB 120 V 60 Hz. 620 V @ 115 mA 6.3 V.C.T. @ 115 mA YBA2-B A-1314 P-T291JX 120 V 60 Hz. 320 V @ 500 mA 60 V @ 20 mA 6.65 V.C.T.
Starting at $76.50
Don't see what you're looking for? Send us your product suggestions!