EL34s and UBT-1 output transformers, the BFT-1 and BFT-. 1A are well suited ...
using both HV windings at the same time). 50 - 60 Hz. 50 - 60 Hz. BFT-1. Red.
BFT-1 BFT-1A Audio-Grade Power Transformers Description The BFT-1 and BFT-1A are high-quality power transformers designed for tube audio power amplifiers. Originally designed for a stereo amplifier using parallel EL34s and UBT-1 output transformers, the BFT-1 and BFT1A are well suited for moderate-power tube amplifiers. Special audio-grade features include an electrostatic shield between primary and secondary and a copper flux band to reduce stray hum fields. (Some production versions of the BFT-1 are missing the flux band). The BFT-1 and BFT-1A were manufactured in the United States to high quality commercial standards. They are protected from moisture by a full vacuum-impregnation with varnish.
The BFT-1 and BFT-1A has been replaced by the BFT-1B. The BFT-1B is physically larger than these earlier models, with greater design margins. The BFT-1B and BFT-1A have a simpler primary winding arrangement. All types have the same performance specifications. The data listed here is for reference. For specifications and application information, see the BFT-1B data sheet.
Specifications (different than BFT-1B) Size: 3.75" x 4.5" x 5.25" (95 x 114 x 133 mm) Weight: Approx. 12 lbs (5.5 kg)
Red
Red
Orange
Orange
120 V 110 V 100 V
385-0-385 V, 340 mA capacitor-input filter
Brown/White Violet/White
Red/White
White/Black
CT
260-0-260 V, 360 mA capacitor-input filter (see application info for using both HV windings at the same time)
Orange
50 - 60 Hz
Red
0V 120 V 110 V 100 V
Black/White
Yellow/White
Violet
Electrostatic Shield
5.0 V, 4.0 A resistive
Yellow
White
50 - 60 Hz
Green/White Green
Black
Grey
Grey
Green/Yellow
6.3 V, 4.0 A resistive
260-0-260 V, 360 mA capacitor-input filter (see application info for using both HV windings at the same time)
Red Black/White Brown
120 V
Violet
110 V
White
100 V
CT 6.3 V, 9.6 A resistive
CT
Orange
Yellow/White
CT
5.0 V, 4.0 A resistive
Yellow
Green/White
50 - 60 Hz Black
0V
Electrostatic Shield
Yellow
Green
Green
50 - 60 Hz 0V
CT
385-0-385 V, 340 mA capacitor-input filter
Brown/White Red/White
0V
Yellow
Brown
120 V
CT 6.3 V, 9.6 A resistive
Green Grey
Green/Yellow
Grey
6.3 V, 4.0 A resistive
BFT-1A, B
BFT-1
www.one-electron.com
BFT-1A data sheet rev 1.0
BFT-1, BFT-1A Audio-Grade Power Transformer
BFT-1A data sheet rev 1.0
BFT-1, BFT-1A Dimensions
4 1/2" 114mm
3 3/4" 95mm
5 1/4"(133mm) (max)
Side View
Top View
Lead Lengths: 15 " (380 mm)
0.20" (5 mm), 4 places
3 3/4" 95mm
5/8" (16mm) min, 2 places
3 13/16" 97mm
BFT-1, BFT-1A Mounting Hole Footprint
One Electron Transformers are exclusively distributed by: Antique Electronic Supply
P.O. Box 1000 Yerington, Nevada 89447 USA www.one-electron.com
6221 South Maple Avenue Tempe, Arizona 85283 USA Tel: 1-480-820-5411 FAX: 1-480-820-4643 or 1-800-706-6789 www.tubesandmore.com
