NEW A431-S, a reproduction of the Dynaco A431 output transformer as used on the Dynaco (tm) MkII and MkIII amplifiers and Sunn guitar/bass amplifiers.
PLEASE NOTE: INK STAMP IS NOW LOCATED ON THE BOTTOM OF THE TRANSFORMER INSTEAD OF ON THE BELL
For the Dimensional diagram and hookup sheet for this unit please click here (Adode Acrobat Reader required)
The coil is wound the same as the original A431, same number of turns, sections and wire size, using the same patented Dynaco winding method, and made on the same core size and material. Only improved insulation material used (thus making the transformer more resistant to abuse) and nice long (10 inch/ 25 cm minimum) teflon insulated leads have been added.
This transformer has what you'd expect out of a Dynaco transformer, like healthy low frequency inductance, high resistance to distortion caused by output tube imbalance, and low distortion overall. They're great for both hifi and guitar amplifier DIY projects (such as the Eiclone project at www.diytube.com ) as well as replacements for Dynacos and Sunns.
Brand new production, MADE IN USA.
This type of transformer can be used with many tube types, such as 6550, KT88, KT90, 6CA7/EL34, 300B, 2A3, 6B4 or push-pull parallel 6BQ5/EL84 & 6V6-GT. It may be used with triode, pentode, or ultralinear (screen tap connection) wired tube arrangements.
Transformer specs are: 4300 ohms CT primary with screen taps, 4,8 and 16 ohm secondary. 20 Hz to 20 KHz response at 60W, within 1 db, 30 Hz to 15 KHz at 120 watts. Max DC per side (suggested) 120 ma. Exact same dimensions as the original A431 Dynaco transformer: Height 4 3/4 inches (120 mm) Width 4 inches (101 mm), Depth over covers 4 1/2 inches (114 mm), mounting centers are 3 inches (75 mm) by 3 1/2 inches (88 mm).
Sunn Replacement Part# 3-6OT