Hammond 290HX 100W JCM 800/JMP Marshall Power Transformer

The 290HX is a Hammond 290 Series power transformer listed as a replacement for Marshall JCM 800 and JMP 100 watt amplifiers. It is designed for technicians and owners who need a drop-in replacement for these amps.

The primary is rated 120/220/240 VAC 50/60 Hz. The ordering table lists a 350Vct @ 420 mA high-voltage secondary, a 6.3Vct @ 7A heater winding and a 50 mA bias winding; the short description reads 175-0-175, 98V, 6.3VCT. The ordering table lists paper winding.

The drawing gives no-load secondary voltages at 120V, 60 Hz of 185.2V per half (370.3V end to end), 104.5V on the GRN-WHT winding and 3.362V per half (6.724V) on the heater, with a maximum excitation current of 200mA. It is hipot tested primary to secondary at 2500V, 60Hz for 1 second, and all leads are 16" out minimum, stripped 0.5". Drawing dimensions A-E are 3.750", 4.256", 4.531", 3.250" and 3.186", with dimension G at 0.219" x 0.438".

Hammond designed the 290 Series for drop-in replacement of original units, with parts made to look similar to the original factory transformers where possible and materials and design specs kept as close as possible to the original part to preserve the stock tone.

The 290HX ships at 8.95 lbs (4.06 kg), is RoHS and REACH compliant, and carries UPC 623980094267 and UNSPSC 39121301. Amp references are for reference only.