I like sound of AC heater for VT4C so I do some circuit modify as drawing.
Old connect as below and no 62ohm/50W resistors & no capacitors shunt to GND.
Original connection picture.
No resistors & capacitors. Sound not good and too rough.
Connect capacitors & mount resistors on water cooling heat sink.
Sounder 10uf/250V sound have clear line,sound not rich, rough and nothing special.
VT4c cathod RIFA capacitor sound color feel not good and change into Spraque 100uf/150V.
CDE 8uf/400V 音色較渾厚 Vigorous tone,音像較淺 audio shallow ,低頻轟轟,悶悶的打不出線條聲音 Low-freq humming.
Old CDE 4uf/200V 低頻聲音線條較清楚有形體 Low freq. have clear body line ,但音色線條清楚偏冷,清瘦 but clear line sound cool & thin.
ERO 4.7uf/250V 響應較佳 better response ,音像(音場)刻化較深 sound filed of the deep carved , 音色線條深刻化清楚, 沒啥毛邊,低頻聲音較有梗的清楚形體 Low freq. have clear body line ,較自然,是以布懸邊為參考.因較不喜歡rubber懸邊低音聲底,軟軟的低音轟聲.
GE-211 plat voltage .