<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:14pt"><div id="yiv1187794264"><div><div style="color:#000;background-color:#fff;font-family:times new roman, new york, times, serif;font-size:14pt;"><div id="yiv1187794264yui_3_16_0_7_1400462471028_13"><span id="yiv1187794264yui_3_16_0_7_1400462471028_26">Several different HF amps have been retrofitted using the Russian GI7BT triode. A Google search will result is dozens of examples. They are cheap, I have bought them on eBay and had them shipped from Ukraine for about $30 each. The plate dissipation is 350W and they work real well in the 2000 - 2500V range. Filament voltage is 12.6 so a new filament transformer will be needed in many cases. I am using one of these tubes on 6M and get 500W out on peaks with 30W of drive and 2400V on the plate.<br><br>Allen, W9DZ <br clear="none"></span></div><div
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<div dir="ltr" id="yiv1187794264yui_3_16_0_1_1400462471028_3109"> <div class="yiv1187794264y_msg_container" id="yiv1187794264yui_3_16_0_1_1400462471028_3113"><hr id="yiv1187794264yui_3_16_0_1_1400462471028_3118" size="1"> <font id="yiv1187794264yui_3_16_0_1_1400462471028_3112" face="Arial" size="2"> <b id="yiv1187794264yui_3_16_0_1_1400462471028_3120"><span id="yiv1187794264yui_3_16_0_1_1400462471028_3119" style="font-weight:bold;">From:</span></b> Kenneth G. Gordon <kgordon2006@frontier.com><br clear="none"> <b><span style="font-weight:bold;">To:</span></b> Heath@puck.nether.net <br clear="none"> <b><span style="font-weight:bold;">Sent:</span></b> Sunday, May 18, 2014 12:27 PM<br clear="none"> <b><span style="font-weight:bold;">Subject:</span></b> [Heath] Concerning the SB-200 and tubes...</font><br clear="none"><br clear="none"><br clear="none">In the meantime, and previous to this delightful news from RF Parts Co, I <br clear="none">had, in
desperation, decided to modify at least one of my SB-200s to a pair of <br clear="none">4CX250Bs, since those tubes are practically ubiquitous on eBay and can be <br clear="none">bought,
NIB, for very little money. I now have almost a dozen of those, all of <br clear="none">which have, so far, tested good.<br clear="none"><br clear="none"><br clear="none"></div></div><div class="yiv1187794264yqt3527380337" id="yiv1187794264yqtfd59710"> </div></div><div class="yiv1187794264yqt3527380337" id="yiv1187794264yqtfd06724"> </div></div><div class="yiv1187794264yqt3527380337" id="yiv1187794264yqtfd14443"> </div></blockquote><div class="yiv1187794264yqt3527380337" id="yiv1187794264yqtfd64249"><div></div> </div></div></div></div></div></body></html>