Gemtune APPJ PA1501A mini tube amplifier with 6AD10 tube (black) The PA1501A is the new machine of APPJ in 2015, It's APPJ PA0901A tube amplifier's upgrade version. PA1501A using imported 6AD10 new import inventory tube, there can be a direct replacement many brands 6AD10 tube on the market, for example Grants Bradford , Amperex , RCA , Sylvania , Westinghouse , GE , Philco , ITT , Chief , Tung-Sol , CBS , Admiral , Standard , Arcturus , Raytheon , Zalytron , Aladdin , Zenith , Motorola , IEC , Amperex , Mullard, and etc. 6AD10 is relatively late in the history of the tube, it is indirectly heated cathode pole double five - five poles composite tube, more powerful and musical, the performance is very good.The performence of 6AD10 tube is much better than 6BM8,ECL805,ECL82,6F3,EL84,6V6.