UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Bell & Howell 8D-655, amplifier question

wd40addict · 27th Oct 2021, 5:29 pm

The 8D prefix marks when production of the Anglicised projectors moved from the UK to Japan. I have the 8D644 which is based on the 644, the amplifier is still valve based but has been changed to use a solid state doubler rather than an EZ81 for HT rectification and a transistor has been added as an extra preamp stage for the optical sound.

The following TQ1 series used a low voltage lamp for greater screen illumination and all transistor anplifiers.

27th Oct 2021, 5:29 pm	#2
wd40addict Octode Join Date: May 2009 Location: Stevenage, Herts. UK. Posts: 1,518	Re: Bell & Howell 8D-655, amplifier question The 8D prefix marks when production of the Anglicised projectors moved from the UK to Japan. I have the 8D644 which is based on the 644, the amplifier is still valve based but has been changed to use a solid state doubler rather than an EZ81 for HT rectification and a transistor has been added as an extra preamp stage for the optical sound. The following TQ1 series used a low voltage lamp for greater screen illumination and all transistor anplifiers.