Yesterday, 03:51 PM
Yeah, don't use the transformer currently on the H-20 (Dopf, I thought "H20, is that new technology, a speaker using water technology?"
), the 1KOhm impedance is too low for almost any output tube, especially a 42 or 6F6.
An 8", 10" or 12" Speaker is very common for PA or distributed sound systems. For stage sound reinforcement systems, smaller speakers ganged into a "Line Array" are becoming very common.
Try to salvage an output transformer (and hopefully a speaker) from any AC set with a power transformer that uses a single 2A5, 6F6, 6K6, 41, 42 or 47 output tube. Most single end 6F6, 42, 47 or 2A5 output stages have a transformer with a 7,000 Ohm impedance. 41 and 6K6 have a 7,500 Ohm impedance. The other consideration, however, is the voice coil impedance of this H-20 speaker. At 1.25 Ohm, it is very low. By the time the 1940s rolled around, most non-Philco speakers had voice coil impedances between 3.2 Ohm and 8 Ohm. By using the same chart that you are looking, use the Transformer Part #, Output Tube and Voice Coil Impedance columns to find the correct Philco P/N for an output transformer compatible with the speaker and tube used.
I cannot find the 32-7198 output transformer in the speakers section or the output transformer section. of the Library parts pages. 32-7198 was likely not the standard transformer for the H-20 speaker.
Hope this helps.
![Icon_redface Icon_redface](https://philcoradio.com/phorum/images/smilies/icon_redface.gif)
An 8", 10" or 12" Speaker is very common for PA or distributed sound systems. For stage sound reinforcement systems, smaller speakers ganged into a "Line Array" are becoming very common.
Try to salvage an output transformer (and hopefully a speaker) from any AC set with a power transformer that uses a single 2A5, 6F6, 6K6, 41, 42 or 47 output tube. Most single end 6F6, 42, 47 or 2A5 output stages have a transformer with a 7,000 Ohm impedance. 41 and 6K6 have a 7,500 Ohm impedance. The other consideration, however, is the voice coil impedance of this H-20 speaker. At 1.25 Ohm, it is very low. By the time the 1940s rolled around, most non-Philco speakers had voice coil impedances between 3.2 Ohm and 8 Ohm. By using the same chart that you are looking, use the Transformer Part #, Output Tube and Voice Coil Impedance columns to find the correct Philco P/N for an output transformer compatible with the speaker and tube used.
I cannot find the 32-7198 output transformer in the speakers section or the output transformer section. of the Library parts pages. 32-7198 was likely not the standard transformer for the H-20 speaker.
Hope this helps.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55