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3cpx1500a7


Thompson is a european company that bought a lot of RCA's assets when they were liquidated decades ago. They did own one or more tube factories back in the day. They might be buying this tube from a chinese supplier, but IDK. I don't think they're associated with Eimac's parent company CPI.

Yet.

73
 
Thales has become the exclusive manufacturer of grid tubes designed by Thomson, ABB and Siemens in their original version.
Industry | Thales Group

Thales (formerly known as Thomson-CSF) is committed to offering the widest, most competitive solution for every professional application. Since 1993, Thales/Thomson-CSF has reinforced its market positions by acquiring the electron tube operations of ABB, Siemens and AEG.

Triode - Electron Tubes & Vacuum Devices - Richardson Electronics (relltubes.com)

Thomson(later Richardson) purchased many these facilities when RCA/Sylvania (Phillips) cease to produce tubes...
Amperex made Some of the best 3-500zg's ever produced in their Holland and French facilities.
Amperex Electronic - Wikipedia
 

3CPX1500A7 verses 3cx1500a7 in Ameritron al-1500 . will the 3cpx 1500a7 have a higher output than the 3cx1500a7. And can you drop the 3cpx 1500a7 in a Ameritron al-1500 without any modifications.​

 
Unless I'm mistaken, the "P" version of that tube is a bit taller. The ceramic ring between the tube's base and the anode ring is a bit taller. The letter "P" refers to a pulse-service tube made for higher anode voltages than the 8877.

If I'm right, the chimney that confines airflow to the ring's fins may be too short if it's meant to fit the straight 8877 version of the tube.

Just worth a look, once the tube is in place. If you have a gap between the top rim of the chimney and the bottom of the tube's anode ring, the cooling air will spill out of this gap, and rob the tube's cooling fins of their proper airflow volume.

And if the chimney is tall enough, you're good to go with either version of the tube.

73
 
Unless I'm mistaken, the "P" version of that tube is a bit taller. The ceramic ring between the tube's base and the anode ring is a bit taller. The letter "P" refers to a pulse-service tube made for higher anode voltages than the 8877.

If I'm right, the chimney that confines airflow to the ring's fins may be too short if it's meant to fit the straight 8877 version of the tube.

Just worth a look, once the tube is in place. If you have a gap between the top rim of the chimney and the bottom of the tube's anode ring, the cooling air will spill out of this gap, and rob the tube's cooling fins of their proper airflow volume.

And if the chimney is tall enough, you're good to go with either version of the tube.

73
I guess it also depends on the socket type and how it's mounted. I have a pair of generic ceramic sockets mounted under a deck and the 8877 chimney fits my 3cpx tubes perfectly.i run them at 5v and have been for 10 years. Hammond transformer defied my expectations.
 
I guess it also depends on the socket type and how it's mounted. I have a pair of generic ceramic sockets mounted under a deck and the 8877 chimney fits my 3cpx tubes perfectly.i run them at 5v and have been for 10 years. Hammond transformer defied my expectations.

If you don't mind what are the Part #'s for the filament and Hammond Plate Transformers?

Thanks,
Dr_DX
 

3CPX1500A7 verses 3cx1500a7 in Ameritron al-1500 . will the 3cpx 1500a7 have a higher output than the 3cx1500a7. And can you drop the 3cpx 1500a7 in a Ameritron al-1500 without any modifications.​

This is incorrect. The 3CPX1500A7 is as you may know, a pulse rated tube. To ahieve the higher breakdown voltage, the ceramic base is extended, making the tube taller. The chimney in the AL-1500 is not tall enough. You will need a taller chimney, that encompasses the tube cooler for proper cooling of the tube. Apart from that, the tube is the same. Additionally, all 1500A7 tubes that are not marked Eimac/CPI, are Chinese and come from the same place, regardless of brand markings.
 
Unless I'm mistaken, the "P" version of that tube is a bit taller. The ceramic ring between the tube's base and the anode ring is a bit taller. The letter "P" refers to a pulse-service tube made for higher anode voltages than the 8877.

If I'm right, the chimney that confines airflow to the ring's fins may be too short if it's meant to fit the straight 8877 version of the tube.

Just worth a look, once the tube is in place. If you have a gap between the top rim of the chimney and the bottom of the tube's anode ring, the cooling air will spill out of this gap, and rob the tube's cooling fins of their proper airflow volume.

And if the chimney is tall enough, you're good to go with either version of the tube.

73
Hah, I just read this after I posted the same thing.
 

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