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  3. 1290083894

sophia 845 markIII and cary 211M AE

specification of this tube:-

Sophia Electric 845 MK3 Vacuum Tube Specification

Nominal operating conditions and parameters:
Filament voltage 10.0V
Nominal filament current 3.2A
Plate voltage 1250V
Grid voltage -200V
Plate current 80mA
Plate resistance 1.7 Kohms
Amplification factor 5.0
Load resistance 3.4 Kohms
Signal voltage(pk) 69.0V
Output Power 25W

Limiting Operation conditions for safe operation-nor simultaneous ratings:

Maximum plate voltage 1250 volts
Maximum plate dissipation 75 watts
Maximum plate current 120 ma
Maximum input power of signal 150 Watts
===========================
CAN I USE THIS TUBE WITH CARY 211m AE
AND WHAT ABOUT IT SOUND.
woodpark
9 responses Add your response
jaytea
78 posts
 
I agree with Brf. I wonder why they can claim that this is RCA standard while the max plate dissipation is only 75W vs. 100W. This could be the reason why these Sophia tubes didnt work in the OP 's amps? I too own a pair of Cary 211AE , love them, but i am afraid of replacing original tube with these kind of "upgrade" tubes and have them blow up in my amps!
brf
1,715 posts
 
I find Sophia's statement confusing. Their website claims the Sophia Electric™ 845 MK3 Carbon Plate Tube is a RCA 845 direct replacement but it will not operate in an amp spec'd for 1000v on the plate, which is normal for an RCA 845.
woodpark OP
4 posts
 
yes they refund my money back.
brf
1,715 posts
 
The Sophia Electric 845 MK3 Vacuum Tube specification that you posted indicate that they take a maximum plate voltage of 1250V, which is normal for an 845 tube. Is Sophia claiming that the MK3 tubes cannot take that amount of plate voltage? Did they refund your money?
woodpark OP
4 posts
 
I got sophia tube last month but they could not be used with Cary211M,fuses of 300B blow out when open the power on.This is the answer from Sophia "The problem was the Cary 845 amplifier operates at a relatively high voltage and our 845 burning process voltage did not set high enough (about 1000V)"
woodpark OP
4 posts
 
Amfibius,tubes used now are original tubes from CARY.
You can read about Sophia tubes in this web.
http://www.sophiaelectric.com/
I shall got new tubes about next month.
amfibius
282 posts
 
Woodpark, what tubes do you have in your 211AE now?

It would be nice if you could report back on the Sophia's once you have them installed. I have the same amp, and would like to know :)
woodpark OP
4 posts
 
Thank you very much for your response.
brf
1,715 posts
 
Based on the above noted specification, yes these tubes will work in your Cary AE211 without issue. I have a lot of 845 tubes, but unfortunately, not the Sophia 845 Mk3 Carbon plate, therefore, I cannot comment on their sound.
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