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Old 8th September 2013, 10:03 PM   #1
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Default OTL question

I saw this circuite on line and wondered if I subsituted a 6c33-b for the
6as7's using a 5ohm cathode resistor about how much power would it be
good for. I know using a pair of 6c33c-b tubes at 150v is good for about
25 watts but what would hapen if I just used 60V.
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Old 8th September 2013, 10:16 PM   #2
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As your choice of valve is designed to run at 400volts, maybe there could be a bit of a problem. A valve used as a diode drops around 75volts across the Anode to Cathode so not a great deal of headroom for a valve of this design running at such a low voltage.
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Old 9th September 2013, 07:10 PM   #3
Ketje is offline Ketje  Belgium
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Since there are two triodes in one 6C33 you need 4 tubes.With a load of 8ohm I think around 4W sine output.
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Old 9th September 2013, 07:15 PM   #4
kevinkr is offline kevinkr  United States
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A pair on +/-140V rails will give you about 20W into => 8 ohm load. (From experience)

A single 60V supply is not going to cut it.
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Old 9th September 2013, 09:22 PM   #5
Ketje is offline Ketje  Belgium
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Quote:
Originally Posted by kevinkr View Post
A pair on +/-140V rails will give you about 20W into => 8 ohm load. (From experience)

A single 60V supply is not going to cut it.
Yes,I supose 20W is possible but how long does the valves last ?
By the way,the schematic shows +/-60V
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