Re: Heat Dissipation

Tubes Asylum

Questions about tubes and gear that glows. FAQ

In Reply to: Heat Dissipation posted by Paul H on September 8, 2003 at 08:21:27:

Remember when the AC line voltage was commonly referred to as '110'? It has not been anything close to 110 volts for a long time. Take a digital voltmeter, set it for AC voltage, and test the line voltage in your home. (The smaller of the vertical flat sockets in the wall recepticle is the hot connection, the larger one is neutral, and the round one is the earth ground. Insert the black lead from the tester into the neutral recepticle so that it stays in place without being held. Do not hold on to the black lead! Using one hand only (for safety), touch the red lead to the hot recepticle of your wall outlet or power strip and read the voltage readout on the meter display.) I routinely get measurements of 122 or 123 volts, sometimes as high as 125 volts. That is quite a bit higher than the nominal 115 or 117 volts.
There is no need to operate equipment with regulated power supplies using a variac. Any audio gear from the late 1960s or newer should be fine. The gear from the 1950s and early 60s is really not designed to run at today's higher line voltages. While it may run, it is operating at the upper limit of its design specification, stressing all components and generating more heat. It will run cooler, and last longer if you drop the voltage. No need to go any lower than 110 volts, in fact if you drop it too much you will draw too much current and blow a fuse.
I have read that the vintage S-C 433 amplifiers tend to run higher than usual voltages on the 6BQ5 tubes. This may be remedied somewhat by using the variac. Resistors, capacitors, and transformers will all be operating in their most linear performance range when the voltages and temperature are well within maximum specifications.

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Follow Ups Full Thread

Topic - Heat Dissipation - Paul H 08:21:27 09/08/03 (8)

Re: Heat Dissipation - mkmelt 19:56:57 09/08/03 (3)

Re: Heat Dissipation - Paul H 07:26:56 09/09/03 (2)

Re: Heat Dissipation - mkmelt 17:23:15 09/09/03 (1)

Re: Heat Dissipation - Paul H 07:24:36 09/10/03 (0)

Re: Normal value is - Russ57 09:19:32 09/08/03 (3)

Re: Normal value is - Paul H 13:46:44 09/08/03 (2)

Re: Normal value is - Russ57 03:35:50 09/10/03 (1)

Re: Normal value is - Paul H 07:27:22 09/10/03 (0)

Follow Ups

Re: Heat Dissipation - mkmelt 19:56:57 09/08/03 (3)

Re: Heat Dissipation - Paul H 07:26:56 09/09/03 (2)

Re: Heat Dissipation - mkmelt 17:23:15 09/09/03 (1)

Re: Heat Dissipation - Paul H 07:24:36 09/10/03 (0)

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