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In the Forum: Melquiades Amplifier
In the Thread: Is it the time to change those tubes?

Post Subject: Melquiades boots faster than Windows8?Posted by rowuk on: 8/1/2013

Romy the Cat wrote:
The concept of self-testing boot cycle is nice one but it for sure could not be done during the amp booting. Some tubes do need to warm up and reach the cruse temperature in order to be tested, some do not. Some tunes (like 6C33C) in fact is best to test during the warming up: by looking how the parameters change during the first 10 mine of tube operation a lot might be said about the tube. Fromm a certain perspective any tube amp is a tube tester and all it take is to slightly reformat the tube operation and bring the data in an interpretable format. The interpretable format is kind of tricky as it would depend from the type of the tube.

Agreed, BUT we first start to listen when the WHOLE amp is finished. That means the "boot cycle" is over when the "slowest" section of the amp is done. If the goal is to replace parts well enough BEFORE disaster and before they start to sound "worse" then we need to identify the parameters that lead to havoc or sonic degradation and test for that. Perhaps a specific impulse measured could identify changes in gain, phase and distortion. Perhaps a change in anode voltage outside of a predetermined range after warmup would give us an indication that the end is near.

Assuming zero intrusion in the sonics of the playback system (all testing sensors either as integral analog devices or switched out of the circuit entirely), boot cycle logs would after a period of time offer very useful data about the life, happiness and death of the devices in question. As the Melquiades amp uses a limited amount of tube types, the formats should be relatively "easy" to generate and maintain. I use EL34 and EL84 output tubes (driven directly from a high gain preamp) and have had no trouble with reliability. The sonics decrease in a predictable way, then the tube is switched out, but I have NEVER had a tube self destruct.

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