Wiring associated with the power supply and filter capacitors, particularly early filter capacitors Wiring associated with the output section, including output tubes Output transformer secondary wiring (i.e., wires to the speakers, external speaker jacks, or headphone jacks) Mains wiring (i.e., wires to the switch and the mains fuse)
#How.to.determine wurlitzer piano value how to#
So be careful and make safe choices! If you’re not sure how to safely proceed at any point, there’s no shame in asking a tech ( like us!) to take over. No amplifier is worth compromising your health and safety over, but getting shocked by a marginally-functional hum-bucket only adds insult to injury. The terminals of the switch always have mains voltage across them when the amplifier is plugged in, even when it isn’t turned on! Furthermore, student model Wurlitzers may have mains voltage in unexpected places, such as ports for the umbilical cord that once connected the various classroom keyboards to each other. Note that electrolytic capacitors can pose a shock hazard even in the amp is turned off and unplugged.Įven if you don’t plan on opening up the amp chassis, always unplug the Wurlitzer before removing its lid. Do not attempt to repair an amplifier without following the appropriate safety protocols, including (but not limited to) discharging the electrolytic capacitors. In the process, you may gain intel about the source of the hum.Īudio amplifiers, and tube amplifiers in particular, contain high voltages. If there is something else wrong with your Wurlitzer’s electronics, you should address that first.
#How.to.determine wurlitzer piano value free#
Replacing the tubes with known good tubesĬonfirming that the wiring harness is free from obvious faultsĮnsuring that noisy wires, such as wires leading to the power switch or the power transformer, are not in close proximity to sensitive preamp or speaker wiringĪs in Part I, we also assume that hum is the worst problem in your Wurlitzer.
This includes:Įnsuring that the hum is coming from the piano itself, and not from dirty mains power or other devices in the room, such as fluorescent lightsĮnsuring that everything is tightly screwed in placeĬonfirming that all of the Wurlitzer’s shielding is present and functioning correctly For the purposes of this article, we’ll assume that you already tried everything in Part I. It’s worth checking out Part I first, because it listed some simple, non-invasive things that you should always be tried before diving into the amplifier’s circuitry. In Part II, we’ll go into further detail on techniques that require some prior electronics experience to execute. In Part I of our guide on fixing hum, we listed some easy fixes.
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