Magnatone 421
Moderators: pompeiisneaks, Colossal
Magnatone 421
Picked up a Magnatone 421 today. It is a small amp from the Estey period. It has one 10 inch speaker. It also has the tremolo/vibrato circuit. The vibrato is the pitch changing that magnatone is famous for. That is why i bought it as I was curious and then sucked in by the cool sound. I got it for 200.00 plus tax. I think that is an ok price but I'm cheap. Everything works but it looks beat up which makes it perfect. Questions are would you change anything as an order of maintenance. My inclination is to leave it be as it sounds fine. I know electrolytic caps age but everything sure sounds dandy. Also, I've heard that there is no way to get varistors anymore. Is that true? What the heck is a varistor anyway. Thanks Steve.
Re: Magnatone 421
The varistors are the cap-like things that influence the vibrato function and the ones in the Maggie amps are world-famous.
And yes, if anything it may need a cap-job at some stage if it hasn't had one before. But unless you know your way around inside a toob amp, you really need to see a tech about that.
The other things that sometimes needs looking at in older amps is whether any CC resistor's values have drifted with age/heat. But unless they are causing problems, I would just leave them as they are.
Other than that its just replacing worn output tubes every-so-often (before they deteriorate to the point where they short and cause expensive damage to your amp). You should always keep a spare/backup set handy anyhow.
And yes, if anything it may need a cap-job at some stage if it hasn't had one before. But unless you know your way around inside a toob amp, you really need to see a tech about that.
The other things that sometimes needs looking at in older amps is whether any CC resistor's values have drifted with age/heat. But unless they are causing problems, I would just leave them as they are.
Other than that its just replacing worn output tubes every-so-often (before they deteriorate to the point where they short and cause expensive damage to your amp). You should always keep a spare/backup set handy anyhow.
He who dies with the most tubes... wins
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martin manning
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Re: Magnatone 421
A varistor is a voltage dependent resistor, in which resistance decreases as the voltage across the device increases. They are common in surge protectors now, but the modern ones are made of zinc oxde due to the abrupt decrease in resistance that it provides. The ones used in Magnatone vibrato circuits are made of silicon carbide, which has a much more gradual characteristic. These are no longer being produced, and accordingly are getting hard to find and expensive. There is a Yahoo group dedicated to Magnatone and Valco amps where you can get some more info and advice. See: http://launch.dir.groups.yahoo.com/grou ... one-Valco/