Not disinterested in your method. I’ve been trying to reach a tech friend who could try your idea. Also looking into a step down transformer as a possibility.
I really appreciate your input as well as the others.
thanks!
Variac noise
Hi all. Not sure if this is the correct place for this question but here goes…
I have a Marantz model 8 from Japan running at 100volts through a variac. The variac hums while under load and it’s (just) loud enough to be annoying. I have a friend who uses the same variac for a similar setup and his is dead silent. Thought it might be a bad variac so I ordered another and set it up and still the same problem, so could it still be the variac? It’s a brand sold through Amazon and quite a few buyers complain about quality control problems with this product. I’ve looked at buying an American made variac but they cost more than $700. Could the amp be causing the variac to hum?
Any thoughts?
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@ccogopher A stepdown transformer will be more expensive. Bucking transformers are fairly cheap, since the transformer does not have to be nearly so large. For example, the Marantz 8 draws 190 Watts. It runs on 100V if the newer Japanese version. That means it draws 1.9Amps at 100V. So a transformer that puts out 20V at 2Amps should do the job. You can get one of those off of ebay, such as this one: The primary of the transformer is simply connected the the AC line to power the transformer. The secondary is put in series with the amplifier. The phase is important; one way you hook it up it will add 20V to the line voltage, which isn't what you want; the other way it will subtract 20V from the line voltage. This little transformer is only $18.00. If it were me I'd get one with slightly more amperage (3-4A) since I don't like running transformers at or near capacity. But even so such a transformer is going to be inexpensive. So this is a simple hookup. You could put the transformer in a box so it looks nice. Bud makes boxes that could do the job. Even with the box this is still cheaper than running a Variac or stepdown transformer that has the current capacity to do the job! FWIW, your variac might be vibrating as much or as little as your friend's. Most of the time when you hear them, you're actually hearing something near them that is vibrating with the variac, rather than the variac itself. If that is so, silencing that bit (for example, a panel) can be inexpensive as well and since you already have the variac, might be a prudent way to solve this. |
- 10 posts total