variac

darrell · Post by **darrell** » Sat Feb 10, 2007 4:03 pm

How big would it need be to use it with a marshall 100 watt amp? What amps and so on..

rgalpin · Post by **rgalpin** » Sat Feb 10, 2007 4:30 pm

i'm not an expert - so get a second opinion - but i use one all the time that is a 5 amp. it's just like this one:

http://cgi.ebay.com/Metered-Variac-Var- ... dZViewItem

darrell · Post by **darrell** » Sat Feb 10, 2007 5:07 pm

Thats the one I was looking at. Im not going E.V.H I just need to turn down the Imput to 105 or 110 My Home zings 125 volts and the tranny Is only 110 and in turn gives me B= Of 510 volt If I played metal or was a shedder this amp is it/ it has all the grind you want and then some. How long have you had it?

rgalpin · Post by **rgalpin** » Sun Feb 11, 2007 8:09 pm

i've had it for a couple years but just started using it all the time over the last 6 months.

i adjusted it until i was getting 400V on the pwr tubes, noted that the voltage coming into the amp was 110V and memorized where that is on the meter (not digital), set the bias. so now my amp is biased to optimum when the incoming voltage is 110V. i use it that way all the time so that i know my bias is right. if i remove the variac, i have no idea what the amp might be seeing from venue to venue and in this way i figure i am 1) protecting the amp and 2) getting more consistency.

mightymike · Post by **mightymike** » Sun Feb 11, 2007 8:42 pm

Using a 10A one here.

darrell · Post by **darrell** » Wed Mar 07, 2007 2:23 pm

Well I got one and Im glad i did man! my amp sounds so much better took all kinds of harshness out of the top... I have it set on 110 volts and have the knob set so no one can turn it..I just wounder if it would hurt to run my jtm45 metro clone at 110 volts?I should not have to do anything exsept rebias the amp right??

Cheech · Post by **Cheech** » Wed Mar 07, 2007 2:35 pm

https://amptechtools.powweb.com/browner.htm

This is a great option if you just are a player. Dont wanna form caps etc.

Cheech

rockstah · Post by **rockstah** » Wed Mar 07, 2007 2:49 pm

ive read 10 amp atleast. is what i use.

JD · Post by JD » Wed Mar 07, 2007 4:24 pm

It only needs to exceed the capacity of your amp's fuses, so 5A is sufficient. The 10A model is really a nice unit as well.

GregN. · Post by **GregN.** » Wed Mar 07, 2007 7:15 pm

Here's another option. I built one years ago and it works great. You can knock the AC down 6 volts or 12 volts. Easy to build using stuff you can get at Rat Shack (or at least you used to. They're very nearly becoming a cell phone business. It's sad).
http://www.geofex.com/Article_Folders/v ... ntvolt.htm

Greg

novosibir · Post by **novosibir** » Thu Mar 08, 2007 3:14 am

darrell wrote:How big would it need be to use it with a marshall 100 watt amp? What amps and so on..

On the rear panel of amps you usually should find a hint, which says: "Power Consumption" or "Power Input"

In case of a 100W Marshall it says (or if not, it is) 375VA (not W, because voltage and current aren't even phased).

This value divided by the/your wall voltage is the wattage of the variac, you'd at least need for a save operation.

In the USA: 375 : 120 = 3.125 => so use 4.0A or higher

In Europe: 375 : 230 = 1.63 => so use 2.0A or higher

Larry

Metropoulos Forum

variac

variac

Re: variac