What is a Variac and how does it work???

[thomasterrible]

Hi

I have seen photos of Variacs, but I am not sure how they work in the context of how they hook up to tube amps and what the change in sound would be like were I to install one? Including how to use one without damaging my amp!

 

I have a Laney AOR pro tube lead with a 4x12 cab, it sounds good but its gain is not as high as most new amps.

 

I have also read that Eddie V used one to hot rod his Marshall and get a better sound.

 

Come to think of it, what is meant by associating Eddie with a "brown sound" what is the definition of brown sound?

 

I am all for modifications, but only when I understand how to properly do them and know what the results will be.

 

Thanks Much!

Tom:poke:

[JamesPeters]

The most important thing to know is that you will not get "more gain" from the amp by using a variac.

 

The rest...I'll leave that up to others to post about. I wouldn't even consider using one, honestly. My honest advice is to get the amp you want.

[Ultron]

perhaps this is what you seek?

[tlbonehead]

Hi I have seen photos of Variacs, but I am not sure how they work in the context of how they hook up to tube amps and what the change in sound would be like were I to install one? Including how to use one without damaging my amp! I have a Laney AOR pro tube lead with a 4x12 cab, it sounds good but its gain is not as high as most new amps. I have also read that Eddie V used one to hot rod his Marshall and get a better sound. Come to think of it, what is meant by associating Eddie with a "brown sound" what is the definition of brown sound? I am all for modifications, but only when I understand how to properly do them and know what the results will be. Thanks Much! Tom:poke:

They connect to your electricity and the amp connects to it. They allow you to change your voltage from what is coming out of the AC outlet. Not worth the price, time, or risk, IMO.

[blargh]

They can change the AC voltage coming into your amp.

Not a particularly good idea, since it'll screw up your biasing, it might wear out your tubes, and it won't make you sound like Eddie. It'll add a bit of compression and change your tone a bit, but it's not the secret to the brown sound.

[jimytheassassin]

I'm sure someone with true knowledge will chime in here soon, BUT I couldnt' resist. Variacs are used to vary voltage loads. The main use I can think of is "reconditioning" old electrolytic capacitors in antique tube electronics. Now I dont' know for sure, BUT there must be do's and don'ts to this. By bringing the voltage from "brown" levels slowly up to a full 110-120, you can "reseal" old capacitors. They call it brown because when you power "sags" light bulbs dim to dark yellow.. and brown. As for brown sound.. this is usually a bad thing. It usually indicates you need new power tubes, or new electrolytic capacitors. Capacitors dry out in time and the values change. This can have detrimetal effects on your amps sound and operation.. especially if one suddenly blows. Sudden voltages to extremely worn out caps can cause this.. like turning your amp on. Normally an electolytic capacitor will last 10+years or more... before you're with in risk of a catastrophic event. Just so you know..the electrolytic caps are most responsible for power conditioning.. they level out the sine curve and make power flow smoothly with out distortion. Distortion can often be heard, like in an amp that buzzes or hums that's turned on with nothing plugged in and volume up slightly.

 

Anyhow, I don't think you'd want to use a Variac AND play at the same time. Tubes can certainly take it.. maybe even the capacitors..but your biasing would definitely be screwed up..and it may put extra load on your transformers.. which would be quite risky if they get too hot. Make sure that thing is grounded very well.

[jimytheassassin]

perhaps this is what you seek?

I just let that thing cycle so long that it's now out of sync.. haha.. I love that little badger:thu:

[almightycrunch]

well, I read an article from Michael Soldano where he speaks about using a variac. It is apparently "NOT" harmful to a proper functioning amplifier as long as you are reducing the incoming voltage to the amp and not increasing it. What ends up happening is the reduced voltage will eventually translate into reduced volume as well the farther down you go with it, it will continue to drop in volume until there is not enough power to keep the heater voltage up where it needs to be for the tubes to operate. The reduced input power, will translate into reduction of all voltages inside the amp including plate voltage on the tubes, resulting in the amp putting out less power, reduced headroom, and increased tube compression and increased distortion. With a Plexi Marshall, set the voltage between 85 and 90 volts and crank the amp for what is dubbed "brown sound"

[thomasterrible]

First thanks for everybodys suggestion. Obviously I did not run out and buy one, but I did want to know why people used them.

 

I understand the person that talked about the color of the tubes. But isnt the "brown sound" something that one can hear? I have loved EVH since they first came out, and although I think it is stupid that they could not keep the band members in check, I still like EVH. I can hear differences in various guitar players songs often just by hearing the guitar players for a few notes even if I have not heard the song before. But I still dont get exactly what one would hear and lable as being "brown" I just dont understand what a brown sound would sound like to ones ears???

 

Line 6's owners manual for the Pod XT Live I recently got (for direct recording and effects) but it showed all the amps it was trying to sound like in its amp modeling section (that I will bypass) talked about a rumor of how EVH got that, once again Brown Sound was to run MORE voltage than the amp was supposed to use, they said that they ran a Marshall head at 140V and that gave them the result they thought sounded like eddie.

 

I am convinced I wont use one though.

 

My Laney AOR just is not as high gain as I would like sometimes, but I figured that one out, I have hated every OD or gain pedal out there, tubescreamers, rats, marshalls, etc. and they were all duds in my mind. Then I found out about Damage Control and their solid metal "pedal" and it uses 2 12ax7 tubes, actually does add saturated tube gain and has several adjusments, even testing it in a solid state amp, it made it sound more "tube-ish" Best 150 bucks I have spent in a long time.

 

After getting my expensive Jackson I dont have much dough, I cant afford a Laboga Mr. Hector right now. I am trying to get a 30 watt Laney AOR 1x12 combo, which may allow a similar sound at lower volumes.

 

I have also had suggestions for my half stack like using a volume pedal in the effect loop to have my amp at full gain but have it not be so loud I cant play where I am located.

 

I was also told about attenuators but if the change to adding an audio taper pot in the effects loop works I would much rather go that way.

 

I just basically wish I could find a way to play the AOR and I guess for gain I should just use the clean input and the solid metal. I just want to maintain the tube sound. I plan to use a different half stack at the same time that is clean with effects, but the AOR to sound like a guitar with good pups just plugged in to the amp.

 

Thanks,

Tom

[tlbonehead]

well, I read an article from Michael Soldano where he speaks about using a variac. It is apparently "NOT" harmful to a proper functioning amplifier as long as you are reducing the incoming voltage to the amp and not increasing it. What ends up happening is the reduced voltage will eventually translate into reduced volume as well the farther down you go with it, it will continue to drop in volume until there is not enough power to keep the heater voltage up where it needs to be for the tubes to operate. The reduced input power, will translate into reduction of all voltages inside the amp including plate voltage on the tubes, resulting in the amp putting out less power, reduced headroom, and increased tube compression and increased distortion. With a Plexi Marshall, set the voltage between 85 and 90 volts and crank the amp for what is dubbed "brown sound"

Strips the power tubes. Very hard on them. The lowest I've ever run my amp was at right at 100 volts and it sounded and responded like sh_t. Just turned it to mush. BTW, I assume variac stands for variable AC?

[TheToneMan]

I use a variac with my 100 watt marshall all the time. I love eddie van halen and try to get his tone and i think the variac really helps alot. when the voltage is really low it adds kind of a roasting brown like tone.

[thomasterrible]

Yes from just seeing the pics of them I could tell they were to adjust the ac level before it goes in to the amp, but everyone here speaks of using less voltage and line 6 spoke of a voltage increase to 140V in their literature.

 

An attenuator may work, but if the use of a volume pedal or audio taper pot mounted in a box would allow me to keep the gain up and volume down I will do that. For the gain I will just use the damage control solid metal in to the low input, it is way too much gain for the high input, but used as the gain source the solid metal pedal actually works, sounds great, adjustable in several ways including whether you use one or two of the preamp tubes.

 

I guess I just have to get the volume down on the half stack, if anyone has experience using an audio taper volume pot or a volume pedal in the effects loop please let me know. The thing is I want to play my half stack instead of it gathering dust, I have solid state and hybrid amps I could use low volume, but I think I will get much closer to the sound of what I will record or play live if I practice on the same amp I will use in those other situations.

 

T

[soc_monki]

if you dont like OD's to boost the signal...how about an EQ pedal? or maybe a dedicated clean boost (i dont know of any off hand but i know they make them). when i feel like boosting i just use my modded SD-1 and it does the trick

 

as for using a volume control in the FX loop, like an EQ or volume pedal, all it does is reduce the volume. it doesnt have much effect on tone (ive tried it). reason being...the FX loop is before the power amp and youre cutting the signal of the preamp down, which is basically turning the volume down.

 

an attenuator would be better than a volume control i think.

[jimytheassassin]

From my understanding.. brown sound would sound like.. putting on a pair of tight fitting ear muffs. Less definition of frequency, compression, distortion. This may all be a symptom of your tubes being off bias. Vari-A/C.. yes On that note.. running above voltage would seem more risky than less. It depends on how much "head room" has been left in the specs of the components to handle such an increase, with respect to voltage and heat. 130v seems reasonably high for a modern amp, but not everything is designed with the same extreme tolerances. Electical service "back in the day" used to be run much closer to 110v while today 120v isn't uncommon. So an older amp may have more trouble with such an increase.

[justcrash]

 

From my understanding.. brown sound would sound like.. putting on a pair of tight fitting ear muffs. Less definition of frequency, compression, distortion. This may all be a symptom of your tubes being off bias. Vari-A/C.. yes On that note.. running above voltage would seem more risky than less. It depends on how much "head room" has been left in the specs of the components to handle such an increase, with respect to voltage and heat. 130v seems reasonably high for a modern amp, but not everything is designed with the same extreme tolerances. Electical service "back in the day" used to be run much closer to 110v while today 120v isn't uncommon. So an older amp may have more trouble with such an increase.

 

 

 

I've always heard Eddie say that originally the term "brown sound" was what Alex used in the studio to describe the sound he was looking for with his kit. Somehow it becamse associated with Ed.

[justcrash]

 

I've always heard Eddie say that originally the term "brown sound" was what Alex used in the studio to describe the sound he was looking for with his kit. Somehow it becamse associated with Ed.

 

 

http://www.valleywebs.com/van-halen/Effects.html

 

"Actually, the term "brown sound" was originally coined by the Van Halen brothers to describe the sound of Alex's snare. Ed has even said "I want my guitar to sound like Al's snare drum."

[Noak]

if anyone has experience using an audio taper volume pot or a volume pedal in the effects loop please let me know.

 

I use volume pedal in the loop sometimes to control the overall volume. It will only help you to reduce volume however, which is a very bad thing play it loud

[ohjimmy]

I took the one we use home from work and tried it with my Laney GH50L. Ran the voltage down to about 80 then 90, 100, 110. the thing i noticed is that it gets quieter (obviously) and spongier sounding at lower voltage. To me the amp sounded much better and much more crisp and "present" without the thing.

[Weathered]

It is useful for "soft starting" amps either during their first power up, or after replacing caps. As James Peters said, it's not going to add gain to the amp.

[almightycrunch]

While it may not technically be "adding" gain, by running full tilt and the tubes being fully saturated at that point, and the added reduction in volume and increase in compression by the lowered voltage, would it not be construed as gainier? in the sense that it cannot saturate any more that it already is?

[Weathered]

 

While it may not technically be "adding" gain, by running full tilt and the tubes being fully saturated at that point, and the added reduction in volume and increase in compression by the lowered voltage, would it not be construed as gainier? in the sense that it cannot saturate any more that it already is?

 

 

That's true, but there are much better ways to get more gain than a Variac. From what I understand, you can also affect the electrolytic caps by running them at low voltage over a longer period of time.

[almightycrunch]

That, of course I have no idea about because my knowledge of whats going on inside a tube amp is extremely limited. As far as better ways of getting gain, I would not argue with you there for a second, sure there are much better ways of getting more gain than a variac. See Weathered, just like I told you, somehow I always end up in these threads, talking about stuff I dont really know much about?????? LOL

[almightycrunch]

BTW, I got my new quartet this morning, and popped em in there. They sent me "middle of the road" tubes as far as matching goes, I am probably gonna try it out like it is, and will see about biasing it I dont like what im hearing. Cuz it would be a good hour and a half ride to a reputable tech for a biasing job.

[Weathered]

 

BTW, I got my new quartet this morning, and popped em in there. They sent me "middle of the road" tubes as far as matching goes, I am probably gonna try it out like it is, and will see about biasing it I dont like what im hearing. Cuz it would be a good hour and a half ride to a reputable tech for a biasing job.

 

 

As long as they don't redplate or sound funny, you should be OK with those guys. Does the amp sound better now?

[almightycrunch]

In the end, the best answer seems to be to find a better tool for your job doesnt it? If it doesnt have enough gain for you, try a pedal, or an attenuator, if that doesnt satisfy you, you need another amplifier that can produce the level of gain you're after.