psychonaut
Joined: Dec 08, 2007
Posts: 1304
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Posted on May 13 2015 07:50 AM
So I've been experimenting with a Variac, and I'm very impressed with the results! I wanted to try this for ages but was always affraid to blow something up. Now I wish I had done this years ago.
For those that don't know, a Variac is a large transformer with a big knob on it that allows you to regulate the line voltage coming from the wall from anywhere between 0-130 volts.
First I tried running my amp, a 1967 Fender Pro Reverb, at 115 volts. This is a pretty good average of where the amp is designed to run at i think.
At 115v it sounded much less harsh in the high end, and the lows were much tighter. At 110 volts the amp noticeably starts to sound sweeter and more responsive. At 100 volts the harmonics and sustain are increased. At 90 volts ( you shouldn't go lower I've been told ) the amp sounds it's best to me. The sweet spot is now at 4 instead of 7 like it is normally, and it feels spongier and the tone is very smooth and creamy, plus noise is greatly reduced. I used it at rehearsal last night, and everybody in the band commented on how good it sounded. All the harshness is gone and the amp is really singing. I tried it with my tweed deluxe as well and got the same results.
Now I can have a consistently good sound from venue to venue. Most venues seem to have the voltages all over the place, especially if the audio power lines are the same as the light lines. A Variac seems like a good solution to this. I don't know how well this would work on a modern amp designed to run on current US voltages, which are way higher than they used to be, but I think everyone who owns a vintage amp should try using a Variac.
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Last edited: May 13, 2015 07:52:37
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Emilien03
Joined: Jul 16, 2008
Posts: 1377
Coyoacán, Distrito Federal
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Posted on May 13 2015 08:33 AM
Pretty interesting, I've done this myself and it's like baking a cake at the right temperature, it just comes out better. I think there are some devices for the gig that keep the voltage in place.
http://www.vintagesoundworkbench.com/Amp_Preserver.html
— When you have to shoot ... shoot! Don't talk.
"Los Grainders" > https://losgrainders.bandcamp.com
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Last edited: May 13, 2015 08:33:51
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derekirving
Joined: Nov 03, 2011
Posts: 660
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Posted on May 13 2015 09:14 AM
I've done it a few times to try to lower the overall wattage of a 45 watt amp (vs attenuator). The results were ok, browned the sound out for sure but added too much compression for me. I've also played places that had bad power/too many plugs extensions, etc and had a similar affect. I've never done it with a vintage amp and would seek the recommendation of a tech on that one myself. I know some people use power conditioners (Furman) to keep power consistent from venue to venue.
Sounds like it's working for you!
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Fady
Joined: Mar 07, 2010
Posts: 2272
North Carolina
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Posted on May 13 2015 10:50 AM
Interested.
That link you posted, Emilien, is great too, particularly the "Maniac" model he offers, granted I've not looked any further at similar variac options out there yet.
Vintagesoundworkbench's FAQ's also note that when using these devices to knock down the voltage fed to the amp, that you'd probably want to have your power tubes re-biased accordingly, which I guess makes sense.
Viktor - have you messed with the biasing on your amps as you've experimented with this?
— Fady
El Mirage @ ReverbNation
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Fady
Joined: Mar 07, 2010
Posts: 2272
North Carolina
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Posted on May 13 2015 10:52 AM
Also, Dario, if you have your ears on... have you made any adjustments in your builds such that your amps want/prefer to see present day voltages in the 120 neighborhood, or would something like this be of benefit for your builds too?
— Fady
El Mirage @ ReverbNation
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CrazyAces
Joined: Jul 31, 2012
Posts: 4053
Nashville, TN.
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Posted on May 13 2015 11:00 AM
A lot of artists I worked with on the road use them.
There are more than a few AC-30 specialists that suggest you don't leave home without a variac when using an older AC-30 or Marshall.
They work great for finding the sweet spot in relation to voltage on an amp and most Furmans and such do not actually regulate and correct the voltage coming out of a wall.
In my experience we didn't get too drastic in lowering the voltage, just enough to where the player liked/wanted it set.
Cheers,
Jeff
— http://www.facebook.com/CrazyAcesMusic
http://www.youtube.com/user/crazyacesrock
http://www.reverbnation.com/crazyacesmusic
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psychonaut
Joined: Dec 08, 2007
Posts: 1304
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Posted on May 13 2015 11:08 AM
Onslow_Beach wrote:
Interested.
That link you posted, Emilien, is great too, particularly the "Maniac" model he offers, granted I've not looked any further at similar variac options out there yet.
Vintagesoundworkbench's FAQ's also note that when using these devices to knock down the voltage fed to the amp, that you'd probably want to have your power tubes re-biased accordingly, which I guess makes sense.
Viktor - have you messed with the biasing on your amps as you've experimented with this?
No, I haven't messed with the biasing at all
— https://www.facebook.com/coffindagger
http://coffindaggers.com/
http://thecoffindaggers.bandcamp.com
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Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
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Posted on May 13 2015 11:21 AM
Well, it's not technically a Variac, but I use this now on my tube amps and reverb.
AmpRX BrownBox
I'll have it at the Instro Summit for any and all to use. Victor, I can bring it to the Asbury Park Surf Festival for you to take a look at, if you're interested.
This record sounds absolutely fantastic! The BrownBox is on top of the Princeton. IMHO. YMMV.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: May 13, 2015 11:22:11
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psychonaut
Joined: Dec 08, 2007
Posts: 1304
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Posted on May 13 2015 11:33 AM
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Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
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Posted on May 13 2015 11:42 AM
Here's a picture of the dials. The upper is normally set to your wall's line voltage, and the lower one is set to whatever reduction gives you the voltage you want to send to your amp. But they can be combined to produce whatever you prefer.
Not shown is that the display not only shows you your active line voltage, but a second readout dynamically displays the active amperage your amp is pulling. It changes as you play, depending on how hard and loud. Cool!
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: May 13, 2015 11:43:10
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derekirving
Joined: Nov 03, 2011
Posts: 660
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Posted on May 13 2015 01:04 PM
All this to give bigger amps tone at lower volumes (instead of a smaller amp) ---- funny I go though the same issue and I'm at the point where a smaller (lower wattage amp like a deluxe reverb 22w or bandmaster tweed 28w) makes sense over my Super Reverb. I tried lot's of tricks and I'm realizing a smaller amp makes more sense until I'm playing theaters/arenas 
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CrazyAces
Joined: Jul 31, 2012
Posts: 4053
Nashville, TN.
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Posted on May 13 2015 01:11 PM
derekirving wrote:
All this to give bigger amps tone at lower volumes (instead of a smaller amp)
Maybe for some but not for me.
A variac would be used just to make the amp sound better not lower the volume.
I'll always be of the same mind as you in that it's good to use the right size amp for the room or place you are playing, not your favorite loud amp everywhere. That is non-sensical to me and my experiences as a musician.
Cheers,
Jeff
— http://www.facebook.com/CrazyAcesMusic
http://www.youtube.com/user/crazyacesrock
http://www.reverbnation.com/crazyacesmusic
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psychonaut
Joined: Dec 08, 2007
Posts: 1304
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Posted on May 13 2015 01:24 PM
Like Jeff, in my case its to get better tone, not lower the volume. I still use an attenuator for that.
— https://www.facebook.com/coffindagger
http://coffindaggers.com/
http://thecoffindaggers.bandcamp.com
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Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
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Posted on May 13 2015 01:30 PM
For me, matching line voltage to what an old tube amp (or its circuit) is designed for, is for reliability and making it sound like it's supposed to. It's scary to me to plug an amp designed for voltage common 50 years ago into a modern wall socket. Dropping from 122 or 124 to 114 line volts won't quiet an amp enough to notice, but it will provide its original tone and extend its longevity. At least that's the point for me. I can't hear a volume drop. I can hear my amps sound better, really more pleasing. And I sincerely feel better knowing they're not getting voltages they weren't designed for.
My MicroPro-200 handles everything from dining room volumes on up to full-throttle Super Reverb territory, all with consistent, pleasing tone. And it seems immune to variations in line voltage.
But, I confess I'd love an old, low-power tube amp. I'd just plug it into my BrownBox to help preserve it, and have it sound the way it was intended.
As always, IMHO. YMMV.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: May 13, 2015 13:36:46
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Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
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Posted on May 13 2015 04:00 PM
Noel wrote:
But, I confess I'd love an old, low-power tube amp. I'd just plug it into my BrownBox to help preserve it, and have it sound the way it was intended.
Noel, you should set your next set of sights on finding a decent little Champ or Vibro Champ (add FRV-1 & you're in biz). These (especally the SF ones) can be found not too painfully. Some folks are BF-addicted but that circuit was so insignificant to CBS that they never molested it other than cosmetics; it was after all just a $60 practice amp. And WGS makes a kick-ass 8" purpose-built speaker for it. Perfect example of an amp that is NOT happy at 123.5VAC out of the wall, but loves me at 115.
— Wes
SoCal ex-pat with a snow shovel
DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices.
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Fady
Joined: Mar 07, 2010
Posts: 2272
North Carolina
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Posted on Jun 06 2015 12:58 PM
Viktor - just a follow up to say Thanks (!!) for posting about this. I've had a Tripp Lite Line Conditioner + Voltage Regulator since the end of last year and this discussion put me over the hump of going ahead and adding a Variac. I still need to experiment with lower voltages, but after a little tinkering at home and using it on a gig last night at 110V, I completely agree with your sentiment and share your experience. Sure, it's a little extra bulk & weight to transport, but not prohibitive IMO. Well worth the benefits I'd say.
So again, just a bump to say Thanks for the tip & sharing your experiences. New benefactor here thanks to you.
— Fady
El Mirage @ ReverbNation
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psychonaut
Joined: Dec 08, 2007
Posts: 1304
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Posted on Jun 06 2015 04:51 PM
Onslow_Beach wrote:
Viktor - just a follow up to say Thanks (!!) for posting about this. I've had a Tripp Lite Line Conditioner + Voltage Regulator since the end of last year and this discussion put me over the hump of going ahead and adding a Variac. I still need to experiment with lower voltages, but after a little tinkering at home and using it on a gig last night at 110V, I completely agree with your sentiment and share your experience. Sure, it's a little extra bulk & weight to transport, but not prohibitive IMO. Well worth the benefits I'd say.
So again, just a bump to say Thanks for the tip & sharing your experiences. New benefactor here thanks to you.
Glad it works for you! I now consider a variac an absolute nescesity for
a vintage amp
— https://www.facebook.com/coffindagger
http://coffindaggers.com/
http://thecoffindaggers.bandcamp.com
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