Does anyone use a variac with their OR120?

[ironlung40]

Thanks!

Based on all of this,

I am going to keep running the OR120 like I am. I measured my wall voltage over the past few days and it is pretty stable at 120.3.

I have an old traynor yba that is rated for 115 as well, that I have been running with no issues, either. I do run it on an 8 ohm load religiously. I know many have ran them on 16 ohm with no issue, but they are only rated for 8 and 4 ohm, and I always impedance match no matter what on all of my amps with no exceptions.

For the Laney, it is biased currently at 240v. I haven't played it since bringing it back home. I think that I am just going to buy a step up transformer and run it at 240 and call it a day. This amp will never get gigged anyway.

The brownie has higher percentage drops than the brownbox. I am not sure how the hi/lo switch works but I think it brings the power down or back up an additional 5v on top of the scaling selection which goes up to 16%. If the brown box would go up to 16% like the brownie, I might would pick one up. But bringing 120 down by the max 10% yields 108 volts. That is barely enough for the Laney anyway and if I have high voltage like 125 or so, which can be common, it would not reduce it to 110. (The way I understand how it works, anyway).

Nick, you are right about the brownie not being powerful enough. Per AmpRX, 100 watt amps can draw over 300 watts and the brownie is rated at 340. The brownbox is rated over 500 watts. But I think I read somewhere that you want at minimum 1.5x the power handling power than you amp draws to be safe. That also puts the brownbox, doesn't it?

[yossarian83]

Somehow I totally missed this post. Although it seems to be resolved, I thought I might share my experiences with you.


IMHO, the best (and cheapest) way to accomplish this is with the transformer mod found on the OFG.
http://orangefieldguide.com/orange_mods.htm#_mod5


I've got ~124 volts typically coming out of my walls and this mod brought the internal amp voltages down so that they match the old schematic's perfectly. I don't really know if this affects tube life or other performance issues. I've had the same pair of Mullard XF2's in the amp for ages but those last much longer than typical tubes anyway.

Similarly, if you setup the Laney PT at the 110 and 230 taps, this would be perfect for 120 vac coming out of the wall.

I've used: variacs (always worried about the knob) and step-up transformers (noisy and voltage is doubled so if you start at 125, you'll be at 250 rather than 240... whats the point?) but this mod is hands down the simplest solution.

Cheers

[fiveightandten]

Somehow I totally missed this post. Although it seems to be resolved, I thought I might share my experiences with you.


IMHO, the best (and cheapest) way to accomplish this is with the transformer mod found on the OFG.
http://orangefieldguide.com/orange_mods.htm#_mod5


I've got ~124 volts typically coming out of my walls and this mod brought the internal amp voltages down so that they match the old schematic's perfectly. I don't really know if this affects tube life or other performance issues. I've had the same pair of Mullard XF2's in the amp for ages but those last much longer than typical tubes anyway.

Similarly, if you setup the Laney PT at the 110 and 230 taps, this would be perfect for 120 vac coming out of the wall.

I've used: variacs (always worried about the knob) and step-up transformers (noisy and voltage is doubled so if you start at 125, you'll be at 250 rather than 240... whats the point?) but this mod is hands down the simplest solution.

Cheers

Interesting, I never noticed that on the OFG before. I guess it makes sense. You're just using a different part of the primary winding, where the ratio is more optimal. But couldn't you just swap the 115V tap to the neutral pole on the switch, and set the voltage selector to 240V? It seems that would be the same thing, and be less intrusive.

Do you remember how much this dropped your plate voltage and what it did to the sound of the amp? I know how lower voltage affects Marshalls and other amps, but the Orange output section clips in a very unique way. Does lowering the voltage make a notable difference in the sound?

Thanks for sharing that.

-Nick

[Gladmarr]

Me and yossarian83 worked this out a couple years ago now. I'm running a White W100 this way and it brings all the voltages back down to where they should be. The problem with modifying wiring to the mains select switch is when someone else goes to change the mains setting after the mod and everything other than the 110/120 selection is totally wrong. That could be inconvenient all the way up to dangerous.

[yossarian83]

Interesting, I never noticed that on the OFG before. I guess it makes sense. You're just using a different part of the primary winding, where the ratio is more optimal. But couldn't you just swap the 115V tap to the neutral pole on the switch, and set the voltage selector to 240V? It seems that would be the same thing, and be less intrusive.

Do you remember how much this dropped your plate voltage and what it did to the sound of the amp? I know how lower voltage affects Marshalls and other amps, but the Orange output section clips in a very unique way. Does lowering the voltage make a notable difference in the sound?

Thanks for sharing that.

-Nick

It did not change the sound or response significantly (at least to my ears). It definitely did not affect the asymmetry in the output section (you can actually SEE that happening if you crank the amp and turn out the lights)

The plate voltage went from I believe around ~516v down to 470v.

My motivation originally came after reading about people running modern 6v6GT's in their vintage high-wattage amps. I wanted to try it but the Orange plates and grids were just too high. After the mod, I was able to run the OR120 at 20 watts with two 6v6's for months without issue. I think I posted a video of it if you want an idea of how it sounded...

edit: found the link: https://www.youtube.com/watch?v=sU7Sy5Xhs40" onclick="window.open(this.href);return false; ... admittedly, it did sound a bit different with the 6V6's and the output section didn't act the same when cranked but it was fun to try and still sounded quite good. I may do it again in the future.

Good idea on swapping the neutral. The only issue here would be to place some sort of warning over the voltage selector so that no one tries to "fix" the discrepancy later. With the original mod, the switch is completely inactive so there's less room for error.

That being said, I didn't find the mod particularly difficult as written.

The problem with modifying wiring to the mains select switch is when someone else goes to change the mains setting after the mod and everything other than the 110/120 selection is totally wrong. That could be inconvenient all the way up to dangerous.

100% this is the only major downside. I've put a sticker over my switch that simply says 120V only!

[yossarian83]

Me and yossarian83 worked this out a couple years ago now.

Read this as he told me what to do and I did it. I think it's a brilliant idea on his part but I had nothing to with it, that's all Gladmarr.

[Gladmarr]

Me and yossarian83 worked this out a couple years ago now.

Read this as he told me what to do and I did it. I think it's a brilliant idea on his part but I had nothing to with it, that's all Gladmarr.

I don't totally recall. For some reason, I thought this was your idea and I just made a pretty diagram for it.