Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Nov 15 2014 05:34 PM
Has anyone heard of these or use one?
Reviewed in the January, 2015, Vintage Guitar Magazine, and a bunch of others, the AmpRX BrownBox is a line voltage reducer designed for vintage tube instrument amplifiers. It is specifically designed to lower voltage reaching the amp to match what vintage amplifiers were originally designed for, to protect their components and tubes, and make the amp sound better, like they did back when line voltage was closer to 110 than today's 120 and up. It's not a variac. According to the reviews, it works as described.
Plug your amp into it, plug it into the wall outlet, and just dial back the voltage reaching the amp to the specs the amp was designed for. I'm going to get one for my Music Man. I will definitely let you know what I discover.
Here's some links. AmpRX Website. Their Facebook page.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: Mar 19, 2015 10:03:28
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Nov 16 2014 09:54 AM
Very interesting Noel, thanks! I'm interested in what you find out. For putting 122.5V to my HF amp so it gets 3000V to the plate my house line is wonderful - replicating an earlier design voltage for a guitar amp not so much. Worth investigating; they are kinda spendy though.
— 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.
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Nov 16 2014 10:15 AM
Badger wrote:
Very interesting Noel, thanks! I'm interested in what you find out. For putting 122.5V to my HF amp so it gets 3000V to the plate my house line is wonderful - replicating an earlier design voltage for a guitar amp not so much. Worth investigating; they are kinda spendy though.
They aren't cheap. Did you watch both videos? The longer one that measures internal DC voltages very far above manufacturers specs is what really got me. It can't be good for components running on almost 500 DC volts when an amp is designed for 430, like the old Bassman. My take is, like with a lot of things, the price will seem cheap if it saves an expensive vintage amp from damaging components due to high modern line voltages. Getting back the original vintage sound is an added benefit.
According to Patrick (a very accessible and friendly guy, btw) it can also benefit older solid-state amps running on more voltage than they were designed for, though to a lesser extent. So I'm going to do some A/B comparisons with my Fender Stage 112SE in addition to my Music Man 212HD-130. Ought to be very interesting. Our line voltage average here is way above 120.
If you have anything you want to know sooner, you can email Patrick at amprx.1@gmail.com and I'm sure he'll get right back to you.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: Nov 16, 2014 10:23:54
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Nov 16 2014 11:47 AM
Noel wrote:
Did you watch both videos?
Will do that later; had to go move some snow and provide some non-verbal gestures of thanks to the town plow guys running by at 40mph who piled in my drive again. 
You mentioned exactly the concern I have, with the resultant internal DC stuff, because of heater voltages higher than I'd like to see and more importantly the B+ & screen grid supplies. The little BF Champ is gonna get a filter cap replacement first but I'd like to be running it a little gentler even if a few higher tolerance components get installed in various places.
I've thought about just plugging it into a leak light & playing with the bulb values to take advantage of the resultant voltage drop. The Champ is true Class A so current reduction of less concern than the nice side-effect of a voltage reduction going in. I'm thinking with a 150w bulb I might be able to get it down to like 116 (assuming my poor math is correct).
This is still a cool idea & will follow along.
— 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.
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Nov 16 2014 05:08 PM
This just in from Patrick.
It has a 5 amp rated power supply, w/a 5 amp CB, Inrush current protection, and a lifetime warranty. The power cord is a 10 amp rated power cord (18-3 AWG ). It consists of a proprietary transformer designed exclusively for Tube Amplifiers. It's not a Variac that can accidently destroy your amplifier. The BrownBox is American made and built like a tank to withstand heavy professional/touring abuse. It's definitely not a mass-produced, cost-conscious stomp-box; the price reflects all the technology and ruggedness built into it.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Dec 07 2014 03:59 PM
Just a couple follow-ups:
- did you get one and, if so, how do you like it?
- I built my leak-light that I was going to do anyway. It's now actually become the "extension cord" for my Champ. Will probably get in to check some internals tomorrow but there is (to my ears) a notable difference sonically, and for the better, between the line voltage it was getting slammed with before and something closer to what the circuit was designed against (117V). It's getting a steady 116.8VAC now and is notably smoother.
Curious now to get in & see what the transformer is sending to the rectifier tube and then points downstream.
— 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.
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Dec 07 2014 04:11 PM
Badger wrote:
Just a couple follow-ups:
- did you get one and, if so, how do you like it?
- I built my leak-light that I was going to do anyway. It's now actually become the "extension cord" for my Champ. Will probably get in to check some internals tomorrow but there is (to my ears) a notable difference sonically, and for the better, between the line voltage it was getting slammed with before and something closer to what the circuit was designed against (117V). It's getting a steady 116.8VAC now and is notably smoother.
Curious now to get in & see what the transformer is sending to the rectifier tube and then points downstream.
No.  Sadly, a budget problem (a very expensive repair to the van) has put this off for a while, what with Christmas coming and all. I still plan to get one as soon as I can.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
|
eddiekatcher
Joined: Mar 14, 2006
Posts: 2778
Atlanta, GA
|
Posted on Dec 07 2014 04:12 PM
An easy way to play that game is to use a long extension cord. 100' of number 14 would probably drop your line voltage at the amp and still pass enough current. As you drop the amps line voltage, it will start sounding spongy.
There is nothing wrong with using an actual Variac to drop your voltage to the 110v mark. That's what they are made for. It's not cool to run amps at a really low voltages....literally.
The advantage of a Variac is that you can 1. bring up a low line voltage situation, and 2. use it to "form" new filter caps or sometimes even re-form older ones.
ed
— Traditional........speak softly and play through a big blonde amp. Did I mention that I still like big blonde amps?
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Dec 07 2014 05:14 PM
eddiekatcher wrote:
An easy way to play that game is to use a long extension cord. 100' of number 14 would probably drop your line voltage at the amp and still pass enough current. As you drop the amps line voltage, it will start sounding spongy.
For an amplifier that draws less than 1A I'd probably need 3 or 4 football fields worth, right?
But you're right. Knowing what I didn't know years ago if I was still carting around Twins or a half-stack to all kinds of places I'd own a Variac in a NY-minute - they are cheap enough. Just saw one that would handle 4A for less than $60.
— 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.
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Dec 07 2014 07:37 PM
Noel wrote:
No. Sadly, a budget problem (a very expensive repair to the van) has put this off for a while, what with Christmas coming and all. I still plan to get one as soon as I can.
Noel, I'm really sorry to hear that. I know it's never a good time but this time of year sux for that kind of stuff. But we have priorities & take care of them which is why our Hollyweird mugshots aren't plastered all over the tabloids.
Merry Christmas anyway!
— 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.
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Dec 08 2014 11:00 AM
Badger wrote:
built my leak-light that I was going to do anyway. It's now actually become the "extension cord" for my Champ. Will probably get in to check some internals tomorrow...
Screen-shot of some probe results; still alive to type this and no magic smoke was let out.  It's getting a filter cap job but, especially looking at the voltage reductions in the power stage pretty easy to see why the amp is happier - especially considering what the B+ and screen readings were before on that 6V6.
— 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.
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Feb 11 2015 11:30 AM
I had to buy mine on lay-away, but it's in the next shipment. Yay!
I'm bringing it to the Instro Summit. I'm curious about the line voltage at the venue, and will happily let anyone with a vintage tube amp use it to dial in the power their amp was designed for.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
|
Badger
Joined: Nov 16, 2013
Posts: 4537
Wisconsin
|
Posted on Feb 11 2015 08:01 PM
Noel wrote:
I had to buy mine on lay-away, but it's in the next shipment. Yay!
I'm bringing it to the Instro Summit. I'm curious about the line voltage at the venue, and will happily let anyone with a vintage tube amp use it to dial in the power their amp was designed for.
Congrats on getting that sorted out.
As to the venue mains power, that would make a good "your correspondent on-the-scene" type report from you. Not a lab, but something where the rubber meets the road so to speak.
— 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.
|
da-ron
Joined: Jan 02, 2009
Posts: 1307
The original Plymouth, UK.
|
Posted on Feb 12 2015 05:26 AM
Here in the UK mains voltage has been reduce from 240Vac to 230V ac (+10%/−6%). Mains voltage is variable according to time of day and location anyway. In North America the voltage can be between 100V and 127V, according to Wikipedia.
Circuits are designed to accommodate this, and the tolerance of the components, which can be around 10%, with capacitors up to 20% tolerance.
It may be a wise investment to protect vintage gear (especially if it's someone else's vintage gear!), but a cap job would be sufficient for most other equipment, I reckon.
— http://thewaterboarders.bandcamp.com/
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Feb 12 2015 05:36 AM
Yes, it's absolutely designed to protect vintage amps.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: Feb 12, 2015 05:36:35
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Feb 27 2015 09:58 AM
I just got an email from Patrick Geraghty, the inventor and builder. He tells me it's perfectly safe to use a power strip plugged into a BrownBox, to provide both a vintage tube amp and a vintage reverb with the line voltage they were designed for, at the same time.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: Feb 27, 2015 10:06:44
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Mar 18 2015 07:57 AM
Here's some neat things I've learned about the BrownBox.
1) It's extremely easy to dial in the line voltage you want to send to your amp.
2) It lets you soft-start a tube amp. Once you know the settings you want to use to play, just dial everything all the way down as far as it can go before turning on your amp. Then slowly return to your settings as the amp warms up.
3) I asked about this first, and it's manufacturer-approved. I can plug a power strip into it, so my tube amp and tube reverb are both fed safe voltage. Obviously, I can't send them different voltages, but this is still way better than plugging my reverb into a hot line.
I'm very curious how an early Fender tube reverb with original internals will sound plugged into one of these, fed the lower line voltage it was made for?
I'm bringing mine to the Instro Summit. It will be there all day, every day. I invite anyone with a vintage tube amp or tube reverb to plug into it and use it. Anyone bringing a '50s or '60s tube amp or original tube reverb?
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
Last edited: Mar 18, 2015 07:58:15
|
BrownBox1
Joined: Mar 06, 2015
Posts: 1
|
Posted on Mar 19 2015 10:06 AM
|
Noel
Joined: Mar 15, 2011
Posts: 8528
Back in Piitsburgh, Pennsylvania, where I grew up.
|
Posted on Mar 19 2015 10:29 AM
BrownBox1 wrote:
Thanks Noel!
Welcome to sg101, Patrick! I didn't know you joined. Very glad you're here.
— This is Noel. Reverb's at maximum an' I'm givin' 'er all she's got.
|
ncgalt1984
Joined: Nov 27, 2013
Posts: 235
Greenville, NC
|
Posted on May 28 2015 02:13 PM
Out of curiosity, would this thing have an affect on modern amps, like a DRRI, if you dropped the line voltage t0 115VAC? The DRRIs can have an ice-picky quality. Would dropping the voltage warm it up any? Also, is there any danger in using it with modern amps if you run it at 115?
Also, could this be used to "replicate" a dying battery sound on a stomp box?
— Kevin
The Out of Limits
www.facebook.com/theoutoflimitsband
https://theoutoflimits.bandcamp.com/
|
May Birthdays 
