Anyone using a Variac with their Marshall Head?

mattpeyton

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My daily driver is a legit 1972 super lead. I run it at 90 V using a Variac that has a voltage meter on the output. I have also made just three small modifications to it. I've jumped the bias resistor with a 100k to allow me to properly bias for 39 mv (or so). I added a mid cap bypass cap to V2, and put a 50 K pot on the mid tone knob (I've kept the 25k CTS). I am also running 6CA7s. All of the mods above have been described to me by the two people I personally know who have been into the original EVH plexi and 72 metal panel. I've been running the amplifier this way for about two years. I've had zero problems with it it sounds exactly like EVH into a 1974 cabinet. The cabinet is running in a small storage closet in my basement inside of a plexiglass enclosure with Clarisonic baffles Because it would be LOUD.

I've been chasing that sound for about 40 years it's my impression that nothing sounds like a super lead at 90 V or so. Completely changes the character of the amp under your fingers....

As an aside My other favorites are a pair of 1968 Bassmans that have been "blackfaced" from the Vintage Amp Repair kit and I run those at 110v using the same Variac. They both have a tweed channel in V1.... those amps sound better variac-ed too!

CACB585A-EAD4-4618-87B5-856CF639D8B5.jpeg F7AB7963-D043-4939-B860-E6F59A2604BA.jpeg E8AAB650-1DEB-429A-876E-257DBCAC3B5F.jpeg 7B962D75-7BA2-429F-BCE9-FA046AF8290E.jpeg 4A657E92-F36C-4334-BE14-6EBEACB0F71F.jpeg
 
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LoudStroud

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Wondering if you've noticed any difference with tone?

My son is in a VH tribute and has switched over from a Kemper to using my jcm800 heads. He's using an attenuator, phase 90, and flanger and that it. The tone is killer and he loves the feel and response. The only issue is that the different venues can have sketchy power. Some have under or over voltage and he's had some issue with buzzing and what sounds like white noise in some of the venues. In some places the amps are quiet so it's a power or interference issue.

So we were considering something like the Furman ac117 that filters the power and supplies a steady 117 volts even if power is lower voltage. I had one years ago and it kept my rig quiet. I think the new counterpart model Furman p1800 is about $1500, so it's not a cheap remedy.

Then we were thinking instead of an expensive combination power filter/regulator like the ac117, p1800, or similar, why not buy a separate EMI/RFI filter and get a Variac to regulate the voltage.....and then he can dial down the voltage and try to get that EVH sag. If it sounds like shit or no improvement, then just set it to 120v and the amp should be fed steady voltage.

Thoughts or experiences?
Thanks!
I've considered the power conditioner route a few times, but have been totally fine with a Variac or more recently the AmpRX Brown Box. I use the Variac mainly to run the amp at it's proper voltage, especially my '68 Plexi that wants to see 115 VAC. With any of my amps fitted with old Mullards or NOS 6CA7's I'll run them just a few volts below the AC they expect to see. Have experimented with dropping voltage for the "brown sound", but not enough of a thing for the chance of the lower voltage putting wear on the tubes by way of "stripping". Which honestly I can't recall the technical aspects of that potential issue. Been a while.
 

WesChilton

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Just remember power conditioners are NOT voltage regulators. They are only there to smooth out the "bumps" in the line voltage, remove any RF interference in the power and stop surges above a certain threshold.

But older amplifiers from the 80s and older were designed and built for line voltages of 110v - 115v. This is what a lot of them list 117 MAX rating. So running these older amps at voltages from 120v to as high as 126v is damaging to them.

If you have wide voltage swings, like a lot of places do, then you need a voltage regulator like the Furman P-1800AR. This is what I use with my vintage amps in my home studio, as well as the BrownBox to then reduce the voltages to the proper range for the amps.

Just FYI, a Variac will swing with the wall voltages as well, and so will a Brown Box... you need to stabilize the incoming voltage first, THEN reduce it.
 

Brian Maiden

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Wondering if you've noticed any difference with tone?

My son is in a VH tribute and has switched over from a Kemper to using my jcm800 heads. He's using an attenuator, phase 90, and flanger and that it. The tone is killer and he loves the feel and response. The only issue is that the different venues can have sketchy power. Some have under or over voltage and he's had some issue with buzzing and what sounds like white noise in some of the venues. In some places the amps are quiet so it's a power or interference issue.

So we were considering something like the Furman ac117 that filters the power and supplies a steady 117 volts even if power is lower voltage. I had one years ago and it kept my rig quiet. I think the new counterpart model Furman p1800 is about $1500, so it's not a cheap remedy.

Then we were thinking instead of an expensive combination power filter/regulator like the ac117, p1800, or similar, why not buy a separate EMI/RFI filter and get a Variac to regulate the voltage.....and then he can dial down the voltage and try to get that EVH sag. If it sounds like shit or no improvement, then just set it to 120v and the amp should be fed steady voltage.

Thoughts or experiences?
Thanks!
Check out David bray amps dude make a killer Eddie brown sound amp he can even mod your amp https://www.davidbrayamps.com/bray4550.html#4550clips
 

valve-amps

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Going to need a 1959 ;-)
Yes I use a variac great for EVH Satriani sound. Sounds amazing. Only thing can cause issues with output tubes / valves but my JTM100 is too loud for studio use and neighbours and no problems so far. It is regulated keeps voltage within a couple volts of settings. Have also tried with ac30's etc. About £60 Ebay. Rated voltage is 220 Vac but lasted for a few years no issues.
 

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sct13

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I started using a variac to bring the voltage to 110VAC from the 120VAC I get … and it will vary from day to day …. Variac doesn’t adjust for it really just keeps it from going too high… I have seen it at 125VAC

Just watch your Bias setting and adjust to a recommended idle …

I started doing this mostly because of tubes getting hard to find … and the older 68 plexi needs to be fed the proper voltage

Not much difference in tone at all

I think ….
 

Stormhenge

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Wondering why you haven't just plugged it all in somewhere where you have the power you need, plug-in a variac, stick an echoplex preamp in front of it, and pull a profile of the amp on the Kemper, and keep using the Kemper, and have consistent tone regardless, that's what we did here, and it's worked out pretty well for us.

 
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patrice

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I use a variac with an original 1974 100W JMP and a 50W plexi clone that I've built from a 1973 Artiste chassis.
I bought an old variac and I put it in a custom wooden box on which I fitted a little led digital voltmeter (like 3€ on Ali Express): so you can use this to check the voltage and adjust your variac to the voltage you used to set the bias..
Led Voltmeter

A Furman voltage conditioner is pretty much useless, especially for $1500. Note that they don't call it a "voltage regulator", because it doesn't do that. It's just an elaborate filter with fancy display and functions like slow startup, etc...If you have seen the AC/DC rig rundown, you have seen the rack with the device they use to get a constant voltage anywhere in the world; that thing costs more or less $10k!

For a R/F filter, I would use something like this for 250V AC / 5A, like this one (or 140V for US voltage):
RF Filter

Clip for reference (disclaimer: obviously I cannot play like Van Halen - who can? - but I'm still trying):
Clip
 

Jackco

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If the sound is there, you just need to regulate the voltage. For stage work, the less complicated the better
 

Dogs of Doom

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One with me in an Ozzy tribute and the other band is a VH tribute.....so for that band it's brown sound all night. I think I'm going to look for decent used power regulator, pick up stand alone filter, and get a Variac....fuck it...lol.
in an interview w/ Max Norman, he said that they were well aware of VH's using the variac, so they used it too, so, VH & RR both used variacs.
____________________

GW What was Randy’s guitar rig for the sessions, and how did you record it?

NORMAN His amp setup was a Marshall stack, with two 4x12 cabs. We had four Shure SM57s right over the voice coils on four of the speakers—two speakers on the top and two on the bottom, catty cornered. The center of the microphone was right on the voice coil edge, on a tangent, facing right at it. Then we had a [Neumann] U82 sitting about eight feet in front of the stack, at the top of the steps and another U87 about 20 feet further back from that. Most of the time all those mics would be mixed down to one track. But sometimes we’d print stereo tracks if we wanted to keep the ambience separate.

GW Did he use basically the same guitar rig for both Blizzard of Ozz and Diary of a Madman?

NORMAN Yes, and it was a pretty advanced rig for the time, I suppose. He’d read somewhere about using the Variac [a variable power supply that can lower supply voltages and cause power tubes to saturate at lower levels]. He had a 100-watt Marshall amp, and we dropped the voltage down to 90 or 92 volts. That smokes up the distortion, gives it a creamier edge. And of course a lot of the effects came from his pedal board, the “chip pan.” [Ozzy gave this name to the setup because it created so much hiss and noise that it sounded like French fries—which the British call “chips” – sizzling in a pan. ]

 

MP+

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Wondering if you've noticed any difference with tone?

My son is in a VH tribute and has switched over from a Kemper to using my jcm800 heads. He's using an attenuator, phase 90, and flanger and that it. The tone is killer and he loves the feel and response. The only issue is that the different venues can have sketchy power. Some have under or over voltage and he's had some issue with buzzing and what sounds like white noise in some of the venues. In some places the amps are quiet so it's a power or interference issue.

So we were considering something like the Furman ac117 that filters the power and supplies a steady 117 volts even if power is lower voltage. I had one years ago and it kept my rig quiet. I think the new counterpart model Furman p1800 is about $1500, so it's not a cheap remedy.

Then we were thinking instead of an expensive combination power filter/regulator like the ac117, p1800, or similar, why not buy a separate EMI/RFI filter and get a Variac to regulate the voltage.....and then he can dial down the voltage and try to get that EVH sag. If it sounds like shit or no improvement, then just set it to 120v and the amp should be fed steady voltage.

Thoughts or experiences?
Thanks!
That's an awesome post, all the best to the young gun. Personally, I've never deliberately set out to chase any sort of replica to the great EVH tone but I might have something to add. Firstly, lot's of issues could cause buzzing and humming in a venue, anything from fluro. lighting to the active and neutral being reversed, or the neutral leaking. The variation in causes could lead to problems finding a single magic bullet solution. Something to put up with if there's no danger or shocks involved. I remember as a youngster reading a "Guitar Player" magazine interview with EVH not long after VH 1 was released. He mentioned that he had the variac wound to the point that his Amp. was blowing fuses, so in some cases the fuse was shorted out using a nail to keep it running. The editor inserted a heavily bordered warning text in the article stating that "Guitar Player" does not endorse or in any way accept any responsibility for any incidents should any reader attempt any such action. The bottom line is that his Amp. tone relied heavily on pushing the output stage hard to the point that this was the distortion source, so an output attenuator like a "Powerbrake" or similar is definitely the way to go. The 4 input preamp which has appeared on numerous Marshall heads is to my ears is the one that will push the output tubes harder than any other Marsh. preamp. I have a 25/50 Silver Jub. and on the clean channel it barely runs into any distortion wound up full. In contrast, the tone of the Jub. relies on getting the preamp tubes distorting. I would add that much of the early VH tone had plenty to do with what was going on with his guitar and front set up. I recall reading that he also ran some sort of analog delay which was fully put to use along with a bunch of car horns for the intro. to "Running with the devil" when recording. There was also a wah pedal which was barely used as a wah, but kept hovering around mid-span during solos. Dunlop have released a wah based on that which actually has a manufactured worn section of taper on the potentiometer. Finally, on the face of it, you would think that the guitar pickup arrangement would have little effect, but it does. Somehow, a guitar with a single pickup only resonates differently to a guitar with 2 or 3 pickups when we're talking distortion tones. I noticed it after I rebuilt an old Ibanez Destroyer which had a single bridge pickup routing only. There are other examples of this, like Malcolm Young's guitars. I would just close by adding some respect to the great guitar scene names mentioned above - RIP.
 

flyinguitars

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I have a Variac I’ve used with my 1959HW, it’s great for those tones. I have recently spent a lot of time working on making Kemper profiles of this set-up, with the Echoplex type boost, 10-Band EQ in line.. going to be releasing a pack couple of weeks with 10-12 snapshots of the Brown Sound included, plus 40-50 other profiles with different classic cabs. I could play the Brown Sound profiles all day long. So much fun!

Website for anyone interested is:

www.blittleprofiles.com

You can check out sound clips of my other packs as well on YouTube:


B
Cool sounds good. I check out your clips and that Friedman sounds great. I'll be buying that as soon as I get the Kemper unloaded and set up. If you ever need a demo player my son would be happy to trade for some profiles....lol... he's a great player and has a real knack for copping a style.
There is a great piece of gear to solve your voltage regulation problems, check out the AmpRX -BrownBox. It’s the best product I’ve seen to save your amp and your tone.

I think it was around $350 new and I use it with my modded 1959 every time I turn the amp on.
Sound cool thanks! Going to check that out!
Just remember power conditioners are NOT voltage regulators. They are only there to smooth out the "bumps" in the line voltage, remove any RF interference in the power and stop surges above a certain threshold.

But older amplifiers from the 80s and older were designed and built for line voltages of 110v - 115v. This is what a lot of them list 117 MAX rating. So running these older amps at voltages from 120v to as high as 126v is damaging to them.

If you have wide voltage swings, like a lot of places do, then you need a voltage regulator like the Furman P-1800AR. This is what I use with my vintage amps in my home studio, as well as the BrownBox to then reduce the voltages to the proper range for the amps.

Just FYI, a Variac will swing with the wall voltages as well, and so will a Brown Box... you need to stabilize the incoming voltage first, THEN reduce it.
Thanks, yea I sold my ar117 conditioner/regulator a few years ago so it looks like we should get something or somethings that clean up the power and regulate and then we'll add a variac. I was just originally wondering is the variac would take care of the regulating, but now think i understand that they just provide a steady ratio of what's set to output from input.
Wondering why you haven't just plugged it all in somewhere where you have the power you need, plug-in a variac, stick an echoplex preamp in front of it, and pull a profile of the amp on the Kemper, and keep using the Kemper, and have consistent tone regardless, that's what we did here, and it's worked out pretty well for us.


We (my son and I) have some really great profiles and a good brown sound out of the Kemper. I love it and have been using it myself in the band that we both play (we play together in an Ozzy tribute and he plays in a VH tribute) but I recently had my jcm800s serviced by our local amp guru and my son fell in love with them. He prefers them for the VH gig because he feels that he has more control and likes the response.....plus i know he just likes fact that he's blazing out of a few stacks on dimes amps...lol.


I use a variac with an original 1974 100W JMP and a 50W plexi clone that I've built from a 1973 Artiste chassis.
I bought an old variac and I put it in a custom wooden box on which I fitted a little led digital voltmeter (like 3€ on Ali Express): so you can use this to check the voltage and adjust your variac to the voltage you used to set the bias..
Led Voltmeter

A Furman voltage conditioner is pretty much useless, especially for $1500. Note that they don't call it a "voltage regulator", because it doesn't do that. It's just an elaborate filter with fancy display and functions like slow startup, etc...If you have seen the AC/DC rig rundown, you have seen the rack with the device they use to get a constant voltage anywhere in the world; that thing costs more or less $10k!

For a R/F filter, I would use something like this for 250V AC / 5A, like this one (or 140V for US voltage):
RF Filter

Clip for reference (disclaimer: obviously I cannot play like Van Halen - who can? - but I'm still trying):
Clip
Nice. Yea the higher end Furman's do regulating and conditioning but they are expensive. Used Furman regulators are going for a few hundred bucks, so I'll probably end up that route and then add a variac.
If the sound is there, you just need to regulate the voltage. For stage work, the less complicated the better
Yes very true.....we can't seem to leave things alone..lol!
 

Wildeman

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Nah, I got some alligator clips and a hamster...
 

flyinguitars

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in an interview w/ Max Norman, he said that they were well aware of VH's using the variac, so they used it too, so, VH & RR both used variacs.
____________________

GW What was Randy’s guitar rig for the sessions, and how did you record it?

NORMAN His amp setup was a Marshall stack, with two 4x12 cabs. We had four Shure SM57s right over the voice coils on four of the speakers—two speakers on the top and two on the bottom, catty cornered. The center of the microphone was right on the voice coil edge, on a tangent, facing right at it. Then we had a [Neumann] U82 sitting about eight feet in front of the stack, at the top of the steps and another U87 about 20 feet further back from that. Most of the time all those mics would be mixed down to one track. But sometimes we’d print stereo tracks if we wanted to keep the ambience separate.

GW Did he use basically the same guitar rig for both Blizzard of Ozz and Diary of a Madman?

NORMAN Yes, and it was a pretty advanced rig for the time, I suppose. He’d read somewhere about using the Variac [a variable power supply that can lower supply voltages and cause power tubes to saturate at lower levels]. He had a 100-watt Marshall amp, and we dropped the voltage down to 90 or 92 volts. That smokes up the distortion, gives it a creamier edge. And of course a lot of the effects came from his pedal board, the “chip pan.” [Ozzy gave this name to the setup because it created so much hiss and noise that it sounded like French fries—which the British call “chips” – sizzling in a pan. ]

Hey dogs!!! Wow, yea I thought I remember hearing that randy had one or tried one, but I didn't know they used it on the albums??... that's a cool fact that I didn't know. I never liked Randy's tone (as I wouldn't want it for me) but he made it work for sure. I think Randy played his way out of a crappy sound and owed it like a boss. I always thought he was still in a stage of learning as far as working out his tone and I'd bet his next album or albums the guitar sound would have improved exponentially like it did from blizzard to diary.
That's an awesome post, all the best to the young gun. Personally, I've never deliberately set out to chase any sort of replica to the great EVH tone but I might have something to add. Firstly, lot's of issues could cause buzzing and humming in a venue, anything from fluro. lighting to the active and neutral being reversed, or the neutral leaking. The variation in causes could lead to problems finding a single magic bullet solution. Something to put up with if there's no danger or shocks involved. I remember as a youngster reading a "Guitar Player" magazine interview with EVH not long after VH 1 was released. He mentioned that he had the variac wound to the point that his Amp. was blowing fuses, so in some cases the fuse was shorted out using a nail to keep it running. The editor inserted a heavily bordered warning text in the article stating that "Guitar Player" does not endorse or in any way accept any responsibility for any incidents should any reader attempt any such action. The bottom line is that his Amp. tone relied heavily on pushing the output stage hard to the point that this was the distortion source, so an output attenuator like a "Powerbrake" or similar is definitely the way to go. The 4 input preamp which has appeared on numerous Marshall heads is to my ears is the one that will push the output tubes harder than any other Marsh. preamp. I have a 25/50 Silver Jub. and on the clean channel it barely runs into any distortion wound up full. In contrast, the tone of the Jub. relies on getting the preamp tubes distorting. I would add that much of the early VH tone had plenty to do with what was going on with his guitar and front set up. I recall reading that he also ran some sort of analog delay which was fully put to use along with a bunch of car horns for the intro. to "Running with the devil" when recording. There was also a wah pedal which was barely used as a wah, but kept hovering around mid-span during solos. Dunlop have released a wah based on that which actually has a manufactured worn section of taper on the potentiometer. Finally, on the face of it, you would think that the guitar pickup arrangement would have little effect, but it does. Somehow, a guitar with a single pickup only resonates differently to a guitar with 2 or 3 pickups when we're talking distortion tones. I noticed it after I rebuilt an old Ibanez Destroyer which had a single bridge pickup routing only. There are other examples of this, like Malcolm Young's guitars. I would just close by adding some respect to the great guitar scene names mentioned above - RIP.
Thanks! Yea good info and I agree about the issue with power variation from venue to venue. Last gig was an old theater from the early 1900s and when the guitar volume knob was up close to max, he was getting a nasty jagged buzz... sounded like someone was welding lol. The week before were were at an outdoor festival with several massive generators and there was some different sounding interference...but at other places it's fine, so conditioner/regulator it is. I was just wondering if the variac would take care of the regulating but now I know.
Btw I read that same article when I was a kid on a flight from Philly to Portland..my mom bought the mag for me at the airport book news stand. I remember reading the disclaimer thinking "I gotta do this".?.lol. but if I remember correctly EVH said that he turned up the voltage and not down..lol....I wonder how many guys blew up there amps trying that move..lol
 

MP+

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Hey dogs!!! Wow, yea I thought I remember hearing that randy had one or tried one, but I didn't know they used it on the albums??... that's a cool fact that I didn't know. I never liked Randy's tone (as I wouldn't want it for me) but he made it work for sure. I think Randy played his way out of a crappy sound and owed it like a boss. I always thought he was still in a stage of learning as far as working out his tone and I'd bet his next album or albums the guitar sound would have improved exponentially like it did from blizzard to diary.

Thanks! Yea good info and I agree about the issue with power variation from venue to venue. Last gig was an old theater from the early 1900s and when the guitar volume knob was up close to max, he was getting a nasty jagged buzz... sounded like someone was welding lol. The week before were were at an outdoor festival with several massive generators and there was some different sounding interference...but at other places it's fine, so conditioner/regulator it is. I was just wondering if the variac would take care of the regulating but now I know.
Btw I read that same article when I was a kid on a flight from Philly to Portland..my mom bought the mag for me at the airport book news stand. I remember reading the disclaimer thinking "I gotta do this".?.lol. but if I remember correctly EVH said that he turned up the voltage and not down..lol....I wonder how many guys blew up there amps trying that move..lol
Of course when you get the output tubes up to distortion level, these noise and hum issues just become more in your face. How many guys blew up their amps? Scary to think of when you also consider how many mutilated vintage Strats. ended up floating around out there. I can't fully remember what he mentioned about his variac settings but either way, it's not worth the risk to maybe get 5% closer to that tone. Powerbarakes and output attenuators weren't a thing back in those days but give a very similar result. Early JCM 800's still had plenty of push driving the output tubes but it all gradually gave way to preamp distortion by the time the Silver Jubilees came about, having channel switches and gain knobs. That would be my go to, Plexi style 4 input preamp cranked to about 8 using the bright volume 1 input with the EQ pretty much maxed out and an attenuator on the output running into Quadbox loaded with creambacks. The JCM 800 will get super close to that and was in fact what came into the mix by the time of the "1984" album. Rock On!
 

Norfolk Martin

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Instead of using a variac, I built an amp that runs 340 vdc on el34 plates and it really sounds great. The lower plate voltage really make most output tubes sound better (to my ears). And I still have around 6.3 volts on my heaters.

With a variac turned way down, your heater voltages might be out of specs. I have heard that heater voltages that are too low can cause damage over time.
Yea. I'm a little confused by claims that you can go down to 90v Ac input and get a better tone . The 6.3 v AC heater supply is not stabilized in these amps . Going from 120 to 90 may drop your heater voltage to less than 5V , and it's going to cut the emissions from the cathode of each tube substantially. Having faulted a number of amps with low heater voltage over the years, IME they usually sound like pud. Dropping the HT sounds like a better idea to me.
 

Norfolk Martin

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it is not all about the power the voltage the grounding can be the problem . a lot of plugs are hooked to lights and other stuff . a power conditioner does not fix this.

IME "Conditioners" that just have filters do a good job with induced noise and switching spikes on the L/N lines but not so much where the ground potential is fluctuating You need something with a full isolation transformer to do that. If its a 1U rack unit , or weighs less than 10 lbs, I wouldn't trust it.
 


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