Lexicon MX200 power supply

  • Thread starter Thread starter Mr Blues
  • Start date Start date
M

Mr Blues

New member
My power supply for my lexicon MX200 conked out on me.

I love the lexicon reverb especailly for live giiging.

I use the large hall setting together with the digital delay.

The only problem is that the lexicon comany Harman pro say I have to order the power supply from a dealer. So i have to order it from either Turnkey stores or Sound control here in the UK , they say it may take two weeks.

Do you think its worth me going to a big electrical store like Maplins and getting something close to the power supply ?

or do you find with these things that they only work with the particular Lexicon reverb power supply?



Its 9 v ac 1.3

dave
 
as long as the supply is rated the same and the connector fits, you should be fine.
 
Thanks attitude

the problem is that its not rated exactly the same they are both 9v but one of them says the lexicon that is 1.3 but the electrical store one , the nearest they have got to 1.3 is 2.9.

Dave
 
That doesn´t matter as long as the amp on the new supply is bigger than amp required.

Amperage on a power supply is the maximal capability of the supply, so if it is 9vAC and has the same connector you´re OK.
 
My lexicon power supply was always noisy. I actually had to shield from the other wall warts. One day I plugged in a supply that went to my studio projects VTB1. Guess what? It worked better than the supply that came with lexicon.

I would find the best supply that matches the adapter size, amps and volts.
 
Hi Randy

I brought a power supply from the electrical store and at first i was pleased as it seemed to be working, the lights were on and I programmed the setings which was large hall and digital delay but the effects were not operating even though the lights were working fine.

My freind who checked the power supply said it was a DC plug but not a 9volt AC.

I will take it back and see if they have any AC adapters. I may have to order it from the lexicon dealer. the identical power supply would be ideal.

Dave
 
If it was DC it shouldn't have worked....
And should have fried the chips in there...
 
Yep, it has to deliver AC volts. Many a Lexicon product has been fried by inadvertent use of an aftermarket DC power supply.

Hopefully no permanent damage in your situation… best of luck.
 
Beck said:
Yep, it has to deliver AC volts. Many a Lexicon product has been fried by inadvertent use of an aftermarket DC power supply.
Click to expand...

Seriously? That seems very odd to me. Electronic circuits (a few old tube heaters notwithstanding) almost universally run on DC. A wall wart supply is usually only AC for one of two reasons: A. the device uses a transformer to step up the voltage to something else (doubtful for most electronics unless it contains tubes for some reason), or B. they wanted the cleanest possible voltage for the device and knew they had to put filtering inside the unit, so they cut costs on the external power supply....

An electronic device acting up usually means a supply is at the wrong voltage. A fried device usually means that the voltage is way over the specified voltage or the contacts are reversed. The question then becomes how they designed the supply circuit inside the unit.

With a 9VAC supply, the circuit probably does not run on 9VDC.. It probably runs on 12VDC. With a full-wave bridge using Schottky diodes, you can get about 11.86 VDC out of 9VAC. That's assuming the output is exactly 9VAC. If it's even as high as 9.1 or so, you're pretty much guaranteed that the device really runs on 12VDC.

So basically, you're drastically underpowering the device. Usually, that shouldn't cause any permanent damage (unlike overpowering it), but it still isn't likely to work, and I could easily see it corrupting memory or something if the device has semi-nonvolatile storage. I rather suspect that a 12VDC supply might work... but I wouldn't even consider trying such a thing without disassembling the device first and studying the supply circuit. :D
 
Right… the AC is rectified to DC within the device just as with many Alesis products, but they are very low voltage… +/- 5VDC for both the audio and processing. I’ve seen many a dead LXP-1, LXP-5, Alex and Reflex over the years from people going to the local Radio Shack and buying a DC supply as a replacement.

The good news is, if it does do permanent damage it’s usually limited to the rectifier and supporting components. The first thing the voltage hits after the jack are a couple caps, diodes and resistors. The 7905 and 7805 voltage regs often exceed maximum operating temps and are toast. Depending on your soldering skills, it’s an easy fix.

:)
 
dgatwood said:
Seriously? That seems very odd to me. Electronic circuits (a few old tube heaters notwithstanding) almost universally run on DC. A wall wart supply is usually only AC for one of two reasons: A. the device uses a transformer to step up the voltage to something else (doubtful for most electronics unless it contains tubes for some reason), or B. they wanted the cleanest possible voltage for the device and knew they had to put filtering inside the unit, so they cut costs on the external power supply....

An electronic device acting up usually means a supply is at the wrong voltage. A fried device usually means that the voltage is way over the specified voltage or the contacts are reversed. The question then becomes how they designed the supply circuit inside the unit.

With a 9VAC supply, the circuit probably does not run on 9VDC.. It probably runs on 12VDC. With a full-wave bridge using Schottky diodes, you can get about 11.86 VDC out of 9VAC. That's assuming the output is exactly 9VAC. If it's even as high as 9.1 or so, you're pretty much guaranteed that the device really runs on 12VDC.

So basically, you're drastically underpowering the device. Usually, that shouldn't cause any permanent damage (unlike overpowering it), but it still isn't likely to work, and I could easily see it corrupting memory or something if the device has semi-nonvolatile storage. I rather suspect that a 12VDC supply might work... but I wouldn't even consider trying such a thing without disassembling the device first and studying the supply circuit. :D
Click to expand...

I have plenty of devices than run on AC and there is a good reason for it. It is very easy to get positive and negative rails from an AC supply which a lot of older analog electronics will rely on and still have a very clean analog ground

A DC supply will never work with a device that accepts and AC input unless it is designed to take either and does not require a negative voltage (very rare,I can think of one example) but even then, it is a risky proposal since wall wart type supplies are almost never regulated so although it say 12VDC, depending how much current is being pulled through it, that may be much more if the rating are miss matched since wall wart transformers are designed to function at a certain load and the output voltage can vary if you go to far out of that spec. Again, this is usually not a problem with newer electronics since they will have regulation and filtering in the circuit itself so they have a broad input range but I have also seen older devices (Roland TR-606/303 is a good example) where using a higher current rated transformer will damage the device over time since it draws so little current on its own (only about 100 mA) and running a transformer rated for 1 amp this low will result in a voltage 3-4 volts higher than what is on the label. But I digress..

Anyway, running a AC powered device with DC will not hurt it, but DO NOT EVER try running a DC powered device with AC, it will DEFINITELY blow something. I would look and see if you have an old external modem, those were always 9VAC powered
 
RandyW said:
My lexicon power supply was always noisy. I actually had to shield from the other wall warts. One day I plugged in a supply that went to my studio projects VTB1. Guess what? It worked better than the supply that came with lexicon.

I would find the best supply that matches the adapter size, amps and volts.
Click to expand...

I've noticed the same. I always had it hooked up to the wall. When i rearranged my rack, i was able to fit it on my furman "power conditioner". It was really noisy. I read this and it just occured to me. I quite litterally just moved it and its much quieter (still noisy). So thanks for bringing that up, helped me out:)

Which leads me to think you may as well just go for another powersupply anyway and stay away from what it came with.
 
talontsiawd said:
I've noticed the same. I always had it hooked up to the wall. When i rearranged my rack, i was able to fit it on my furman "power conditioner". It was really noisy. I read this and it just occured to me. I quite litterally just moved it and its much quieter (still noisy). So thanks for bringing that up, helped me out:)

Which leads me to think you may as well just go for another powersupply anyway and stay away from what it came with.
Click to expand...

I guess it must be a super cheap power supply they are using. I actually wrapped mine in a double layer of tin foil cutting out about an 1.5" square
for the AC plug to go through will out shorting anything out. I guess if I was
advising anyone else to do it I would recommend wrapping some electrical
tape to keep the foil from shifting and causing a short.
 
RandyW said:
I actually wrapped mine in a double layer of tin foil cutting out about an 1.5" square
for the AC plug to go through will out shorting anything out. I guess if I was
advising anyone else to do it I would recommend wrapping some electrical
tape to keep the foil from shifting and causing a short.
Click to expand...
That tin foil trick works really well for my head as well... you know, when the voices get too loud
 
Hi Guys

I tried again today with the Maplins power supply and though the lights and settings came on I still could'nt get any of the reverb effects working.

Someone mentioned I may have fried the chips out of them if that was the case would the lights still come on?

I might buy a cheaper Alesis midiverb 4,for now I noticed Alesis do a microverb one too , are they both good or would you say the midi verb was better?

Dave
 
Does the demo button give you test sounds but no reverb?
If so make sure you have the 3 knobs on the left of the
face plate turned up full tilt the wetter the better.
If the demo produces nothing and you have the right PS
then I would send it back to the factory.

If you used a PS with double the current it could have
messed something up you would think it would be fused protected
but that may not be the case hence you still have LEDs
working on the display.

I have some type of Alesis reverb processor I believe it's called
a Wedge or something like that. It is okay but not stereo it
also has to much background noise for recording in my opinion.
I bought a Behringer proverb after reading rav reviews but mine
only lasted about 5 minutes if you can find one that works they
were selling them for $99 at MF.
 
I wouldn't give up on that unit yet... Find it hard to believe that a power supply could burn up anything in the signal path without harming anything on the power buss...

Are you sure of your audio routing... does the 200 have a dry output??
Is the effect turned up... take the suggestions from above... (although a power supply with a higher current rating won't cause it's own problem, I'd assume an under-rated supply responsible for causing these symptoms) try the demo mode.

The midiverb would be in the same league... not farmiliar with the micro... but I've worked with the nano series of Alesis sound moduals and was very impressed with the quality (Still regret parting ways with my nanobass) Sold it because of it's 16 digital sample rate.

But I'm confident you'll sort out the Lexicon before you start shopping
 
Thanks MoJo

Could it be my phonic powerpod 620. i mean it could be that the connectors need a bit of cleaning.(maybe not sure)

The inbuilt reverb processor works fine but the reverbs are very basic.

When the Lexicon was working I use to have the settings on large hall and digital delay for the voice and loved the open sound.

Dave
 
Decided to buy another MX200 and yes it was the power supply that was the problems .

I'll keep the old one for back up.

David
 
You must log in or register to reply here.
Back
Top