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Problem with the Alesis RA-150 Amplifier

Amp cuts out after a while


By Blueshift on Oct 17, 2007
The amp works great for an hour or so then starts to crackle and cut out intermittently.  Any ideas?

  1. Thanks Koolkidkip! It's not a tube amp, so that rules that out. As for the OHM load, not too sure how to check that. I'll try reducing the signal going to the amp and turning up the gain on the unit, so if that helps... the problem is it would cost about $100 to have someone look at it, and it's about $150 to replace it! (I sure appreciate the suggestions though!)
  1. @ Cloudio.

    Hi,
    Any chance you could elaboarate on your solution?
    Where would I find a 44.62.9.012 12VCD Coil 2x 10A changeover relay and are they expensive?
    Was this the only thing you replaced? I have no idea about electronics unfortunatly but I may approach someone who does so knowing what to replace and where to get it from would be very useful.
    Is your amplifier still working perfectly now after a few days of use?

    Oh yeah, Alesis have ignored every one of my emails on their technical support page. What is more frustrating is that other amplifiers on the market at the price range (i.e Samson) are apparently fitted with the same components as the Alesis RA series so I assume they would have this problem too. This makes looking for a replacement amp on a budget very difficult.



  1. Had the same issue as described (RA-300). Replaced the offending relay with an 8A version: Finder 50.12.9.012.1000 -

    http://nz.farnell.com/finder/50-12-9-012-1000/relay-pcb-safety-8a-12v/dp/1329680

    Now works a treat.
  1. I just replaced the "relay in question" on my RA300 and initial results are great! *crosses fingers* FIXED!
  1. I've got an Alesis RA300 that worked well for about 1 year then the channels started crackling in and out. Tapping the top shifts the problem from one channel to the other.
  1. I'm also having crackles and dropping channels with with RA-150. I'm tempted to try replacing the relays. Do I need to drain any capacitors before working on this thing?
  1. Same problem will replace relay thanks fellas RS 300

Best Solution (1 of 17)

posted 2 years ago

tonedrone
  • Rank: Apprentice
  • Rating: 88%, 2 Votes
I got no reply from Alesis, hmm I see...

Well I cracked into my RA300 the other day to check out the relay (black box, rear, main board, shirty2008 pointed out). I was instructed by an former co-worker that relay contacts in power amps sometimes arch and get burnt or pitted, usually from current moving through while switching poles. This happens when you have an input signal or music playing when you turn the amp on. His suggestion was to re-surface the contacts by running between them very fine emery cloth, 600 grit or so. I thought I'd try this and move on from there. While doing so I noticed a cap was scorched and coming apart. This was a green 2A104J polyester film type near where the power transformer (big heavy thing in the middle of the unit) connects to front of main board. I got a $2 four-pack of 104J caps w/ same specs and used one as a replacement; re-surfaced the contacts with $1 sheet of sandpaper and $5 can of contact cleaner from the electronics store. With the cap in place and a refurbish relay making sure all excess of cleaner was gone before putting the cover back on, WALLA she works like new! mmmhmm all tell hu what.

In conclusion I think: the relay was the problem, the capacitor a near future problem, and Alesis makes cheap chinese bukaki with the sin being lack of support for their products.
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Solution 2

posted 2 years ago

shirty2008
  • Rank: Apprentice
  • Rating: 100%, 5 Votes
I had the same problem with my RA150.
Searching the net found Samson Servo 170 has same problem.
Further search reveals its exactly the same circuit as Alesis RA150 - Mmmm!!
the fix? change the relay on PSU board (the black boxrear right. It's a 12vdc double pole changeover type.
I used an Omron G2R-2A (only has the contacts that are used - has two pins missing).
Perfect amp now - very happy
Hope this helps someone else.
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Solution 3

posted 2 years ago

irishsounds
  • Rank: Apprentice
  • Rating: 92%, 2 Votes
Not a solution as such but maybe a pointer:

I have exactly the same problem first in one channel then in both. I wrote to Alesis - but they were completly unhelpful on the matter and could suggest no solution.

I found that by giging the amp a tap the sound came on. This means the problem is affected mechanically - that sounds to me like a dry solder joint or similar. It might also be a faulty capacitor they can sometimes be affected by tapping.

To date I have not been able to locate the exact point of the problem - I am pissed off with Alesis and wont but another amp from them.
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  1. Shirty2008 That sound about right for the sort of problem being expressed - a relay with dodgy contacts would explain ALL the symptoms. Must try this - Thanks

    Reply


  1. Sorry Guys I'm new here and posted a comment to my own post. Hopefully it will go to the right place this time.

    @Shirty2008
    That sound just about right place to look for the sort of problems being expressed - a relay with dodgy contacts would explain just about ALL the symptoms. Must try this one - Thanks

    Reply


  1. The Alesis Ra300 Ra150 etc amp problems have highlighted a issue so common these days where a company sinply tries to ignore service issues. On that basis I am publishing here my correspondence with Alesis and the addresses to which others may write with complaints. I think we should spread the word far and wide to Alesis customers.

    To Alesis:

    Hi - I have been using an RA300 for about 2 years and must say I am most pleased with the performance. It has however developed an intermittent fault seperatel in both channels. The sound kicks in and out every so often, and a sharp tap on the case can correct it.

    I suspect a dry joint is the problem. The fault seems exactly the same sort of thing on both channels BUT happens seperately and independently.

    What I am hoping is that you guys might have indentified this problem and can point me in the right direction. I am an engineer myself and also have access to a firstclass tech guy so no problem with the repairs here. I would help a lot to have a pointer as to where to looks for the problem.

    Thanks,
    Tony McGinley

    Alesis Replies:

    Hi, It will be hard to diagnose without looking in the unit, as you probably realize. It does sound like a dry joint so it’s definitely worth looking at the circuitry for the amp modules.

    Best regards
    Ian Bigg
    Technical Service & Support
    Numark Alesis Europe Ltd
    Tel: 01252 353850
    Fax: 01252 353811
    email: ibigg@numark.com


    To Alesis:

    Thanks for the reply Ian,
    I would seem not to be the only one with this problem - I found several on a Google. Hey!! - you cannot be serious about looking for the problem in the "amp" modules. Imagine amp modules in an amplifier!!! Whatever will they think of next!! Can I quote you on the forums???

    Seriously, Alesis must have a listing of faults, and this seems a common enough fault, is it possible to reference a database and get a list of the most connon dry joints that cause a clean sound cut??

    Cheers,
    Tony McGinley

    Alesis:
    Hi,
    Unfortunately there isn't a list of "common" faults that we can look at for you. The only way we are going to know what the fault is, is by looking in the unit.

    Best regards
    Ian Bigg
    Technical Service & Support

    To Alesis
    Hi Again, If Alesis hasn't found a common fault link - then I have. Here is a discussion where at least 5 people have much the same fault. There is also a good suggested fix by shirty2008.

    You will also notice that people are well annoyed with Alesis on the lack of interest in this obvious problem.

    Here is the link: http://www.fixya.com/support/t224708-amp_cuts_out_after_while

    Can you offer a recommendation regarding the problem being related to a faulty 12volt changeover relay??

    Regards,
    Tony McGinley



    Reply


Solution 4

posted 2 years ago

Cloudio
  • Rank: Apprentice
  • Rating: 85%, 1 Votes
I have a RA300 with the same problem. Symptoms exactly as described by Blueshift and jdmille. It's definitely the crappy relay. I replaced it by a Finder 44.62.9.012 12VCD Coil 2x 10A changeover relay. It fits in nicely. The Amp works perfectly now.
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Solution 5

posted 3 years ago

koolkidkip
  • Rank: Apprentice
  • Rating: 85%, 1 Votes
I have some Ideas , Two come to mind.Check the OHM load that you are driving it at most amplifiers start having trouble if they are ran at medium volume of higher at less than a two ohm load.This can happen if you are driving two 4 ohm speakers on each channel.If you are running the amp bridged the problem is doubled.
If it is a tube amp or tube preamp in the setup,Try replacing the tubes. They do not last very long if used every day or professionally.
Please wright us back and let us know if this is the problem,If it is not there are only about 100 other things it could be.
Thank You
Koolkidkip
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Solution 6

posted 8 months ago

notme403
  • Rank: Apprentice
  • Rating: 100%, 1 Votes
My Alesis SA-300 started the cutting out when at moderate levels some months ago... Well, Radio Shack has instant gratificaion for those who have one in the neighborhood. Part number 275-249 will do the trick!
http://www.radioshack.com/product/index.jsp?productId=2062483

I replaced the Dong Woo part with the Radio Shack item and the amp is back to its old self... maybe even a little better. Loud, clean and steady.

Thanks to all you who have contributed to this thread.

Steve
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Solution 7

posted 8 months ago

bassbill
  • Rank: Apprentice
  • Rating: 100%, 1 Votes
I had the speaker relay problem with my RA-300 as described in these posts - intermittent output sometimes one or both channels. I was able to obtain the exact relay from a company in Dayton Ohio. It is Parts-Express (www.parts-express.com). The part number for the relay is: 075-128. Cost is $6.24. Unsoldering the old relay was a challenge, so make sure you have the proper soldering tools and experience before diving in.

Cheers!
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Solution 8

posted 1 year ago

daveS602z
  • Rank: Apprentice
  • Rating: 88%, 2 Votes
Hi
Disgruntled Alesis owners....think you have problems... I have 30 of these amplifiers...
You may be interested to hear that there are at least two faults associated with the "dog-poo" (sorry Dong Woo) relays.
Crackly intermittent sounds on L/R (or both) is usually down to poor relay contacts.
I am also finding instances of intermittent relay operation whereby the relay clicks in and out for no reason. I have traced the problem to the actual relay coil (or internal coil connections).
I will break this latest one open tomorrow and see what's actually causing it!
Either way REPLACE with Farnell (Part No. 1329680).
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  1. REPLACE relay with Farnell (Part No. 1329680).

    Reply


Solution 9

posted 2 years ago

seasharp
  • Rank: Apprentice
  • Rating: 88%, 2 Votes
I had the same problem with cutting out. My amp is about 5 years old and the problem started about 6 months ago. I was sure the problem is with the relay that keeps the output switched off until the power is up and stabilized. You can hear this relay click a few seconds after you power up. It is the only non-solid state device in the audio chain so it is a logical suspect. Others have replaced it. I did a quick and dirty fix by drilling a 1/16" hole on two opposite corners of the top of the relay cover. I then shot some contact cleaner into one of the holes. If you do this, be sure to put a drill stop on your drill because you don't want it penetrating any deeper than the cover thickness, about 3/32". After that I reconnected but I have not put the cover back on yet. It has been working now for several days. When I am convinced it is now OK, I will seal the holes with a dab of silicon sealer and put it all back together.
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Solution 10

posted 2 years ago

elliotwilson
  • Rank: Apprentice
  • Rating: 75%, 1 Votes
Normal 0 false false false MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} I mentioned in my previous post that Alesis have ignored all my emails so I felt compelled to send them one final email and received the following reply.

“Sorry, this was the first email I have seen on this. Something must have been preventing it from coming through. We always strive for quick response times.
First, there are no 'mass faults' with the RA series amps. The forums can make anything seem widespread when it is only a handful of people. From your description of the sound cutting out, there are a few possibilities why this is happening.
If it cuts out completely, there might be a problem with the power supply to the amp. I would check your ground connection. This is something people often overlook. This may have come loose or is not providing an adequate completion of the circuit. If that is not your problem check your power cable. Also make sure you are using the proper gauge speaker wire, as recommended in the RA manual. If this does not help out, I would recommend this to be serviced. Our UK office can be contacted for assistance at 01252 341 400. I’m not positive on the cost for servicing, though our UK office will be able to provide this.”
I think I will try looking at the relay since others are reporting this is correcting the fault when replaced.
Cheers
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Solution 11

posted 2 years ago

tonedrone
  • Rank: Apprentice
  • Rating: 88%, 2 Votes
I sent this to Alesis today. hope it helps!


Dear Ian,

I owned a RA300 for about 2 years and am mostly pleased with the performance. However, it recently developed an intermittent problem with both channels cutting in/out (manly the right channel) with crackle here and there. a tap on the case can correct it sometimes.

I noticed after I googled the symptoms other people have the same problem and would like to be pointed in the direction of a solution. I have worked as a technician for a major audio company and understand that liability and policy often keep an employee from offering this kind of information.

with that said, and because it looks to be obvious manufactures defect, I'm asking you to fix my amp beyond the warranty (free of charge) or email me the solution and I'll do it myself. please let me know.


Thank you,

Anthony Krause
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Solution 12

posted 3 years ago

jdmille2
  • Rank: Apprentice
  • Rating: 75%, 1 Votes
I have an RA500 with a similar problem - for a few months now, often the left channel would be "crackly" and cut out, but then seem to "warm up" and be fine.  Now, the right channel started to behave like Blueshift's RA150, crackly and cut out.  There's no problem with load; I'm using 6 ohm Polk Audio Model 11 studio monitors (circa 1982 and still some of the best speakers I've ever heard, IMHO).  Note that these behaviors have nothing to do with volume, either - I typically run the amp's controls between 9 and 12 o'clock.
The amp is only about 15 mos old, so I wouldn't think caps are going yet from age, unless they were crappy to start with.
Thoughts?
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Solution 13

posted 2 months ago

daveS602z
  • Rank: Apprentice
  • Rating: 88%, 2 Votes
REPLACE output relay with Farnell (Part No. 1329680).
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Solution 14

posted 2 months ago

Failbot
  • Rank: Apprentice
  • Rating: 0%, 0 Votes
Hi all,

Just letting you know I was experiencing these same symptoms with my RA300. Suspected it was the protection relay... did a search for ra300 relay and found this page.
Went out straight away and picked up a replacement and installed it within an hour. Initial testing is good...

Thanks for this thread - I'm so glad to have this amp working reliably again!
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Solution 15

posted 1 year ago

multiamp
  • Rank: Apprentice
  • Rating: 100%, 1 Votes
Hi,

For everyone who have this kind of problems with this series amplifiers of Alesis RA-150 -> RA-300.

I've just repared one by replaceing the cheap-*** OpAmp BA-4560 in the feedback circuit, it was feeling a bit hot too.
You can use any type of dual low noise Opamp (I used the LM385).

Good luck,

Greetings from Jonathan
(Holland)
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Solution 16

posted 2 years ago

ingsoc
  • Rank: Apprentice
  • Rating: 0%, 0 Votes
I had the same symptoms as others posting here with my Alesis RA-150. After reading solutions here by Cloudio, etc... I replaced the suspected relay and it is working now with no issues. A big thanks to previous posters for their groundwork!

The most difficult part for me was disconnecting the PC board and its connections believe it or not. I am including information I used to fix the problem below as it may be helpful to others:

Faulty relay info:
"Dong Woo"
Model DW323-D12S
2 Pole DPDT relay
The rated coil voltage is 12 VDC
Contact Ratings are 5 amps @ 250 VAC/30 VDC
My relay's coil resistance was about 290 Ohms @ room temp.

I replaced it with a relay made by Tyco Electronics. Its specs are located at:
http://relays.tycoelectronics.com/datasheets/OMI-2P.pdf
12VDC coil voltage
270 Ohm coil resistance
Contact Rating of 5A @ 240 VAC/24 or 30VDC?

I purchased this relay at a local Radio Shack for $5.50. It is found online at:
http://www.radioshack.com/product/index.jsp?productId=2062483

This relay has 2 more prongs than the Dong Woo one. There were spots for these on my PC board so I just soldered them in. I cannot attest to this relay's quality, so I am not necessarily recommending this specific relay other than it is easy to find at a local Radio Shack.

Good luck to all and hope this helps someone.
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Solution 17

posted 2 years ago

MUSICTRACER
  • Rank: Apprentice
  • Rating: 100%, 1 Votes
@ Elliotwilson

It is not difficult to find such a relay. A place you can get it from is this one:

https://www.preisroboter.de/ergebnis2684678.html

It shouldn't cost more than 4 - 5 euros. I couldn't find thisparticular relay where I live, but - taken an electronic engineer'sadvice - I will replace the old one with a 8A relay which should workperfectly - as he said. 10A are needed on 500W amps and above. Mine isRA - 300W and I never need to work it on max amplitude anyway. I'm about toreplace it next week so I will let you know the results. Cloudio thanx a lot for posting this solution! Let's all hope that this will work! Meanwhile I am about to write negative reviews in several sites about the Alesis amps and their ignorance on our e-mails. I think that everyone of us should...
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  1. THE PROBLEM IS SOLVED!!!!!!!
    Guys, what can I say!
    I removed the printed circuit that contained the relay and the 2 caps from my RA 300 amp and took it to an electrician the other day. He diagnosed that, though the circuit was working, the relay was twinkling and the caps were clinking when moved back and forth. Couldn't find the exact 10A 30Vdc Relay so I used an 8A 24Vdc one. The caps were replaced with same kind ones (10000μF 63V). Got a new amp now! No crackles, no cut outs.I think that the sound is even more detailed - because of the new caps.
    My conclusion is:

    1) If you are experiencing crackles and cut outs then I am 99,9% sure that the problem is the crappy "Dong Woo" (!) trade relay. Chinese is cheap but crappy as proved...

    2) You don't have to replace the caps unless they don't work or clink when moved back and forth.

    Ofcourse I haven't turned the volume all the way up yet cause I never need to. This may cause a relay damage though since it is 8A 24Vdc rather than 10A 30Vdc, but I really don't mind. If it ever happens I know exactly what the problem is and so I will just have to find a 10A 30Vdc to replace with. It really is a cheap component. But u see I was in a hurry so I couldn't wait for an order to arrive.

    What I am still wonder-struck of is the Alesis ignorance on our e-mails. There is no way that they don't know what the problem is. They Manufacture these amps!!!

    Anyway, I'll keep you tuned in if something goes wrong with my amp, but it seems that everything is fixed since it's been working great for 3 days now!!!

    Reply


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