The amp works great for an hour or so then starts to crackle and cut out intermittently. Any ideas?
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
Posted on Jan 09, 2010
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.
Posted on Sep 17, 2008
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.
Posted on Dec 11, 2008
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!
Posted on Dec 29, 2009
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).
Posted on Sep 07, 2009
REPLACE output relay with Farnell (Part No. 1329680).
Posted on Jul 15, 2010
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)
Posted on May 09, 2009
yes, it makes the +15v output from the power supply to 19v which clips the protection circuit. Replaced the opamp BA4560 as you suggested. Now its working like new! Many thanks Multiamp, you're a real pro!!!
Hey Hi,
can i use this one?
http://de.farnell.com/national-semicondu...
thx
×
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.
Posted on Dec 05, 2008
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.
Posted on Nov 30, 2008
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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
Posted on Dec 05, 2008
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?
Posted on Jan 27, 2008
An expert who has achieved level 3 by getting 1000 points
In the event that there are these kinds of problems by buildig up warmth its sometimes hard to find somewhere in electronic components, then you can search for a canister cold-spray to search for the place that could be having the faulty parts
Electronic repair dying art
Posted on Jun 24, 2016
OK, first of all, with a little research, you'll see that the REAL
reason for all the RA series amp failures are the crappy ****-WOO relays
Alesis chose to use. RA-150, 300, and 500 all have the same problem.
Simple solution for the RA-300 (providing you can solder/desolder or
have a friend who does):
* Buy one NTE R25-11D10-12 (at $6.24)
* Disassemble the amp (6 screws on top, and four on the side, inside the heat sink fins, the inside screws)
* Carefully unscrew the power supply board (it's the one on the bottom with 4 screws and one screw that holds the rectifier)
* Using a 40w or higher desoldering tool (or solder braid), remove the black relay (8 contacts, total)
* Replace with the NTE one you bought
* Reassemble
Voila! One working amp! Total bench time? One hour. Also, check out the
10000uF 63v caps. If they are bulging or "rattle", replace them, too.
-=> Andrew
http://www.fctr.net
Posted on Jul 26, 2012
Thank you guys so much. You saved my amp!! I've had an Alesis RS150 and have been banging on the case for years because both channels kept shorting out constantly and I didn't want to pay $100+ to get it fixed when I only paid $200 for it. I went out and purchased the PC Relay 12VDC part # 275-0249 from Radio Shack for $5.. Problem solved.. I wonder how many owners of these amps never knew a cheap $5 part turned their amp into junk and it's a shame that Alesis just doesn't care..
Posted on Sep 25, 2011
I am glad that I found this discussion! Although it is not updated recently. I have a 3 year old RA500 with this problem and today I replaced the relay. Now the amp works great again!
I am not an expert but I know how to deal with soldering iron, and I succeded.
Thank you all for your clear instructions and details about this problem. I was able to save a lot of money for the club!
Posted on Jan 12, 2011
I have the RA300 which takes a different relay, harder to find than the smaller one for the RA150. This needs to be 30v 10amp. Don't know much about specs and substituion but knew if I could find the exact replacement I could fix it. Took a couple of weeks and finally AUDIOLAB of Georgia had the finder 44.62.9.012.0000 and their catalog says it replaces the Dong Woo.
They shipped it in two days and I fixed in today, works good, no more cutting out. Yeah! I had this amp for several years and hardly got to enjoy/employ it and was using a Yamaha PA amp in my home studio instead.
It was difficult getting the 8 pins out of the board without burning anything else. Desoldering wicking braid works okay but it would be nice to have a desoldering vacuum. Also, for those ready to try, be sure to label every wire. I almost reversed the white volume and AC leads on reassembly as my labels fell off but I noticed where the ac goes to the on/off switch.
I like Alesis products but you get what you pay for and I just hope that now I will be using it regularly it will hold up. I've never had problems with basic single duty equipment, especially for studio use like this is supposed to be, so if I have to replace it won't be an Alesis.
Posted on Sep 11, 2010
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!
Posted on Jul 15, 2010
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.
Posted on Dec 29, 2008
@ 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...
Posted on Dec 05, 2008
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!!!
×
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.
Posted on Sep 17, 2008
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
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
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: [email protected]
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...
Can you offer a recommendation regarding the problem being related to a faulty 12volt changeover relay??
Regards,
Tony McGinley
Just a note on the CRAPPY Alesis relay and other parts.
RELAY: Here is an EBay link for a quality Finders relay with full 10Amp rated contacts at under £5:
http://cgi.ebay.ie/12V-10A-DPCO-Miniatur...|66%3A2|39%3A1|72%3A1301|240%3A1318|301%3A1|293%3A1|294%3A50
BTW the Alesis black relay can have the casing popped off and this allows you to clean the contacts with 000 grade paper and re-fit the relay cover. Use some WD40 on the contacts soak a piece of paper and run it between the contacts.
It is well worth while replacing the shitty 10,000Uf 63v capacitors while you have the amp open. The Alesis rubbish will have bulged or leaked and affects the sound. Here is a link for EBay for Aerovox capacitors:
http://cgi.ebay.com/Aerovox-BHC-Electrol...
New relay and new capacitors makes a NEW amp of the Alesis RA300.
I repeat here I am well annoyed with Alesis lack of ANY useful help - Alesis you are a CRAPPY outfit with very poor customer support.
.
×
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
Posted on Nov 24, 2008
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
Posted on Nov 10, 2007
15,687 views
Usually answered in minutes!
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!)
I have 3 speakers hooked to a 2-channel amp, it works great when the car is not started, just in acc mode, but when started and driving somewhere, the amp cuts off, I have these 3 speakers bridge on a 300w amp. What could be the problem. email address - [email protected]
Thanks
David
The RA150 is connected to a pari of Alesis Monitor One MKIIs.
Channel one will start to crackle a bit but I if crank it up then back to the original posistion it goes way for a bit. Cleaned the volume pots and swapped them beteeen channels so it's not that.
There are a few resistors that looked pretty cooked. Wonder if there is some heat damage. Sounds like an input gate malfunction.
I have an RA-150 with exactly the same problem in the right channel.
The amp runs fine for a while and then gives a crackle and cuts out,
usually if there has been a sudden level increase. Switch off and wait 30 mins seems to be the only solution that works for me... :(
Hey, well this is a start, i have found people experiencing the same problems.
I have been using the Alesis RA300 amplifier within my studio setup, to power my Alesis Monitor One MK2 speakers. My whole setup has worked great for years but recently problems have started.
After around 30-40 minutes of it beinbg on, playing music, one of the speakers begins to crackle then cut out completly. Which speaker channel this is, often alternates but its usualy the left. I thought it may be a problem with the speakers or wiring but now I am certain it is the amplifier.
The reason I am certain is because when the speaker cuts out, if I turn off the amplifier four about 5 minutes then turn it on again, everything works fine. It is like the amp needs a rest every 30 minutes. This is really frustrating me so I emailed Alesis with the problem. As of yet, I have not had a response from them. I may point them to this post.
If anyone has a working solution to combat this, I would be grateful to hear it. I really dont want to purchase another amplifier just yet.
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This post is in response to Irishsounds solution.
I too have tried to contact Alesis directly but was totally ignored. The fact
that we are all having the same or similar problems speaks volumes and shows it’s
definitely the build of the amplifier and not just an isolated case. Certainly
I've looked after my amplifier carefully and adhered to all the maintenance guidelines
and recommendations set out in their instructions. Quite frankly this puts me
off purchasing another amplifier by them. It sort of reminds me of the internal
problems of Microsoft's Xbox 360 which caused the same problems for many people
before they changed some components in the newer models.
I have noticed that if I tap the top of the amplifier lightly it will either
fix the problem for a few seconds or completely cut the sound out in which case
I have to turn the amp off and on again.
I agree with you that it is likely an internal mechanical problem with a
component or soldering but I wouldn’t have a clue where to start if I were to
open it up. Does anyone know how long the RA series of amplifiers are under warranty for?
I gather Alesis won’t help at all without it being covered by warranty but it
may be worth showing them this topic.
Hi to all. I am also experiencing the same problems - you guys posted - with my RA300. I have sent it to 2 electronics engineer and none could justify the problem. I hope that suggesting shirty2008's solution will help them solve it since I don't know much about electronics... But what seriously should be done is a mass response to Alesis. They have to do something about their so many disappointed costumers...
Yours,
VAL
I fully agree with MUSICTRACER Alesis are seriously in error here. They should have recalled this problem but instead they try to fudge the issue. I for one am NEVER going to buy anothe Alesis amp.
Hello Everyone,
I'm just chiming in the say that I have the same problem with the RA150 model. I have had it for about 4-5 years now and have been running Alesis Monitor 1 Mk2's with it.
I am going to try taking it apart and looking at the caps and specific relay mentioned by previous posters. Thanks for the suggestions!!!!
All Alesis told me to do was "send it in" for $100. I don't think so!
Same problem will replace relay thanks fellas RS 300
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?
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.
I just replaced the "relay in question" on my RA300 and initial results are great! *crosses fingers* FIXED!
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...
Now works a treat.
@ 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.
×