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RedJamaX

Determining Wattage on an undocumented Amp (Matrix MA100SC)

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I have a 2x8 Amp that has the branding "Matrix MA100SC"... A few other people have questioned this amp on other forums, but have gotten no answers. People speculate that it might be a predecessor to the Hughes & Kettner Matrix series... I've sent an inquiry to them, but I doubt they would give me any information other than "buy our new one"...

 

In any case, I am looking to replace the speakers because one of them is blown and I need to know the wattage. I would "assume" that it's a 100 watt amp... but there is no guarantee. The speakers are labeled with the brand "Star", with model numbers FR-2005-09, 8ohm. The Amp is made in Korea, and specifies 8ohm minimum on the external cabinet connections in the back. I'm leaning toward the Jensen C8R, or the Peavey Marvell, but I can only find them in 4ohm and/or low wattage (25w-30w). So I'd really like to know if there is a way to definitively determine the wattage rating for the Amp??

 

There are limited options for 8ohm and high wattage ratings that are affordable, so that would certainly make it easier. Not looking to put a whole lot of money into this.. it sounds decent, but it's certainly not worth more than about $50-$60 for new speakers.

 

Can this be done by someway of identifying some of the internal board components or the transformer?

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Edited by RedJamaX

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When I searched Matrix MA100SC on google, I got pages of hits which [although many were in European languages] immediately identified the amp as 100W, and some said Kaman. Apparently these amps were marketed worldwide. They typically sell for under $100 used.

Interestingly, the brand name 'Matrix' was used by Kaman for its precursor to the Applause line of aluminum necked guitars back in the 1970s.

Edited by daddymack

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Thanks!

 

Aluminum Necks... now I'm going to have to look that up... never heard of that.

 

Interestingly enough... I don't get those same results on a Google Search. I've found a "few" hits the reference other people asking the same question... and a few old sale listings that have "100w" in the description, but no actual information on the amp... Pages and Pages of results that are completely unrelated... weird.

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many of the forum questions get answered...just as yours did here:thu:

 

Kaman of course was/is best known for Ovation guitars, and the Matrix was their 'entry level' line of molded back guitars. The were also early adopters of acoustic electric technology. The Matrix guitars came with aluminum neck and fingerboard, which wore down/scalloped due to the use of steel strings...but the necks were replaceable. Eventually Kaman put rosewood fingerboards on them...and shortly there after discontinued the line.

Edited by daddymack

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many of the forum questions get answered...just as yours did here:thu:

 

Indeed!

 

Perhaps you can answer my next question... Being that this is not a really expensive amp, I'm not looking to put a lot of money into it. I was considering getting a Jensen C8R8 ($40) to replace the blown speaker, and if I like it, then I would get the second one so they would match...

 

That speaker is rated at 25W... I am assuming that a pair of them for this amp would be fine. I like to turn it up loud from time to time, but never full bore... Can I assume that the same principle applies here as it does for other amp/speaker applications... ? 100w amp going to 50watts of speakers is fine at normal volume? Or is there something I am not considering in regards to Guitar amps? (this is the first time I have really had any need to replace a speaker... typically I end up with a different amp before that happens)

 

Or... if I do need to consider wattage... could I just wire in a 1ohm 25watt resistor in series on the Positive line for each speaker??

Edited by RedJamaX

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you should meet or exceed the wattage of the amp when selecting speakers, but as this is a solid state amp, you cold fudge downward a little, like a 50W rating should stand up to a 100w SS amp [i would go with 75W, myself, but I like a wide margin of 'safety']. And putting an inline resistor will not solve the wattage under-rating issue.

I would look at the Eminence American Alpha-8A, it is a 'PA' speaker, but would work in that amp; or for a bit more $, a Celestion TF0818.

Edited by daddymack

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Thanks!

 

Aluminum Necks... now I'm going to have to look that up... never heard of that.

 

Fair number made over the years. I played a few Travis Bean guitars back in the 80's. They were OK, although I don't think they were anything to write home about. Here is a link to a few of them.

 

https://reverb.com/handpicked/aluminum-neck-guitars

 

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Travis Bean, and then Kramer took over the line...the drawback on teh Beans and Kramers was weight....they were brewtull

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you should meet or exceed the wattage of the amp when selecting speakers' date=' but as this is a solid state amp, you cold fudge downward a little, like a 50W rating should stand up to a 100w SS amp [i would go with 75W, myself, but I like a wide margin of 'safety'']. And putting an inline resistor will not solve the wattage under-rating issue.

I would look at the Eminence American Alpha-8A, it is a 'PA' speaker, but would work in that amp; or for a bit more $, a Celestion TF0818.

A pair of speakers would see 50 Watts each. The Eminence 8A or Celestion TF0818 should work as well as anything without breaking the bank as long as the existing speakers are 8 Ohm.

Edited by DeepEnd

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Just wanted to update this thread to close it out... I ended up getting those cheap Pyramid StudioPro Speakers , the WH-8, 200w 8ohm.

 

They sound nearly identical to the speakers that were originally in this amp... just a tiny (very tiny) bit less mids. And for my purposes, this is actually a good thing... even better, I got both of them for $30 (including shipping) from Parts Express.

 

However... as it turns out, what I thought was a blown speaker was just crackling and drop outs which "appear" to be caused by the spring reverb box. I disconnected the RCA cables connecting to it and the crackling in the left speaker went away... maybe it just needs cleaning? Maybe new springs?

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Just wanted to update this thread to close it out... I ended up getting those cheap Pyramid StudioPro Speakers ' date=' the WH-8, 200w 8ohm. [/quote']

 

Cheap is what you ordered, cheap is what you'll get.

 

First off they aren't guitar speakers, they are general purpose Hi Fi / PA speakers.

 

Second, its not wattage that determines how loud they will be, its the SPL rating which is an efficiency rating on how well the speaker convert power to sound. Those Studio Pro speakers are some of the worst made. They have an SPL rating of 89dB which is horrible for guitar.

 

They'll run but you'll only get 1/4 the loudness compared to most guitar speakers and the tone is awful. (I know because I bought a pair as Hi Fi speaker replacements but they even sucked for that. The 89dB rating is overly optimistic too. They sound more like 80dB tops and they don't get loud no matter how much power you pump into them.

 

My best suggestion is when you get them, don't even open the boxes. Its not work your effort even to try them out, and so you wont get questioned about having mounted them when you return them for a refund.

 

Buy yourself real guitar speakers, even if you have to buy them used. Those speakers some of the worst crud on the market, but you should have known that just by the prices.

 

I usually recommend them to someone who has a loud amp head and wants to be able to use it at super low volumes without using a hot plate attenuator. They simply use one of those cheap speakers and they're volume is cut down by 3/4.

Edited by WRGKMC

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Cheap is what you ordered, cheap is what you'll get.

 

First off they aren't guitar speakers, they are general purpose Hi Fi / PA speakers.

 

Second, its not wattage that determines how loud they will be, its the SPL rating which is an efficiency rating on how well the speaker convert power to sound. Those Studio Pro speakers are some of the worst made. They have an SPL rating of 89dB which is horrible for guitar. . . .

 

. . . My best suggestion is when you get them, don't even open the boxes. Its not work your effort even to try them out, and so you wont get questioned about having mounted them when you return them for a refund.

 

Buy yourself real guitar speakers, even if you have to buy them used. Those speakers some of the worst crud on the market, but you should have known that just by the prices. . . .

I checked those out online and they appear to be at least partly marketed as car audio speakers. The OP never said anything about how loud they were, just that they have less mids. Since the OP knows how they sound, clearly it's too late to send them back unopened. And what guitar speakers do you recommend that would be appropriate for a 100 Watt SS amp? I'm not aware of any that won't cost more than the amp is worth and they're mostly made for bass amps. That leaves PA speakers like the Eminence 8A or Celestion TF0818 daddymack mentioned.

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I am aware of what they are... And I don't expect them to be anywhere near as good as decent, or even "low end" guitar cabinet speakers. but, this is a cheap, old amp that I would be hard pressed to even get $50 if I sold it. What's the use of putting $100 - $120 worth of speakers into it? It'd be better to just get a better used amp off Craigslist or eBay for $200.

 

I don't expect them to get as loud... and I don't expect them handle 200w. At this point, it would cost me half as much just to mail them back... and, let's be honest.. most people spend more than $30 on fast food each week.

 

This is a hobby for me... I have no professional involvement for music for any way... I just like to play guitar as a method of stress relief. The amp is mostly used as an output for Guitar Rig from my AudioBox iOne because it sounds better than my computer desktop speakers for Guitar Rig. I fully intend on getting some monitors in the future, but that's going to be about a $300 investment.

 

Just seemed silly to put $120 into speakers for "this" amp.

 

 

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Didn't say you have to leave the speakers in there when you sell it. Functional used no name amps sell for $1 a watt. Combos with decent speakers sell for $2 a watt.

 

What I'm just saying there are allot of great options out there which will sound good. You do have to scrounge around to find the good deals. I bought a 100W Peavey speaker in mint condition the other day for $30 and free shipping. I was the only one to bid on it.

 

Just a quick check I found several decent pairs.

 

Cant beat the price on these Celestion Rockets. https://www.ebay.com/p/?iid=152227029427&&&dispItem=1&chn=ps

 

Two of these 80 watt Celestion, $35 http://www.ebay.com/itm/Celestion-Seventy-80-12-Speaker-8-ohms-80-Watt/252954927527?_trksid=p2385738.c100677.m4598&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3D9d26ea26de0e43da8af9b94012834c25%26pid%3D100677%26rk%3D3%26rkt%3D39%26sd%3D152227029427

 

$20 http://www.ebay.com/itm/Used-Celestion-G12P-80-speaker-1-x-12-8ohm/182579948731?_trksid=p2385738.c100677.m4598&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3D9d26ea26de0e43da8af9b94012834c25%26pid%3D100677%26rk%3D1%26rkt%3D39%26sd%3D152227029427

 

Older vintage stuff - The selection isn't that hot this morning. Allot of people sat home over the holidays and snatched up the best deals, plus its the end of the month when everyone gets paid. There are trends when buying used. I've saved many thousands by waiting for the best deals.

 

http://www.ebay.com/itm/Pair-of-Vintage-1976-Eminence-12-speaker-Square-back-excellent-130053-67-7604-/292109448300?hash=item440314746c:g:PdQAAOSwo4pYi6n6

 

http://www.ebay.com/itm/Marshall-Mg-Series-12-inch-Speaker-Pair-Celestion-model-G12-412MG-8-ohms-/282499901692?hash=item41c64e68fc:g:qC0AAOSwlndZJcFr

 

http://www.ebay.com/itm/Pair-of-Vintage-12-Utah-Woofers-/352067949060?hash=item51f8e29204:g:yD0AAOSwB-1Y7h39

 

http://www.ebay.com/itm/Oxford-12-12TJ4-10-12J4-11-Pair-12-Guitar-Speaker-8-ohm-pair-/282501486898?hash=item41c6669932:g:q7UAAOSwIaFZLhB5

 

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. . . Just a quick check I found several decent pairs. . . .

Unfortunately, those are all 12" speakers and the OP's amp is a 2X8.

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Didn't say you have to leave the speakers in there when you sell it. Functional used no name amps sell for $1 a watt. Combos with decent speakers sell for $2 a watt.

 

What I'm just saying there are allot of great options out there which will sound good. You do have to scrounge around to find the good deals. I bought a 100W Peavey speaker in mint condition the other day for $30 and free shipping. I was the only one to bid on it.

 

Just a quick check I found several decent pairs.

 

 

Thanks for the quick look into the other options... unfortunately, as Deepend pointed out, these are 8".

 

And, just for the record... Those cheap StudioPro speakers sound nearly identical to the cheap ones that were already in there. A tiny bit less mids, and tiny bit more low end. All in all, if you have a cheap amp and need a cheap replacement speaker... they work.

 

Another update... I "thought" the distortion in the output was from the spring reverb box... but it seems to be directly tied to the Left side speaker. No crackling from the right side regardless of which speaker I connect... and it follows for every speaker that is connected to the left side.

 

Based on what I can find, it would seem that my next step is to Re-Flow the solder joints on the Amp Circuit board.

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Hey RedJama,

I think I have exactly the same issue: it's unwanted, very quiet distortion in a right speaker as you've mentioned. Have the speaker replacement solved the issue?

Thanks in advance!

Rado

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unfortunately, RedJX has not stopped by here in almost 2 years, so do not expect a direct response.

We would be happy to assist you in trying to determine the issue with your amp.

What is the amp?

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@daddymack 

It's Matrix MA 100SC and it's hard to find any info on it. It's cheap and sound is not too promising, but I actually have it so I'm thinking about give it a go.

Mine needs all the pots replaced, they're clearly described on the board so I'll change it no problem.

I can see two problems:

First one is that right speaker is giving, along it's nominal loud sound, the very quiet distortion, so there's never a clean guitar sound. I think it's just a mechanical fault of the speaker, so that's why I asked RedJX if replacement solved the issue. Hard to deicide on choice of a speakers, I would love to give it a try with Celestion TR0818, but they're worth more than the whole amp itself, so maybe some other time, unless there are some 8" 100W guitar speakers that one could recommend instead of those neat looking Celestions.

Anyway, second thing is, I guess, something may be wrong with a audio amplifier/s. At low volume at Channel A (which is very distorted at high gain), there is this broken amp, distorted, artefacted sound. Also the amp sometimes just stops working when the volume is turned very high, and works back after a while of turnings off/on. Does it sound like a possible cause could come from a Trafo? Also; how to determine what's the transformer installed? It vaguely says "?S - 27613". Could it be a problem with it?

I also plan to replace the audio amplifiers (TDA2030), sensible?

So that's all, I attach the photos of the amp.

Thanks in advance for your time!

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IMG_4082.jpg

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Now, IIRC, RedJX discovered that his distortion seemed to actually be coming from his reverb tank...have you tried disconnecting yours?

But wow...looks like somebody already modded that amp, and scorched the board. I'm not familiar with that amp, so without a schematic, I can't do much for you from here, but the way those 'jump leads' are installed, it looks to me like they had an issue with the output transformer and installed a 'substitute' [as you suspected], and that could very possibly be where the distortion is being generated. The other jumper on the 'lands' [green] side may be related to the reverb...hard to tell...

It also appears that the [left side] TDA2030 amp has been replaced [from the look of the heatsink compound], so replacing the right side one may be a simple solution, as you already surmised;  I would be curious if it is seeing the correct input voltage [it would not take much variance to generate distortion], or if it is just not still up to spec.

I would hold off replacing the pots [although a good cleaning may be in order] and speakers [50W would likely be adequate, 75W better...also check the 'efficiency' rating] until you check the three potential issues we've discussed here [reverb tank/circuit, Output Xfrmr, audio amp].

I take it you are in the EU [or the UK] based on the voltage draw of the amp...so that makes suggesting replacement parts iffy...but I think you are on the right track. See if you can find an online schematic. That should give you a target spec on the xfrmr, and may help explain the jump leads.

 

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