Code 50: Take the back off?


I'm curious to hear about anybody experimenting with removing the back on their Code to see what it sounds like.

I'm not a big fan of the closed back sound, especially on small combos.  I've noticed my Code vibrates like crazy even on low volumes and I swear I can feel air puffing out of the headphone and/or pedal jacks.  The speaker seems stifled closed inside that little box like it can't move or "breath".  I'm wondering if that is causing the boomy vibrating noises this amp likes to make.

I did find one forum where someone mentioned taking the back off their 50 and they were amazed at how much it opened up the sound and it removed some of the feedback these amps seem prone to.  I'm a little worried about voiding the warranty on the amp, but am real curious about what it would sound like if I made a 1/3 back like a standard combo or something along those lines.

asked 14 Mar 2017 at 02:22 PM

Dennis Bowen (20)
Hello Dennis,
We cannot recommend running the CODE 50 will the back off as the mains socket will have no support as it is screwed to the back and all the circuitry will be exposed.
Kind Regards
Marshall Support
- Marshall 20 Apr 2018 at 07:45 AM
Answers: 3


Hello Keenan,

We cannot recommend running the CODE 50 without the back on as the mains socket is unsupported and the circuitary is exposed.


Kind Regards


Marshall Support

answered 20 Apr 2018 at 07:47 AM



Okay, I couldn't resist.  I first took the screws out of the back and leaned it back against the wall to try the amp with an open back.

I found that it didn't sound too bad, but it was quite a bit more bassy and boomy with the back off.  Which is the opposite effect I thought "or hoped" it would have.

I then pulled the speaker and tried one I had laying around.  It was a Celestion G12P-80, an 8ohm 80 watt speaker out of my old Line6 2x12.  Thinking if it was designed for a modeling amp it should work well in another modeling amp.  What I found was, the sound did seem a little tighter but it was real mid focused.  I lost the highs and lows the stock speaker has.  It kind of made every  preset sound the same and sort of nasily like a wah pedal in the half way position.  Other then the smaller magnet on the back of it, the stock speaker looked real similar in build as the Celestion.

In the end, I ended up putting the stock speaker back in it and screwed the back on again as that was the best it sounded.  Probably with a differently voiced speaker I would be able to make an improvement, but I don't feel like spending the money and flipping through new speakers to get there when I'm already getting my $249 worth of fun playing around with it as it came.  

I haven't played in a band for a couple years but am curious about the speaker and particle board box not mattering anyway if I were to run it direct to the mixer in a gig situation.      

answered 29 Mar 2017 at 08:28 PM

Dennis Bowen (20)
Sweetwater, Musician's Friend; American Musical Supply they all have some great, great speakers you can use to upgrade the stock speaker. I'm certain that the speaker (load, is it???) it's an 8 Ohm speaker for sure. with a 50 Watt output. So you want a replacement speaker that is 8 Ohms and can handle at LEAST 50 Watts. So 50 Watts or greater, 8 Ohms 12 inches. Marshall's lower end amp cabinets ordinarily come as 2x12 (2 twelve inch speakers) or 4 X 12 (you have to figure this one out. You can do it.)

The point is those low end cabs are wired in serial I believe which would mean you add the amount of Ohms to determine the load (I think.) Let's make this simple. There's only one speaker in there. (My bad.) You can get a Celestion Seventy 80 12" speaker for around $69.00. Sweetwater is often giving them away for $29.00 (Seriously, but those are refurbished speakers.)

So if you want a decent Celestion speaker found in lower priced Marshall speaker cabinets that might me a low-priced option as a replacement speaker. Just make sure you get a 12 inch, 50 Watts minimum (The Seventy 80 can handle 80 Watts). 8 Ohms. Good luck.
- WILLIAM F NAPPI 27 Mar 2018 at 07:45 AM
Wow Michael I'm sure you're a f*ing legend for sure. Truth be known, I got my source of information, the statement that the CODE 50 has a 12' 8 Ohm speaker was on another related thread which was answered by one of MARSHALL'S well-informed 'specialists" who stated as such. So, it should come as no surprise if I was misinformed, foolish enough to think that someone employed by Marshall whose job it is to respond to questions posed on these forums actually gave a knowledgeable response. My bad..

Ideally, the Ohms will be printed on the speaker. Marshall's not-so-well documented products (seriously) might not even have a spec sheet. seriously. But they might...okay, I just checked. NOPE. No spec sheet and try finding some reference to it here. I searched high and low for an answer to my questions here and came up empty and frustrated. In that search I came across this question and answered it with the information I had available.

A previous question I came across to a 'tech' asked what kind of speaker was in the CODE 50 to which the tech responded, "A 12 inch 8 Ohm Speaker." No brand was mentioned. Don't quote me on this, but not a Marshall 'Tech' but reader responded to a similar question saying that the speaker in the CODE 50 was a generic speaker, no name. Since you're the f*ing expert, maybe you know the answer.

YES, you ARE correct that just because a speaker costs more does not mean it is a better speaker. SOMETIMES it is a matter of taste. Other times, there are other issues. I am going to keep my CODE 50. I am considering swapping out the stock speaker for a Celestion Red back. I have two Cream Backs and I want to keep them as a pair for a speaker cab I'm building myself, (f* these people I'm sick of them, seriously.) Thing is the red back (I have an 8 Ohm and if it turns out there IS in fact a 4 Ohm speaker inside, I will try a 4 Ohm Jensen I have on hand.) Anyway, the Red back will handle 150 Watts by itself. The Creamback 65 Watts but I don't want to break up the pair and I am going to wire them in serial for a 16 Ohm load.

Good choice the Mesa, but I'll stick to my own. The speakers they use can be purchased separately and my overhead is WAY lower than theirs; fewer employees, fewer bills; fewer people who show up at work that are more concerned with putting in their 8 hours and going home without actually doing anything meaningful, but who can at least say they have a job and insult people who don't have one who might actually be better qualified and are capable of more than responding to customer questions the standard 'Tech Support' mantra, "You could try GOOGLING _________ " <--- fill in the respective subject of the question) or , "Well there are some You Tube videos on _______ <--- fill in the blank again. that we are all so familiar with. One online retailers tech support guy ACTUALLY said to me as an eventuality, "Well, I hope you get it figured out." Since he was the 2nd or 3rd person I'd asked about it I moved on and DID get it "figured out." The manufacturer's tech team wasn't much help on that one either.

I DID get it figured out and if they cut me a check I'll tell them the problem. So, I'm keeping my code, I WILL find a suitable replacement that will work, you were correct about the functionality and sound characteristics of different speakers. I don't doubt your ability as a guitarist, but beyond limited knowledge as a guitar amp end-user, you've got more to learn than I do on the subject and I hardly consider myself an expert. Above average, yes. I also have at least 10 (lowly) Peavey Amp cabs of various configurations, Marshall; Fender and Bugera with upgrades all in progress where required. Rock on dude, play the blues do what you like to do but your tact isn't too good. You need a good manager and if you keep your mouth shut you'll probably do better because when you insult better informed people who dole out answers based on what SHOULD be considered safe as a reliable source you only serve to p*ss them off. No problem here, but, wait who is your publisher? Do you have any songs you wrote yourself? Never mind. Go play your guitar kid.
- WILLIAM F NAPPI 27 Mar 2018 at 07:19 PM
It's a 4 ohm speaker but 8 will work, you will lose a few decibels of volume so your CODE 50 will be quieter. Not necessarily a bad thing if your struggling to find a useable bedroom practice volume. - Adrian Tysoe 31 Jul 2018 at 08:18 PM
Adrian I am not 100% sure how to wire it; but my understanding is that if you solder a 4 Ohm resistor across the terminals that it will then have modified an 8 Ohm speaker to one with a resistance of 4 Ohms. What I had in mind or what I pictured then was assuming an 8 Ohm speaker was on hand to swap out for that crummy thing that comes in the CODE 50 (you DO get the cool Marshall electronics at an affordable price) ... that soldering a 4 Ohm resistor (available at electronic stores or even Amazon) from the terminal ends on the (4 Ohm) resistor across the positive & negative terminals on the 8 Ohm speaker thus muscling down the 8 Ohm resistance to 4 Ohms.

Thing is I'm not sure that's the correct way to do the job. If you have any input to take into consideration regarding this please let it fly. I Googled it a few times. Not sure I have it interpreted correctly though from the information I was able to gather on it and I've got more pressing things to get to. But for somebody who has a perfectly good 8 Ohm speaker laying around and more time than money that resistor soldering option could look quite attractive as a resistor can be gotten for around or under 5 bucks.

Just for sure make sure you have the wattage and Ohms correct. For example the CODE 50 as it turns out, as it's printed on the back nameplate actually puts out 75 Watts I think. BUT a 50 Watt speaker is installed. So be it. Read the tag for yourself. I put a 100W Jensen in I think. 4 Ohms for more headroom if I have the definition of headroom clear. For instance whether the CODE 50 puts out 50 Watts as it has been assumed or 75 Watts as printed on the plate on the back of the amp that 100 W speaker will take every Watt the CODE 50 can force out at maximum volume and STILL be able to take more if the juice was there to pump it out.

That's all I got right now except in conclusion: if you replace the 4 Ohm 50 Watt speaker as it has been set forth on this thread with say another 50 Watt speaker at 8 Ohms but choose to attempt the resistor soldering venture MAKE SURE you have a 50 Watt 4 Ohm resistor. If you have a 75 W speaker at 8 Ohms but solder a resistor, ensure the resistor is a 4 Ohm 75 Watt resistor. The Watts and Ohms have to be consistent with one another. That much I am 99.8% certain I am correct about. Good luck.
- WILLIAM F NAPPI 31 Jul 2018 at 08:58 PM
The speaker in my Code 50 is 4 ohms. I replaced it with an Eminence Texas Heat 150 watt 4 ohm speaker and it made a huge difference. The presets had to be adjusted but I actually decided not to sell it and buy a DSL because of the difference. I am thinking I will try it without the back now to see how that sounds. - Phil Wheeler 08 Sep 2018 at 12:54 PM
Dude that sounds awesome. Why did you choose to got a full 150 W though? Extra headroom? I used a 4 Ohm Jensen 100 W and I think that was wise because I noticed on the plate on the back of the CODE 50 that the output is 75 W as opposed to what I THINK most people assume to be a 50 W output.

I mean the output of the CODE 25 is 25 W as advertised I believe. The CODE 100 output? 100 W, right? Why would the CODE 50 NOT be a 50 W amp? Maybe it is. But if that is the case why does the plate on the back of the amp state outpur at 75 Watts? Am I not understanding something?

Anyway, back to "your" CODE 50 upgrade. Don't you think 150 Watts is a bit much? I guess that you could go full crank with that baby and sustain it without blowing out your speaker or getting any unwanted distortion for sure! I don't know, what the heck, right? Personally I'm glad I decided to go with the 100 Watt Jensen instead of the 50 like I was going to. The price difference wasn't THAT painful AND considering the output might be 75 W and not 50 ... wow. Cool, huh?

Anyway, I took the liberty of answering for you with my best guess. What is your actual rationale for your choice? You wanted an Eminence speaker and the only 4 Ohm available was in the 150 Watt variety?? Seriously. What's your answer? Why did you choose what "you" chose?
- WILLIAM F NAPPI 09 Sep 2018 at 05:59 AM
My choice was pure convenience - I got a new 150 watt 4 ohm locally for half price. It works fantastic. - Phil Wheeler 09 Sep 2018 at 02:31 PM
Sounds awesome. You won't have to worry about ever blowing the cone out of that woofer. WOW. Cool. I like it.

Myself, I mentioned I got the Jensen 100 W 4 Ohm. I was going to get the 75 Watt 4 Ohm version, though it might have only been 50 W I don't remember exactly. Either way the price difference was barely significant so for a few dollars more I could not be happier with my choice.

It wasn't til after I installed it that I noticed that the actual output is 75 Watts not 50. Yours has the same plate on the back as mine. Yeah. Cool. Nice chatting with you. Maybe see you in the big time some day or on the same stage; who knows, right. Rip it up,baby! Me gone for now. Best of luck to ya'!
- WILLIAM F NAPPI 10 Sep 2018 at 07:02 AM
More strange info in this thread... smh... I really need to turn off notifications. The output IS NOT 75W. Goodness gracious. Unless you're the president, let's not make up stuff as we go... The 75 watt spec is the maximum power drawn from the power mains. The amp is rated at 50 watts RMS. Since amps are never 100% efficient they will draw more than 50 watts from the mains if played flat out (which I'd put money on, nobody on here is even doing). - michael s 10 Sep 2018 at 05:29 PM
Michael; Thank you for your clarification regarding the 50 Watts RMS -vs- the 75 W spec. as that is the max. power drawn etc. Had you read the thread observations and questions in my comments as opposed to someone who had stated them as facts .. well maybe you would not have chimed in.

I thank you for chiming in due to the uncertainty in my mind til now. Thank you for sharing your knowledge and resolving the conflict in my mind regarding that matter. Much appreciated. Seriously. Thanks again. May your karma get bonus points minus 1 for picking on our president whom has my support on many issues. Shame on you. But thanks again just the same.
- WILLIAM F NAPPI 12 Sep 2018 at 10:39 AM


I want to take the back off and I’ve already got the screws out but I Cant get the actual cover off the back, how did you do it

answered 19 Apr 2018 at 10:11 PM

Keenan Borgerson (2)
Nevermind I got it - Keenan Borgerson 19 Apr 2018 at 10:30 PM
I want to take the back off and I’ve already got the screws out but I Cant get the actual cover off the back, how did you do it - tamago futsu 07 Jul 2021 at 08:29 AM
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