New Amp Day! JCM 800 [Photos/Questions]

[NewReligion]

You probably need to put a screw (or 2) thru the center back of the cab like I do to all of my cabs to keep the center post from rattling around. JCM 800 2210's have been my favorite amps since their introduction, they are my work horse. They all are a bit different but try to max out the Gain and Volume knobs and bring up the master to about .5 and adjust from there. I run the mids almost all the way off, the bass is maxed and the treble is usually at 4-5. I adjust the Presence according to how loud I am due to the fact that it really is a treble control for the output section. When biased correctly and using a quality guitar with a serious humbucker the tone is hard to beat for what I play Good luck and congrats. The settings will vary due to the fact that your cab most likely has celestions loaded and will reproduce much more treble than what I use but it should get you in the park to what these animals are capable of. Should tighten up the lows and help give the chug you are looking for.

David

David C. Hopkins on MySpace Music - Free Streaming MP3s, Pictures & Music Downloads.

 

[MonstersOfTheMidway]

Extremely helpful post Monsters, thank you very much. I set the cab and head both a 4 ohms. However, I noticed that when I made the amp "thump", i.e if I were to chugg the low E with a high bass setting, something would buzz, and it sounded like it was coming from the cab. Also, when I flipped the standby switch, it popped, it didn't do this when I was at 8 and 16 ohms.

Can you post a close up pic of the loud speaker outputs and the ohms switch on the head? It's possible that when playing in 4 ohms, you may have connected to the wrong side. Also, are you using a speaker cable to connect the cab and head, or are you using a guitar cable to hook up the cab and head?

Open up the cab to see if there are any loose part inside. Becareful not to take off the back too fast or you will pull on the wires that are connected to the cab's switch plate and cause some damage. Make note of the kind of speakers you have in it (if it's a stock 1960B, then you might have the Celestion G12-T75). If you bought it new, then that's probably what in there, but if you bought it used, then you might want to look at the speakers carefully and make note of the make and model. Also, check to see that the speaker cone isn't torn.

You took some good pics of your new amp! I posted some too of my JVM 410H and my 425B cab (I love Marshall's bottom cabs).

 

[pinto79]

The CSA (Canadian) versions of the JCM800s are ALL set to only have 8 or 4 ohm selections. I know this as fact as I have owned 6 of them over the years. It means just that, 8 Ohm or 4 Ohm speaker loads. MotM mentioned in a previous post that it could mean "I'd suggest that it's wired for 8 ohms if you are using TWO 8 ohm cabs, AND it is wired for 4 ohms if you are using ONE 4 ohm cab."

This is not the case. To use your 1960B cab, select MONO, and plug into the jack marked 4 Ohms and set the head to 4 Ohms.

 

[Jesstaa]

That looks like a speaker cable to me, there's 2 defined pieces of wire.

Also, you say it thumped, are you suggesting you changed the ohm selector/half power switch whilst it was on? Because I wouldn't recommend that, just because of potential stress on the amp/speakers.

 

[cicone]

Adam---Sorry I bailed on you, but it became apparent I was in over my head as I know nothing about the Canadian version Marshalls. Have you got it figured out yet? I might be able to help with some other questions you may have. Didn't want to come across like an expert and blow your baby up!!

 

[Adam SE]

I will try to take some detailed pictures of both the selectors/outputs. The cab has the original Celestion 75's, or so the person who I purchased from said. I will open it up to double check everything though. I'm sure the cab is fine though, but bass-ey notes did make a little bit of a buzz from what sounded like the cab. This was only present when I had both the head and can set on 4 ohms. The cable is in fact a speaker cable, it even has "speaker cable" printed on it. I think it may look unfamiliar because it is probably a lesser known brand.

I had both the head and cab on 4 ohms, but this seemed to bring worse results. Like I said, the cab buzzed a bit, and the standby switch would pop. When I had the head on 8 ohms and the cab on 16, no buzz was present and the standby would not pop. I made sure not to switch anything while it was on.

Cicone, no problem. JCM 800's all seem so inconsistent, no two are alike. Not only is mine Canadian, but it has been modded. I don't see this as a problem though.

I do have a little thing I noticed that I'd like some input on. Occasionally when I would play a note, then play one lower, the note would have this kind of wavy sustain to it. It didn't sound natural. Is this normal? Is the certain frequency causing a disturbance with a certain part?

Also, I noticed my amp is still a but mushy and not defined, which is not what I expected. Is this most likely because of the tubes? Like I said, they are old.

Thanks again. I've been playing my new amp a lot since I have gotten it. I'm really happy with it.

-Adam

 

[MonstersOfTheMidway]

I had both the head and cab on 4 ohms, but this seemed to bring worse results. Like I said, the cab buzzed a bit, and the standby switch would pop. When I had the head on 8 ohms and the cab on 16, no buzz was present and the standby would not pop. I made sure not to switch anything while it was on.

I do have a little thing I noticed that I'd like some input on. Occasionally when I would play a note, then play one lower, the note would have this kind of wavy sustain to it. It didn't sound natural. Is this normal? Is the certain frequency causing a disturbance with a certain part?

Also, I noticed my amp is still a but mushy and not defined, which is not what I expected. Is this most likely because of the tubes? Like I said, they are old.

-Adam

Sup. The "wavy sustain" and the "mushy" and lack of definition sounds to be that two things should be checked out by a technician. First, I'd ask the technician to check the bias. It is possible that the tubes are working fine, but the bias has drifted a bit and so you just need the tech to set it for you properly. Checking and/or adjusting the bias on an amp is not difficult, but if you have never done it before, you could harm yourself due to the potential lethal voltage that exists even when the amp is turned off. So, be safe and take it to a tech; then, you can watch and learn for the next time, when you can try it yourself.

The other thing that might cause these "mushy" sounds and lack of definition would be the power tubes. They might need to be changed out, so you will need to do some research to see what you need and like. Again, because the power tubes are being changed, you would need to have the amp biased. Talk to your tech and see what he can do for you.

 

[MonstersOfTheMidway]

The CSA (Canadian) versions of the JCM800s are ALL set to only have 8 or 4 ohm selections. I know this as fact as I have owned 6 of them over the years. It means just that, 8 Ohm or 4 Ohm speaker loads. MotM mentioned in a previous post that it could mean "I'd suggest that it's wired for 8 ohms if you are using TWO 8 ohm cabs, AND it is wired for 4 ohms if you are using ONE 4 ohm cab."

This is not the case. To use your 1960B cab, select MONO, and plug into the jack marked 4 Ohms and set the head to 4 Ohms.

Wrong paraphrase. While I saw two loud speaker outputs, I made an educated guess that the head could be set up to be played through two cabs since that is an option available on most Marshalls. I knew it was possible for the head to be set up where only one output was for 4 ohms and the other was set up for 8 ohms, but like I said, the two outputs in addition to the selector switch lead me to believe that he had additional options, if he chooses to take advantage of it; but without a clear image of the loudspeaker outputs, it was tough to say. So, if he is using one cab, then yeah, it's either 4 or 8. But if it has the capability to be plugged into the two cabs, then my initial description is correct (or see below).

Sup. I can't get a real good detailed look at the output connections or dial, but I think I see the two loud speaker outputs and the dial, as you mentioned. If that is the case, I'd suggest that it's wired for 8 ohms if you are using TWO 8 ohm cabs, AND it is wired for 4 ohms if you are using ONE 4 ohm cab. It is possible that it could be wired for just one 8 ohm cabinet, but given that there are only two loud speaker outputs and one dial with 4 and 8 ohms settings, my best guess is its wired for TWO 8 ohm cabs or ONE 4 ohm cab.

My suggestion is play it safe and set it to 4 ohms on the dial, make the connection with a speaker lead at the back of the head at the 4 ohms output, set your cab to MONO and plug the speaker lead into the 4 ohms input. Remember to set the cab to MONO and match the ohms rating that is printed ABOVE the cab's inputs (you will be using the left input when you are looking at the back of the cab).

 

[Adam SE]

Thank you so much Monsters, you've been such a great help, I truly appreciate it. I love this forum.

I am going to try to learn how to bias the amp myself. I am aware of the lethal voltages and all dangers and extra precautions. I have read up a lot about tube amps. I will make sure to research until I am 101% sure about biasing and working with the amp.

Anyways, here are some detailed pictures of the back panel. Here's a link to all of them, which can also be viewed in higher resolution.

This will sound silly, but how do I find out the year of my amp? And what does the red reset button do?

Thanks!

-Adam

 

[Jesstaa]

The reset button appears to be a circuit breaker, and there should be an inspection tag on the top, if not, the serial number will hold the answers.

 

[Procter2812]

Thank you so much Monsters, you've been such a great help, I truly appreciate it. I love this forum.

I am going to try to learn how to bias the amp myself. I am aware of the lethal voltages and all dangers and extra precautions. I have read up a lot about tube amps. I will make sure to research until I am 101% sure about biasing and working with the amp.

Anyways, here are some detailed pictures of the back panel. Here's a link to all of them, which can also be viewed in higher resolution.

This will sound silly, but how do I find out the year of my amp? And what does the red reset button do?

Thanks!

-Adam

It replaces the standard Mains fuse.

If there happens to be a problem within the power supply, the switch will trip, cutting off the power to the amp. You can then reset it without having to change a fuse.

There may be a sticker on the chassis to tell you the year of your amp.. if not check the serial number.

So leave your cab set to 4 ohms.. plug into the left input of the cab.

Set the head to 4 ohms and play away!

 

[Adam SE]

Well I got some bad news. My amp started sounding mushier, started sputtering and then stopped producing sound.

I will get some tubes and replace and bias them, hopefully this will restore my amp and I am sure it will sound amazing. But it does suck, I knew it was in desperate need of a re-tube, I just didn't think it would be so soon, while I wasn't yet prepared.

The tubes are 10 years old, and the amp wasn't used a whole lot during that period. Perhaps a filter cap replacement might be needed as well.

 

[truckdub]

If it stopped producing sound you need to take it to a techto be checked out. It seems you have some things going on there that can't be fixed or diagnosed on an internet forum. take it to a tech. You will save yourself a lot of time, money, and heartache.

 

[Jonathan Wilder]

I'd have an amp tech look at it and he should be able to find a 16 ohm tap off the power transformer and wire it for ya. Should not cost more than a bench charge.

Don't you mean the output transformer?

 

[Vince]

Yes.

 

[cicone]

See if this helps you.

How Old is My Marshall? - Page 2

 

[HOT TUBES 70]

I don't recall having a Hi Low switch on my 2210 !!!
Fucking sweet amp Man !! I loved my 2210 .....

 

[Adam SE]

Well, I popped over to the tube store, took the amp to a tech and now it sounds amazing.

I'm really happy with the amp, it sounds excellent. JCM 800's really are amazing.

Thanks for all the comments, it's appreciated.