Marshall Cab Ohm question
- Thread starter WhoFan
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krall
New member
Re: Marshall Cab Ohm question
Not all the JCM 800's have a 16ohm option...My 1987 JCM 800 (2210) head only has a 4 or 8 ohm option..Which is a pain in the ass since most Marshall cabs are 16 ohms..
Not all the JCM 800's have a 16ohm option...My 1987 JCM 800 (2210) head only has a 4 or 8 ohm option..Which is a pain in the ass since most Marshall cabs are 16 ohms..
Jeff_H
Dean Hardtail Fanologist
Re: Marshall Cab Ohm question
Wow, that IS a pain in the arse. I can't imagine what Marshall was thinking there...8 ohms on one of our heads, but 16 ohms on our cabs. The only other option I can think of is running at 8ohms in stereo, my Marshall cab has a switch for that, but of course you'll need another cab.
That's just crappy design from Marshall, IMO...and I'm a Marshall fan.
Wow, that IS a pain in the arse. I can't imagine what Marshall was thinking there...8 ohms on one of our heads, but 16 ohms on our cabs. The only other option I can think of is running at 8ohms in stereo, my Marshall cab has a switch for that, but of course you'll need another cab.
That's just crappy design from Marshall, IMO...and I'm a Marshall fan.
krall
New member
Re: Marshall Cab Ohm question
You can thank the strict Canadian electrical guidelines for that..Marshall just did what they had to do to get them into Canada.
My Canadian JCM 800 2210 has a toggle switch and square led pilot light like the older 70's JMP amp..But they sure sound awesome...Here's a little thing I found on another forum about the Canadian issued Marshalls:
"About a year ago I posted a few pictures on here about a Marshall head that I purchased over e-bay. In my quest to restore the thing, I came up with interesting information about it. The head had the lettering rubbed off the face and it's power and standby switches were toggles instead of rockers. The decoded serial said it was an '86 and the model was a 2203. Oscar called it right by calling it a JCM 800. But the toggle switches threw everyone off.
Here is some new info that is none in any books for those of you Marshall amp nuts like myself. Like most of you know, in the 80's Marshall made both UK version and US of the JCM 800 series head the UK was outfitted stock with EL-34 tubes and the US with 6550's. The UK version was mostly desired due to the diffrences in tone. A majority of US heads were re biased by various custom shops for the el-34.
What I recently found out is that there was a Canadian model produced too it was also stock outfitted with EL-34's but instead of rocker switches it had the toggles like the JMP series.
Another note. In '84 and up USA Heads the pots were affixed to the circuit board. This became less desirable due to the noticeable change in tone plus making it more difficult to work on. On Canadian models the pots remained wired up like the originals. This is something that was also confusing on guessing the year of this head I own since the Serial was an '86 and the pots were wired. But a big whammy is no 16ohm tap.
According to a collector of Marshall heads that I have located in Virginia,these are rare and that US models outnumbered Canadians by 10 to 1. Canadian Models are a rare breed."
So, there's a little extra info about the Canadian versions...Although no 16ohm is a drag, the fact I have a very rare amp is cool.
You can thank the strict Canadian electrical guidelines for that..Marshall just did what they had to do to get them into Canada.
My Canadian JCM 800 2210 has a toggle switch and square led pilot light like the older 70's JMP amp..But they sure sound awesome...Here's a little thing I found on another forum about the Canadian issued Marshalls:
"About a year ago I posted a few pictures on here about a Marshall head that I purchased over e-bay. In my quest to restore the thing, I came up with interesting information about it. The head had the lettering rubbed off the face and it's power and standby switches were toggles instead of rockers. The decoded serial said it was an '86 and the model was a 2203. Oscar called it right by calling it a JCM 800. But the toggle switches threw everyone off.
Here is some new info that is none in any books for those of you Marshall amp nuts like myself. Like most of you know, in the 80's Marshall made both UK version and US of the JCM 800 series head the UK was outfitted stock with EL-34 tubes and the US with 6550's. The UK version was mostly desired due to the diffrences in tone. A majority of US heads were re biased by various custom shops for the el-34.
What I recently found out is that there was a Canadian model produced too it was also stock outfitted with EL-34's but instead of rocker switches it had the toggles like the JMP series.
Another note. In '84 and up USA Heads the pots were affixed to the circuit board. This became less desirable due to the noticeable change in tone plus making it more difficult to work on. On Canadian models the pots remained wired up like the originals. This is something that was also confusing on guessing the year of this head I own since the Serial was an '86 and the pots were wired. But a big whammy is no 16ohm tap.
According to a collector of Marshall heads that I have located in Virginia,these are rare and that US models outnumbered Canadians by 10 to 1. Canadian Models are a rare breed."
So, there's a little extra info about the Canadian versions...Although no 16ohm is a drag, the fact I have a very rare amp is cool.
Rich_S
HomeGrownToneBrewologist
Re: Marshall Cab Ohm question
Since they were tweaking the basic amp to get it into Canada, I'll bet you anything it's the same transformer, and the 16 ohm tap is sitting inside the chassis, capped off. It would be no problem to change the switch to the standard 3-position rotary and re-connect the 16 ohm tap, OR simply add a dedicated 16-ohm jack.
Get some details pics of the guts (especially around the OT and output jacks) and PM me.
Or, buy a second cab. Halfstacks are for wussies. :laugh2:
Since they were tweaking the basic amp to get it into Canada, I'll bet you anything it's the same transformer, and the 16 ohm tap is sitting inside the chassis, capped off. It would be no problem to change the switch to the standard 3-position rotary and re-connect the 16 ohm tap, OR simply add a dedicated 16-ohm jack.
Get some details pics of the guts (especially around the OT and output jacks) and PM me.
Or, buy a second cab. Halfstacks are for wussies. :laugh2:
krall
New member
Re: Marshall Cab Ohm question
After checking with the Marshall forum regarding the Canadian models, I found a thread that a guy started..He had the Canadian model and wanted to know if the tranny had the 16 ohm inside and could he bring it to tech to get it changed and the answer from a Canadian model expert was: "
"There is no 16 ohm tap on the OT"
Options were:
-Take a 16ohm cabinet and wire all the speakers in parallel. Then you get 4 ohm.
-Get a 4x12 with 4 x 8 ohm speakers (Marshall supplied cabs like this for their Canadian customers back in the day, but they're hard to find now)
-Run two 16 ohm cabs
After checking with the Marshall forum regarding the Canadian models, I found a thread that a guy started..He had the Canadian model and wanted to know if the tranny had the 16 ohm inside and could he bring it to tech to get it changed and the answer from a Canadian model expert was: "
"There is no 16 ohm tap on the OT"
Options were:
-Take a 16ohm cabinet and wire all the speakers in parallel. Then you get 4 ohm.
-Get a 4x12 with 4 x 8 ohm speakers (Marshall supplied cabs like this for their Canadian customers back in the day, but they're hard to find now)
-Run two 16 ohm cabs
Rich_S
HomeGrownToneBrewologist
Re: Marshall Cab Ohm question
Oh, poo. That is surprising. I guess it was the output transformer (rather than the selector switch) to which the Canadian authorities objected.
Tribal knowledge says that the 2204's could do with a transmformer upgrade anyway - they really improve with a good OT (moreso than the 2203, which had a good OT to start with). Looks like the only solutions are upgrade the tranny or rewire the cab for 4 ohms.
Rewiring is easy enough - the only problem is you won't be able to use it with a second cab if the mood ever strikes you.
You could install a series/parallel switch on the cab to select 4 or 16 ohms, but 8 is out of the question without different speakers.
Oh, poo. That is surprising. I guess it was the output transformer (rather than the selector switch) to which the Canadian authorities objected.
Tribal knowledge says that the 2204's could do with a transmformer upgrade anyway - they really improve with a good OT (moreso than the 2203, which had a good OT to start with). Looks like the only solutions are upgrade the tranny or rewire the cab for 4 ohms.
Rewiring is easy enough - the only problem is you won't be able to use it with a second cab if the mood ever strikes you.
You could install a series/parallel switch on the cab to select 4 or 16 ohms, but 8 is out of the question without different speakers.
