PLEASE HELP!!!!! EASY FOR YOU MESA GUYS

[mrt]

OK,,, I was rack guy all my life, marshall everything, power amp pre amp, even Marshal effects, and cabs,,, but i cant move this stuff from show to any more,, way to heavy,, and everything was 8ohms

So I got a rect o verb,, combo,,,(still heavy) it smokes any marshall i ever played, but the thing is there is a 8 ohm for the 1 12 speaker, but i am playing a rather large show and wanted to hook up my marshall 1960 cab to it??? but i never really looked before but there is only two 4 ohms out puts???? and the 1960 is a 8 ohm i think,, so what i need to know,, how do i hook this up to my marshall 1960 cab,,, Please let me know ASAP,,, thanks a freakin ton to anybody who helps,, tony

 

[Platypus]

From the product manual it looks as though there is an 8ohm output but that might just be on the head only.. look inside the amp and see if there's an 8ohm output.

http://www.mesaboogie.com/manuals/sRec_Sers2.pdf

 

[mrt]

the combo has the same speaker out puts as the head, it just has the 1 12 already hooked up to the 8 ohm. leaving me with the two 4 ohms out puts,,


WOW,,, from what that is saying its OK to run from the rect 4 ohm out put into a 8 ohm cab?????? i thought its bad to run lower ohms into a higher ohm cab??? ,, but this telling me i can so i will,,,, thanks a lot i looked all over the the net to find something like this,,, thanks again, tony

 

[fx2]

First, some things to know:

Marshall box comes usually with 16 Ohms celestion speakers (G12T-75 or vintage 30) (www.celestion.com)

You may wire them like you want to combine the impedances of the speakers to get a load of 4, 8 or 16Ohms

Second, some theory:

The resistance of two resistances in parallel (R1//R2) is: R’ = (R1 x R2) / (R1+R2)
Note: if R1=R2 we have a simpler formula : R’=0.5 x R1

The resistance of two resistance in series is the sum of resistances : R’ = R1+ R2
Note: if R1=R2 we have a simpler formula : R’=2 x R1
So depending on the load you want you can combine your 12" speakers to get the load you want.

How to wire parallel?

Connect the “minus” ( - ) wire to all “ – “ side of the speakers and plus (+) wire to all “ + “ side of the speakers.

How to wire series ?

With the ( - ) wire you “enter” in the ( - ) side of your speaker, and you connect the (+) side of this speaker to the ( - ) of next speaker and so on till the (+) wire.

And now some concrete examples (S1, S2, S3, S4 are your four 12" 16Ohms speaker in your marshal box 1960) :

S1//S2+S3//S4 = 16Ohms
S1//S2//S3//S4 = 4Ohms
(S1+S2) // (S3+S4) = 16Ohms
S1+S2+S3+S4 = 64Ohms  don’t use this configuration
S1+S2 = 8Ohms (half cab or “stereo” setting)


If you’re not able to match exactly the amp output (f.i. 8 Ohms) to you speaker load, prefer a higher load than the one the amplifier expects. This means, it is better to connect a 16Ohms speaker on a amplifier expecting a 8Ohms speaker than connecting a 4Ohms speaker to the same amp.

I hope this will help you!

 

[hal9000]

OK,,, I was rack gut all my life, marshall everything, power amp pre amp, even Marshal effects, and cabs,,, but i cant move this stuff from show to any more,, way to heavy,, and everything was 8ohms

So I got a rect o verb,, combo,,,(still heavy) it smokes any marshall i ever played, but the thing is there is a 8 ohm for the 1 12 speaker, but i am playing a rather large show and wanted to hook up my marshall 1960 cab to it??? but i never really looked before but there is only two 4 ohms out puts???? and the 1960 is a 8 ohm i think,, so what i need to know,, how do i hook this up to my marshall 1960 cab,,, Please let me know ASAP,,, thanks a freakin ton to anybody who helps,, tony

Most 1960s can be run at 4 Ohms mono. Plug a cable from either of the 4 Ohm jacks on the Rectoverb into the 4 Ohm mono jack on the 1960 and you'll be good to go with matched impedance.

You could run the 8 Ohm output into the 1960 set for 16 Ohms mono, but you would loose a bit of bass, treble and power since the impedance is mismatched. This setup will also wear the tubes faster, but won't harm the Rectoverb.

 

[Melvin1011]

If your 1960 cabinet is in fact 8 ohms, then you can connect it to one of the 4 ohm jacks on the combo and plug the combo's speaker into the other 4 ohm jack. This would be a correct match for that amp. If you want to use the cab without the internal speaker, plug it into the 8 ohm jack. If you cab is 16 ohms, disconnect the internal speaker and plug the cab into the 8 ohm jack.

 

[Micah]

Are you hooking up the 112 and the 4 x 12? If so go with the 4 ohm to the 112 and 412 for the correct match to the amp. If you are just hooking up the 412 go with the 8 ohm output for the correct match. The nice thing about this setup is that with more speakers to power you should be able to turn up the amp to seemingly be the same volume which with give you a nice power tube squeeze!! :wink:

 

[mrt]

Are you hooking up the 112 and the 4 x 12? If so go with the 4 ohm to the 112 and 412 for the correct match to the amp. If you are just hooking up the 412 go with the 8 ohm output for the correct match. The nice thing about this setup is that with more speakers to power you should be able to turn up the amp to seemingly be the same volume which with give you a nice power tube squeeze!! :wink:

thats what i will do,,,, thanks to all... for the input :!: :!: :!:,, FX2 you know what you are talking about(for sure) but what you siad was way over my head, i e-maid what you said to my guitar tec. and he said he can do that,,, that would make the most of what i have,,, thanks again,,

THIS IS A GREAT FORUM FOR INFO

 

[MesaENGR412]

First, some things to know:

Marshall box comes usually with 16 Ohms celestion speakers (G12T-75 or vintage 30) (www.celestion.com)

You may wire them like you want to combine the impedances of the speakers to get a load of 4, 8 or 16Ohms

Second, some theory:

The resistance of two resistances in parallel (R1//R2) is: R’ = (R1 x R2) / (R1+R2)
Note: if R1=R2 we have a simpler formula : R’=0.5 x R1

The resistance of two resistance in series is the sum of resistances : R’ = R1+ R2
Note: if R1=R2 we have a simpler formula : R’=2 x R1
So depending on the load you want you can combine your speaker to get the load you want.

How to wire parallel?

Connect the “minus” ( - ) wire to all “ – “ side of the speakers and plus (+9) wire to all “ + “ side of the speakers.

How to wire series ?

With the ( - ) wire you “enter” in the ( - ) side of your speaker, and you connect the (+) side of this speaker to the ( - ) of next speaker and so on till the (+) wire.

End now some concrete examples (S1, S2, S3, S4 are your four 16Ohms speaker in your marshal box 1960) :

S1//S2+S3//S4 = 16Ohms
S1//S2//S3//S4 = 4Ohms
(S1+S2) // (S3+S4) = 16Ohms
S1+S2+S3+S4 = 64Ohms  don’t use this configuration
S1+S2 = 8Ohms (half cab or “stereo” setting)


If you’re not able to match exactly the amp output (f.i. 8 Ohms) to you speaker load, prefer a higher load than the one the amplifier expects. This means, it is better to connect a 16Ohms speaker on a amplifier expecting a 8Ohms speaker than connecting a 4Ohms speaker to the same amp.

I hope this will help you!

Wow, somebody knows their electrical engineering....I'm studying some of that stuff right now for mechanical haha gotta love physics

 

[SteveP]

The marshall cabs can be run in either 4/16 ohm mono, or 8ohm stereo. This is the 1960 cabs.

 

[fx2]

Hi,

Yes I am very sure about what I say! wouldn’t say it if I was not ;-)

The marshall cabs can be run in either 4/16 ohm mono, or 8ohm stereo. This is the 1960 cabs.

He’s right. On my cab on one mono input I have:
- 4 Ohms (all celestions wired parallel S1//S2+S3//S4)
- on the other input : 16Ohms ((S1+S2) // (S3+S4)),
- and if I use both input I have twice 8Ohms (S1//S2 = Ohms for left and S3//S4 = 8Ohms for right)

I believe that all marshall 1960 cabs are wired this way.

If you have an “Impedance meter” (available on most standard mulimeters) you can mesure the impedance of your speaker. Just connect standard mono cable to it an measure between tip and ring on the plug.

To be able to help you more specifically on your issue you should clarify your setup.

I Have understood that your amp Output and you combo speaker are both 8Ohms. But I don’t undersand :

… i never really looked before but there is only two 4 ohms out puts???? …

Are you speaking about the output of your amp or the input of your cab?

*****If your amp has two 4Ohms outputs and you cab two 8Ohms inputs****** (if this is not right please provide more info about your setup!!!)
Then you should connect each 8Ohm input (cab side) to one 4Ohm output (amp side), you need two cable for this. This way the left (Sleft =S1//S2=8Ohms) and right speakers (Sright=S3//S4=8Ohms) of your cab are connected parrallel to create a total load of 4Ohms (Sleft//Sright=8//8=4Ohms). This matches your amp’s output , see you mesa manual.

Was this helpfull?

 

[mrt]

well,,,,, i played the show,,, we cover maiden,,, and like i said i always had the rack,,, with the marshall jmp-1, 9200, rocktron, bbe, ect,,, i loved the sound,, but like i said to much to move!!!!!!


everything worked great,,, out side of the cab???? i hooked up the 8 ohm out to the marshall 4 ohm input,,, and the 1 12 to the 4 ohm(combo),,, but there was little sound coming from the marshall 1960, and only the right side speakers were working?????, the sound guy just put the mic on my 1x12, so the cab was just a $500 prop :x ,, the only way i can get that real metal scooped sound it with the marshall 1960,,, so i went home and plugged my jmp head into the cab and worked fine,, you tell me :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?: :?:

 

[fx2]

The current flowing out your power amp and that grives your speaker will flow mainly in the smaller load 4Ohms rather than in the 8Ohms speaker. It will prefer the smaller resistance. So your description seems not logic. Seems like your cab has a higher impedance than your Combo’s speaker … ?

 

[mrt]

Well,, i learned a lot from all you guys,,,, i'll see tomorrow what the deal it with it,,, thanks again,,, tony

 

[Shep]

You could run the 8 Ohm output into the 1960 set for 16 Ohms mono, but you would loose a bit of bass, treble and power since the impedance is mismatched. This setup will also wear the tubes faster, but won't harm the Rectoverb.

Is this true?...having a safe mismatch and loosing tone..i use 16 ohm oranges and run them at a mismatch at 8...so 8 ohm tap to a 16 ohm cab..i know how to rewired them to 4 ohm but i really think it doesn'yt need it..

 

[mrt]

well,,,, i took the marshall 1960 cab and the rect-o-verb(combo) to the my guitar guy,, he said leave it alone :?: :?: :?: :?:


he did put new tubes in it,,, but big deal, he said use the 8 ohm from the rect-o-verb to the 4 ohm mono cab,, and use the 4 ohm for the 1 12 speaker :?: :?: :?: :?: he did say it would wear down the tubes faster but thats going to be the best punch i can get from it,, I asked him when i was leaving "DID YOU JUST NOT WANT TO WORK TODAY", plus i only get sound form 2 speakers???? I love the way this thing sounds but this hooking it to a cab is killing me,,

 

[4Draw]

You wear out tubes FASTER, when running from lower ohm on amp to higher ohm'ed cab?

I always thought it was the other way around, that the powertubes were actually living longer this way...?

 

[Russ]

Actually, it wasn't until the invention of the stereo inputs on the 1960 cabs in the JCM900 series that the cabs had stereo. The cabs before the JCM900 series were single ohm load rated, meaning that they were a single input jack that was whatever the load was created by the wiring inside (usually 16 ohm). However there were some cases where there were 8 ohm cabinets made but they used 8 ohm speakers. The standard 16 ohm cabinets were loaded with 16 ohm speakers. If you rewired your 16 ohm cabinet you could make it into a 4 ohm cabinet but Marshalls never supported a 2 ohm load so you could not have more than that one 4 ohm cab ever connected to it.

This is probably why many Marshalls had either a 4 or a 16 ohm selector position. Some had the 3 position ohm selector and were more versatile for your speaker selection. Those that had a 2 position ohm selector switch were wired for one or the other 4 or 16 ohm depending upon where the amp was made and where it was going and I would suppose what transformer it had in it. I may be wrong here but I think it was that the US versions had the 2 position while the UK version maintained the 3 position ohm selector switch. I know that the US versions dropped the voltage selector switch at one point in time. The UK versions maintained the universal voltage selector switch thus giving them the capability of being used anywhere. This is why you find discrepancies between the backs of the chassis on some Marshalls of even the same model from the same year. Don't even get me started on Canadian versions and their oddball fuse blocks inside and their insistance of using the bat style switches even after the rest of the US and UK Marshalls were already using the rocker switches not to mention the red French translation of the warnings in addition to the normal English warnings.

Sorry about the tangent here but I just thought those that needed a little more education on Marshalls could use the help.

If you run your 16 ohm cabinet into your 8 ohm tap then run your 8 ohm speaker into your 4 ohm tap and you should be fine.

As far as tubes dying faster is concerned, think of them as disposable because they are. They are consumable and should not be thought of as otherwise. There is a certain amount of expense in owning a tube amp and achieving the tone you want. For example, you probably didn't skimp on the price of your amp if you are here and own a Mesa. I assume you picked your Mesa for its tone. Why be so concerned if your tubes should have a shortened life. Besides, compared to your amp tubes are cheap. If you were that concerned about tube life why not play a low gain amp so your preamp tubes will last longer and keep your amp volume down to keep it from achieving power tube distortion and have tubes that will last much longer? Or even switch to an amp modeler or some other solidstate incarnation for that matter. Do you change your strings often? Same thing. Strings are consumables too. This is an expensive undertaking (playing electric guitar through a quality rig). Enjoy it and don't worry about it as much. There are some guys (like EVH) that have had to change their tubes nightly. Would you say that EVH had terrible tone? There are billions worldwide that would argue against you if you did. That brown sound had a price. He wasted tubes like crazy (if you would call it wasting) in order to achieve his sound. I see his approach as successful. He sacrificed the tubes (and quite a few amps) to get his tone. I know we all don't have the financial backing necessary to be buying new tubes everyday much less a new amp every other week but I am saying this to make a point. There is a certain amount of outlay required to get the sound you want out of your rig. Just deal with it or change your gear to make things more economical (though you may or may not still achieve the same sound you wanted or you may improve your sound).

Sorry if I appeared to ramble a bit... and please do not take this personally. Think of it as a rationalization or even philosophical noodling.

 

[Russ]

I almost forgot something that keeps me at odds with myself. For all of us who love our NOS tubes and keep a little stash of them among other key tools (tubes) we must come to the realization that some day we will not be able to find them much less afford them should we find them. Their supply will run out like the life of those few gems we now own. Someday there will be a need to move on. Hopefully before then, the world's tube manufacturer's can get their heads out and return to making consistently good tubes for our use like the manufacturers of yesteryear. I know that audio glass is a niche market but there is new hope for us in that some new computer soundcards are being developed with 12ax7s as part of their design for a more analog kind of sound. I recently saw an article talking about a soundcard company going back to tubes. The only problem I can see with it is the introduction of more heat into an already heat sensitive environment. But, time will tell. Hopefully, it will create more demand for higher quality tubes. Maybe it will create a desire to run a tube power amp in home stereos again too. I know this is reaching but it would be a nice turn of events for those of us still using tubes and could force the hand of the tube manufacturers to improve quality. I know that the quality of the steel is important and that steel isn't being produced in as high of quality for tubes as it had been in the past (probably due to the gov't contracts once in place that are no longer as rigid and the introduction of lighter materials such as aluminum and recycling thereof not to mention the Asian countries buying up the good ol US steel) and that the old machines do not get as nice of vacuum as they once did nor is the QA of the manufacturing processes of tubes as good without reason (other than medical equipment and military equipment no longer use tubes so there is no reason to be to any gov't controlled spec). It would be nice though if we were offered what was once readily available. Some tube manufacturers are trying but I still think they are all in it for the money and not for truly satisfying the end user with a formidable product. How does technology regress anyway? Other than ignoring and neglecting what was once a good thing. To simplify things, how do you forget how to make a peanut butter and jelly sandwich? Why would you let your equipment (butter knife in this case) to make them become unusable or allow it to make substandard sandwiches? If you really cared would you buy crap bread, peanut butter, and jelly (cheap steel for the internals) or would you buy good stuff that was tasty? Like I said, I think that money clouded the vision of the tube manufacturers and kept them from continuing to produce their products as they were once done thereby putting us in the situation we are now in. Deprived of products that truly rival NOS. I am a firm believer that the improvements to the internal structures came out of necessity because of the lack of quality being produced. I believe that had the old practices been continued and the machinery maintained that we would have no such thing as NOS because current production would be the same as it had been. Just further support for "They don't build them like they used to..."

I didn't mean to slightly highjack this thread but I just had to vent a little. It does relate somewhat to tube life though which was being discussed as a side effect to mismatching ohm loads. I do not think that the side effect would be even cared about if tubes were to last longer. If the tube build quality were better then they would certainly last longer and take more abuse. But then again, we would be purchasing less tubes and there would be even less global demand and that might drive prices up even higher and could force some of the manufacturers out of business thus creating even more of a problem. So I guess we are kind of back to square one with longer life tubes.

...They could still make the tubes sound better though. For example, why is it that there are some iconic tubes that cannot be replicated? It just doesn't make sense.

 

[hal9000]

You could run the 8 Ohm output into the 1960 set for 16 Ohms mono, but you would loose a bit of bass, treble and power since the impedance is mismatched. This setup will also wear the tubes faster, but won't harm the Rectoverb.

Is this true?...having a safe mismatch and loosing tone..i use 16 ohm oranges and run them at a mismatch at 8...so 8 ohm tap to a 16 ohm cab..i know how to rewired them to 4 ohm but i really think it doesn'yt need it..

Mesa states that the mismatch of one direction (8 => 16, 8 => 4, etc.) won't damage the amp, and may be a tone you prefer. The tubes will wear faster. You'd have to consult Orange to see if the transformers can handle the mismatch. Since you haven't had any problems, you're probably fine. Just because the tone is different, doesn't mean it's worse.