Why would Marshall have put a 16 ohm instead of 8 in my JCM combo amp?

[axuality.com]

It's capable of 4,8,or 16 output. Why would they choose 16?
I'm replacing the speaker, and I'm tempted to get 8.

[pgissi]

possibly to give you the option to run an external cab in tandem with the combo speaker for a total 8 ohm load

[axuality.com]

Originally Posted by pgissi

possibly to give you the option to run an external cab in tandem with the combo speaker for a total 8 ohm load

Good idea, pgissi.

Another question:

I have a JCM800 4210 50 watt combo amp and I am likely putting an 8 ohm speaker in it. I also have a 16 ohm extension cab. If I run these 2 together, I will show a total load of 5-1/3 ohms. If I run the amp on a 4 ohm output setting, will I be safe, or should I exactly match the ouput of the amp?

I may post this as a thread, if I don't get any answers here, pardon me.

[remocity]

Neither of course is ideal but from what I know, with a 5.33 ohm load it would be better to put the amp on the 8-ohm setting.

[gldtp99]

running an 8 ohm internal speaker together with a 16 ohm extension cab is pretty much a waste of time--- most of the amp's power will go to the 8 ohm speaker and very little will get to the 16 ohm cab--- it will seem like it's sitting there doing little or nothing, because it will be getting so much less power than the 8 ohm internal speaker.
Get a 16 ohm internal speaker--- when you run it with the 16 ohm external cab then the power will be divided more equally between the internal speaker and the external cab---- run the amp at 8 ohms when using two parallel 16 ohm loads.............gldtp99

[axuality.com]

Originally Posted by gldtp99

running an 8 ohm internal speaker together with a 16 ohm extension cab is pretty much a waste of time--- most of the amp's power will go to the 8 ohm speaker and very little will get to the 16 ohm cab--- it will seem like it's sitting there doing little or nothing, because it will be getting so much less power than the 8 ohm internal speaker.
Get a 16 ohm internal speaker--- when you run it with the 16 ohm external cab then the power will be divided more equally between the internal speaker and the external cab---- run the amp at 8 ohms when using two parallel 16 ohm loads.............gldtp99

Believe me, I want to buy it in 16, but the 100 Celestion G12K-100 isn't available in 16 ohm, according to website. Maybe I'll have to go with the Classic Lead if it's available. Otherwise it might have to be the Vintage 30, and that's in doubt for this amp.

[pgissi]

Believe me, I want to buy it in 16, but the 100 Celestion G12K-100 isn't available in 16 ohm, according to website. Maybe I'll have to go with the Classic Lead if it's available. Otherwise it might have to be the Vintage 30, and that's in doubt for this amp.

I have a JCM800 4210 50 watt combo amp and I am likely putting an 8 ohm speaker in it. I also have a 16 ohm extension cab. If I run these 2 together, I will show a total load of 5-1/3 ohms. If I run the amp on a 4 ohm output setting, will I be safe, or should I exactly match the ouput of the amp?

when reading dc resistance, your actually reading 75% of the total ac impedance generally so 5 1/3 rd ohms is probably 7 or 8 ohms, a 16ohm cab will read 14 to 15 ohms so that poster is correct, set it for 8 ohms not 4

mixing speakers of different imps is safe as long as you maintain the proper total load imp but what ends up typically happening is one speaker will be louder and generally the lower imp speaker would be it given the senstivity ratings are not too far off from each other

i am not a fan of doing this nor am I really a fan of mixing speakers in a cab given the differences in efficiency (sensitivity) for starters, there are other factors to consider like if I have 2 speakers in a cab that I like, which one do I put a mic on for a live show

I can appreciate the idea of mixing speakers but I just find in practice it creates as many problems as it solves


Deciding on a speaker is of course a crap shoot, its all about trial and error, have to be honest, I hate the G12K-100, sound like my early 90's G12M70, shrill and harsh

the V30, IMO is trash unless you want to bring the trash with you 100% of the time

classic lead is an all around good choice, good power handling for your 50watter, then there is the G12T-75, that is the sound of the 80's

but maybe as an alternative there is the G12M-65 Heritage, it is somewhere between a greenback and classic lead although the 65watt rating is low for a 50watt combo, if your not playing full out your fine and being a 65watt speaker being driven by a 50watt combo, you could get it to break up earlier for a more volume friendly rig, full and fat jacked tones at lower volume

lastly, if you go 16ohm for the combo speaker you can always experiment with other cabs/speakers in tandem

I like avatar's description-
Like the original G12-65, the Heritage Series re-creation of this legendary Celestion guitar loudspeaker has a tone that’s best described as sitting somewhere between the G12M and the Classic Lead 80, with plenty of definition for high-gain playing styles without being too bright or aggressive. By adhering precisely to the initial design notes, specifications, materials and construction techniques, the Heritage Series G12-65 dishes up the cherished guitar tones of the ’80s with almost unnerving accuracy. 8 or 15 ohm

[Flameout12]

I'm dealing with a similar situation but without the external cabinet. I might build another cabinet for my chassis and run 2x12. I like 2x16 ohmers in parallel which is an 8 ohm load.
Like posted above, my experience with mixing speakers with different ohmages is it doesn't work well, especially when you compare it to a pair that are the same ohmage.

And if you're interested in the G12-65, check out the WGS ET-65...less expensive and there are some that swear it's a better speaker than the Celestion.

[pdf64]

8 ohms in parallel with 16 ohms creates a total impedance of 5.33 ohms. The dc resistance will be a little less than that.
It's so close that either the 4 or 8 ohm tap would be as good as the other, so see which one sounds best.

[HoboMan]

I also have a 4210 combo. When the original speaker died I replaced it with an 8ohm CL80.
I'm glad I did.

[motogrinder]

Since were on the topic of ohms I have a combo amp that is 16 ohms and I want to run an extension cab, it is a 212 at 8 ohm's, what would I set the impedence selector on the back of the amp at? 8 ohms?

[VaughnC]

Originally Posted by motogrinder

Since were on the topic of ohms I have a combo amp that is 16 ohms and I want to run an extension cab, it is a 212 at 8 ohm's, what would I set the impedence selector on the back of the amp at? 8 ohms?

Total impedance would be 5.3 ohms. Set the amp for 4 ohms...but the 8 ohm cab will be getting more power so it may sound louder than the internal 16 ohm speaker.

[stump]

I have the 4104 212 combo and have tried a number of speakers with it. For me the Scumback M75 LHDC 100 watt speakers sound best with this and my other amps. You could load your combo with one of these at 16 ohms, 100 watts and be ready to go.

[zombiwoof]

To answer your original question, I believe that Marshall only uses 16 ohm speakers in most of their amps. Also, it gives you the option of using the amp with a Marshall 4-12.

Al