#1
on the back of my 50 watt jcm 900 combo theres a switch to select impedence
its says 8 - 4(16)
where should i set the switch? at 8 or at 4(16)?
it only has one G12H-100 speaker
Last edited by pebbles123 at Aug 13, 2011,
#2
Directly from the manual:

6. Impedance Selector Switch
Two-way switch for matching the amplifier to speaker impedance.
Amp heads feature 8 or 16 Ohm operation.
Combo versions feature 4 or 8 Ohm options.

G12H-100 speakers are normally 16 ohm but in the 1x12 combo they are usually 8. Have a look at the back of the speaker, it will be written on it. Don't guess, have a look.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
Last edited by Cathbard at Aug 13, 2011,
#3
its marked 8 and little horseshoe( the ohm symbol)
i always had it on 4(16) that means i was completly wrong :O?
#5
The switch likely only applies to external speakers. I'm not sure, though. You should set it to 8ohm to be safe.
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#6
Quote by Raijouta
The switch likely only applies to external speakers. I'm not sure, though. You should set it to 8ohm to be safe.

Nah man. A Marshall combo is just a head flipped upside down as far as control goes. The internal speaker just plugs in the back in one of the two output sockets. The impedance switch is for the resultant of everything hanging off those two jacks.
It has to be set to 8. Don't panic though, you had on the safe side of things. You'll be fine.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#7
does that mean that if i connect a 4x12 cab will it sound the same as the head version?