50w Cab and 100w Head
- Thread starter Kais
- Start date
koshikas
New member
Re: 50w Cab and 100w Head
the ideal solution would be to have 4x12 of greenbacks, or another set of speakers capable of handling 100W (150W really). the power lost as heat in this case is the excess power that speakers are not capable of handling. if @quaiso wants to crank the amp to get that power stage drive going while keeping his cab with greenbacks, then this is the shortest path there is, granted it is not the ideal path. the head if approaches the 150W mark the speakers would be working with 25W load each (which is their rated wattage).
the ideal solution would be to have 4x12 of greenbacks, or another set of speakers capable of handling 100W (150W really). the power lost as heat in this case is the excess power that speakers are not capable of handling. if @quaiso wants to crank the amp to get that power stage drive going while keeping his cab with greenbacks, then this is the shortest path there is, granted it is not the ideal path. the head if approaches the 150W mark the speakers would be working with 25W load each (which is their rated wattage).
koshikas
New member
Re: 50w Cab and 100w Head
u dont need to see the speakers to know whether they are blown. they will sound distorted in the cleanest of settings with the volume very low.
u dont need to see the speakers to know whether they are blown. they will sound distorted in the cleanest of settings with the volume very low.
koshikas
New member
Re: 50w Cab and 100w Head
did bit of search for guides didnt find any. but this is a very simple mod.
first things first;
1) does your amp head have a 4 ohm speaker out.
2) do you value the cab so much that altering it might ruin its value. (you'll need to drill a hole or two in the back cover to attach the heatsink.
if u are ok with that;
you' ll need;
1 x 8 ohm power resistor (150W rating)
1 x SPST toggle switch (3A 125V, 1.5A 250V dont go for a mini-toggle)
18AWG wire to make connections
the internal wiring of the cab would be simply the two speakers wired in series. the resistor should simply be wired parallel to the speaker cab jack socket.
you'll need to solder to make the connections as shown in RED. SPST toggle switch is meant to use the cab either in its stock impedance/rating (16 ohms/50W) or the new (4 ohms/150W). SPST in open position (off) will take the resistor out of circuit, making the speakers wired as they were stock (16 ohms/50W). SPST closed (on) will put the resistor in parallel with the speakers wired in series, with power attenuation (4 ohms/150W).
with or without the switch make sure that the impedance matches the wiring. or else you will either cook the speakers or the output transformer of the head. if you are using one of those non-master volume Marshall beasts, I would only advise bringing up volume slowly (those are the heads notorious for going well above their rated 100W).
did bit of search for guides didnt find any. but this is a very simple mod.
first things first;
1) does your amp head have a 4 ohm speaker out.
2) do you value the cab so much that altering it might ruin its value. (you'll need to drill a hole or two in the back cover to attach the heatsink.
if u are ok with that;
you' ll need;
1 x 8 ohm power resistor (150W rating)
1 x SPST toggle switch (3A 125V, 1.5A 250V dont go for a mini-toggle)
18AWG wire to make connections
the internal wiring of the cab would be simply the two speakers wired in series. the resistor should simply be wired parallel to the speaker cab jack socket.
you'll need to solder to make the connections as shown in RED. SPST toggle switch is meant to use the cab either in its stock impedance/rating (16 ohms/50W) or the new (4 ohms/150W). SPST in open position (off) will take the resistor out of circuit, making the speakers wired as they were stock (16 ohms/50W). SPST closed (on) will put the resistor in parallel with the speakers wired in series, with power attenuation (4 ohms/150W).
with or without the switch make sure that the impedance matches the wiring. or else you will either cook the speakers or the output transformer of the head. if you are using one of those non-master volume Marshall beasts, I would only advise bringing up volume slowly (those are the heads notorious for going well above their rated 100W).
Kais
New member
Re: 50w Cab and 100w Head
thank you for all the info! I'll have the decide if I want to mod like you stated, sell the greenbacks and get higher wattage, or just be care ful with the volume. I must say I really like the greenback tone, so I'm definitely staying in the realm. Just a matter of choices. Thanks again.
thank you for all the info! I'll have the decide if I want to mod like you stated, sell the greenbacks and get higher wattage, or just be care ful with the volume. I must say I really like the greenback tone, so I'm definitely staying in the realm. Just a matter of choices. Thanks again.
