#1
I know, I know, amp modeling sucks, but I play a whole lot of different music and can't afford an axe-fx. I want to use the amp modeling on the GSP1101 but not the cab modeling as I have two 2x12s with Eminence Private Jacks that together sound better than any other cab I've ever owned. Would this be a situation of using a generic ss power amp? If so, are there adapters that can convert the power amp outputs back into 1/4" cables?

Any thoughts or advice are appreciated.
#2
Quote by DrGnosis
I know, I know, amp modeling sucks, but I play a whole lot of different music and can't afford an axe-fx. I want to use the amp modeling on the GSP1101 but not the cab modeling as I have two 2x12s with Eminence Private Jacks that together sound better than any other cab I've ever owned. Would this be a situation of using a generic ss power amp? If so, are there adapters that can convert the power amp outputs back into 1/4" cables?

Any thoughts or advice are appreciated.
Amp modeling does not suck with modern day units. To answer the question: yes, just get an SS power amp with output ratings that match what your cab(s) can take. Many power amps output to 1/4 speaker cable outputs. If not, the usual other type is Speakon which you can get adapters for. However, you need to know how imp and wattages work depending upon how you hook up your cabinets to the power amp.
Impedance is the resistance of the speaker or rated output matching of the power amp, measured in ohms. For SS equipment, impedance mismatches UP (power amp rated 8 ohms, speaker/cab rated 16 ohms) is okay. But never down (power amp 8 ohms, speaker rated 4 ohms). Some SS equipment is okay when there is not speaker load attached at all, some will be grumpy about it. To be safe, I always and only operate SS power amps with a proper load attached.

Wattage is the amount of heat energy the speaker can handle or the output of the power amp delivers. It is safe practice to have the power amp put out total LESS wattage than what the speaker/cab can handle at maximum. So a 90w power amp at 8 ohms delivering to a 100w cab at 8 ohms. Obviously, going over wattage (200w at 8 ohms output into 100w 8 ohm speaker cab) will likely blow the speaker/amp or both.

Having speakers rated for higher ohms than the power amp will reduce total wattage. A 100w power amp at 8 ohms will be seen as 50w by a 16 ohm speaker. If you double the ohms from the speaker compared to the power amp, the wattage will be halved.

Also, how your speakers are wired themselves can vary the imps. Two 8 ohm speakers wired in parallel will be 4 ohms total load. Two 8 ohm speakers in series will be 16 ohms total load. Wattage is calculated by taking the wattage of the lowest-rated speaker in the cab, and multiplying it by how many speakers are in the cab. Presumably, your 2x12 cab will have just one input which makes things much simpler. It will be rated by a single ohm measurement, and a single wattage measurement.

At least I think that is all right.


When you start looking at power amps, you will want to know how exactly the outputs will work with your setup. Presumably you can get one that has two outputs, both rated a bit under 100w at the same impedance as one of your 2x12 cabs. That way you can use 2 outputs, totaling > 200 watts (your speaker cabs are 100w each).
Last edited by Will Lane at Oct 28, 2016,
#3
Amp Modeling doesn't suck (I can't speak for the GSP1101, of course). And there are a LOT of modelers on the market that are excellent that don't cost what an Axe-FX costs.

I'm using Carvin power amps -- an HD1500 and an older DCM1540L. Both are 1500W power amps. The HD1500 weighs about 9 lbs, the DCM is a bit heavier.

Both are actually *stereo* power amps, and you can use them stereo OR as a mono power amp by bridging them. For example, I have a pair of 8 ohm speaker cabinets that will handle 900W each. The HD1500, bridged/mono will output 800W RMS into an 8 ohm load and 1500W RMS into a 4 ohm load (which happens to be what a *pair* of 8 ohm speakers produces for impedance.

But if you use the HD1500 as a stereo amp (essentially a pair of power amps), you'll only see about 300W per cabinet (8 ohm cab). I don't see the HD1500 on the Carvin site at the moment (discontinued?) but it was right around $300, as I recall.

Generally, adapters aren't required -- if you don't have speakon inputs on your cabinets (which is likely if they're guitar cabs), you can simply get cables that have whatever the power amp is using for output connectors on one end and 1/4" plugs on the other.
#4
Quote by dspellman
Amp Modeling doesn't suck (I can't speak for the GSP1101, of course). And there are a LOT of modelers on the market that are excellent that don't cost what an Axe-FX costs.

I'm using Carvin power amps -- an HD1500 and an older DCM1540L. Both are 1500W power amps. The HD1500 weighs about 9 lbs, the DCM is a bit heavier.

Both are actually *stereo* power amps, and you can use them stereo OR as a mono power amp by bridging them. For example, I have a pair of 8 ohm speaker cabinets that will handle 900W each. The HD1500, bridged/mono will output 800W RMS into an 8 ohm load and 1500W RMS into a 4 ohm load (which happens to be what a *pair* of 8 ohm speakers produces for impedance.

But if you use the HD1500 as a stereo amp (essentially a pair of power amps), you'll only see about 300W per cabinet (8 ohm cab). I don't see the HD1500 on the Carvin site at the moment (discontinued?) but it was right around $300, as I recall.

Generally, adapters aren't required -- if you don't have speakon inputs on your cabinets (which is likely if they're guitar cabs), you can simply get cables that have whatever the power amp is using for output connectors on one end and 1/4" plugs on the other.
If you're suggesting. his cabs are only rated at 100w each... He will need something much lower powered.
#5
Quote by Will Lane
If you're suggesting. his cabs are only rated at 100w each... He will need something much lower powered.


why? if he uses that one, what might happen??
Last edited by Dentry at Oct 31, 2016,
#6
Quote by Dentry
why? if he uses that one, what might happen?
Exceeding output wattage from the amp into a speaker load that cannot handle the wattage will blow the speaker and/or the amp. 200w (let alone what else dspellman's amps can put out) at 8 ohms output into a 100w cab at 8 ohms, and you will see smoke, burning, fire, unhappiness, regret, and there is no pill for it in the morning.
Last edited by Will Lane at Oct 28, 2016,
#7
Quote by Will Lane
If you're suggesting. his cabs are only rated at 100w each... He will need something much lower powered.


I actually started with standard 100W each cabinets (2x12s) when I bought the DCM1540L. I'd been using a 50W/50W Carvin TS100 tube power amp. FWIW, those things weigh about 25 lbs. The solid state power amp was lighter and worked just fine with those cabinets -- didn't burn out any voice coils, didn't have one jump the tracks. I did want more bass out of the sound, however, so I built a new pair of ported cabinets designed around the Eminence Delta ProA, and that took the bottom end down to 52Hz (give or take). Those have 400W (per speaker) power handling, so I was able to use whatever the power amp had.

Here's the thing I found about getting a lower power amplifier; they're about the same price (the Carvin TS-100 is actually quite a bit more expensive) and eventually you'll want the power. They won't blow speakers if you've got any sense at all, but you can always put higher wattage-capable speakers in the existing cabinets if you want/need more volume.