Power amp questions for Axe Fx users! Tubes vs SS (big difference?)

Anyone try out the Carvin TS-100?

- All tube design, 4 12AX7, 4 6L6
- Internal bias selection switches for each channel (EL34 or 6L6/5881)
- Front panel volume and presence controls
- Front panel power and stand by switches
- Rear panel impedance, bridge, parallel, and ground lift switches
- Premium construction features metal bushings and shafts
- 19" 2U all steel chassis with Chrome front panel and knobs
- Dimensions: 3.5" high x 19" wide x 10" deep
- Weight: 25 lbs
- Made in San Diego, California

http://www.carvinguitars.com/products/single.php?product=TS100

$600
 
I'll go for an SS power amp at first and see if i like that!
I still got one more question about ohms.
As an example I'll use the Crown XLS 2500

Specifications:

Stereo, 2 ohms (per ch.) 1200W
Stereo, 4 ohms (per ch.) 775W
Stereo, 8 ohms (per ch.) 440W
Bridge-Mono, 8 ohms 1550W
Bridge-Mono, 4 ohms 2400W

Is this like a tube amp?
For best result the power amp and cab need to have the same Ohms?
And as long as the cab ohms is higher than the head or power amp = safe mismatch?
 
The general rule of thumb is that a SS power amp should be 3x what you would be using if it were a tube power amp.
There was a sticky done by Jay Mitchell that explained this, but it may have been lost in the board transition.

The cab and amp have to operate at the same ohm level.
Your cab will have an ohm rating on the back. Make sure your amp can do that ohm rating (8, 4 or 2), in the mode it's in (mono or stereo).

If you post the specs of your cab, it will be easy to tell you if that Crown XLS will be a good fit (power wise).
What ohms and watts is your cab?
 
I just sold my orange 2x12 cab (16 ohms) this morning for a great price (650$!). He really wanted the cab!!

I'll order an avatar 2x12 G12 contemporary in Burgundy / Oxblood color with V30's as soon as I know the options i should take!
But I want to add another one later, same avatar 2x12 but with G12T75.
This is where I'm not sure what to order: Choice of 4 ohm cab, 8 ohm cab, 16 ohm cab, stereo cab or mono cab.

I want two 2x12 cab to have the option to run two different setups in the axe fx ultra (ex: a marshall on one cab and a mesa or bogner on the other)
and split the 2 cabs to have like a stereo effect.
But I may also prefer to just use the 2 cabs stack like a 4x12 with only one setup in the axe Fx.
I guess that I should go with 4ohms if i look at the specs of the Crown power amp?
I would get 2400W on 4ohms in bridge mono and 775W (per chan) in 4ohms stereo?
Right?

Crown XLS 2500

Stereo, 2 ohms (per ch.) 1200W
Stereo, 4 ohms (per ch.) 775W
Stereo, 8 ohms (per ch.) 440W
Bridge-Mono, 8 ohms 1550W
Bridge-Mono, 4 ohms 2400W
 
I have the Mesa Dyna-watt 20/20 and a custom 212 cabinet with Eminence (not sure what model speaker) but I am very pleased with the sound I get. I have a peavey Classic 50/50 a Rocktron velocity 100, Carvin DCM 150 and just sold a Marshall 9200. Out of these I think the peavey classic 50/50 sounds the best, presence and resonance controls are nice also but I'm using the Mesa 20/20 cause its makes my rack smaller and lighter. .......Donnie
 
Yeah I use to own that little power amp with a sans amp psa 1, great little unit with lots of power!
But I want to try an ss power amp since I've been told that mesa power amps color the sound a bit too much!
 
webstersp said:
This is where I'm not sure what to order: Choice of 4 ohm cab, 8 ohm cab, 16 ohm cab, stereo cab or mono cab.

I want two 2x12 cab to have the option to run two different setups in the axe fx ultra (ex: a marshall on one cab and a mesa or bogner on the other)
and split the 2 cabs to have like a stereo effect.
But I may also prefer to just use the 2 cabs stack like a 4x12 with only one setup in the axe Fx.
I guess that I should go with 4ohms if i look at the specs of the Crown power amp?
I would get 2400W on 4ohms in bridge mono and 775W (per chan) in 4ohms stereo?
Right?

Crown XLS 2500

Stereo, 2 ohms (per ch.) 1200W
Stereo, 4 ohms (per ch.) 775W
Stereo, 8 ohms (per ch.) 440W
Bridge-Mono, 8 ohms 1550W
Bridge-Mono, 4 ohms 2400W
Click to expand...
You need to read up on speaker/amp impedance matching and learn how to calculate the impedance when using more than one cab.
http://www.the-home-cinema-guide.com/speaker-power-rating.html
http://www.the-home-cinema-guide.com/speaker-impedance-matching.html

Yes, you may well get 2400w at 4-Ohms bridged and 775w stereo at 4-Ohms, but what does that mean to how you hook it all together? Is it safe to do so with what you have? Will you be under-powerd or will you damage or destroy your speakers?

That will depend on the cab you chose and its power handling and it's impedance rating(s). Many 2x12's are 8-Ohm, some are 4-Ohm.. depends on what the manufacturer decided put in there (2 x 16-Ohms or 2 x 8-Ohm speakers). They can be mono (both speakers driven off same source) or stereo (individual speakers driven). The impedance rating will differ for mono and stereo capability in a cab. Either way you probably need to know the impedance rating for the enclosure, not the individual speakers.

Let's make some assumptions here for brevity and [layman's] example purposes:
- your 2x12's are 8-Ohm and rated at 300w program (don't ask what "program" means right now). They are not switchable and have one 1/4" input jack and a thru jack.
- you have 2 cabs.

When running in stereo the output from each side of the XLS 2500 (Left and Right) would be connected to each enclosure (cab). The amp, at full power delivers 440w into each cab. That is OK, 'cus "program" power is approx. half of the peak [maximum] rating of the enclosure. Program power is also called continuous or RMS power.

If you want to run both cabs in a mono stack then you have to "daisy chain" them together - connect cab A out to Cab B in. This would cause them to be connected in parallel (as opposed to series, and yes it makes a difference). This changes the impedance that the amp will see - which for two 8-Ohm enclosures in parallel is about 4-Ohms.

You now have 2 options... run the 2 cabs off one side of the amp or in bridged mode.
If choosing the former, the amp will deliver 775w at 4-Ohms. Each cab will get 1/2 of that, or about 387w each. That's well within their power handling ability.
If you choose bridged mode, you will be delivering 2400w at 4-Ohms to the same cabs. Program power (~50%) for the cabs is 600w (300w + 300w) with a peak handling of around 1200w. You are giving them TWICE that power and will very likely blow them off their mountings. NOTE: You cannot run bridged mode in stereo as you are combining the output of both L/R channels into a single output.

I used this simple example to illustrate the need to understand impedance matching in amps and speakers. Rule-of-thumb for powering speakers is that one should select an amp that can deliver 1.8 to 2.5 times the intended speakers program power. Why 1.8 to 2.5? This allows for the headroom need to produce the dynamic range of the music being replicated safely to the speakers.
In our scenario, your 8-Ohm 300w program cab should be powered by an amp that can deliver between 540w and 750w. Thus, a 4-Ohm 600w program/continuous/RMS rated speaker should be driven by an amp that can produce between 1080w and 1500w at 4-Ohms.

IF you already own the Crown, you need to ensure that the cab(s) you buy are both impedance and power match with the amp. Usually one starts by buying speakers then finding an amp.

Hope this helps..
 
A really big thanks for technical explanation!!
I don't own the crown yet but I'll take the time to understand everything in your post before deciding wich model to buy! But right now I think the crown XLS 2500 may be a bit overkill and that maybe the XLS 1500 would be enough.
A 2x12 cab (mesa, orange etc) or the avatar cab that I want to buy are 120 Watt RMS and usually 8ohms mono
so I'll go with that.
Is 120W RMS the same thing as your 300w program ? I mean does 120W rms = 120W program!?
If so I would need a power amp that can deliver between 216W and 300W?!
 
I don't think the Dyna-watt colors the sound very much at least in my small room at the volume levels I play at. I have a set of mackie near field monitors and what I get out of the Dyna-watt compared to direct recording is very close... The thing I found that made the most difference was the speaker cab. I've experimented with that a little also..
But i believe that if I gigged out I would go ss because of the maintenance factor for tube amps. ..........Donnie
 
webstersp said:
I mean does 120W rms = 120W program!?
If so I would need a power amp that can deliver between 216W and 300W?!
Click to expand...
Yes. Program, continuous and RMS ratings are usually the same thing. Different vendors use different terms and different ways of measuring (coming up with) that value for their products, but is basically about 50-55% of the peak handling power of the speaker. So.. when buying speakers look for both values peak or max, and whatever the other label show. So match your amp rating to the speaker.

120w Program = 120w RMS. So 216w to 300w is good. That range allows the amp to adjust to the dynamics of sound and have enough power to handle them, while sending that to the speaker and not blowing it up! There are exceptions to this rule (aren't their always) but they are not applicable in this context.

While I didn't allude to it in my prior post, the XLS 2500 would have have run two 8-Ohm 300w cabs in stereo just fine. In bridged mode.. NOT! instant speaker casualties!

I would suggest an amp (assuming budget is OK) that can deliver around 250w per channel (stereo) at 8-ohms.
Crown - XLS 402, Xti 1000
QSC - CX502, RMX1450, GX3 (no bridging), PLX1104 (no bridging)
Yamaha - P2500S

That will let you run 2 cabs - one from each channel. I would avoid bridging amps unless you really understand what that does and the limitations/challenges that come from using an amp in that mode.

Good luck.
 
NeoSound said:
I don't think the Dyna-watt colors the sound very much at least in my small room at the volume levels I play at. I have a set of mackie near field monitors and what I get out of the Dyna-watt compared to direct recording is very close... The thing I found that made the most difference was the speaker cab. I've experimented with that a little also..
Click to expand...
Most (if not all) professional "modern" power amps, tube or SS, including the 20/20 do NOT color sound, and provide clean transparent power. The speaker cab chosen, the guitar cable you use (capacitance) will have an effect that is w-a-y more noticeable.
 
The mesa 20/20 may lack in the headroom department!!
And many people on these boards say mesa power amps color the sound and give your amp
a mesa type of sound. The only tube model that would be neutral is the Fryette 2/50/2 but at 1599$ it is
out of my budget!
I dont want to have many options on the SS power amp I,m looking for something that work like a tube power amp without hte tube!
I don't need that bridging or 2 ohms options!
The reasons why I was looking at the Crown XLS drivecore is because they had a good price and they were lightweight (under 11 lbs).
But any good model will do!
 
Old tube amps would give u the best tone?

Old tube amps work the best?? Have 200 watt traynor similar to a Marshall major any thoughts of this with aX ? Or just use od/dist pedals in front of the traynor what will sound better for high gain tone?
 
petstar said:
Old tube amps would give u the best tone?
Click to expand...
Contrary to popular opinion, old or new has nothing to do with it. There are some great old amps, and some really crappy ones, too. Likewise, there are great and crappy new amps.

Most of the people on this forum are of the opinion that the Axe-FX is hard to beat for high-gain tones, or for any other tones, for that matter. We've drunk the kool-aid and are looking for another glass. :)
 
s0c9 said:
Most (if not all) professional "modern" power amps, tube or SS, including the 20/20 do NOT color sound, and provide clean transparent power. The speaker cab chosen, the guitar cable you use (capacitance) will have an effect that is w-a-y more noticeable.
Click to expand...

Thats just not true, although maybe colour isnt the best expression. That implies an EQ or tonal differnce, but in fact the differences are more about response, compression, linearity (not of the EQ but of amplification of the signal). The way valves amplify, and their imperfections mean the behave differently to a SS amp which is actually the more perfect amplification method. It does mean valves make for a more pleasing audio output but thats not the issue.

If your putting a perfectly good audio signal into an amp (like a recorded track), a SS should give you the best replication of that signal. For something that relies on a valve power stages imperfections (like a tube pre) the SS amp sounds harsh because it isnt altering the signal like the valve amp, its amplifying it more accurately. This happens at all volumes not just loud ones. Loud signals that push a valve to its limits of operation just add more compression and eventually distortion but it is still happening to some extent whatever the level. Its why playing dynamics ARE dynamic through a valve amp. As the picking intensity goes up, so does the signal strength, and the valve amp reacts by adding more compression, maybe some harmonic and maybe some distortion to the loudest bits and less to the quieter bits of the note. A SS doesnt.

The biggest issue/debate comes when you start putting modellers into the amp. in theory a SS amp gives you the best output because the modeller is supposed to replecate the valve response and the SS amp is the best replication of that output. However we all now some modellers dont do that job fully. there is still something missing (a different amount with different modellers). Its why some modellers (or at least some people) think that a valve power amp still gives the best (or more pleasing) result. You dont push it so hard to get high compression and distortion BUT you still adding some valve non linearity, compression, softening etc. if you have a perfect model of an amp then the valve power amp adds stuff you dont want and muddies up the sound a little.

So - with the Axe it all depends on whether you think its the best available BUT is still a little short in the Power Amp modelling (in which case you'll think a valve amp gives a better result) OR whether you think the Axe is spot on (in which case a SS would give the better result). That decision can only be made by the individual user.
 
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s0c9 said:
Yes. Program, continuous and RMS ratings are usually the same thing. Different vendors use different terms and different ways of measuring (coming up with) that value for their products, but is basically about 50-55% of the peak handling power of the speaker. So.. when buying speakers look for both values peak or max, and whatever the other label show. So match your amp rating to the speaker.

120w Program = 120w RMS. So 216w to 300w is good. That range allows the amp to adjust to the dynamics of sound and have enough power to handle them, while sending that to the speaker and not blowing it up! There are exceptions to this rule (aren't their always) but they are not applicable in this context.

While I didn't allude to it in my prior post, the XLS 2500 would have have run two 8-Ohm 300w cabs in stereo just fine. In bridged mode.. NOT! instant speaker casualties!

I would suggest an amp (assuming budget is OK) that can deliver around 250w per channel (stereo) at 8-ohms.
Crown - XLS 402, Xti 1000
QSC - CX502, RMX1450, GX3 (no bridging), PLX1104 (no bridging)
Yamaha - P2500S

That will let you run 2 cabs - one from each channel. I would avoid bridging amps unless you really understand what that does and the limitations/challenges that come from using an amp in that mode.

Good luck.
Click to expand...

But wouldn't that mean that you are running a 300 peak handling driver with an amp that has a total of 800 peak watts?
 
s0c9 said:
I would avoid bridging amps unless you really understand what that does and the limitations/challenges that come from using an amp in that mode.
Click to expand...

Outside of it being mono, what *are* the limitations and challenges of running an amp in bridged mono mode?
 
No, I wasn't referring to a bridge connection. The crown @ 8ohms has an RMS(average) of 450 watts/channel. Each cab of drivers has an RMS(average) of 300 watts. The peak power handling of the drivers is around 600 watts where as the peak power per channel of the amp would be 900 or so watts. I would think that if one were to be too loud they could blow there speakers.
 
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