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Tube and SS poweramp differences?

fredster

Inspired
Hey folks,

So I've been experimenting between SS power amps (Alesis RA300, SLA-2, Carvin 1540L) and using the power section of various tube amps into various cabs. What I'm finding is that using the tube amps' power section is invariably brighter than the SS amps. With the same patch, guitar and cab (changing only the amp) I find I need to crank the presence and treble in the Axe to get a similar sound from the SS amp as the tube power section. I've tried the power section of a Mesa Lonestar Special, Mesa Dual Rec, and a Bogner XTC Classic by running the Axe output into the fx loop return. I'm running at low volumes so I'm not pushing the tubes very hard. Is this an expected difference between the two designs? Would a tube power amp like a Mesa 20/20 or VHT show the same brighter characteristic?
 

paulmapp8306

Fractal Fanatic
Yes is the short answer.

I used an SLA-1 bridged for 14 months, then after tey ing an Orange Thunderverbs Power section came to the same conclusion. I also found, appart from the brightness, the Tube solutions also gave more weight/body in the low end, whilst still being quite transparent. On the SS amp, the lows were flatter, and more muffled. This may be because the SS amp is flatter, but its something I couldnt dial out. Also the sparke in the highs is hard to get with the SS amp. If I added too much presence, I got the sparkle but it got a little harsh. It was a ballancing act.

I tried a Marskall 9100 monoblock which gave the same results as the Orange amp did. I bought a VHT 2:50:2 last week and its way better to my ears. My patches needed tweeking to take out some of the presence but overall its more 3d, lively (to quote used terms) with more weight in the lows. Couldnt be happier.

I had tried sopme Lab Gruppens which are expensive SS amps (more than I actually paid for the VHT - though I got a steal) which were better than the Art (5 times the price though) but I still thought the Valve PA had the edge.
 

Tricki

Inspired
I had a similar experience when I tried the AxeFx through the FX-Loop of a H&K Triamp, very bright in comparison to a SS-PA, I did not like it at all. A Gmajor and a Rocktron VooduValve worked fine in this loop but a Boss VF-1 showed the same behavior.
It was different when I connected the AxeFx with a Tube power amp (Seymour Duncan KT-2100). I find the differences to a SS-PA are rather subtle. The SS sounds somehow tighter. I think if a SS-PA is powerful enough it can handle also the low end well. There is a “Dynamic Control” on the KT-2100. I can get the Tube-PA with this control quite as tight as the SS-PA but I prefer to have it a bit more “open”/more dynamic. I also have the impression that the “Highs” sound rounder (?). I stayed with Tube-PA but I believe that nobody would hear a difference in a live situation.

@paulmapp: I think that the ART-SLA1 is simply not powerful enough and the lower ends - especially of the rectifier simulations - push the power supply of the PA to the limit.
 

paulmapp8306

Fractal Fanatic
Maybe. It does trun at 260W when bridged into 8 Ohms, but sounds much better when backed off by some 9db. That putts the actual power at around 30-40 Watts but with plenty of headroom.

The SLA-2 in stereo mode would actually give me less than the 1 bridged. When looking for a higher quality SS amp, I was looking between 300 and 400W into 8 Ohms (preferably per channel but bridged would have been OK). Thing is, with the exception of the Powersofts I could track down, that meant 2U power amps anyway, so I wasnt saving any space, and they were priced. The LG ip amp was 200W per side, and 500+ bridged so would have been OK, but was an installation amp - at nearly £900. The fp version - build for touring was twice the price. I got my 2:50:2 for £650 (ex demo) so it was (to me) a no brainer.

The only reason the tube PA sounded bright was because my patches were dialed that was fot the Art. Once the presence was backed off a tounh, and the mids upped the VHT is great. It has a voiceing switch too that is really usefull. The maual says it upps the high mids and trebbe. I find that it does a great "instant" compensation for the differences in home and live volumes. At home I have the switch on - bringing out the highs and tightening up the bass. Live I have it off which compensates for the different apparent sound. i then use the Depth and Presence on the amp to suit the room (at home there both on just a touch).

TBH though - If I hadnt tried the P{ower Stage on a real amp - Id still be happy with the Art. Only 1 out of the 9 guitarists that hear the Art alone said it sounded "flat" compared to his amp. Not any more.
 

Jay Mitchell

Fractal Fanatic
paulmapp8306 said:
Maybe. It does trun at 260W when bridged into 8 Ohms, but sounds much better when backed off by some 9db. That putts the actual power at around 30-40 Watts but with plenty of headroom.
No. Power output has nothing to do with level setting. If you reduce the level by 9dB, then increase the signal going into the amp by the same amount, you get the same power out.
 

RDeraz

Experienced
Jay Mitchell said:
No. Power output has nothing to do with level setting. If you reduce the level by 9dB, then increase the signal going into the amp by the same amount, you get the same power out.

i had my suspicions about this.so with axe output 1 at 12:00 with 1/4" jacks,would that be +6db?+9db with XLR?since 1/4" is +12db and XLR + 18db.I ask,because i'm running a Carvin DCM 1000 8ohms stereo 225/225 watts into 2 cabs 100watts per side.i'm at a total loss for correct information on what the levels should be on the Axe-fx and the Carvin.Carvin suggests to run the amp full and control volume on the preamp.is this correct?
 

Jay Mitchell

Fractal Fanatic
RDeraz said:
i had my suspicions about this.so with axe output 1 at 12:00 with 1/4" jacks,would that be +6db?+9db with XLR?
You're mxed up here. First, without a reference (dBx, where "x" is one of several standard letters), decibels represent a the logarithm of the ratio of two numbers. Second, the signal strength at the output of a device depends on the signal strength at its input and the amount of gain (which does not mean at all the same thing as "drive" or distortion") it is producing.

Carvin suggests to run the amp full and control volume on the preamp.is this correct?
There is no "correct" here. What Carvin suggests will work fine. I recommend you take their advice and don't worry about it.
 

paulmapp8306

Fractal Fanatic
Jay Mitchell said:
paulmapp8306 said:
Maybe. It does trun at 260W when bridged into 8 Ohms, but sounds much better when backed off by some 9db. That putts the actual power at around 30-40 Watts but with plenty of headroom.
No. Power output has nothing to do with level setting. If you reduce the level by 9dB, then increase the signal going into the amp by the same amount, you get the same power out.

I know that Jay. I set up the art so that 1st, with the Axe full on the OP 1 knob, and the Art on full, the clip lights on the Art JUSTY flickered (I used the level in global to set this). I then backed off the global a further 3 bd. The Art clip lights were then not lighting at all whith the axe up full. This was still near the clip point though. At this point, the Art SHOULD have been delivering its 260W or close as the i/p signal was driving the amp to its max - ie just before clipping.

At his point it doesnt matter whether I back off the Axes output or the amps imput, it gives the same effect. That is to drop the Amps actual output. When I lowed the Arts gain knob by 9db, but dont change its input signel, the output power should actually drop by 9db. That should giva an output of around 30-40 W. I get this as -3bd is half power? so -6db is 1/4 and -9db 1/8th?

I bow to Jay here as hes the professional - and my memory of Watts, dbs etc may be off. I think im in the right kind of ballpark though.

I suppose the point is that by lowering the amps gain without chaning its input signal, the amp is working with more headroom - and sounded better for that. Still not as nice to my ears as my VHT tube amp. Again though, the Art was £200 new and the VHT SHOULD be £1250 - so not really that surprising.
 

Kriig

Fractal Fanatic
My Mesa 50/50 works perfectly. Running Out2 to the Mesa, and Out1 to PA. People are talking about tube hassle.. Never had any trouble at all. Had tubeamps since 1991... Never tried it with a SS poweramp. It may work just as good.
 

fredster

Inspired
That's interesting - thanks for the replies. Maybe I can play more with some EQ, but so far the best "live" amp sound I'm getting is through a tube power section. Of course, the SS Yorkville is working great for FRFR, but that's a different sonic goal.
 

relaxo

Inspired
My personal experience is that tube power amps, as a whole (as in not all) tend to have less brittle, sharp. as a group, they tend to be a bit more organic and compressy...less hard sounding. Most of these are adjectives desirable to eliminate in guitar tracks.

If I was seeking a loud FRFR, I would first look into the Aragon SS power amps from the 90's and early part of this decade. They were designed by David Krell and the 4004MKII can be had for less than $600. They are one of the best kept secrets in medium high end audio. They don't have harsh SS frequencies. They have power coils that are 55 pounds in weight. Why is that good? Never trust an amp that is lightweight. I've been told that these power coils store electricity...when the bass notes hit, all of the energy is right the to explode with immediacy out of the speakers without having to wait to draw in the full amount, and also lower amount, from the wall outlet.
 

jb70

Experienced
relaxo said:
They are one of the best kept secrets in medium high end audio. They don't have harsh SS frequencies. They have power coils that are 55 pounds in weight.

that sounds great but the weight makes it impractical to haul around to gigs. with the axe, the power amp, and the rack you're up to at least 80 lbs!
 

fredster

Inspired
Jay Mitchell said:
fredster said:
so far the best "live" amp sound I'm getting is through a tube power section.
Then you're not using the Axe-Fx's full ability.
So Jay, would you expect the same guitar-patch-cab combination to sound the same with a tube power amp vs. a SS amp? That's really what I'm asking - that with a tube power section the Axe acts more like I expect a real-world amp with regards to settings, IMO. A solid state amp has me setting things very differently than what I'm used to, and doesn't quite sound the same. What abilities do you mean? Some extra EQ to mitigate the differences?
 

Jay Mitchell

Fractal Fanatic
fredster said:
So Jay, would you expect the same guitar-patch-cab combination to sound the same with a tube power amp vs. a SS amp?
That would depend entirely on the tube power amp. Guitar-specific tube power amps are not generally designed to be completely clean and neutral, whereas every ss power amp from mid-level upward will have those attributes, as long as you don't drive them into nonlinear operation.

That's really what I'm asking - that with a tube power section the Axe acts more like I expect a real-world amp with regards to settings, IMO.
The Axe-Fx is specifically designed to emulate all of the sonic attributes of guitar-specific tube power amps. IMO it is completely successful at that. You don't need any physical tubes. That would have been the deal-breaker when I bought mine in October 2007. If I'd felt like I needed a tube power amp and/or preamp to get the sounds I wanted, I would never have considered keeping the Axe-Fx.

A solid state amp has me setting things very differently than what I'm used to, and doesn't quite sound the same.
Which tube amp? Which ss amp?
 
I'm tossing up SS v Tube poweramp as well. I tried an RCF ART310a powered speaker for while, but for the moment I'm going back to Mesa Boogie 20/20 and 2 cabs (a 112 and a 210).

When I first bought the AxeFX, I intended to go SS all the way. But the 20/20 sounds pretty good. I am a new buyer so I really have not had a lot of time to experiment with getting ANY presets dialled in perfectly with either the FRFR of the 20/20.

I know I can play around myself, but I am new to all this tone shaping power. I don't really know what I am doing and don't want to chase my tail too much if possible. I know PA sims are not "supposed" to be used with tube PAs, but I hate the idea of giving up some of the special characteristics of the modelled power amps and missing out on something.

Has anyone else got an Axe into a 20/20? I'm interested to know if you find it better with all amp sims off on? If you use them off, how do you like the results? Any tips on how to combine the Axe and 20/20 (or any other tube PA for matter)?

I need to get a wide variety of sounds, clean to dirty with mostly JC-120, Rectifier, Fender and Marshall tones.

I'd hate to go down this road tweaking everything for the 20/20, falling short and having to start again with an SS poweramp.
 

axel

Power User
If I had to choose between using the Axe FX to all of its abilities, or a better end result, I'll go with the latter. If the two coincide, then great, if not so what. Because it was designed to do that, it surely must? Not necessarily.
 
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