Shuttle 6.0 - does the poweramp section color the tone?

[mikeddd]

I am curious if the poweramp section in the Shuttle 6.0 colors/effects the tone of the preamp circuit in any way? I ask because when I run the effects out from the Shuttle into my QSC PLX amp, it sounds different to my ears. More sterile, for lack of a better word. Not as warm as the Shuttle.

Maybe when using the external power amp I need to adjust the controls on the Shuttle a little to try to add warmth? Anyone else have this experience? I appreciate your input.

Mike

[aledeville]

These Class-D amplifiers tend to be awfully honest, so I would vote for "No - they don't color the tone significantly".

[Son of Bovril]

SS poweramps are not "supposed" to color the tone but if you have ever tried several different poweramps you will often hear differences... usually it's in the "playability" and feel of the amp (quickness etc.) and how it controls the speakers which are not really a function of coloring the tone within the electronics of the amp but do change the tone slightly

hence why some guys will still lug an SVT over a VT bass + poweramp... it's about more than just the tone sometimes

[mikeddd]

That's a good explanation, Son of Bovril. There's definitely more "oomph" when using the outboard amp, but the overall tone/feel is not as good as when using the Shuttle's onboard amp.

[Son of Bovril]

can you eq the outboard amp to sound the same or is it quite drastic?
Out of interest, are you playing much louder, because of the way the ear works, things will sound different when louder

[mikeddd]

Not playing louder...yet. I added the external poweramp for when I get a 2nd cab which was supposed to happen already...money didn't happen so 2nd cab didn't happen. 1400 watts b/t 2 cabs makes a significant difference over 600 watts b/t 2 cabs, especially in headroom.

Currently only playing thru a 2x12 but I hear the diff, particularly at practice to moderate volume levels. I honestly haven't tweaked the Shuttle's setting too much; i just stopped using the poweramp for now.

[Son of Bovril]

hehe 1400watts across two 212's should be VERY loud

[tombowlus]

I believe that the "limiter/tube emulation" that Genz-Benz uses is non-defeatable in the Shuttle series, and I believe it comes between the preamp and power section. This limiter/emulation does add some coloration, which you would likely perceive as some added warmth and more harmonic content. It also seems to increase the total output of the power section a bit.

I'm sure Andy or Roger can give you a more detailed/accurate/concise answer, but that's been my understanding of what's going on in the Shuttle heads.

Tom.

[mikeddd]

Thank you, Tom. I seem to remember reading that somewhere as well. On a side note, IMO the output on the Effects Out is weak, despite being told that the pre-out has "plenty of voltage." In my experience, it doesn't. With the gain wide open on the poweramp (which has more than 2x the wattage of the Shuttle) my volume isn't close to what it is thru the Shuttle. But that's another thread.

Thanks again.

[svtb15]

The question is.. are you measuring it with you ears or with calibrated test equipment? Sound coloring on any power amp...... do class D sound different in general from tranny /caps.. I think they do ... but the coloring thing.. ughhhhh
I often ask myself..... are these people gigging in a sterile Lab anechoic chamber or a real gigging environment with an audience, people, many other issues that color sound.. such as carpet and tile, ceilings wood floors, concrete floors.. hi humidity, low humidity, dirty strings, crackly cables,these color sound more than most amps,..,. ect,,ect,,

[mikeddd]

In my practice room at home (my office, small room, lots of crap in there, carpet on floor) the difference is very clear to me. The Shuttle thru the outboard (QSC PLX) poweramp sounds a bit sterile and cold as compared to the Shuttle's internal amp. At the small gigs I've played (outdoor pool parties/small bars) I hear the difference as well, but the diff is not as great due to the other instruments in the mix.

The measurement instruments I use are some of the best known to man; the ears I was born with.

[tombowlus]

Originally Posted by svtb15

The question is.. are you measuring it with you ears or with calibrated test equipment? Sound coloring on any power amp...... do class D sound different in general from tranny /caps.. I think they do ... but the coloring thing.. ughhhhh

Two different issues, really. There's the whole class-D/SMPS versus "conventional amps" thing (which is another debate, for sure), and then there is the Genz-Benz limiter/tube emulation thing (which is a "coloration" of sorts).

I often ask myself..... are these people gigging in a sterile Lab anechoic chamber or a real gigging environment with an audience, people, many other issues that color sound.. such as carpet and tile, ceilings wood floors, concrete floors.. hi humidity, low humidity, dirty strings, crackly cables,these color sound more than most amps,..,. ect,,ect,,

Not to mention the AC supply available in a gigging environment...

Tom.

[agedhorse]

Originally Posted by tombowlus

I believe that the "limiter/tube emulation" that Genz-Benz uses is non-defeatable in the Shuttle series, and I believe it comes between the preamp and power section. This limiter/emulation does add some coloration, which you would likely perceive as some added warmth and more harmonic content. It also seems to increase the total output of the power section a bit.

I'm sure Andy or Roger can give you a more detailed/accurate/concise answer, but that's been my understanding of what's going on in the Shuttle heads.

Tom.

Yes, this is most likely what Mike is hearing. The output tube emulation circuit is part of the power amp and is always part of the signal path, it's present even after the power amp in (effects return) point.

This is something that helps not only with the sound but also the feel and playability of the Shuttle series.

[agedhorse]

Originally Posted by mikeddd

Thank you, Tom. I seem to remember reading that somewhere as well. On a side note, IMO the output on the Effects Out is weak, despite being told that the pre-out has "plenty of voltage." In my experience, it doesn't. With the gain wide open on the poweramp (which has more than 2x the wattage of the Shuttle) my volume isn't close to what it is thru the Shuttle. But that's another thread.

Thanks again.

I would expect there to be sensitivity differences... if you are going unbalanced into the PLX, the sensitivity of the PLX will generally appear lower due to the influence that the balanced input normally has on the rated sensitivity when using a balanced source. Most pro audio power amps are rated using a balanced source through the balanced input which contributes another 6dB to the overall appearant power amp gain. Not knowing which version of the PLX you have, I am not positive that this is the case but I am reasonably sure.

Internally, the shuttle's power amp is driven by a differential balanced source which would measure 6dB higher, but this point is not accessable to the user. I would expect that the channel volume would need to be set about 6dB higher (can't say how many clicks on the volume control because it's not a linear function) for use with a typical external amp compared with the internal amp for this reason.

Another point... often the larger the power amp, the lower the sensitivity if it's of the fixed gain (across the series)design. Some manufacturers choose gain based on clip point sensitivity so the gain will vary with amp model and all amps will clip at say +6dBu.

Bob Lee may want to add something to this (sfterall, the PLX is his product) because I suspect that this very issue may influence some of the differences users may hear when comparing power amps from different manufacturers.

Hope this helps.

[mikeddd]

Hi Agedhorse; thanks for the detailed reply. I'm using a PLX3602; not exactly a weakling of an amp. Though obviously, I am going in unbalanced. The preout of 6.0 doesn't have enough juice to properly drive the PLX. I'm thinking of getting a preamp/DI to boost/convert the signal to balanced, but then that's getting into overcomplication and I may as well rethink my whole rig. Would a passive DI (a good one, like a Radial) provide the proper signal level? I dunno...it's a conundrum for sure.

I love the tone out of the 6.0 but want more oomph. I have been thinking about the 9.0...GB have a trade-up program? Hey I lose nothing by asking, right?

[agedhorse]

Originally Posted by mikeddd

Hi Agedhorse; thanks for the detailed reply. I'm using a PLX3602; not exactly a weakling of an amp. Though obviously, I am going in unbalanced. The preout of 6.0 doesn't have enough juice to properly drive the PLX.

Let's not jump to this conclusion yet. The power amp has a balanced input sensitivity of 1.25V RMS for rated output. The Shuttls will have no problem achieving this drive level. Where do you have your channel volume set? How about eq? What bass and pickup system are you using? It's possible that some very low level pickups may not drive the preamp to rated output but 98% should do just fine. Another option is to use the direct out set to line level, this is a balanced signal.

Originally Posted by mikeddd

I'm thinking of getting a preamp/DI to boost/convert the signal to balanced, but then that's getting into overcomplication and I may as well rethink my whole rig.

Let's look at the problem first then look at solutions.

Originally Posted by mikeddd

Would a passive DI (a good one, like a Radial) provide the proper signal level? I dunno...it's a conundrum for sure.

Most likely even worse as a passive DI steps the signal level down as part of the impedance transform.

Originally Posted by mikeddd

I love the tone out of the 6.0 but want more oomph. I have been thinking about the 9.0...GB have a trade-up program? Hey I lose nothing by asking, right?

The 9.0 would certainly be a much simpler and cheaper solution than a PLX-3602. I'm sure there are some folks here on the forum who might be interested in your 6.0

[mikeddd]

Channel volume? On the outboard amp? Dimed. My EQ on the Shuttle is flat, save for a very slight dip in the mids (freq set at about 11 o'clock, same for cut). I've been using my SXs which have pretty hot pups for passives and a Spector Legend which has a preamp in it.

Thanks for the heads-up on the outboard DI; you saved me from wasting money. I have tried the DI from the Shuttle to the outboard amp but don't remember if I set it to Mic or Line. Thanks for the advice.

Mike