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Using powered PA speakers

Started by vortmaxx, July 19, 2012, 12:34:44 PM

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vortmaxx

Hello, All.

After pining over these threads here for too long, I finally pulled the trigger on a 1980 54 MkII. I played my first gig with her the other night using a QSC K12 and it sounded alright. I know many believe that the twin is really the best way to compliment the Rhodes, or just about any tube amp with 2 12s, but I already have the QSC and am really close to picking up a second as I have found a good deal on a lightly used one and would also be using these for my Nord. The problem, as you might have guessed, is the lack of control over the tone- I pretty much get what the Rhodes/QSC gives me, so I am really on the fence here. I have seen quite a few used Twins and Twin Reissues for around the same price as the second QSC I am considering, but it would be really nice not to have to bring out 3 amps/speakers, plus, there generally isn't that much room to set up anyways. I am not that smart when it comes to such things, and am mainly wondering if preamps and powered PA speakers are a bad combo. If anyone out there has any experience using preamps with powered PA speakers, could you recommend any that would give me the same features as a Twin or similar (mainly EQ and vibrato/tremolo), or do I just bite the bullet, go for the Twin, and scrap the idea of running everything through 2 PAs. Thanks in advance for any suggestions.

Matt

OZDOC

What you need is an AVID Eleven Rack - your Rhodes can then be whatever it wants to be.

http://www.avid.com/US/avid-tv/ElevenRackOverview

The Eleven Rack has user selectable input impedance and models many amps including the Twin.
It provides a complete user editable effects string as well - so you can have a pre-set patch for every song you play if you want.
Then all you need is a clean amplification source such as your PA speakers.

A side benefit is that you can get the right sound at low volume levels when necessary.

And it weighs a lot less than a Twin.
Co-author, "Classic Keys: Keyboard Sounds That Launched Rock Music"

Learn about the book: http://www.classickeysbook.com/
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Black Pearl

There are loads of amp simulators you could use between your rhodes and QSC (I have a K10 which is awesome). Check out some of the pedal varieties like this from tech21
http://www.tech21nyc.com/products/sansamp/characterseries.html

For even less $$ check out some of the clone pedals by Berhinger or Joyo available online for as little as $40.

Most come without vibrato or reverb but you can add whatever flavour you like to the chain.

vortmaxx

Thank you both for your suggestions. I think I found this somewhere around here in another thread and was thinking along the lines of something like it: http://www.tasteundtechnik.de/135501.html
Either my German or Dutch is not quite strong enough to figure out how to try one out, or I am not looking in the right places.

The Eleven Rack looks over-the-top amazing, if not well above my price range at this point (though probably in the same league as the TRamp). The Sansamp Blonde looks very interesting, and is a little more in line with my budget. It also looks like they have a fairly standard return policy, so I may just have to check that out. Thanks again.

Cormac Long

#4
I'm using my stage at home through a mixer and set of monitors. The mixers EQ is ok but a lttle noisier than I'd tolerate. So I took a chance on an MXR M80 Bass DI.

http://www.jimdunlop.com/product/m80-bass-di

..the reviews said that it was a very quiet pre-amp and they were right.. no noise from this. It was also within my budget at the time.

My Rhodes is wired straight from the harp to the box and the bass, mid and treble EQ does a great job of giving me the tone I want. I even power mine from my mixer using the supported phantom power.

That said, I think in hind sight, I should have gone with the Vintage Vibe rail pre-amp which is based on the original circuit. So its a more authentic match to the original pre-amp and tremolo.

http://www.vintagevibe.com/p-725-stereo-vibe-stereo-tremolo.aspx

I don't know if the 54 stage rail is pre-drilled for the same number of holes.. but if it is, fitting this is very straight forward.
Regards,
   Cormac

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vortmaxx

I have considered going with a DI as I have heard others say it can be a good way to go with keys in general and especially when playing out. The Dunlop looks interesting to me, I imagine it would work well with a Rhodes going into it- the ad alone is worth enough to at least take one for a test drive 8) . Still, I'd be interested to hear what it might do to my piano, though when I start getting into that price range I am getting pretty close to a VV stereo preamp, which has also been on my radar for quite awhile. I don't think I've heard anyone say they got one, installed it, didn't like it, and took it back out. I'd be curious to know what kind of mixer you were using. I have considered going that route as well, but most of the smaller stuff like the Mackie, Yamaha, Behringer 2-4 channel mixers don't really give you much in the way of eq, and I don't really need a 6-8 channel mixer. Not yet anyways. 

OZDOC

I think there may be some confusion building up here.
Wasn't the original question how to get tube amp character from your clean full range QSC K12?

A DI box is generally intended for converting unbalanced signals to balanced signals for longer cable runs on stage to protect against noise being pricked up by the lead. It also can serve as a ground lift to avoid ground loop hum.

A Rhodes after-market pre-amp is generally for improved EQ control and added effects like tremolo.

Feeding the Rhodes passive pickups to a full range PA speaker has the following issues:
Impedance matching (and resultant change to frequency balance).
Flat extended response of the PA speaker compared to the frequency response of a guitar amp.
Absence of valve amplifier distortion and speaker cone distortion.

So the ideal interface between your Rhodes and the K12 provides a high impedance input, models the EQ profile of a guitar amplifier, models the overdrive distortion of a guitar amplifier and can be varied over a sufficiently wide range to cater to the differences between keyboard playing and guitar. This is quite apart from whether you change the pre-amp in the Rhodes or add any effects.
Co-author, "Classic Keys: Keyboard Sounds That Launched Rock Music"

Learn about the book: http://www.classickeysbook.com/
Follow us on Facebook: www.facebook.com/ClassicKeysBook/

vortmaxx

Maybe my original intentions were not clear. I am primarily looking for more control over the EQ across the spectrum of the piano, while utilizing the QSC(s), which do not really have any EQ capability. Currently, when I use the input on the QSC set to mic and I am using the built in pre on the amp, I get a noticeably fatter and warmer sound, but it is still somewhat muddy overall, and the highs get buried by the mids and low end of the piano. This might also be a voicing issue, as I have found that adjusting the pickup distance in the top octave helps to some extent, and tells me that I probably want to boost the signal first before trying to shape it, either with EQ or effects.

I'm pretty sure that I do not want to attain distortion at the speaker as it is probably not designed to be pushed like that. I am generally more interested in obtaining a "cleaner" tone, with some occasional vibrato/tremolo. At most, I think an open wah pedal would give me enough "crunch" but again, I am uncertain of how this would interact with the speaker. Is this where impedance becomes a factor? The flat frequency response of the QSC seems to work quite well with DSP, and so far is not even that hateful for the Rhodes, and I really think that having the ability to just roll off some of the bass, keep the mids and boost the high end will alleviate some, if not a lot of the muddiness.

I guess I get confused about frequency response. When I search, I find a lot of different curve charts for various speakers, including this: http://demonstrations.wolfram.com/FenderToneCircuit/, which is probably closest to what I am after. It seems that a lot of frequency response can be based on how the signal is EQ'd, but I guess I don't really understand the relationship between impedance matching and frequency balance. The specs for the QSC impedance using the mic pre is 2260 (no units) and is apparently supposed to be balanced. I am not using balanced cables. Would this be part of the solution?

I have some doubts about whether it would be good for the speaker to run a preamp like the VV stereo into it. From the demo video, I can't quite figure out what if any speaker amplification they are using, or if they are just going straight into a board. I suppose I would want to employ a small mixer between the preamp and the QSC. I have also been considering trying a Tine-Bomb in tandem with a small mixer that has a good 3-band EQ, which would also give me control over gain staging and would probably also give me the ability to attain some overdrive at the mixer as opposed to the speaker.

Will it sound like a Twin? Probably not. But, will it sound better, cleaner, punchier and a little more dynamic than it currently does, without having to bring a separate combo out just for the Rhodes?

Cormac Long

A pre-amp with EQ is what you need then. Once you get this in the mix, you need to set the K12 input selector to Line from mic so that it can take the line signal.

The K12 will get set to some max volume level and the pre-amp used to control performance volume.

I would be suggesting something like the VV rail-mounted amp or an external pre-amp or stomp box. As mentioned earlier, I use an MXR M80 which is marketed as a DI, but its very much a preamp and its bass/mid/treble are perfect for the Rhodes frequency range. But there's a lot of cheap cack out there that will not work well. So watch out for noise levels in any reviews you read. The reviews of the M80 were very positive over it being very quiet... thats what got me interesting in trying it out.

A small mixer could also service this function of taking the passive Rhodes signal (through a mic input), adding some gain and EQ. However cheap mixers can be noisy. So if you think about this direction, try borrowing one first.

I had a cheap Alesis mixer and it broke my heart with the hiss it created. But others have noted that some of the cheap Behringer mixers can be made to work fine. The trick with a mixer is to add gain until the loudest playing hits the peak indicators on the mixers.. then pull back gain a little until the peaking stops.. you are now putting in as much signal as possible which will help drown out more of the noise. Then the performance level is controlled by the track level knob/slider or the master mixer out if no other devices are sharing the mixer. As it happens, a mixer is what is generally used with such powered speakers.

The Tramp has also had a lot of praise. Another rail-mount pre-amp is the El Potator used by forum member MrJeanPapa (http://www.youtube.com/watch?v=_Iy1CCOAllI). This one is battery powered and has good EQ control but no tremolo.

One last point.. if you end up using a mixer or external pre-amp, try routing from the harp direct to the pre-amp/mixer, skipping the rail pots. Its often the case that the old stage pots and capacitor tend to dampen the sound too much. The pre-amp EQ can ease off the bass if its muddy.
Regards,
   Cormac

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vortmaxx

Thank you again for taking the time to educate me. I have come across El Potator before- probably around this forum. I have to say that the demo sounds really good to my ears. I would love to check one of those out sometime but, like the TRamp, they seem to be a little hard to come by.

I decided to start with a smallish Samson mixer for the moment: http://www.sweetwater.com/store/detail/MDR624/
I have been trying to avoid going the mixer route, but it is starting to seem more and more inevitable since I am generally going to be running at least the Rhodes along with a Nord into both speakers, and the QSC's gain is not really all that smooth- sort of goes from 0 to about 3-4 before jumping to around 9 or 10. It makes sense to me now to start with the mixer, since it will be the last link before the speakers, and if I can't keep the noise floor down there, the rest would seem to be moot.

The vibe I've gotten on small mixers in general is that the pre's are generally cr@p, but the Samson stuff doesn't seem to get the knee-jerk reaction that is sometimes associated with the other models in this $ range. I like that I can have separate control over the bass, mid and highs for each channel, plus I will still have room to run another board in stereo (just in case someone ever decides to buy me a Moog).

I have heard more than enough people recommend going direct off the harp, and I have already committed to trying this as I can already see that the "volume" and "tone" sliders on the rail are basically worthless. I haven't quite sorted out all of the issues with the duff notes yet, and she could probably use a proper tuning, but I am hopefully going to be able to lay down a few tracks soon and am anxious to hear the difference.

Thanks again, all. I was starting to feel a little stupid for not just going out and picking up a Twin, or similar amp, but I really think the QSCs are great speakers and will ultimately be able to give me what I want.