Best amp for stage piano?

[MBAnderson]

Hi all!
I've been playing jazz piano for 12 years and just bought a new stage piano, and now I need an amp for it. I'd like to build my own partly as a personal project and as an experience to learn from, but partly because I want a quality, tweakable amp for less than the standard commercial price.
This would be my first time building an amp, so I'm not looking for something hard. But it does need to be able to produce good sound across the full piano range. I'd like to have EQ controls built in, and minimum 2 line ins. So the first question arises: is this reasonably possible? I do have a knack for building and designing things, so I'm not overly worried about delving into a new field. Other questions I have are:
Parts - what drivers etc. are appropriate, how much do they cost? (I'm trying to keep my total cost at around or below $400 CDN)
Which BF design is best? I'm looking currently at the Jack 110 or maybe the OmniTop 15 - what's the main difference and which is better? If you have other suggestions let me know.
How much time do you think it would take to order parts? I live on Vancouver Island in British Columbia, so there's not a lot of places I can readily get them except by ordering.
How much time do you think it would take to build? I've got decent woodworking skills and electronics experience, if it makes any difference.
Mainly, I'm just looking for advice on what's the best option for a portable amp (I'll probably put wheels on it, but I don't want it to weigh more than 50 lbs) and what tips you have for building the thing. Feel free to ask any questions if my response might help!

Thanks a lot!
-Matthew

[Tom Smit]

Howdy, and welcome to the forum!

This chart shows a Jack12 compared to a Jack10 and an Omni12, to give you some food for thought.

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[spl dbmin=80&dbmax=110]J210F12,DR250,O12[/spl]

This chart represents the O12 with a Delta12LF. If I'm not mistaken, with the 3012LF or dual BP102s, the O12 is about 6dbs hotter in the low end. If so, that would put it about neck and neck with the Jack 2x10 from 70-100hz, but the O12 would kick Jack's ass from 40-70hz. In either configuration, the driver(s) would have greater Vd than the Jack's drivers, so max possible output wins, too.

If the Jack 2x10 is about the same size and weight as two Jack 1x10s (size not given on the sales page), then the O12 is less than a half a cubic foot larger than the Jack 2x10, and weighs about the same.

The obvious advantage to the Jack design (compared to an O12) is that two Jack 1x10s would give you small, lightweight cabs, with the ability to use either one or both cabs. For a bass player deciding between an O12 and a pair of Jacks (no poker pun intended) , another advantage is that a pair of Jacks can also be used for a small PA, with or without subs.

I don't think it's been brought-up yet, but the Jack design is absolutely brilliant in the fact that it's sensitivity and frequency range rivals that of a lot of 1x15/horn commercial cabs. Granted, a 2510 doesn't have the Vd of most 15s, but Bill's managed to coax a little 10" driver into producing amazing bass, while also providing very good overall freq response, in a cabinet that's a fraction of the size and weight of it's "competition". Bill, you really out-did yourself with this one!

[SirNickity]

By "build an amp" -- do you mean, build a combo amp by including a power amp into your enclosure? Or, actually "build an amp" from raw parts and a schematic?

If you mean the latter, it's not trivial. But if you're really interested, you gotta start somewhere, so don't let that stop you. However, you may have better luck on diyaudio than here. This forum's focus is definitely more on the cabinets.

[MBAnderson]

Thanks to the both of you - SirNickity, I do mean the latter (sorry I should've specified!). I'll be sure to check out diyaudio too!
EDIT: However, I'm still considering just building a cabinet, so any info is great

[BrentEvans]

Good to see a fellow keyboardist here. We seem to be few and far between in these parts...

What's your weapon? I play a Roland RD-700NX...

Take a look at the Wedgehorn 10. It will give you all you need. I'd pair it with a smallish powered mixer to get your tone controls, maybe something like the Soundcraft Gigrac 600 ($289 at Full Compass right now). That would actually be able to drive two of them (I much prefer stereo monitors ) It could also serve as a small PA amp in a pinch... and if you're playing out, you can get a line level mix from the console and add a little "More me."

[MBAnderson]

Wow - BrentEvans, I play an RD700GX. Great minds think alike?
I'll take a look at what you're suggesting there, thanks!

[SirNickity]

That'll definitely be the more economical way to go. If you just can't resist the urge to roll your own, though... post back. I'm working on a self-powered PA design based on the SLA Pro cab. (Wedgehorns would work, too.)

Not sure exactly how far I want to take it, but I had some ideas floating around, like:

- Balanced front-end with DC blocking, over-voltage protection, level control ... the essentials, basically
- 100Hz 24-dB/oct. highpass so I can run them w/o pre-processing if I want (may need a little corrective EQ though)
- 3.5kHz 12-dB/oct. lowpass, 18-dB/oct. highpass (subject to modification based on how the filters align with the acoustic roll-off of the drivers)
- Microprocessor-controlled turn-on delay, output DC latching, signal / clip detect, thermally-controlled fan, and over-temp protection
- LM3886 (~50W) to each woofer, another for the piezo array (so, five total)

It's ambitious, but I've done most of these things individually, so I think I can pull it off. One way to find out!

[MBAnderson]

Just a question - if I were to connect the keyboard to the powered mixer to the cab, would there be a need for an amplifier? Also, what specifically defines a "powered mixer"? Obviously all mixers have to have some sort of power supply, so what makes the difference?

It's always great to learn new things, even though it sometimes takes awhile to understand.

[Bruce Weldy]

Just a question - if I were to connect the keyboard to the powered mixer to the cab, would there be a need for an amplifier? Also, what specifically defines a "powered mixer"? Obviously all mixers have to have some sort of power supply, so what makes the difference?

It's always great to learn new things, even though it sometimes takes awhile to understand.

Powered mixer means it has an amp internal. You connect the speakers directly to it.