Slah pro amp help please

Is this amp OK?
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Rob Shasta Guitar
Posts: 46
Joined: Wed Apr 20, 2016 4:34 pm

Slah pro amp help please

#1 Post by Rob Shasta Guitar »

Hello all,
Just ordered the parts for some sla pros with the 5" drivers, and a single tuba sub, 16" wide.

I'm a guitar builder/musician and am looking to show off the great sound of my acoustic sounding electric guitar. I need a clear mid range for vocals and guitars to share, and stuff needs to fit in a subaru forrester.

Leland has been a big help with stuff, now I'll give him a break from my zillion questions and ask here.

So QSC cx 404 is a 4 channel amp, 250 each channel and weighs 21 lbs. Seems a good choice and I seem them on ebay around $3-400. This would be a nice diverse way to have stereo (a must for me) and power a sub and maybe a monitor, stays in budget too.

I kinda jumped on one on ebay that is a toa amp, same thing 4 x 250 but it is a high impedance 70v thing. It was $60 (1200 new) and I did not realize that it was not a standard ohmed amp. Wondering if I can use it for something. Can I drive a 16ohm monitor with the 19.6 ohm amp?

What is the minimum power that I need to drive these 3 speakers I'm making?

Sorry for the woodworker questions, I've been trying to learn from here and other sources, but really I want to build stuff with wood and then play guitar, so I'll thank ya'll for the help and keep singing songs.

Thanks,
Rob
Sla Pro 5" drivers, t39 10" driver

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escapemcp
Posts: 1219
Joined: Thu Feb 07, 2013 8:57 pm
Location: Bristol, UK

Re: Slah pro amp help please

#2 Post by escapemcp »

4 options as far as I can tell. Either:

1) Get a step down transformer for each speaker (this is the correct way to wire these amps up) - expensive and frequency response will suffer (so I guess that's out for your purposes)
2) Somehow modify the amp - probably best left to an EE
3) Double check that the amp doesn't have any low impedance outputs, just in case
4) Sorry to say it, but sell the amp and buy a low impedance one

Those public address 70V (& 100V) amps are not really designed for high fidelity sound, but rather to make announcements and play elevator music in shops. I'd resell it and get something else if I were you. Best of luck with whatever you decide. Keep us informed so that we can help out with the build.
Last edited by escapemcp on Thu Apr 21, 2016 6:45 am, edited 1 time in total.

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Slah pro amp help please

#3 Post by Grant Bunter »

G'day and welcome to the forum :)

Some of those TOA amps also have 4 and/or 8 ohm speaker outs as well.
Post up the model number, or search online for a user manual.

As far as what you need in terms of power;
Tell us exactly which tuba sub you ordered plans for, and which driver you intend to use in it.
Also, monitor: brand and model
Same for the drivers you propose putting into the SLA's...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Rob Shasta Guitar
Posts: 46
Joined: Wed Apr 20, 2016 4:34 pm

Re: Slah pro amp help please

#4 Post by Rob Shasta Guitar »

Sla drivers:
Pro 5w-8
http://www.eminence.com/pdf/Pro_5W_8.pdf

Tuba:
BP 102
http://www.eminence.com/pdf/Legend_BP102.pdf

High impedance amp:
Toa DA-250FH CU
http://www.toaelectronics.com/media/da250f-cu_mt1e.pdf

Amp I think I'd like to use:
QSC CX 404
http://www.qsc.com/resource-files/produ ... _specs.pdf

Monitor I'd like to build, though this is down the line, is the W10, I saw in the plans that there is a 16 ohm option, I'm open on drivers with that since it will be in a while. But I'm also not willing to build a system around a $60 ebay mistake. My current rig is one Ev zlx 12p. Decent inexpensive powered wedge, so for now that will become my monitor, I like a lot of volume for me so I don't overplay.

The toa is from ebay, so I'm gonna see it in a couple of days and see what it actually is when it is in my hands, but from what I'm seeing and reading, this is high impedance only. I did work at an out door ice skating rink that has crazy long speaker wire runs and burns stuff out regularly, I think the high impedance amp may be able to find a good home.

Thanks a ton for the help and the welcome.
Sla Pro 5" drivers, t39 10" driver

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Slah pro amp help please

#5 Post by Bruce Weldy »

This would be a much better option if you just have to have a 4 channel amp.

http://www.carvinaudio.com/collections/ ... -power-amp

The QSC is absolutely the wrong amp for your application.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Rob Shasta Guitar
Posts: 46
Joined: Wed Apr 20, 2016 4:34 pm

Re: Slah pro amp help please

#6 Post by Rob Shasta Guitar »

Bruce Weldy wrote:This would be a much better option if you just have to have a 4 channel amp.
The 4 channel option is compact and light for a small diverse system, but I'm open to 2 small 2 channel amps. I am coming from the perspective that there are other sound systems in town that are good for bigger outdoor or loud rock, so light and compact is key. Perhaps some day I'll put together a larger rack.

The mixer I'll be using is an Allen and Heath PA 12.
http://www.allen-heath.com/ahproducts/pa12/

That carvin would be fine for me, nice and light. Within budget too.
Sla Pro 5" drivers, t39 10" driver

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Slah pro amp help please

#7 Post by Bruce Weldy »

Rob Shasta Guitar wrote:
Bruce Weldy wrote:This would be a much better option if you just have to have a 4 channel amp.
The 4 channel option is compact and light for a small diverse system, but I'm open to 2 small 2 channel amps. I am coming from the perspective that there are other sound systems in town that are good for bigger outdoor or loud rock, so light and compact is key. Perhaps some day I'll put together a larger rack.

The mixer I'll be using is an Allen and Heath PA 12.
http://www.allen-heath.com/ahproducts/pa12/

That carvin would be fine for me, nice and light. Within budget too.
You haven't mentioned a crossover - what are you using for that?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Rob Shasta Guitar
Posts: 46
Joined: Wed Apr 20, 2016 4:34 pm

Re: Slah pro amp help please

#8 Post by Rob Shasta Guitar »

For a crossover I was thinking of getting a dbx driverack. Open to suggestions for this as well. We have several terrible rooms in this town that are venues, so the drive rack may help me tame those a bit.

As a solo guitar player singer, I think I may want to cross over a little higher then the standard 100hz, I play an alternating bass style, (Mississippi John Hurt), so I want both bass notes to thump in the sub. However I wonder if I will want much if any vocal in the sub, I have a deep voice and can sing down to 80hz or the bottom note on a guitar. I do tune down to drop D and open D for several songs. The driverack idea at least lets me play with these parameters a bit.

I have a dbx rack 2 channel compressor that I like for the guitar, I've used channel two for a mic on recording. Not sure how this will fit into the new system, likely it will just stay as a guitar effect. This does get me to a 6u rack, 2 for amp, power cond., processor, compressor, leaves me one unit open.

I think all said and done I can keep this project in the $2000 range which is the goal, I'm guessing by the time cables are purchased I'll be a little over.

To stay on budget, I have about $1100 left and still need an amp, processor (or crossover), power conditioner, cases and cables, one tripod stand. I will go a little over if needed. I'm trying to make something small and light that will not need upgrading for a long time and will be able to sound great enough to sell some guitars where ever I may go.

Phase two of this project would be more slah mains and a pair of subs, but I doubt I'll need that. I am hoping that some of the venues will love this sound enough to get me to build them speakers, cause we all need better sound in our towns.
Sla Pro 5" drivers, t39 10" driver

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Slah pro amp help please

#9 Post by Bruce Weldy »

Rob Shasta Guitar wrote:For a crossover I was thinking of getting a dbx driverack. Open to suggestions for this as well. We have several terrible rooms in this town that are venues, so the drive rack may help me tame those a bit.

.
Good choice. You can pick up a used one pretty cheap. Any of them will do what you need - PA, PA+, PX

And get a reference mic also. Then, you can RTA every place you play and save it in the driverack for next time.
As a solo guitar player singer, I think I may want to cross over a little higher then the standard 100hz, I play an alternating bass style, (Mississippi John Hurt), so I want both bass notes to thump in the sub. However I wonder if I will want much if any vocal in the sub, I have a deep voice and can sing down to 80hz or the bottom note on a guitar. I do tune down to drop D and open D for several songs. The driverack idea at least lets me play with these parameters a bit.
Cross it over and see how it sounds. The guitar will get what it needs and there is nothing wrong with the vocal in the sub. I also sing low, and the sub just enhances the bottom - gives it some width.

However, I question your choice of a Tuba24. Based on what you are doing, a slim T39 gives better output and is perfect for the frequency range that you'll be playing in. While it's dimensions are taller, it's not as deep as a Tuba. It could be built as narrow as 13 inches utilizing a 10 inch driver. And it would be easier to either carry with one hand or you could put wheels on it. The Tuba is too short to tilt back and roll....and it's too bulky to carry.
I have a dbx rack 2 channel compressor that I like for the guitar, I've used channel two for a mic on recording. Not sure how this will fit into the new system, likely it will just stay as a guitar effect. This does get me to a 6u rack, 2 for amp, power cond., processor, compressor, leaves me one unit open.
You can certainly use the compressor as an insert on your guitar and mic channels on the board. Although, don't know if you will really need it on vocals - depends on how good your mic technique is.
I think all said and done I can keep this project in the $2000 range which is the goal, I'm guessing by the time cables are purchased I'll be a little over.

To stay on budget, I have about $1100 left and still need an amp, processor (or crossover), power conditioner, cases and cables, one tripod stand. I will go a little over if needed. I'm trying to make something small and light that will not need upgrading for a long time and will be able to sound great enough to sell some guitars where ever I may go.
Power conditioner isn't absolutely necessary if it breaks the budget.....they are really just a fancy power strip unless you plan to spend several hundred dollars.
Phase two of this project would be more slah mains and a pair of subs, but I doubt I'll need that. I am hoping that some of the venues will love this sound enough to get me to build them speakers, cause we all need better sound in our towns
Yep.....we all end up building more.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Slah pro amp help please

#10 Post by Grant Bunter »

Bruce Weldy wrote: However, I question your choice of a Tuba24. Based on what you are doing, a slim T39 gives better output and is perfect for the frequency range that you'll be playing in. While it's dimensions are taller, it's not as deep as a Tuba. It could be built as narrow as 13 inches utilizing a 10 inch driver. And it would be easier to either carry with one hand or you could put wheels on it. The Tuba is too short to tilt back and roll....and it's too bulky to carry.
Bruce's suggestion is certainly worth more than casual consideration.
The Titan series have higher output than the Tuba's, as a generalisation, the tuba's play lower.
If you get the T39 plans as well though, you will notice under the "Protecting your drivers" section that the High Pass setting is exactly the same for both the T24 and the T39, and both can use the BP102 driver.

I'm guessing, but I reckon you're thinking you don't need a lot of sub output power. IMO BP 102 loaded subs fit your PA reasoning quite well, simply because you can only give them a maximum of 35V to reach max output.
That figure means lower output requirements in terms of power amp, ie less $.
You will be surprised at the output capability of the SLA pro's. So a T39 is more likely to keep up with them than a T24. If you have the pack space of course.

Also, don't get to hung up on the bass notes to much.
It might surprise you that most commercial bass cabs aren't capable of reproducing fundamental low E on a 4 string bass. It's more likely you're hearing 2nd, 3rd and higher order harmonics.
As far as having bass notes thumping in the subs, that's basically about volume, which is certainly something to consider in small venues as a solo act...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Rob Shasta Guitar
Posts: 46
Joined: Wed Apr 20, 2016 4:34 pm

Re: Slah pro amp help please

#11 Post by Rob Shasta Guitar »

Thanks, yeah the T 39 idea does seem to have lots of merit. It will still fit in the subaru, and I need support in the 70-120hz range which the t39 seems to accel in. Perhaps the better choice for having only one sub.

Seems I'm pretty close to being on my way, Carvin 4 channel amp, dbx drive rack. Drivers will be here early next week and then off to the shop to build some slah pros, then the sub.

I've been a woodworker as a profession and do have lots of tools, so I do expect to be making more speakers. The w10's look like a cool little speaker that will just be fun to make.
Sla Pro 5" drivers, t39 10" driver

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Slah pro amp help please

#12 Post by Bruce Weldy »

Rob Shasta Guitar wrote: The w10's look like a cool little speaker that will just be fun to make.
The W10 is not little. It's actually pretty big. If you are only doing guitar and vocal, the W6 or W8 is plenty.....especially if you wall-load the sub.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Slah pro amp help please

#13 Post by Grant Bunter »

Rob Shasta Guitar wrote:Thanks, yeah the T 39 idea does seem to have lots of merit. It will still fit in the subaru, and I need support in the 70-120hz range which the t39 seems to accel in. Perhaps the better choice for having only one sub.

Build it as wide as you can and still make it fit in the Subby, do a cardboard mockup is a handy way to work that out.

Seems I'm pretty close to being on my way, Carvin 4 channel amp, dbx drive rack. Drivers will be here early next week and then off to the shop to build some slah pros, then the sub.

I've been a woodworker as a profession and do have lots of tools, so I do expect to be making more speakers.

If you do, please respect Bill's IP. The buyer of such cabs will need to buy plans.
And you should consider becoming an authorised builder if you're going to go that way;
From here http://www.billfitzmaurice.com/Builders.html
If you'd like to obtain an authorized builder franchise please email billfitzmaurice@myfairpoint.net


The w10's look like a cool little speaker that will just be fun to make.

In comparison to the WH6 and WH8, the WH10 is a monster, nearly 22" deep at it's widest point, and 20" wide and 19" high. Given you should be able to hear any bass in the subs, it may pay to think about a WH8 as far as pack space goes...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Rob Shasta Guitar
Posts: 46
Joined: Wed Apr 20, 2016 4:34 pm

Re: Slah pro amp help please

#14 Post by Rob Shasta Guitar »

Another amp option: Behringer iNUKE NU4-6000 Also 4 channels, bout the same weight, a bit more advertised wattage. Behringer has such an ominous reputation of mediocrity though. It is about $100 less than the carvin.
http://www.parts-express.com/pedocs/buy ... -guide.pdf

A plans worth of royalties per speaker seems quite reasonable for Bill. I can't really foresee selling speakers until I have actually made some, though the sla pros should be easy. I would love to sell a guitar with a matching set of speakers.

The w10 is enticing because as far as I can see it is really the Jack of the speaker offerings. It can kinda do anything anywhere. I envision being able use it like a sub/monitor in a small setting. Since those frequencies are not directional, I can put the sub frequencies there if the sub does not fit in a venue. I also want all that bass in my face too. Seems like it can support the bass frequencies since I'll only have one sub for a while.

I'm going to order up the Carvin amp today, unless some one has some great words for the Behringer. Likely start cutting slah parts on Saturday, Monday the mixer arrives, Tuesday the speaker parts. So I'll be ready for an amp pretty soon.
Thanks for the help.
Sla Pro 5" drivers, t39 10" driver

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Slah pro amp help please

#15 Post by Bruce Weldy »

Rob Shasta Guitar wrote: I envision being able use it like a sub/monitor in a small setting. Since those frequencies are not directional, I can put the sub frequencies there if the sub does not fit in a venue. I also want all that bass in my face too. Seems like it can support the bass frequencies since I'll only have one sub for a while.
.
As you said, the low frequencies aren't directional - so there won't be any bass in your face. What you are perceiving as bass most of the time is harmonics from front loaded speakers. With the sub up against the wall behind you - you'll have plenty of bass in your face.....or your booty.

Nothing wrong with the WH10 as a monitor, but it's big and you really won't be utilizing a lot of what it offers in your setting. It is not a substitute for a sub and putting sub frequencies is not a good idea. I wouldn't run a WH10 below about 60-70hz....

Every tool has a job...don't try to force it to do something it isn't designed for.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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