Sub amp: Expensive, new & light or cheaper & heavier

[Charles Jenkinson]

I thought I'd better call it a day chipping in on DJH's thread. http://billfitzmaurice.info/forum/viewt ... =6&t=20323

But before I do, I phoned the Ashly UK distributor up. They can do a KLR2000 for 15% off list price (list = £660), then there's VAT to add (at 20%), ...which for reference as a total in dollars is $1043. It's a shame.

The VAT and import duty makes it not worth importing even a second hand IPR3000 and switching the voltage, IMO.

Ultimate purpose of the amp is to initially drive 2xlab12 T30's, with capability for 4 eventually, and with ideally a 2-ohm-capable safety margin.

The QSC GX5 isn't 2ohm capable, which for future (2 ohm safety margin) proofing is leading me towards Peavey IPR, but their generation 2 models (IPR2 3000 specifically) don't seem to be shipping widely yet - we wait to see what the prices & availability will be (but I can't wait too long!), where the Crown XLS 2500 is the sort of equivalent of the IPR 3000, but the Crown is more expensive in the UK (hovering around £500, or slightly more). I have however seen:

http://www.ebay.co.uk/itm/Citronic-PPX1 ... 1164000827

and a buy it now:

http://www.ebay.co.uk/itm/C-AUDIO-SR606 ... 1156706938

I'm not too bothered about weight - not moving these things every day. Besides, the cabs will weigh more than any amp, and I have a trolley for the former.

Any thoughts, anyone?

[MissileCrisis]

Imo you'll never want to run more than 4 subs of the gx5 which gives you 4 ohm per channel so that would be my first suggestion. I have a gx3 and it hasn't let me down, a friend runs the gx5 same thing. Now one thing to notice is the first amp you posted won't happily run 4 subs because it is 600 w at 4 ohms, not 8. You want 350 watts per lab 12/3012lf. I can't remember what you're running but you definitely want more power than you need and the first amp would be pushing it's limits. The second listing I haven't looked up. Ime the weight issue shouldn't be too big of an issue if you're younger but if you're serious about buy once cry once then go with the light amps. I eventually will upgrade to one.

[Michael Murphy]

http://www.blue-room.org.uk/index.php?showtopic=15563

This topic states the second amp is 390w@8 and 625@4 which is 55.8v and 50v respectfully. If its a reputable amp and the spec sheet is valid its ok. Id spring for and IPR though, yeah im biased I know.

http://www.ebay.co.uk/itm/Peavey-IPR-16 ... 2581ed0d91

or maybe the non DSP version, dont know what/if you plan to run DSP up top.
PS owners manual states max voltage swing 55v and well you've seen the test results from a couple of us.

[PulseMan]

Hey Charles

What about the bigger "synq" brother ? You already have the baby one ....

Don't know how their pricing is in the UK but weight wise and power wise
Used them extensively, best bang for buck amps I've ever had and my back agrees too.

PulseMan

[Charles Jenkinson]

Thanks guys!

I’m getting the idea about head room, so the amp is not struggling - the e-bay old iron listings I showed are therefore not really going to work, in one sense. The only way to tackle this then is to look at all the options on weight and technical parameters and price them up. I've got DSP in a DRPA+, just to cover that base. Also, to cover the suggestions made first; The IPR1600 is just about ok for one pair of subs, but doesn’t have the max power umph for full effect 4ohm operation from my chosen subs. The Synq Digit 2K2 is £498 from the UK distributor (– I think they’ve got their pricing wrong on this model (of the order of 50 to 100 £’s too expensive) with the 1K0 pitching in at £248, and the 3K6 at £588) – and again no 2 ohm safety margin. On this score, I’m a bit wary of the T30’s with lab12’s (a 6 ohm driver) – whilst the cab is ‘8 ohm’, impedance is normally stated as a ‘nominal’ value – ultimately running 4 cabs on an amp with only 4 ohm capability (i.e. no rating at 2 ohms, as a safety margin) is asking for trouble, at the limit.

I phoned Peavey UK yesterday afternoon. They don't know when the IPR2's are coming. Without any more market knowledge, the IPR seems to be the best technology and power for buck at the moment, UK-side, and particularly if the 2nd generation are available in UK at the same price as the first generation were, whilst available (£399) - they have 2 ohm capability too. I need something for early October, however I could possibly borrow something for October gig if IPR2 3000's haven't arrived here by then. If I can’t borrow, old iron is still an option, and then there’s also always something to hand should it be required – and if that’s the case, then old iron can be spec’d down to something that will handle just 1 pair of subs (where I am at just now!), rather than a 4-ohm 2-pairs setup (later, potentially).

The QSC GX5 (£330 in UK) is tempting, but the 4-ohm 700 watts rating is really the bleeding edge for this amp – there isn’t any comfort in running at 85% of that! (i.e. 600 watts per channel for 2xT30). The Crown XLS 2500 is about £490 in UK (XLS2000 price is similar). If I buy old-and-heavy as a stop gap, I would probably take a punt on something on e-bay and possibly permit a spec down for one pair of subs operation.

I nearly forgot the T.amp and Behringer offerings at Thomann – respectable power, price, weight and 2-ohm operation:

http://www.thomann.de/gb/the_tamp_tsa_2200.htm

http://www.thomann.de/gb/behringer_inuk ... dstufe.htm

[Grant Bunter]

Charles,
You seem to have taken what I said about the bleeding edge and amp capability very much to heart.
That in itself is a good thing, but what I didn't discuss is that you set your limiter with a sine wave, yet playing music doesn't seem to get up there voltage wise. Well, it does, but, unlike a sine wave that is there nonstop, music is dynamic, so it's not up there all the time like a sine wave.

50V (or whatever the current plans say about the limit for the lab 12's) is astoundingly loud.
I can only surmise how loud. My T39 BP102's are limited to 35V and I ran it as hot as I ever have a short while back, it was smashing it! But I still wasn't hitting the limiter (or clipping the amp), so obviously I wasn't up to 35V.
Do you think you'll get that loud?

Headroom is space above your "ceiling" for want of putting it any other way.
I've also said (and discussed) this before, but brick wall limiting to a set voltage eliminates headroom.
It's a hard concept to understand at times, because if you aren't running flat strap, then you do have headroom up to your voltage limit. But once you hit (in your case) 50V, there is no headroom. It's gone.

Whatever you get, for 2 x lab12 loaded T30's at 50V is 625W/4ohms. IMO, the closer you can get to that with an amp, the less you have to limit.

Speaking of Crown, the XLi series is somewhat lighter than old iron, no frills. The XLi2500 does 750/4 (so limit by around 5V) and goes for about 430 quid at Thomann.

If you don't think your going to be banging on the bleeding edge a lot, don't get caught up to much with 2 ohm capability if it means you're going to miss a good deal is what I guess I'm trying to say...

[88h88]

Last event I did was with a GX5 running 8ohm (2x T60s) going hard for 6 hours. Subs were limited at 40v and the amp didn't appear stressed at all, the fans were running as normal, signal light flashing in time with the kicks... I've yet to run it hard @4ohm but I intend to give it a whirl, the idea with running 4 speakers though is you have 4 cones working together meaning you don't need your amp to be running full whack all night. If you do need that then you need more speakers rather than anything else.

I do still intend to pick up a Synq 3K6 in the future though if only to save space in my rack which is only a widdly little 7U wheel along. The idea being I roll up with a ridculously light amount of kit and still outrun rigs pushing 10k worth of amps.

[Michael Murphy]

+1 On Grants post and "headroom". Im a nubie, I dont have the clout as a vet but I agree 100% with him and that and the setting limits using a sine wave and also the more headroom means more limiting and less average SPL.

+1 On 88h88 post. Bringing a total of about 25lbs of gear (1 PA+, 2 IPR 1600) to a gig and destroying 100's of pounds of amps @ 10000's of dollars is like the ad goes, priceless!

[PulseMan]

I do still intend to pick up a Synq 3K6 in the future though if only to save space in my rack which is only a widdly little 7U wheel along. The idea being I roll up with a ridculously light amount of kit and still outrun rigs pushing 10k worth of amps.

That's what I'm doing here with my synq rack of amps and it "pisses" off some of my sound opposition guys badly

PulseMan

[Charles Jenkinson]

Charles,
You seem to have taken what I said about the bleeding edge and amp capability very much to heart.
That in itself is a good thing, but what I didn't discuss is that you set your limiter with a sine wave, yet playing music doesn't seem to get up there voltage wise. Well, it does, but, unlike a sine wave that is there nonstop, music is dynamic, so it's not up there all the time like a sine wave.

50V (or whatever the current plans say about the limit for the lab 12's) is astoundingly loud.
I can only surmise how loud. My T39 BP102's are limited to 35V and I ran it as hot as I ever have a short while back, it was smashing it! But I still wasn't hitting the limiter (or clipping the amp), so obviously I wasn't up to 35V.
Do you think you'll get that loud?

Headroom is space above your "ceiling" for want of putting it any other way.
I've also said (and discussed) this before, but brick wall limiting to a set voltage eliminates headroom.
It's a hard concept to understand at times, because if you aren't running flat strap, then you do have headroom up to your voltage limit. But once you hit (in your case) 50V, there is no headroom. It's gone.

Whatever you get, for 2 x lab12 loaded T30's at 50V is 625W/4ohms. IMO, the closer you can get to that with an amp, the less you have to limit.

Speaking of Crown, the XLi series is somewhat lighter than old iron, no frills. The XLi2500 does 750/4 (so limit by around 5V) and goes for about 430 quid at Thomann.

If you don't think your going to be banging on the bleeding edge a lot, don't get caught up to much with 2 ohm capability if it means you're going to miss a good deal is what I guess I'm trying to say...

Hey Grant, I take everything you say to heart, especially because you communicate it so well.  I had an inkling about the sine wave testing having a different voltage characteristic generally than normal music, but wasn’t sure what those characteristics were. This is where your posts influence me to have to go look things up!  My understanding (anyone correct me if I’m wrong) is that an AC voltage reading with a multimeter is the RMS value of the wave form, therefore a pure sine wave has a peak voltage of 1.414 times greater (3dB) than what the meter reads, i.e. someone winding their 300w/8ohm amp up to the hilt with a 60Hz sine wave and measuring 50Vrms across the terminals must actually be having 70v peaks in the signal, and one assumes that these peaks must be OK for speakers that have a 50Vrms limit value.

Will I get that loud? (i.e. 50Vrms): I have no reference for how loud that is for 2xT30, …but from what you’re saying and the immediate uses I have, probably not. It’s just my getting the theory straight (and right!) whilst building experience. As you’re saying, and for me as a noob-theorist, I have the feeling that amplifier power sizing in the form of headroom numbers calc’s are part of the tension between theory and practice at least for voltage-limited subwoofer applications, i.e. 750w/4ohm as an amp max power versus a speaker limit (600w/4ohm) is a head room of just 1dB; hardly worth having from an average power perspective.

However, I’m not so sure about the closer one gets to the power limit of an amp, the less one has to limit. I’ve read various opinions on here about this, and not enough to be certain. The plans are clear about potential amp peak capabilities blowing drivers. EDIT: Unless of course you mean 'less' limiting as opposed to 'no limiting', which I think is the case.

I would prefer not to miss a bargain either. I can get that Crown Xli2500 for a bit cheaper in the UK, but I would prefer the Peavey IPR2 for weight and about the same money. While I’m on it, Peavey are starting to grate me: I’ve been in touch with their UK office twice and they cannot tell me anything, and that is after being advised by the US office to speak to the UK one. I know, I’m not a dealer, so there’s still some slop/delay to trudge through when things start moving, but they should at least know when they are going to move, but they don’t. I’ve gone back to US ‘Customer Service’ to see if or how they wish to proceed with my query. And they’re selling IPR2’s in the states!

I do still intend to pick up a Synq 3K6 in the future though if only to save space in my rack which is only a widdly little 7U wheel along. The idea being I roll up with a ridculously light amount of kit and still outrun rigs pushing 10k worth of amps.

Yo 88, what driver and wiring configuration do you have in mind for using the power/load rating available in the 3k6?

[Charles Jenkinson]

This, just in, from US Peavey International sales, regarding IPR2 3000's into UK.

'It will be at least late November or early December.'

Hmm. Do I say thank you and walk away or ask if there's any more they can do, like permit a US distributor to sell me a 240v one, supported on any warranty issues by the UK?

[88h88]

Yo 88, what driver and wiring configuration do you have in mind for using the power/load rating available in the 3k6?

4 Lab12 driven subs, 2x parallel into each output for a '4ohm' load. I'm expecting the amp to need some serious adjusting down on the DCX as my GX5 is virtually on the limit of how far back it can be dialled. This is a question I need to ask before I grab it really but what I'm thinking is that I can use the input gain on the sub channels of the DCX to just wind it down until the amp is outputting whatever... I'll probably test that Saturday with the GX5.

[Grant Bunter]

Charles,
I don't think I would suggest no limiting here lol.
So, yes, I mean keep the amount of limiting you need to do to a minimum, so buy an amp that requires 5 volts of limiting rather than one that requires 25V of limiting...

[Charles Jenkinson]

Some news to report:

Courtesy of a tip off from a DJ friend at work, I've found an amp. Not to everyone's taste, but it suits me; a Matrix UKP1300 from whybuynew.co.uk for £125. 390w@8ohm per channel, 650w@4ohm. British made. 17kg - will put in it's own case. I'm not too bothered about limiting (i.e. running up) to 50v (lab12) - there's naff all difference dB-wise between 40 or 45v, so in 4 ohm config., there could still be ample breathing space on power.

I may at some point try it on the tops, and use the Synq dig 1K0 (class D) on the subs - influenced by audiophile persuasions on class D's, but for now it'll do for subs.

Funny too, a friend originally recommended Matrix, as a nice amp to work on when they're broken!, for an amp for the Jacks, but I didn't want to stretch to their lowest rated class D offering, on money grounds. I figure he meant it was nice to work on the old iron ones anyway.

Pictures attached are from the whybuynew website.

Thanks for the help, chaps!

I'll tart up the scratches with some matt black and a fine brush.

[escapemcp]

I hope you have more luck with whybuynew than I did...I Bought a berry nu3000dsp and it went pop at very low power after a week or 2... Thought it may have blown my lab 12s it was such a loud pop!!
Returned item to be told I could only have store credit annoying as they had no more of them amps in stock. So I ponied up £300 for an identical (but new) amp from another shop (which was only 20 more than at wbn) as I had a gig in a few days.
I then used my store credit - plus £90 - to buy a laser-uk laser that had supposedly only been used for an hour at a trade show. Got the item and one of the mirrors was broken but far worse than that, the fan had obviously been turning for hundreds of hours as it had a significant buildup of dust and gunk on it!! At least this time when i complained they gave me a refund... I then found the same laser online and brand new for £250 (lex 650rgb), saving me £120!
Overall not happy with them, but it all worked out OK in the end. Your mileage may vary, and I may have just been one of the (doubly) unlucky ones!