stevie

"[This Audio Precision (”AP”) measurement shows a 1kHz sinus burst (20 ms) that have a peak value of 60V, corresponding to 42.42Vrms 450W RMS in 4 Ohm]" In that case, perhaps TC will rate this amplifier accordingly, at 450 watts PMPO (Peak Music Power Output) in future. To answer the original question - no, the RH450 is not a 236W head. The power output measured in the test was at 2.5% distortion into 1kHz. The accepted level of distortion for these measurements in most circles is 0.1% across the rated bandwidth. So the RH450 is probably not even a 200-watt amp. I'll bet my bottom dollar that the technical guys will have issued a disclaimer in writing to protect their backs when they heard that the product would be rated at 450 watts. My guess is that they are laughing up their sleeves now that the marketing experts have been caught with their pants down.

[quote name='bobpalt' post='1358467' date='Sep 1 2011, 09:39 AM']I have been through a number of cabs in the last year, constantly looking for the Holy Grail, but the fact of the matter is, I really dont know what I'm looking for![/quote] What you're looking for is a cab that uses a top quality driver, and the only way you're going to get one is by fitting it yourself. Screw a BMS 15N620 into your EBS cab and you'll never look back. They're around £300 from UK sources but some German resellers were charging £200 last time I checked. I had a good look inside an EBS Proline cab not too long ago (a 2 x 12"). Apart from the serious omission of proper bracing and the lack of t-nuts, it was beautifully built from Baltic birch ply and I doubt if anybody else makes anything better. Just get a premium quality driver and you'll be sorted.

My hot tip: be very sceptical of anyone who says they are fluent in German.

[quote name='Monckyman' post='1348726' date='Aug 23 2011, 09:40 AM']Doesn`t immediately suggest a speaker fault, a cable maybe.[/quote] That's quite likely. I'd check the wiring from the amp through to the driver very carefully. It's impossible to tell at this distance but it sounds like it might have been a short circuit across your amp. Look for broken insulation and frayed wires. Check inside the speaker as well.

That sounds like a manufacturing fault, but it's easy enough to fix if you have a soldering iron and there is enough lead-out wire available to put some slack back in it.

[quote name='Kalim' post='1341392' date='Aug 16 2011, 12:40 AM']I have just had a Ciare Tweeter replaced in my Techsoundsystems ND210 cab but I am still getting a crackling, interference typed of sound.[/quote] By "crackling interference" are you saying that the noise is random, or does it appear in time with the signal?

[quote name='walbassist' post='1337646' date='Aug 12 2011, 02:07 PM']Thanks for this. What should I be looking for in the wiring?[/quote] Loose connections, that kind of thing. It would also be a good idea to measure the driver with an ohmmeter to make sure it is actually dead. If you don't have access to one, swap the faulty driver with a good one to make sure it is actually faulty and not a loose wire or dodgy connection.

[quote name='alexclaber' post='1337534' date='Aug 12 2011, 12:45 PM']The weight or density of the cab has absolutely no bearing on the tone or the bottom end [b]if[/b] it's made properly.[/quote] Although I've never seen a prosound bass cab made of anything less than 3/4" birch ply.

[quote name='walbassist' post='1337408' date='Aug 12 2011, 11:20 AM']Thanks for all the help. Having had the driver out I can confirm based on the markings on it that it is a Z005190, spec [url="http://h-audio.de/lautsprecherdaten/sica/8%20Inch/Z005190.pdf"]here[/url].[/quote] If Ashdown are not going to help (which is a shame, because their spare parts prices are reasonable) you are reliant on Hotrox to get you one. It shouldn't be too expensive - £65 at a very rough guess. You might also like to try JHS in Leeds, as it seems HK Audio also use exactly the same driver in one of their products and they might have one in stock. I'm assuming you've checked the cab wiring, just in case ......

[quote name='Mr. Foxen' post='1337348' date='Aug 12 2011, 10:37 AM']Pressed chassis makes pretty much no odds to the spec, it could be an OEM equivalent in the ways that matter.[/quote] If the Ashdown driver has a pressed steel chassis, then it's not the same driver. It could be the OEM equivalent and it could not, but there's no point in guessing. You can probably get the information you need by finding out what's printed on the Ashdown driver or by asking Ashdown straight out. You're going to have to take the faulty driver out anyway - you might as well do it now. It might be the driver you mentioned earlier or it might be something else. The Ashdown Sica drivers I've looked at had the model number printed on them.

[quote name='walbassist' post='1337137' date='Aug 11 2011, 11:33 PM']Oops, yes I have, and was told they won't be able to help with a direct replacement.[/quote] Isn't there an EU regulation that requires manufacturers to supply spare parts for 10 years after discontinuing a product? There certainly used to be. Anyway, it's clear that Ashdown simply couldn't be bothered. We seem to be getting more and more reports like this about Ashdown. As for the driver you mentioned, it's highly unlikely that they would fit a driver of this quality to their cab. To make sure, take one out of your 4x8 and compare them. I'd wager yours has a pressed steel chassis.

The impression I had when I switched my 450 on for the first time was that it was not as 'full' in the bass as my Trace Elliot 300, but went lower. This is in fact the opposite of what is happening, judging by the test results. My subjective impression was complicated by the fact that there is a bad resonance at 50Hz in many places in my practice room although, interestingly, that is now no longer a problem.

[quote name='paulbass' post='1329366' date='Aug 5 2011, 10:59 PM']Hi Sam, i have taken it to a tech who has a very good reputation and he simply cant find whats causing the fault.He has replaced many parts and it still doesnt work and he still cant understand what has actually gone wrong with it.He has had it for 6 weeks and i'm now at a point where i'm considering writing it off as he has said the repair bill will be very expensive.He too has contacted Trace Elliot and they told him they couldnt help him either.[/quote] I would be tempted to wonder whether your tech really knows what he's doing. Why don't you contact Trace Elliot yourself and explain the situation?

Yes, I liked it too. Carry on!

As long as you realize the LF section of the crossover is seeing a different impedance in each diagram. In figure 1 it's seeing 8 ohms and in figure 2 it's seeing 4 ohms. The simple solution is just to use a crossover on the brightbox and to let the bass end roll off naturally. I assume that's what Trace Elliot did, although I've not seen their x-over circuit for the Bright Box.

I was almost right!

As long as you use a crossover in front of the bright box of tweeter, the impedance shouldn't be a problem.

As long as the cone isn't shredded, a competent repair should last as long as the cone. Google for cone repair techniques using tissue paper and glue. There's nothing wrong with fitting new drivers, but if you are looking for a genuine improvement over the original Trace drivers you need to be looking at something like top of the range Celestions or one of the Italian brands like B&C or 18sound.

He's taken it back and smashed it over the seller's head. That's what I would have done too.

And I was agreeing with you.

I think the issue Alex was referring to, and which was also pointed out by the reviewer, is whether TC should be calling this a 450-watt amp when it isn't. Fit a turbocharger to a 1600cc engine and it's still a 1600cc engine. Just because it performs like everybody else's 3-liter engine doesn't mean you can claim it is one. Not that TC is alone here, as virtually all bass amp manufacturers exaggerate the power output of their products. How TC get this performance out of the amp is certainly interesting and I didn't have time to read the fairly complex technical explanation in the magazine. I'm not sure I would have understood it anyway. My superficial understanding is that it is down to compression. They are also reducing the level of the lowest fundamentals of the bass and compensating with a boost slightly higher, which I would imagine will also help. If people are happy with the amp, as they certainly seem to be, perhaps it is nitpicking to criticize.