Phil Starr

Given some of the earlier comments I ought to say I'm not being critical at all just that you made an interesting point The theoretical maximum power of an amp is determined by the operating voltage, the power in practice by heatsinking. If you are buiding a 60V amplifier than a lot of your components need to be 60V rated particularly in the power output stage. Running at 30V saves you a lot of money. Most Class D amps are complete amplifiers in a chip though there are also class D driver chips where the processing goes on in a bog standard chip and manufacturers can add the output devices of their choice. Designing and fabricating the first chip is an expensive process but then mass producing them costs pence. Nearly all of the high power chips are manufactured as stereo chips and many as quad amps. Power is proportional to the square of the voltage and you can use a stereo amp module in bridge mode to get four times the power. The same chips are used in domestic hi-fi electronics and things like in car entertainment systems. If you have a car stereo with a sub it's probably running one of the 50W quad amps with two of the amps running each side and two others bridged to drive the sub. It was these chips that stimulated the whole 2.1 phenomenon. So there are a few manufacturers of these chips who make ones of the right voltage to produce 200W into 4 ohms given the limits of their power supplies and heatsinking. Guess what is in the Gnome ,Elf,BAM at their heart they are car stereos with a bit of bass orientated EQ. It's also how they can be so cheap. Bass amps aren't really a big market so a lot of innovation is piggy backed upon what happens elsewhere in the market especially at the bottom end of the market. It also makes sense for amps to go up in 3dB steps which is doubling amplifier power. So, 100,200,400,800 does make sense both for the bassist and the manufacturer.

well if you've been running on those supplies without issues then you'll know by now. The supplies are probably manufactured in the 100,000's if not millions and then badged with lots of different brands. China is getting better all the time at quality control but if your failure rate is 0.5% that's still a lot of dud supplies. Even if A&H check every one which I doubt, they wouldn't pick up the fault and I don't suppose Andertons would either. Nobody checks something for the 2 hours plus that your supply needs to manifest the problem. Just bad luck, it's good to hear that A&H are showing an interest it's not good for them either if a batch of these have gone through or there is an under-specced component in the supply.

First of all not all bands are rock bands, some may not even have a drummer, people who play quieter genres of music still need an amplifier if they play electric bass. Secondly we don't all use our amps to fill a room with sound. In my current band the bass amp is just a monitor for the band. The audience hear my bass through the PA. My bass amp only needs to fill the stage and if it is too loud it ends up going through the vocal mics and distorts the sound for the audience. If you are so loud that only a 500W amp will do then your band probably sounds quite poor however well you play because of the volume in the vocal mics. Finally you need to take account of the range of speakers we all use. A 100W amp through a 102db/W is going to be louder than a 300W amp through a 96db/W speaker. Like most people who are commenting I carry a 200/130W micro amp as a backup to my 500/300W amp but I tend to use the smaller amp almost all of the time as it is more than loud enough for the gigs I do.

That's correct, I took the opportunity when I changed from your original cab to reshape the whole cab to specifically fit onto a 1220x610 sheet.

I've just had a read of that discussion and it looks like a reasonably common problem. These power supplies are usually pretty reliable so this is looking like a lack of quality control. They are the same sort of supply we rely on for running laptops and pretty much anything nowadays and the 5.5/2.1 mm plugs are pretty much standard too, though I'd expect better on an £800 mixer. The standard price for these seems to be around £12-13 and it looks like people who have the same problems as you are just buying them with a backup. Looking at them they are all very similar whatever the branding with a suspiciously similar sized case. Sadly it looks like Allen and Heath have cut corners with the power supply and haven't done the quality control, they've just bought them in. In your circumstances I'd just order one up from Farnell or even Amazon and try it. If it works then get a spare just in case.

I think any 60W 12V power supply would be ok to try. Obviously it should be DC and one not designed for this purpose might not be as quiet but it would let you test to see if it is the power supply. @Chienmortbb is more up to date than I am on these things so maybe wait for his input before trying that. https://cpc.farnell.com/c/electrical-lighting/batteries-power-supplies/power-supplies/12v-power-supplies/12v-5a-power-supplies

Hmmm first of all @Woodinblack is right, I've left my RCF M18 on overnight and for several days without a problem and you should be able to do that as well. This is not something that is going to go away and it willl happen at a gig sooner or later. I don't know where you bought it but I'd be asking for help and a possible loan of a repacement until it's fixed. You can't risk your band's reputation with dodgy gear, losing a regular venue is potentially worth more than the cost of a new mixer. Heat often affects components and soldered joints due to expansion. Many/most intermittent faults are affected by heat so turning the mixer off will probably give you a few more minutes before the fault cuts in. There's nothing very surprising going on here, and it was a good shout to try it, but personally I wouldn't take that mixer to a gig. Imagine if you'd just managed to fill the dance floor and had the audience fully engaged and then cleared the dance floor for 10 mins half an hour before the gig was due to finish anyway. Do you have any mates who could lend you a mixer? At a pinch I have a backup M18 I hope to never use. You can pm me if that would help

It's funny how people who differ over whether 10" speakers sound better than 15's and upgrade pickups on perfectly good basses also differ over vinyl and CD's If like me you have a collection of vinyl at home and just want to play it on something that won't degrade it any faster than you have to then any of the modern £500ish turntables will do the trick. I'd probably avoid vintage decks just because these are mechanical devices with bearings that wear. I want something I can use for the next 20 years without having to source parts. Once you get into hearing the difference it depends upon the cartridge you are using and the amp and speakers. There's no point sonically spending £1500 on a turntable if the speakers aren't equally revealing. The argument for the used Linn is surely that you like the way it looks and you can get your money back if you sell it whilst the poeple who lusted for them 40 years ago are still alive and feeling stirrings (note to self: sell that old Sex Pistols single) FWIW I have a Rega Planar 2 with the better tone arm fitted, can't remember which one. I've had it for years and have only had to replace the belt and needle. You don't have to replace the whole cartridge but spare needles aren't always available for such old gear. I've gone from Thorens TD160 (rumbled like hell) to a Pioneer 12D to the Rega. I used the Technics 1200 in my disco days. A mate has the Linn with the top arm at the time and the external power supply. It did sound better than mine in the shop but not through his amp and speakers. We spent many happy hours comparing systems to find that some records sounded great on his system and others better on mine. Nowadays we do almost all of our listening via streaming but it is nice sometimes to get the vinyl out and wallow in nostalgia, definitely worth spending £500 on that. Go for a decent cartridge though, it makes more difference than the turntable and will conserve your vinyl. Then just love what you have, if you've ever played bass with a drummer I doubt your hearing is still 100% anyway.

Since you are based in Bingley maybe you should use Fanes, a West Yorks speaker It's quite possible to use a ready made cab as the basis for a new cab if you don't want to go to the trouble of building yourself. I'd think of it as giving you the fun of having a unique cab rather than an upgrade though. The problem is that you won't have the free choice of any driver you want as not all drivers will give their best in that cab, each driver has a cab size and tuning that will work best with it and cab design is about choosing the right driver for the outcome you want and then designing the ideal cab to match. Choosing to go for an 8ohm cab is limiting as many 10" speakers aren't widely available in 4 or 16 ohms, finding ones that also match that cab is even more limiting so it's likely you won't have a lot of choice. Even the idea of 'best' and 'upgrade' are tricky. Which aspect of your speaker's performance do you want to improve? Is it power handling, overall volume, extended bass, general tone, weight and portability? However the cab is likely to be better finished than most of us can achieve by a home build and it could be a lot of fun. The outcome could be a cab you love and you can always refit the old speakers if you aren't happy with the changes and you can probably get half your money back on the replacement drivers by selling them on. You do need to think of cost though, the Kappalites mentioned above are now £170ea. If you think the risk is worth it and see it as a fun project there are plenty of BassChatters who will help with technical advice, so perhaps start with deciding upon a budget and by identifying what aspects of your speaker you want to change/improve.

One last thing from me and I'll shut up. The above is more or less what I do, except my 'pedalboard' is just a Sansamp Programmable. In my case I have a single lightweight speaker, an LFS Monza, and my amp (TC Elf) is in the bass case with the SansAmp so bass on my back and one hand free to open doors. The Monza is beyond the £600 budget but the Goodwood is cheaper and only 9kg. The LFSys have a ruler flat response which is what you need from a 'does everything' set up. The only issue is that LFSys are such new designs that your chance of buying a used one are remote and you would have to stretch your budget.

Have you contacted Allen and Heath? This is a very odd fault.

The port will add noticeably more bass. I hope you will be happy with it. For the jam session see if you can get the cab in a corner and the bass will be reinforced by the room.

I'm an unreformed fiddler, nothing I ever do get's finished. I always have mods I want to try. In this case I thnk you could set a limit/tolerace of 2% of cab volume and be perfectly safe and maybe 10% would be liveable with. There's always more mods I want to add so I'm finding publishing designs and seeing them live on as a stable design a new experience. I decided early on that designs had to be built and tested before publishing and nowadays I have to refer back to my own designs on BassChat to answer questions

That's a great question and I had to think about the answer. Part of this is that I rely on experience, I've spent a lot of time building and modifying cabs. When I build pairs of cabs I'll often try modifications on one cab and then A/B them next to each other so you do get an instinct about small changes The first thing is that the efffects are slight. First of all most of the 'sound' of the speakers is what goes on above 200Hz and the box modelling is about the response of the true low end below that frequency. The other David has tried the cab out as a sealed cab andit 'works' and it probably sounds OK, even though he will get 3db of boost of the low end with a port plus a lower roll of frequency. Secondly the calculations give incredibly percise answers but in real life it's a bit messier. Manufacturing tolerances mean measured speakers vary and the published figures I use can't always be trusted. Thre are always air losses from a cab which are allowed for in the calculations but I use a 'standard' value of Ql=0.7 which is middle of the bell curve. Importantly I then build the cab so ay significant error would show up. I'ver no control over how accurately people build the cab so calculating port sizes to 3 decimal places doesn't make much sense. You can build the cab successfully even if you make small mistakes, which should be reassuring Anyway I've looked at the responses with the same tuning and the box sizes increased and decreased by 10% but tuned to the same frequency. This is the box you are all building with the Fane in blue. You can see that increasing the cab by 10% (red) gives you a bit more bass but reducing the cab 10% makes a smaller difference. The red trace gives 1db extra at 60Hz and you'd hear that with the cabs next to each other but only just. You wouldn't be able to detect the difference with the smaller cab in this case. This is a 2l shift in volume and the increase in port size is only 0.2l so insignificant. It looks like my instincts were good in this case, Phew

Hi David, to keep the same tuning you only have to match the area of the round port and keep the same length. Those are the only two numbers that matter. I keep using the drainpipe because it's simpler for most people. if you can calculate pi r^2 that will be ok, but if you are forming a port then it would be better to make it slightly bigger to reduce potential wind noise in the port. I've had a look and something 8x5cm inside measurements and 11.4cm long would work. You can change the shape so long as you keep to 40cm^2 area