Chienmortbb

It is bad because the two outputs feeding each other. As said earlier, use a small line mixer.

Bill is correct. A square wave is like an infinite collection of sine waves in its purest form. If you gave square wave going into a speaker it will sound awful but will not damage a speaker per se. It becomes a problem when approaching the thermal limit of a speaker. At that point you could be putting approx 40% more power through the speaker than if you were putting a pure sine wave into it. Of course unless you play bass flute or whistle through your system, you will not be putting a sine wave through your system. I can find you many men who bash their heads against walls every day for years and some if them will escape brain damage. Overpowering your speaker is the same, some will last years but some will fail the first time you go to 11.

[quote name='monsterthompson' timestamp='1410390748' post='2549061'] Under-power is bunk. I will say I've found lower power amps don't push hard enough to get good tone. For example, I had a Crown XLS 1000 power amp, and I could tell when it was in bridge mode (for more watts) because the speaker reacted differently, and the sound was fuller even if the volume was roughly the same (I wasn't using any form of measuring device). I'm not sure what was going on in the guts that made it that way, but it was noticeable. [/quote] if you bridge an amp you will get 3-6db more power output at the same settings on the preamp comlared to a single channel.

Everyone take care when using power saws. Duke from Audio Kinesis had a fight with a table saw and lost. He is now only able to offer a Hi Three. Duke has been designing and building cabs for many decades so it can happen to anyone,

[quote name='taunton-hobbit' timestamp='1410198093' post='2547055'] 'Hybrid' amps are nothing new - stuff a valve input stage on to a class D solid state and you get something fairly close to a cooking great valve amp without the drawbacks - try it with a Crown xls - it's an interesting mix.......... [/quote] Most hybrids have a valve front end but much of the valve sound comes from the power supply and output transformet. Surely an SS pre with a valve power amp ia the right way? I should add that as an electronic engineer of 62 years, no valve will find its way into my pre amp or power amp.

As I have owned both an AC30 and a Selmer Selectatone 30 ( i wish I still had them both) ,I can atest to their volume. Not as beefy as a 4x12 with a Marshall/Sound City/HiWatt/Simms Watt head but plenty where it reallly mattered. Is it me or was their just more balls in those early british valve Combos? Got to also say the AC30 bass was a POS.

[quote name='Bill Fitzmaurice' timestamp='1410178204' post='2546782'] Most cabs reach maximum driver excursion at no more than half their rated power, so that's all you need to get full output from them. You can have more power on tap if you wish, but you simply won't use it. The same applies to PA. Where PA differs to some extent is with respect to high frequency drivers. They can be harmed by clipping, so plenty of amp power used to be a necessity to prevent that, but clipping is very effectively prevented with electronic limiting, something which was not an option when this was written: http://www.jblpro.com/pub/technote/lowpower.pdf As for the link's take on guitar speakers, he misses that by an even wider margin. Most guitar drivers have such short xmax, 1mm or less, that they reach maximum uncompressed output in the lows with only 10-15w input. The power required where guitars get most their decibel output, between 500 and 2kHz, is quite low, and doesn't require massive driver capacity to handle it. Anyone doubting that has never been on the receiving end of a Vox AC-30. [/quote]

[quote name='JTUK' timestamp='1410180092' post='2546821'] Horrid little things [/quote]i think you are being harsh on the OP and others. They are entitled to their opinions😎

I had a BLX130. Trace used to use the same power amp in all the mosfet amps but change the number of mosfets for higher powers. I suspect that the 130 was 80 watts with the internal speaker but would output 130w when connected to an external 8R cab. I found the standard BLX130 OK for rehearsals and small pub gigs but but great for almost anything when used with the extension cab.

So the questions are: 1. Are you getting a replacement or just giving up on the MiBass? On a more technical note, 2. Why fit fan when the power amp is designed to be used without one? 3. Is the fan on all the time or or temperature controlled?

They are welcome to it. Once water gets into an electric circuit it just keeps corroding away until something fails.It does not do paper cones a lot of good either.

I was chatting to Blue Aran the other day re stock on the SM212 and told them about this thread. After reading it they sent me this response; "I had a bit of a read of the thread, looks very interesting. There is a driver that is mentioned mid-way through: Faital Pro 12PR300 http://www.bluearan.co.uk/index.php?id=FTP12PR300AP It won't be everyone's cup of tea for this design but should certainly be a contender - it has great mid-range and is about as lightweight as they come. Assuming it is indeed suitable for this design we can do a Basschat special on these: £115 inc VAT, free delivery. We tend to keep them In order to get the price all you need to do is register on our website then email us with a link to that forum thread. Unfortunately there isn't anything we can do on the Beyma SM212 but it's already fairly well priced." I have no affiliation with Blue Aran and although the PR300 is a neo, it does not model as well as the SM212 so I will stay with that. For those that need a lightweight cab it might be an option though.

Why should we not get you started on Steely Dan?

I agree Phil. I prefer 3/4 Spuce ply to Baltic Birch. It is a little softer but easier to work and as you say 3/4" butt joint are better that 1/2". Spruce is 1/3 lighter that Birch so tye overall weight is the same. I once visited one of the big PA hire companies when big bins were the order of the day. They spray painted the cabinets each time they came back from tours. Filled any dents, then sprayed the matt black so they looked pristine everytime they went out on hire.

Just thinking about this further it seems that companies that are predominantly selling bass amplification find it difficult to survive. Small music shops will tend to specialse in a single manufacturers and so the solus bass companies findit hard to get the beginners. For example Guitar Mania in Poole sell only Marshall Group products so Marshall and Eden. Eden would not have got into GM if they were not part of Marshall. Of course the internet may give small companies (Barfaced) the chance to bypass traditional channels and thrive. On another matter, weight. I spoke to an ex Trace employee when I had my BLX130. He said that Trace's designers thought that MDF had the best Sonic properties and so tended to make speaker cabinets from MDF, not for low cost.

Thanks Phil, I am building my own amp and was considering using the same power stage as the MiBass. I might turn it into a build diary but as the preamp was a collaboration with Charlie Escher (passinwind on TB) in the States I need his permission first.

A couple of questions Phil. Are you replacing the Hartke? Also can you do a comparison of the two amps. The MiBass amps use an Anaview power amp output stage and despite the marketing BS it is good for 200W into 8 ohms and 350 into 4 ohms at 1% THD + noise. The Ashdown figures are at 10% THD + Noise. I suspect the Hartke also uses 10% for its power figures like many other manufacturers but it would be good to hear you views. Especially with the 1x12 DIY build cab.

I used to have a BLX130 what a little beast that was. Always wanted the extension cab but never found one.

[quote name='JTUK' timestamp='1409213476' post='2537452'] I've got a gig on sat with a TE210 500w combo... that is all the detail I have on it and we will have decent stage monmitoring so I am not stressing too much. The load-in will be a sod which is the only reason I am contemplating it, tbh, but I might through in another 210 to go underneath, if need be. Why does a proper stage think a 210 will be enough? It will surely get a caning unless the monitoring is really sorted and in the quick change-rounds that may be the problem. Far easier for the bass player to be able to look after himself and the band and that is one less issue for the engr to sort out in the limited time available. [/quote]Take the low sliders down rather than up and take the 2x10 with you and you will be fine.

[quote name='VTypeV4' timestamp='1401494048' post='2464318'] I suspect wooly thing comes from excessive bottom end boosting on the graphic allied to using the pre-shape. The pre-shape gives boost at 50Hz and 2k6 but also cuts around 400Hz (All low Q seemingly) so any boost on the graphic is adding to the already boosted low . The effect is further enhanced by that reduction in the low-mids adding to the amount of apparent bottom end. The classic deep 'smiley face' generally yeilds a poor result with a Trace as it's all boom and clank with nothing left in the middle. It might work for a certain effect but doesn't tend to work in a group mix. On 12 band models the first two / three bands are generally better as a cut - do we really need 30 and 40Hz as frequency components in our sound? On 7 band models it's a 50Hz slider with a lower Q which covers a similar range. For me it's a no so I save the speakers and headroom by reducing them in my sound. I treat them in the same way I approach PA, (afterall it's where they were developed from anyways) I'd never boost the lowest frequencies as it would murder my drivers and sap amplifier power without achieving much in terms of sound. 20, 25, and 31Hz are moot on my FOH graphic anyway as my HPF is in at just below 40Hz but a trace doesn't have an HPF. I believe this is where things go wrong as folk assume the left side of the graphic 'must mean bass' rather than looking at the numbers, understanding where and how those frequency components fit into their sound. I'm not trying to defend Trace here, put simply their products don't work for everyone in every situation but I do believe a little investgaton and an open mind goes a long way.. [/quote] Finally some sense!

[quote name='spacey' timestamp='1401484963' post='2464218'] They went through a period of bad reliability, had a few and they never could keep working, shame sounded good, just did not lpike the built in smoke machine. [/quote]All manufacurers have a period of unreliability. Look at the Ampex PF500!

Lightweight is subjective. Government recommnedations are for a maximum of 25Kg for a single person lift ans 30Kgs is a lot heavier (what are these lbs things?). The first thing most go for is Neodymium drivers but they are expensive and not always ideal for bass. The 1 x 12 cab build diary on ( [url="http://basschat.co.uk/topic/227904-1x12-cab-design-diary/"]http://basschat.co.uk/topic/227904-1x12-cab-design-diary/[/url]) here is alomst complete and the current estimate for that is approx 14Kg and under £150. I strongly suspect that this will outperform all the cabs mentioned in this thread already except perhaps some of the Barefaced cabs and/or Bill Fitzmauricedesigns and Greenboy Designs. If you are really confident in your woodworking skills look at Bill's Jack Lite range. Plans will cost you approx. £10.

OK I have now checked and the MiniDSP amp can be used at 4 ohms but it is not recommended to run them at over 200W continuously at 4 ohms.

[quote name='lefrash' timestamp='1409078467' post='2536138'] I had a cab that was wired up at 16ohm. I then rewired it to 4ohm. The difference in volume was massive, when everything else was the same. I would suspect that if every other variable was the same then you would still get a noticeable volume increase going from 8 to 4ohm, but thats going to be a much more difficult experiment. Most peoples experience of running a cab 8ohm then 4 ohm would be just simply adding another 8ohm speaker which in turn will completely change all the other variables thusmaking it impossible to compare. [/quote] Assuming a good solid state amp, changing from 16 to 4 ohms is the equivalent of changing from a 100watt amp to a 400watt.

[quote name='Bill Fitzmaurice' timestamp='1408647578' post='2532253'] In the US it's SOP that the band provides the PA. The worse the job pays the more likely that you have to provide the sound. Since most bands don't want to pay for or carry any more gear than they have to the average PA is a powered mixer and a couple of cheap boxes on sticks, hardly something you'd run your bass through. The same applies to sound engineers, if you want one you'd better bring one with you. Consequently most bands mix from the stage. Maybe one in ten venues has PA, and those are mainly larger clubs in major metropolitan areas. Outside of cities you'll be lucky to find one in a hundred clubs that has PA. [/quote]In my experience it is the same in the UK Bill.