Chienmortbb

[quote name='Sparky Mark' timestamp='1499202641' post='3329971'] I had a class D LM3 in my CMD121P and it sounded just as punchy as my class AB separate LM3. The sound is primarily down to the pre amp which was identical. Markbass developed its own 500w class D power amp and it is very full sounding. The 1000W power amp is based on the same design elements. [/quote]I suspect one of the other italian Class D companies designed it like Powersoft.

What did you end up getting?

Bill is right the power will be roughly similar (although a distorted signal will push more power than a clean one. The biggest issue is noise here. If your gain pot is at the start of the pre-amp, having it too low will mean amplifying noise later in the signal chain. A lot of bass amps are not designed with a low noise figure as the main design criteria so higher gain is usually better, My advice, have the Volume or master control lowish, set the gain for the sound you like then turn up the master/volume for what you need. Alternatively turn up the gain until it starts to distort then back it off a bit. Then turn up the master/volume to taste.

[quote name='kev b' timestamp='1499036735' post='3328789'] Its not only class D amps that play up, my band plays a couple of venues where there is a issue with the power supply. The ancient keyboards (4) use 9volt phone charger type power supplies and I use my 1970s HH solid state head for bass. At various points during the set my bass will sound horribly distorted but one keyboard in particular will fail altogether, just producing a clicking noise. We put this down to a voltage drop caused by the long extension leads and demand from the fryers and other equipment in the venue, the cure is not easy to find. I dont look forward to playing one of these gigs as our sound is always compromised, the place was rewired last year but we use the same setup elsewhere and never have a problem. [/quote]If the voltage goes down so does your headroom and distortion will start earlier. Incidentally I have two HH bass amps and no valve amp watt is equal to an HH watt (tin hat on).

[quote name='Count Bassy' timestamp='1498935694' post='3328142'] AFIK a power conditioner can't increase a low voltage. [/quote]True a waste of money if you ask me.

Duplicate post please ignore

Many class D amplifiers will have under voltage protection as the control chips do not behave reliably at very low voltages. Class A/B Amos will operate but not put out the full power and will distort early. If you had both, the voltage was too low ( that is way out of the 230V +\- 10% that the mains are guaranteed). Do you know the power of the generstor?

[quote name='mcnach' timestamp='1497988309' post='3321856'] The one thing this bag was not so good at is... the bottom: there is no padding at all!!! Very strange. Fortunately, I had some very tough and dense foam from work, from the packaging of some large piece of equipment, and it came very handy to make a nice supportive bottom layer: So with that at the bottom, the back of the amp is now protected too. I use some of the remainder foam to cut a frame to fill the gap when I only carry the amp inside. It makes a good space for accessories, so I'll probably take the power and speaker cables there, and use the side pockets for other things. It could have been better... but I'm not complaining. It'll do the job nicely and I trust this with my amp, something I could not say about the original bag, which I will use as a dust cover at home. [/quote]Where did you get the bag?

[quote name='Sparky Mark' timestamp='1498086168' post='3322506'] I understand that manufacturers need to control retail pricing but in this instance the UK customer is paying a massive premium because it seems of the extra hands the product is passing through without adding any value. [/quote]That is against the law and if you have proof that a manufacturer or distributor is trying to control retail prices you shaped report it to trading to the EU....oh funk.....

https://i.imgur.com/g7dEyJT.jpg Front panel dry fit. Wiring starts tomorrow. I cannot decide whether to keep the knob colours as they are here or go all back. I will try all black once so remember where so put the other black knobs. Charlie I do give you a credit on the rear panel, Sorry but I cannot get the image on the post from my phone. I will do it later when I get home.

Luke the latest drawings can be used for the MK1 or MK2. Just leave out the HF unit home and that is a MK1 on a different shape. I would suggest you use the big port though and don't stand in front of it. It is amazing how much air comes out of that port.

[quote name='geoffbyrne' timestamp='1496750612' post='3313591'] OK, I sat down on a stool in front of the cab with the grill removed & had a right good listen. The 'flutter' was coming from the piezo unit. I disconnected it & screwed it back on, but the sound was still there - coming *through* the slots in it - it's not a sealed unit!. I removed it leaving a 75mm diameter hole. No flutter. Any suggestions for a sealed replacement would be welcome, or, alternatively, the best way to seal up the hole that's left. G. [/quote]i am sure Stevie will comment later. But the tweeter from the original MK2 design was pretty good and not too expensive. From Stevie's post "The first HF unit we will be working with is the P. Audio PHT-407, available in the UK from Blue Aran for a very reasonable £13. Don’t be put off by the price; it’s a quality unit." I will let Stevie comment on crossover arrangements.

I got the finished Front panel From Michael at Modulus Amplification today. I am very pleased and now have no reason to prevaricate. Build restarts tomorrow. An apology to Passinwind, the model number should have read PW7B-500UK as the preamp is basically his design PW7B. The name Cand Heat? I live in Canford Heath near Poole. Having had a business before that used the Canford name (because that is where the business was) and being ferociously pursued by Canford Audio's Rottweilers (Trade Mark Lawyers), I thought two fingers up to them would not go amiss.

[quote name='TheGreek' timestamp='1496261847' post='3310079'] Snapped up an absolute bargain today - virtually stole it TBH - ridiculously low chancers' bid - didn't expect to win it - laughing my head off.... Not telling yet...photos and review when it arrives on Tuesday (hopefully). [/quote]Mick you are a tease. Any news one the Elf?

[quote name='geoffbyrne' timestamp='1496148395' post='3309115'] ....or, could someone suggest a comlimentary port to cut in an Ashdown Mibass 12" cab so the Beyma works properly? I think the porting is the problem, the cab isn't 'breating' smoothly at low frequencies. G. [/quote]Geoff is it this one?

[quote name='geoffbyrne' timestamp='1495907223' post='3307512'] Hope not to derail..... I have a Beyma 212 - but am totally hopeless with tools. Anyone building these cabs for money? G. [/quote]As Phil says it is not difficult and if you look at the first post there are very detailed plans. I have now built 2. The size is such that you get two cabs from a 1220 x 2440 sheet of ply. If you only build one cab it will be expensive. The poplar ply we used was 15 mm and the cost approx £50 per cabinet or £100 for two. I am planning to build a combo version so if [size=4]we can get two other people interested, I will buy some ply and dry fit the cabinets, cut the holes and then send them out to you for easy assembly. That means just [/size]glueing [size=4] [/size]and[size=4] screwing the [/size]cabinets[size=4] together[/size]

[quote name='molan' timestamp='1495990046' post='3307973'] One thing to think about in the pairing you're suggesting is the porting. The HR 4x10 is rear ported whilst your HF210 is front. This tends to mean that the 210 is going to be a bit more dominant in the stage sound than the 410. I've tried this with Bergantino cabs and the newer front ported ones were significantly louder up close than the rear ported ones. There is an HF410 that might match the 210 a bit better - depends on the tone and stage sound you're after of course. It could be that the 210 will be the clarity for onstage monitoring whilst the 410 will be the 'big thumper' to spread around the stage and out into the audience. [/quote]If the Bergs use the same drivers, and are tuned to the same frequency and are the same volume, at the place were you were standing, you may be correct. If any one of those parameters or the power supplied to the speakers is different, then you may be mistaken.

I looked at the 407N as it is a lot lighter but the response at the low end is not as good as the 407 ferrite it would have needed a crossover frequency above 2KHz.

[quote name='FinnDave' timestamp='1495459795' post='3303872'] In the 120 plus gigs I've played with The Wirebirds, I doubt that more than 10% have had the bass through the PA. Apart from vocals, the only thing we mic up is usually the bass drum. Only when we play a festival or bike rally (and not always, even then) do we have the benefit of a big PA and sound crew. [/quote]+!

Well another trip over to Casterbridge (Dorchester) Stevie and I (well Stevie really) compared my cab, fitted with the Beyma SM212, Celestion Compression attached to a P Audio horn with the Prototype MK2 cabinet fitted with an Eminence Kappalite 3012LF and a Celestion 6" mid range driver. Firstly we put some recorded bass guitar through both cabinets. We were both surprised how different they sounded. Initially the impression was that the Kappalite went a bit lower and the SM212 went a bit higher. However you cannot trust your ears. When we measured the response, the low end was very similar. At the lower end around 50Hz there was very little in it but the 3012LF had a tad more low end but not much. However the mids showed a dip in the response of the 3012LF of around 2dB from 150Hz . So our ears interpreted the lack of mids as more prominent bass. For bass guitar both were excellent, although with music through them the SM212 plus Celestion Comp driver was superb. It's measured response would shame most hifi speakers being fairly flat from about 55Hz to 20KHz. Of course the Kappalite is well over 1Kg lighter than the Beyma so all things being equal the cabinet will also be lighter. It will also handle more power than the Beyma although how much louder it can go is debatable. I was persuaded to build the Mk2 after hearing a full range 12" cabinet of Stevie's that had a Deltalite (I think) in it. Whilst the Deltalite cab did not go as low as either of those tested today, it proved, along with the BC 1x12 MK1 that a single 12 can make a great bass cabinet. Stevie was going to build a 3 way speaker and he told me he did prototype it before building the 12/6 but as the placement of the drivers was determined by the dimensions of the baffle, it was far from ideal and sounded no better or maybe worse than two way the 12" plus horn I built. I should add the caveat that today's lesson is that you cannot design a cab on paper and you can only compare cabs when A/B ing them. One of the best things about this whole process is that I have learnt a lot about speaker design. Having the measuring gear at Stevie's meant we could check our ideas and those of others and prove, or disprove, theories and ideas. The basic idea of a low cost relatively light weight cabinet has been achieved even if the cost was higher than I imagined. The cost? About £250-£300 for the materials for mine. The weight? 15.3Kg (34lbs). The next test is Saturday when it will have a 250W amp driving it at a gig.

[quote name='Passinwind' timestamp='1494471460' post='3296265'] FWIW, I've gone as low as 18K on some of my amps and preamps. My passive/high impedance inputs are usually at around 270-330K or so, but they are really just meant as a courtesy for guest players at open mikes and the like. My preamps can make crazy high end up into the ultrasonic range quite gracefully, and a higher input impedance tends to necessitate reining that in, which I prefer to avoid given my own wants and needs. My workaround for unbuffered piezo pickups and the like is to insert an active DI/buffer box inline with the active input. I've also been playing around with discrete FET preamps lately (Tillman/Kruetzer style), and I could see adding one of those boards working well for John if he needs a higher impedance and or a little more gain at the front end. Tradeoffs, always tradeoffs. [/quote]Well I have three basses, one, my Greg Bennet, is active. The other two are a passive, a Fender Aerodyne Jazz and a Peavey Milestone (V )P type). I will be putting a Musician 2 band in the Peavey at some point and the Fender is about to get new pots, probably followed by a buffer although that might change if I decide I am good at routing. The idea behind the new pots for the Fender is that even with the J pickup fully off, there is still some interaction with the P pickup. So I was going to put switched pots in so I can really solo the pickups. Ironically I usually use either a BDI20 or my Korg AX3000B in the front anyway so I am already buffering it.

I contacted Michael at Modulus Amplification and he can do a silve /black panel to my design. To buy more decals sheets would be at least £10, you need lots of spares as I, at least, never get it right first time. For £22 from Modulus I get a properly produced front panel. I am really happy with the design except for a few things. The switch next to the input jack will go. It is too close to the jack and might get knocked and damaged. I will put two sockets, one high impedance for passives and one lower impedance for actives, as on passinwind's original design. Charlie only plays active basses. There is an argument that the lower impedance works well for passive basses too. Having the option will mean I can test that theory for myself and it may reduce induced noise. The switched mids was not on Charlie's original design, that was 450 Hz fixed, but I love the Mid on my old HH amps at 650Hz so I put a switch in so I could choose. The original design also had the capability of a bright switch but, like Charlie, I have decided not to implement that. I have also wrongly labelled the EQ and PEQ switches. They are PEQ and HPF on and off, the normal EQ section is in all the time. The switch on the far right is a MUTE switch but I may or may not include that. Power on the right is for an RGB LED. If I include the mute then the colour will change if muted. Blue for on, Red for mute. I will make all these taxing decisions after a pint of Ringwood beer. More later.

Ok latest front panel mock up almost ready for wiring. It does not look too bad except some pf the decals are slightly off centre and some off the pots need their location tags removed and the shafts cut to size.

Well I was not happy with the last look so i stripped it, sprayed it Silver and tried again. It is still not perfect but I will use it as is to complete the wiring and if I cannot live with it, will do as passinwind suggested and use Front Panel software from [url="https://www.schaeffer-ag.de/en/downloads/front_panel_designer/?no_cache=1"]Schaefer[/url]. Current estimate is about £40 for a really professional front panel but if the amps is as good as I hope, it will be worth it. The alternative is to go for an engraved panel from [url="http://modulusamplification.com/CUSTOM_FACEPLATES-W3.aspx"]Modulus[/url]. So on to wiring! Incidentally the empty holes are from left to right, High/Low switch, Input jack, and Mute.

[quote name='Beer of the Bass' timestamp='1494253444' post='3294352'] That panel does look quite good for decal paper. I've been using it on various things myself, and the results are rarely entirely perfect. I've found it likes to creep when coated over, and my prints always seem to end up a little low-resolution looking, but I'm not computer savvy enough to figure out why. One thing I do quite like the look of is to apply clear decal paper to the reverse side of 1mm clear polycarbonate and use it as an overlay, rather than applying directly to the metal panel. I would be able to get access to a laser cutter, but I've never got around to sorting out my graphics skills well enough to figure it out properly. [/quote]Applying to the rear of acrylic or polycarbonate sheet in reverse is probably the best idea. That or an engraved panel may be my best step but I am trying one more thing tonight before I give up. More later. As for they graphics, all done on the free drawing package in Open Office or Libre Office. Oh and I do have a Laser printer but only a cheap Samsung one. One more thing. Even the good decal paper is very fiddly. I found when I did the back panel that it was best to cut the decals into the smallest size possible. Much easier to handle.