Chienmortbb

One of the lessons from this little blip is firstly to to get your design down on screen and/or paper before committing to any hardware and secondly to read datasheets properly. Each hole in the panel costs money so I have wasted a few £s there. On the subject of the panels, I may have already mentioned it but the holes to attach the IEC/Switch/fuse module to the panel were threaded. As a result there is no need for a nut on the inside. The extra cost was 11p per hole (£0.11). The cost of doing all the screw holes would have would have been about £2.50. It has cost more than that to buy nuts so it was a false economy to not get all the holes threaded.

Looking back at the reat panel, I now have redundant holes, the Stereo/Bridge swith and the Bridged Speakon in the centre. I have decided to put a grille over the two holes that will act as the air inlet for a small fan. The white writing will be covered by black paint as the text is all engraved and filled with white paint currently. The amplifier modules have a temperature monitoring pin each, such that I can turn a fan on, only if the temperature rises too far.

Well spotted, I missed that. However unlike the ASX series modules, the circuitry is built on the board so it does not need external bridging circuits.

I was starting to think that way. The easiest and most sensible course is to abandon the bridge mode possibly utilising the switch as a stereo/dual mono switch.

That shows the internal balanced input circuit but the output from that is single ended feeding the power amp. It could be that there is bridging going on inside the 700AS1 but as you say, the ASX range have two separate amplifiers that have to be fed antiphase signals.

Many of the ICEPower modules are bridged for maximum power for example the ASX series as used by many, are really stereo modules that have been bridged for use in bass amps. Let’s take some examples. The Aguilar TH350 uses the 125ASX2 bridged to give a conservative 350 watt rating into 4 ohms. The 125ASX2 is rated at 125watts per channel into 4 ohms but bridged can achieve between 250-450 watts bridged depending on how you measure it and how you cool it. The. Same module is used in the. RM500 by Ashdown as far as I know and I’m that case they rate it at 450 watts. The TH500 uses the 250ASX2 module. The GK MB200 and several of their 200 watt combos use the 50ASX2 module and all have to have have bridging circuits added to the preamp to achieve this. The 700 and 800 watt modules used by the like of Mesa etc. are not bridged, they use the later AS700 module that is a single ended module capable of 350/700 watts into 4/8 ohms.

So the rethink about the wiring, it is going deeper than I had thought. I have two choices, either I change the wiring and accept that the volume or level controls are at max in bridge mode or accept that I am unlikely to need an amp outputting close to 1200W into 8 ohms. To achieve bridge mode while taking out the volume controls in bridge mode would require an inverter stage and this is a lot of fuss for something I will probably never need. However it may be possible using the DSP but the learning curve for the DSP is quite high and I really need to have a working amp quite soon. I am going to investigate and make a decision tomorrow. If I do decide to go deeper into DSP then there are other things may be possible.

They are based on the IR/Infineon IRS2092 mosfet driver chip. More information at https://www.infineon.com/cms/en/product/evaluation-boards/iraudamp7d/. However they also include an integral Switch Mode Power Supply. Connex have been supplying SMPS and amplifiers for years for the DIY audio market. They are a bit cagey about publishing too much about their designs as they say the do incorporate proprietary circuits that make them a cut above the usual Chinese modules and they charge accordingly.

Yes I originally did a long explanation of bridging but it looked so complex I deleted most of it. Yes is you like the amplifiers push and pull. One amp goes +ve while the second goes -ve. So the voltage swing is doubled. This should increase the power by 4 times but in reality two is usually the best you can do.

As an aging rocker, I often find my left hand index finger gets sore after playing. I have often been intrigued by Scott Devine's glove and while searching for something to make up Amazon's £20 free postage offer I saw some musician's practice gloves. I thought it was worth a punt. They came about a week ago and I have been quite impressed with them. My fretting hand technique does seem to have improved and I can play for longer or so it seems so Emperor's new clothes or useful practice/performance tool? Has anyone else tried them and what do they think?

As with all these home brew projects, you are constantly re-evaluating the design and as Ivthink about the switch wiring, I realise that my thoughts were wrong. Bridging an amp (or more correctly amps) require that two or more power amplifiers run in anti-phase. One amplifier will drive the +ve terminal of the speaker and the other will drive the -ve terminal of the speaker. By doing this we double the voltage swing across the speaker and potentially quadruple the power available. In reality most amplifiers will be currently limited, that is that they will only be able to supply a given amount of power and in most cases That would limit the increase in power to a factor of two. Many of our favourite amps run bridged amps including the Ashdown RM range, Aquilar TH range and some GK amps like the MB200. Of course there is no such thing as a free lunch and the increase in power comes with several negative including increased distortion. Luckily in most cases this is minimal and still well below what we could hear. Tfe problem with the Kilowatt design as shown in the original wiring diagram is that the level or volume pots have to be set exactly by hand/eye to exactly the same level otherwise the distortion will rise considerably and one amplifier worked harder than the other. So I am now rethinking the wiring to take human error out of the equation.

The speaker connections are done and I have tried to tidy them up with some cable ties. The cable is quite heavy duty as it carries the most current. The mains cable carries more power but you need thicker cable to higher currents. You might notice that the RED Speakon connector has two red cables. That is for Bridged operation where the +ve connection from both amps are used to drive the speaker. Neutrik recommend that the 1+ and 2+ Terminals are used for bridged connection. This is to ensure that normal Speakon leads cannot connect to the amp in bridge mode. The thinking is that you have to know what cable to connect to get bridged operation but that installing a conventional Speakon cable would do no damage. The speaker cables should be twisted if possible but these are quite stiff and I can only get a couple of turns on them. Next to with up the inputs and switches.

Well done John and I am sure the lessons learnt are almost as satisfying as the combo itself. Many don't realise that the acoustic basses by Washburn were only produced to be used at MTV's unplugged series and of course they were amplified at the sessions by the FOH system, In my opinion they are almost useless without amplification and it does not have to be "in yer face". Just a little push makes all the difference. Well done.

I don't have any of these but would go for the Gnome for the following reasons. Firstly although I love the design of the Elf and it did create this section of micro amps, it is a higher priced for no obvious gain. Secondly, the Gnome has more power and suggests it could handle being pushed harder for longer. The power amp in the GK MB200 needs serious heat management to operate at anywhere near full power and that needs a bigger box. Add the fact that the EQ section is rather unique to GK and that would be out for me (I used to own a GK combo with effectively the MB200 amp inside). The Gnome now comes with a 4 year warranty, that is a double edged sword. It does protect you for longer BUT sometimes an extended manufacture's warranty indicates a product has had reliability problems, or is not selling well. I have heard nothing about the Gnome being unreliable but its worth keeping in mind. Markbass, seem to be a problem if something does go wrong and are extremely unhelpful if it does, so that is a no from me. I think the pre-amp pedal with DI makes a lot of sense to take as well as, rather than instead of a micro amp as you never know what FOH you will get.

True the humbuckers help but a standard tele, on the bridge pickup into a Fender amp? it is horrible, barely musical.

I would say that many songs I did grudgingly became my favourite songs.

Half decent but telecasters?

Snap, usually song 1 set 2.

Its a crossover song between blues and soul but has enough in it to keep a simple soul like me happy. I know a lot of musicians hate it though.

IAs you probably know by now, this project trundles on at its own pace. Today I wired up the amp modules to test that all was well. The protection lights for both modules came on and went off while the modules were settling down and a brief sound check on both was fine. As I was checking module B, I noticed that all the lights had gone out on module A. I checked everything But could not see the reason. Took it out and checked it out of the case.., all good but then when reinstalled it again was dead. Module A was the original module I bought and it has been on and out of the chassis, a new mains terminal block was fitted and it was the test module that has had lots of work done to it.I suspect it is something to do with the new mains terminal block. So I got my drill out, drilled mounting holes on the spare module and that is now installed as module A. The original module has been put on the “look at later” pile. All good now both modules working and now to start tha boring part, wiring. The switching arrangements are not that complicated but have added to the amount of wiring. I also need to make sure all the metal panels connect directly to earth. The black anodisation on the aluminium panels is not very conductive. I will take more pictures next time but it looks like a rats nest at the moment so that will wait.

In that enclosure I would be skeptical that you could get full power without active cooling via fans.

The 57-60 Les Pauls really created this one. However it is nothing to do with the age, the wood, it is the alnico pickups that slowly lost some of the initial magnetism giving a sweeter sound than a new humbucker.

Probably but they did some great songs.

Try telling someone that their ideas about tonewood are false......

The profanity filter changed my real word, that rhymes with duck into flip.