Mottlefeeder

Often a crackle can be traced to something as simple as dirty contacts on a socket, to my first action would be a plug into each signal socket in turn and see if the noise persists or disappears. For the effects loop, take a guitar lead and link the Fx send to the Fx return. Next, you could try splitting the circuit into blocks and checking each block. Try feeding the signal from the Fx send to a mixer or another amplifier and see if that crackles. Next, take a signal from another source into the Fx return, and see if that crackles. That's probably as far as I would advise you to go unless you are knowledgeable enough to take the amp out of the combo and work on it without electrocuting yourself. David

Pretty much what I thought - for the same money or less, you can have a well known brand with no resale problems, or an unknown with the problems that might bring. David

Why would anyone bring an expensive, unknown brand into the UK and hope to make a profit from it? David

You said it weighs like a boat anchor - that isn't going to change much by taking some material off the back, and you then run the risk of it being neck heavy. Before you put more effort into it, ask yourself, are you going to play this regularly, because you like it, or occasionally, out of guilt, because you put lots of money/effort into it? If your only motivation is 'I've started so I must finish' then you are basically making an ornament. Advertise it and let it go. David

That is my take too. I build electronic gadgets, park the ones that didn't work, and use the ones that work until making a Mk 2 is required. Park your project for several months. If you still don't feel inclined to fix it, or don't feel you have the skills to fix it, or don't feel inclined to pay to have it fixed, strip it for parts and reuse/dispose of them. David

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Jim bought a pedal from me. Paid my price, transferred the money speedily and confirmed receipt of the item. Would happily buy from / sell to Jim again. David

A cab with ports will perform better if it is not also leaking air from the joints, so what you may have is a sealant around the speaker, or just a speaker chassis that is a tight fit in the rebated cavity. It is unlikely to be glued in place because in addition to the eight screws, it would serve no useful purpose and would make servicing more difficult. Your repair tech may be able to confirm that. If you have confirmed that it is faulty, you have nothing to lose by taking the screws out and hitting the rear of the chassis (or the magnet) with a mallet to break the seal. David

Yes, you've got it. However, the bootlace / red line will not be straight due to the weight of the bass - it will form a shallow inverted V with the strap fixing at the point. David

I use A, but keep the cable ties separate from the cables when playing. When I pack up, I know how many cables to collect by the number of cable ties that I have. David

Yes I have used it on both a neck heavy 5-string Corvette with a light-weight swamp ash body, and on a 5-string Hohner headless, to move the fretboard two frets to the right so that it sits like a horned bass. The only down side I found was that the bootlace makes an uside down V. But with a dark bootlace and a dark strap, that is not noticable. I have seen advertisments for a commercial product that uses a rigid bar instead of a bootlace, and that gave me the idea. David

Depending on how severe the neck dive is, your cheapest non-permanent fix might be to tie a black boot lace to the bridge end of the strap, and tie the boot lace ends to the existing strap buttons, so the strap end is behind the bass. It has the same effect as making the horn longer, and is quite discreet. David

Market demand? 4R is mainly for cars, 8R is mainly for HiFi etc. or something along those lines. And as for 4R neo 5" or 6" - I have not found any yet. David

My experience is that 4-plugs won't fit 2-sockets unless they are speakon/jack combo sockets, but 2-plugs will fit 4-sockets. Most budget scrapped speakers that I have dismantled had 4-sockets with terminals 1+ & 2+ connected together and likewise for 1- & 2- . David

I've done a quick check, and all I can find under 'gainclone' is class AB. For battery use, class D would be a better option - if they exist at kit level. Thanks for contributing. David

Thanks for that - I had forgotten about gainclones as a search term, and it does bring up pcbs for through-hole components. I'll have a read and see what sort of bridged power you could get from about 20v of lithium power-pack, or a pair of lead acid batteries. David

I started that project with a cheap class D module, and ended up buying a car audio amplifier instead. There are some nice one-chip amps out there, but the marketplaces are full of cheap, badly designed Chinese modules using them, and that overwhelms Google's search engine. I wouldn't be surprised if there were pcbs for diy amps using those chips, but I don't know how to find them. Anyone have any ideas? David

If you are in the market for another amplifier, can I suggest that you consider this, or its rivals https://www.caraudiodirect.co.uk/catalog/product/view/id/6331/s/kenwood-kac-m1814-400w-class-d-4-channel-compact-digital-amplifier/category/37/ Ignore the marketing department's power rating, the CEA2006 standard defines RMS power tests into 4 ohm loads. This has a SMPS feeding 4 Class D amps giving 4 * 45 W into 4 ohms, or as two bridged pairs, 2 * 45W into 8 ohms or 2 * 90W into 4 ohms, and it runs off an 11-15V supply. It is purpose designed for harsh environments (car boot on a sunny day) and seems to be pretty much bomb proof. It also includes a variable HPF. I get about 3-4 hours of use from a 7AHr lead acid battery, at outdoor market busking levels with vocals, guitars and electronic drums going through the PA. You only need one channel, but you could use the other for a second cab as and when required. David