Mottlefeeder

Yes. Been there, done that - I once managed to connect my main amplifier output to my back-up amplifier, and only one survived. Your option of making your back-up amp have the same connection as the combo amp is the safest option to prevent two amps being connected at the same time. David

I built a kit which used 'Overlord of Music' hardware. It was fine for EADG, but useless for BEAD tuning as the string clamp bends the string through 90 degrees, and the B string would not take that. I ended up making an in-line clamp to get round the problem David

I'm trying to squeeze as much bass out of a small cab as I can, and the constraints I have accepted are that I need the steeper filter to reduce the port velocities. So my filter does not need to be variable, which makes things easier. With regard to digital options, the last digital circuit I designed was the logic behind a discharge-then-charge battery charger. I think it had eight gates in it. Also, learning new languages has never been easy for me, so I'm pretty much 100% anogue. I'll check out LTspice and see how steep the learning curve will be. David

It's funny how when you only have a hammer, every problem starts to look like a nail! Thanks for the info - I'll check it out. (And thanks for correcting my typo which I only noticed last night) David

Feeding WinISD'a filter calculator with the cookbook recommended Q per section for a two-section filter, I get two 12dB filters to give the same response as a 24dB filter. Unfortunately I cannot model the Rod Elliott twin 18dB filter design as WinISD only allows a triple 12dB design. But that gives me a design that I can work with. David

My understanding is that the Q defines the sharpness of the knee, and that also affects the likelihood of ripple. The Butterworth 'design' maximises the range of the flat response, and the WinISD Butterworth graphs show no ripple. Chapter 16 of the op-amp cookbook @tauzero linked to does show graphs for various filter configurations. David

Thanks @tauzero - towards the end of chapter 16 there is a comment that to achieve an overall Butterworth response in a multi-section filter, each section should have a different Q. That implies that the copy-and-paste sections in the FDeck and Elliott designs are approximations, and the WinISD calculated responses are correct. I'll have a play in Win ISD and see if I can get a two section filter to produce the same response as their composite one. @nekomatic - as far as I can tell, the Q defines the sharpness of the corner, and is not related to the slope of the curve further downhill, so for example with a high Q, low order filter, you could have a high peak at the corner followed by a relatively gentle slope. David

The busking band are out pretty much every weekend, doing 5 hour gigs in all weathers, sometimes on both Saturdays and Sundays. That makes our annual total about 70-75 gigs. Pre-Covid we were out almost every Saturday and Sunday and doing sheltered accommodation gigs some afternoons and some parties in the evenings. We peaked at 180 gigs in one year just before Covid, and that included nine gigs in seven days in the run up to Christmas. A few years ago I told the BL I would be cutting down to three gigs a week, and this year I am doing one 5 hour gig most weekends. I no longer have the stamina to do two 5 hour gigs on successive days. David

I'm confused! Rod Elliott's 36dB rumble filter uses two cascaded 18dB sections and he says it has a combined Q of 0.707, making it Butterworth. FDeck's 3rd generation 24dB HPF uses two 12dB sections and global feedback to sharpen the corner and make it Butterworth when both the variable and fixed frequency sections are tuned the same. However, WinISD gives you different responses for two cascaded 12dB Butterworth HPF filters compared with one 24dB Butterworth HPF filter. My question - Does cascading two HPF filters, each with a Q of 0.707, give you an HPF filter with a Q of 0.707, or is the Q related to the sharpness of the knee, so a steeper filter will have a higher Q? David

Loose Change Buskers routinely play one 5 hour set once or twice most weekends. The back line is there for the duration. The two 'front line' singer/guitarists alternate songs and play for either one or two hours, swapping in fresh singers one at a time and as slickly as possible. David

When I checked with Warwick whether I could convert my jan1 from EADG to BEAD I was told I could, and sent a replacement screw for the one string position that was not compatible with its new string diameter. That's the sort of thing they are for. David

We've recently been using a battery pack to power a Yamaha 500+500w one box mixer/amp, and my Ashdown MyBass 500w head and when the battery runs down, the mains goes off and the amps shut down - no fuss and no damage. One thing I would look out for is any small power supplies that are not switched-mode. Small transformers, e.g. in older fx pedal supplies, can get fried by the harmonics generated by cheap inverters, but with modern gear, that issue is becoming less common. David

I couldn't see the linked advert without joining the Facebook group. David

I have a mix of hardware and plans to cover scenarios with spares and things we have in use. For example: The band uses a one box mixer and pa amp, so I carry a spare mixer and cables to feed it into my bass amp, and out to the pa speakers. We often have to use a 3rd party's generator which sometimes fails, so my backup rig is battery powered and the spare mixer can also be battery powered. And so on... David

I have similar hearing problems and my iem solutions are: a) feed bass and monitor feeds and/or ambient mic feeds into a small mixer with 3 band eq, and set that eq up to mimic your hearing aid profile. The cheapest suitable mixer I found was the Alto ZMX 862. b) use an intelligent lapel mic with adjustable eq as your ambient mic and set that eq up to mimic your hearing aid profile. The Mackie OnyxGo can be set up with a phone app and this works for me. David

You do not mention your transport plans, which will probably have a major impact on the recommendations. Your cheapest DIY option is to plug together a series of modules - a small 12-15V battery pack, a stand alone amp designed for car audio, a small speaker like the Basschat 6.5 or Basschat 8, and a basic preamp pedal like a Behringer BD 121 or AD121. The cheapest options are likely to be heavier, eg lead acid battery and ceramic magnet speakers, but if you plan to use a trolley, that is less of an issue. It would probably not be viable if you were thinking DB on back, amplification in hand. If you want a light one-box solution, other members can advise you - its not the route I chose. David

While I agree that there may be a marginal increase in safety if you fuse the cable to suit the equipment, the downside is that if you use that cable with another item of equipment, you run the risk of blowing that fuse at power up, and then having to fault-find while you are already stressed about setting up and sound checks. On that basis, I would fuse each cable to suit the equipment with the largest current draw, so you can swap them around without worry. David

Thanks @agedhorse. So, from the table, for a 0.75mm^2 conductor (commonly used with moulded on 'kettle connectors' and rated at 6A) you can use a 10A fuse in a rewirable plug and a 13A fuse in a moulded on plug. David

Typically, UK domestic and pub wiring will be a 30A ring main, which is why we have a fuse in the plug. Having said that, if the cable and connector can withstand the forces and heat monentarily generated while blowing a 20A fuse in Europe, does it matter what size of fuse (up to 13A) you fit in the plug in the UK? David

The same cable and kettle connector is used with an unfused plug in Europe, where the house wiring could be a 20 Amp radial feed. If that is safe in Europe, do we need to worry about 13A/10A/5A/3A fusing for cable protection in the UK? David

I agree. If you can set your tone using the bass onboard EQ, and you compensate for the room using the PA EQ, then you don't need an EQ pedal, unless you need to switch between tones between songs. David

Thank you @obbm and @tinyd David

Sounds good. I heard that the original had db and a bass guitar overdub, and that Herby Flowers gets twice the royalties because he played both instruments. True or urban myth? David

My experience with D'Addario customer service has been good. I clamped and then cut to length the strings on a headless, but when I loosened them to mask the sharp edge, one unraveled. D'Addario sent me two replacement strings by return - no charge. David

If you are aiming for 'either A or B' then a pair of splitters, (left and right) used as blenders, should work for you. David