Long cable run for speakers

[Mike Stranks]

Useful updates one and all...

We're now into 'it depends' territory...

It depends on the size of the building, whether this is just for amplifying speech, the accustomed volume that the congregation expects, the efficiency of the speakers etc.

But as a general observation, in my experience if Wonks is right then that output power is on the low-side for the task required. But if the cong is happy with what they already have then changing the speaker cables is not going to materially alter things.

I generally use the 1.5mm 'Speaker Cable' from CPC... good value (https://cpc.farnell.com/pro-power/78-0- ... er%20cable but currently on back-order.) However CPC have loads of other options... just search for 'speaker cable'. But Dave is also right... any decent 2-core mains with conductors of the required thickness is equally good. IME finding it at a sensible price in non-orange or non-white can prove a challenge. Maybe I didn't look hard enough!

[Wonks]

As Rodgers make organs, organ amps and organ speakers, I would guess it's for amplifying an electronic church organ rather than for a PA.

[Kwackman]

As Rodgers make organs, organ amps and organ speakers, I would guess it's for amplifying an electronic church organ rather than for a PA.

Yup, if you google the speaker model the results show it's for an organ.

[Folderol]

It depends on the size of the building, whether this is just for amplifying speech,

This is rather critical information that's missing!

[twotoedsloth]

Hello,

And thank you for helping me out here.

This is primarily for voice amplification.

Not sure why they purchased organ specific amp/speaker combination.

To summarize your advice, I should use "brown lamp cable"?

Many thanks,

Peter

[ef37a]

No, I would go for this: https://discountelectrical.com/6242y-tw ... efEALw_wcB

Just tie the earth to Blue and reduce the loop resistance a bit. A 50mtr drum will do your 140feet and while you are in the Lekky store get a couple of ABS boxes to make 'posh' end terminations. Some 6 or 10 amp 'choc-bloc' will serve for connection.

Dave.

[Mike Stranks]

Hello,

And thank you for helping me out here.

This is primarily for voice amplification.

Not sure why they purchased organ specific amp/speaker combination.

To summarize your advice, I should use "brown lamp cable"?

Many thanks,

Peter

'Brown lamp cable' is almost certainly not what you want.

Dave's put you on the right track. You need cable with a diameter on each connector of a minimum of 1.5mm. Chose colour according to taste.

... and the plot thickens wrt the amp. It has no mic inputs so there must be some form of upstream mixer or preamp(s). But that needn't concern us...

I don't know how the church is placed financially or numbers-wise, but it may be time to start over with something more suitable...

For churches on a budget I've sometimes provided a 'second-user' Inter-M mixer-amplifier... There are some absolute bargains to be had out there at well under £100.

[AlecSp]

Some 6 or 10 amp 'choc-bloc' will serve for connection.

But not very well. Really, these days, spend a few pennies more and use Wago connectors - quick and easy to terminate, much more reliable, and easily re-usable.
https://cpc.farnell.com/wago/221-412/co ... connectors

[ef37a]

Some 6 or 10 amp 'choc-bloc' will serve for connection.

But not very well. Really, these days, spend a few pennies more and use Wago connectors - quick and easy to terminate, much more reliable, and easily re-usable.
https://cpc.farnell.com/wago/221-412/co ... connectors

I've not come across those Alec but I take issue with your "not very well". Used ' chocs' for 1/2 century and they are still used in junction boxes and used to be used for balanced mic conns!

Not pretty I grant you but I mean OP to use them in the ABS boxes and fit a more presentable connector, jack, Speakon, to the speakers and amplifier.

Dave.

[Folderol]

Some 6 or 10 amp 'choc-bloc' will serve for connection.

But not very well. Really, these days, spend a few pennies more and use Wago connectors - quick and easy to terminate, much more reliable, and easily re-usable.
https://cpc.farnell.com/wago/221-412/co ... connectors

I've not come across those Alec but I take issue with your "not very well". Used ' chocs' for 1/2 century and they are still used in junction boxes and used to be used for balanced mic conns!

Not pretty I grant you but I mean OP to use them in the ABS boxes and fit a more presentable connector, jack, Speakon, to the speakers and amplifier.

Dave.

Weird. There is no real information as to how they are used, and I would never trust any kind of connector at high voltage (and these are supposedly mains rated) with snap-down locking.

[Wonks]

Wago are fine. Used them quite a lot on lots of control panels for both sensor wiring and 24v and 230v control signals.

But I really think 1.5mm2 is undersized. 85m (140 feet round-trip) of it will give about 1 ohm resistance, which is significant in comparison to the 8 ohm speakers (which probably drop to 6 ohms orcso in reality). Remember that the existing wiring is 4mm2 and the amp is certainly not overrated for its task. 4mm2 (12 gauge) has about 1/3 the resistance of the 1.5mm2 cable. If the existing cable is undamaged and can be reused, I’d just reuse it.

This in an installation in the USA, so you need to be aware of different codes/regs and any cable needs to comply with both local and national regs. I’ve worked on a few US buildings from afar, and know that cabling in public spaces and atria often need to be ‘plenum’ rated (LSZH). So as I’ve said before, compliance with code really needs to be checked before any cabling is purchased.

I’d agree that the whole PA system could do with reviewing and probably replacing as the existing system seems a bit underpowered and mismatched for its purpose. But that’s impossible to do remotely.

[DGL.]

Some 6 or 10 amp 'choc-bloc' will serve for connection.

But not very well. Really, these days, spend a few pennies more and use Wago connectors - quick and easy to terminate, much more reliable, and easily re-usable.
https://cpc.farnell.com/wago/221-412/co ... connectors

I've not come across those Alec but I take issue with your "not very well". Used ' chocs' for 1/2 century and they are still used in junction boxes and used to be used for balanced mic conns!

Not pretty I grant you but I mean OP to use them in the ABS boxes and fit a more presentable connector, jack, Speakon, to the speakers and amplifier.

Dave.

Weird. There is no real information as to how they are used, and I would never trust any kind of connector at high voltage (and these are supposedly mains rated) with snap-down locking.

Perfectly fine to use, meet all applicable safety regulations and all the sparkies I see on YT use them and the Ideal equivalent and have had no issues. Nice for connecting multiple cables together without having to try and jam conductors in "choc-block" connectors.

I've used the clear 20A connectors and love them.

[AlecSp]

I've not come across those Alec but I take issue with your "not very well". Used ' chocs' for 1/2 century and they are still used in junction boxes and used to be used for balanced mic conns!

Try Wago connectors once and you'll be converted instantly.

Weird. There is no real information as to how they are used, and I would never trust any kind of connector at high voltage (and these are supposedly mains rated) with snap-down locking.

The link was a retailer link. Maybe better off checking Wago's info

Much more reliable than a screw based terminal, maintenance-free, and widely used across the world.

It's normally just the US electricians who won't trust the repeatable and well supported Wagos, instead bizarrely preferring the horror that is wire nuts.

[Folderol]

Much more reliable than a screw based terminal, maintenance-free, and widely used across the world.

It's normally just the US electricians who won't trust the repeatable and well supported Wagos, instead bizarrely preferring the horror that is wire nuts.

Well, that link confirms I don't want them around in my house. A properly fitted screw terminal block is far safer - Oh, and I've not seen a wire nut/acorn in this country for over 50 years.

[AlecSp]

Well, that link confirms I don't want them around in my house. A properly fitted screw terminal block is far safer - Oh, and I've not seen a wire nut/acorn in this country for over 50 years.

We're off at a tangent here, but a worthwhile one.

Your words are typical of those of those who've never used a Wago connector. They are widely used, and commonly specified for commercial installations.

Maybe worth trying one before you pass judgement so quickly...?

[Hugh Robjohns]

I agree. I first came across them a while back when my tame electrician was installing some new power sockets here. I was dubious but he swears by them and gave me a couple to try. I'm really impressed and use them myself now in preference to traditional choc-blocs. Much easier to use in awkward spaces, more reliable, smaller, and just an all round step up. I'd back the suggestion to give them a go before passing judgement based on legacy technology!

[Mike Stranks]

We're way off-topic now, but what's new?

I've not come across these before... I like 'em!

[Hugh Robjohns]

It's usually the off-topic asides that I find most interesting and helpful!

[Sam Spoons]

Just bought a few for stock (along with some 60/40 solder) from CPC.

[Drew Stephenson]

My shed is wired with them, first time I'd encountered them was when I had to redo the wiring switch here because of my cutting-holes-in-the-sound-proofing error...

[Folderol]

Well, if any come my way I'll try them, and if satisfied I'll say so.

[twotoedsloth]

Hello, and many thanks again.

I suspect I'm missing something here, as I don't always understand cockney rhyming slang... Specifically "lekky store" and Choc bloc.

How do I reduce the loop resistance?

I suspect I'm out of my depth here, probably I should tell them to find a suitable professional.

[Sam Spoons]

Hello, and many thanks again.

I suspect I'm missing something here, as I don't always understand cockney rhyming slang... Specifically "lekky store" and Choc bloc.

Electrical trade suppliers and those 'Lego' like screw terminal blocks.

How do I reduce the loop resistance?

Use thicker wire, but, as Dave says, using three core (which is often cheaper than similar spec two core) you can halve the resistance of one side by doubling the green/yellow and blue conductors so the resistance will be 1/3rd lower.

I suspect I'm out of my depth here, probably I should tell them to find a suitable professional.

This is about as easy as electricals get so you should be fine, just use the recommended wire sizes and double check all connections before switching on.

[ef37a]

Hello, and many thanks again.

I suspect I'm missing something here, as I don't always understand cockney rhyming slang... Specifically "lekky store" and Choc bloc.

How do I reduce the loop resistance?

I suspect I'm out of my depth here, probably I should tell them to find a suitable professional.

I would not worry about resistance, you cannot avoid some anyway. Even if you ran 'cooker' cable to the speakers the loop resistance (of the cable) would still be at least 10 or more times that of the transistor amplifier (be comparable to that of a good valve amp). But! You have a speaker in that loop! The woofer will have a DC resistance of at least 5 Ohms (for a nominally 8R speaker) but the crossover components will add some to that figure. Not worth then chasing down THE lowest cable resistance.

The matter of 'Damping Factor will surely come up. This is the ratio of the speaker's nominal impedance to the amplifiers specified output resistance (good luck finding that!) For a top notch power amplifier that latter figure could be as low as 0.01 Ohms (at 1kHz, rarely do they give you a plot!) and thus the DF for an 8R speaker would be 800. "Nice" says thee but remember, the speaker's resistance is in that loop so with no cable at all the DF cannot be better than
about two!

That is not to say the amplifier will NOT have some control over the speaker but that is most necessary at the resonance where the impedance rises hugely, speaker DC resistance stays the same but DF for say a 50R resonant peak is now around ten. So, another Ohm or so in the loop is not going to make a huge difference.

These are just MY interpretations and I would welcome any input, especially from such as Phil Ward. Bottom line though? Don't fuss cable resistance for a remote speaker handling a bit of speech reinforcement IMHO.

Dave.