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Speaker Pops When Powering DIY Cube Speakers

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Speaker Pops When Powering DIY Cube Speakers

Postby dlsmusic » Fri Mar 05, 2021 1:16 am

I made my own powered cube speakers, along the lines of Auratones as a midrange reference. I'm using a Kemo 18W power amplifier in each speaker (Model No. M033N). I get a loud pop when I power up the speaker. Has anyone encountered a similar issue and if so, were you able to find a remedy (e.g. adding some components or circuitry)? Any insight would be greatly appreciated!
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby James Perrett » Fri Mar 05, 2021 2:40 am

I don't know that particular module although Kemo are usually a good make. One solution to switch on spikes that I've seen recommended is this Velleman module (which also provides some protection to the speaker)

http://www.velleman.co.uk/contents/en-uk/p240.html
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby forumuser931182 » Fri Mar 05, 2021 8:27 am

Unfortunately probably a feature of a cheap power amp IC. Unknowable what’s inside the memo module but probably something like a TDA2030 Amp ic. Because it is only using a single dc supply there may well be a capacitor on the speaker output which would reduce the pop a small bit. Probably best option is to buy a speaker relay module - slow start so speaker only connects after a couple of seconds. Otherwise buy a more expensive amp with soft start function.
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby forumuser931182 » Fri Mar 05, 2021 8:41 am

https://www.velleman.eu/downloads/0/ill ... _k4700.pdf

This is the velleman kit mentioned previously. You would need to see if it runs on a single supply like the speaker amps do.
The cheaper option is just a simple switch on the speakers themselves.
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby ef37a » Fri Mar 05, 2021 9:41 am

Or, make your own,
https://www.learningelectronics.net/cir ... delay.html
But yes, cheapest option is a switch in the speaker circuit but if you do that, don't forget to put a 'drain' resistor across the amplifier's output pre switch or you will still get a plop when you switch on the speaker. 220R would suite but not at all critical.

Actually! A switch is probably the best idea as it gives you a quick mute facility. Or, if you build the relay circuit you could incorporate a remote mute into that. SPSW switch to turn off the transistor.

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Re: Speaker Pops When Powering DIY Cube Speakers

Postby dlsmusic » Fri Mar 05, 2021 12:03 pm

Thank you all very much for your thoughtful replies. It's much appreciated. I think I'm going to go the route of adding a switch to the speakers. That should do the trick. The delay relay circuit was a nice option but I don't have any AC voltage in the speaker, just 18VDC.

I must say, this was my first post on this forum and you're a kind bunch of folks. Thanks again!
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby ef37a » Fri Mar 05, 2021 12:44 pm

dlsmusic wrote:Thank you all very much for your thoughtful replies. It's much appreciated. I think I'm going to go the route of adding a switch to the speakers. That should do the trick. The delay relay circuit was a nice option but I don't have any AC voltage in the speaker, just 18VDC.

I must say, this was my first post on this forum and you're a kind bunch of folks. Thanks again!

My apologies! I did not see that circuit was run from 24V AC. You could I am sure run it from the 18V supply (leave out the diode) with a 12V relay. Bit of Ohm's law will get the right voltage on the relay with a resistor. If you DO have a go at that delay circuit do NOT leave out the diode across the relay coil or the transistor will be instantly destroyed!

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Re: Speaker Pops When Powering DIY Cube Speakers

Postby James Perrett » Fri Mar 05, 2021 12:50 pm

The Velleman kit runs from a mains supply - no need for any special powering.
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby ef37a » Fri Mar 05, 2021 12:54 pm

James Perrett wrote:The Velleman kit runs from a mains supply - no need for any special powering.

Point taken James but I am never comfortable suggesting folk mess with mains voltages when I don't know their technical ability.

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Re: Speaker Pops When Powering DIY Cube Speakers

Postby James Perrett » Fri Mar 05, 2021 1:30 pm

ef37a wrote:
James Perrett wrote:The Velleman kit runs from a mains supply - no need for any special powering.

Point taken James but I am never comfortable suggesting folk mess with mains voltages when I don't know their technical ability.

Dave.

I must admit that I was assuming that someone who has a Kemo amplifier module knows a bit about electronics. They're not the most obvious brand to buy and seem to be mainly available from specialist places like Rapid.
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby ef37a » Fri Mar 05, 2021 2:05 pm

James Perrett wrote:
ef37a wrote:
James Perrett wrote:The Velleman kit runs from a mains supply - no need for any special powering.

Point taken James but I am never comfortable suggesting folk mess with mains voltages when I don't know their technical ability.

Dave.

I must admit that I was assuming that someone who has a Kemo amplifier module knows a bit about electronics. They're not the most obvious brand to buy and seem to be mainly available from specialist places like Rapid.

Ah yes, got one of those somewhere. I would bet OP is running it on a wall rat?

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Re: Speaker Pops When Powering DIY Cube Speakers

Postby dlsmusic » Fri Mar 05, 2021 6:22 pm

I'm located in the US where I purchased the Kemo amp module from an online dealer called Parts Express. And yes, I'm running the amplifier module using a wall wart. As such, I'm reluctant to add a delayed relay that would need AC power.

I'll be adding a speaker mute switch that should do the trick. I'd essentially be doing what the relay would be doing except I'll be switching the speaker on manually. Once installed, I'll come back here and report on how effective that solution was!

Thanks for all your support! Truly appreciated.
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Re: Speaker Pops When Powering DIY Cube Speakers

Postby dlsmusic » Sat Mar 06, 2021 11:38 pm

I added the speaker mute switch along with the bleed resistor and it works like a charm! I tried different resistor values until settling on 1k ohm. Thank you all so much for your help!

The speakers sound great. Mostly midrange which is what I was looking for. This was a fun project!
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