Teach me PA Systems - Conference Room, Community Center?

[SomeGuy]

You'll probably turn your nose up at it, but I snagged one of these for ~$160 with tax and shipping.

Concert 288 Handheld Wireless System | Samson

Take the worry out of wireless with the Concert 288 handheld wireless system. Offering easy setup, flawless operation and premium sound, it's the ideal high-performance UHF wireless solution.

samsontech.com

Not the worst, at least it's UHF (avoid the 2.4ghz stuff like the plague, wayyyy over saturated band) and assuming it's in a clear legal band where you are, will probably work fine.

 

[Roc Doc]

Not the worst, at least it's UHF (avoid the 2.4ghz stuff like the plague, wayyyy over saturated band) and assuming it's in a clear legal band where you are, will probably work fine.

I've got a two channel Shure UHF system, UL or UR or whatever the top level system was at the time, that was going to get thrown away when the new bands were changed by the FCC. Works fine and have not had any problems of getting stepped on by HDTV. Also have an old Vega VHF mic that was the shit back in the 90's, it works fine as well.

 

[Lee]

Not the worst, at least it's UHF (avoid the 2.4ghz stuff like the plague, wayyyy over saturated band) and assuming it's in a clear legal band where you are, will probably work fine.

This place is rural, no internet let-alone WiFi in the Community Center, not even at the nearest neighbor's place (my grandmother's house). The neighbor across the road is a younger guy, probably has WiFi but he's 100+ yards away.

The Library (managed by the same governing body as the Community Center) has fiber and free WiFi, a little over 1/4 mile away. There's line of sight I think, looks like it on Google Maps, between the SE corner of the Library and NE east corner of the Community Center. My goal after the PA system is to set up a wireless bridge between the two and set up a couple APs in the Community Center. Longer term I want to run some out to the ball fields too.

 

[SomeGuy]

This place is rural, no internet let-alone WiFi in the Community Center, not even at the nearest neighbor's place (my grandmother's house). The neighbor across the road is a younger guy, probably has WiFi but he's 100+ yards away.

The Library (managed by the same governing body as the Community Center) has fiber and free WiFi, a little over 1/4 mile away. There's line of sight I think, looks like it on Google Maps, between the SE corner of the Library and NE east corner of the Community Center. My goal after the PA system is to set up a wireless bridge between the two and set up a couple APs in the Community Center. Longer term I want to run some out to the ball fields too.

Those wireless mics you bought aren't on 2.4ghz, they're probably somewhere in the 400-700mhz range...what I was saying is avoid 2.4ghz wireless mics, which you did, which is good and means they should work perfectly fine.

I've got a two channel Shure UHF system, UL or UR or whatever the top level system was at the time, that was going to get thrown away when the new bands were changed by the FCC. Works fine and have not had any problems of getting stepped on by HDTV. Also have an old Vega VHF mic that was the shit back in the 90's, it works fine as well.

Yeah, buddy of mine has a Sennheiser wireless in the 600mhz whatever no longer good range, still works fine and just hope they CRTC (our FAA) doesn't come snooping around ever lol

My Shure BLX is in the H9 band and SLX-D in the G58 band, so both in the good legal areas here, so I don't have much to worry about unless they fuck around again with the bands.

 

[Lee]

eBay seller of the bad amp has been surprisingly easy to work with. They sent me another one but the new one doesn't work and is missing a bunch of screws. Someone has had it open before. 🫤

Seller claims to not have a way to test them other than powering on.

Internet claims the speaker protection relay is a common failure on these. May be the culprit on this 2nd one, it powers on but absolutely no output, not even a hiss or power on pop.

 

[Lee]

Confirmed the speaker protection relay was bad. Found a reasonable replacement on Amazon.

Dong Woo DW321-D12S is the bad one. New one is a lot shorter and advertised as 10A but the text embossed on it says it's 12A, maybe it's only 10A for DC?

Here's the new relay installed. It's the thing that says NTE on it.

Also found the fan was missing on the 2nd amp. There's supposed to be an 80mm fan in front of the big aluminum heatsink all of those mosfets are screwed to.

After replacing the relay on the 2nd amp and powering it up, a capacitor blew on the right side input/graphical signal indicator circuit board, and let all of the factory smoke out. I replaced that cap, and had audio working on both channels, but the graphical display didn't work. I wound up just swapping that board from the first amp into the second amp.

I used the front panel and potentiometers from the first amp as they were in better shape, and I had already swapped front panel while trying to diagnose the graphical display issue and didn't see any point in swapping it back. The speaker level output board on the first amp was in better shape than the second one, so I swapped it too.

Without knowing any better I thought one of the wires on the board was being really stubborn to pull out, so I pulled harder. Turns out it wasn't in a socket on the board it was in a little plastic terminal permanently affixed to the board. My Optometrist has been trying to put me in bifocals for 4 years now, it may finally be time. I improvised a new solution.

It all seems to be working now. The eBay seller has been great, really bent over backwards to help. Without the second spare parts amp I would have never fixed the first one. I guess really, I used parts from the first amp to fix the second amp. Regardless, dgd_surplus on eBay is good people!

 

[Lee]

Acquired a 12U rack off FB Marketplace, even had it delivered.

Cattle dog approved:

It's got a glass front door not pictured. It's also upside down in the photos. It hinges away from the wall too. Looks like a pretty good place to house a bunch of secondhand audio gear.

Roof is done on the Community Center, drop ceiling is next. I should have everything ready by the time the ceiling is done.

 

[Lee]

Any advice on getting rid of hiss?

I think I've isolated it to the wireless microphones. The Shure mixer has noisy pots when turning them but they don't make any noise if you aren't turning them.

I made my own XLR to Phoenix mic cables for the wireless receiver, I used shielded 3 conductor cable, hiss is only there if they're plugged into the Samson wireless receiver. Hiss is only present on the channels the wireless receiver is plugged into. I tried 4 or 5 different channels on the mixer, hiss is on whatever channel the microphone receiver is plugged into. I plugged a wired Shure SM48 into one of my DIY cables, no hiss with it so I don't think it's my cables.

I guess there might have been a reason someone was selling these on eBay. Sucks as this is the most expensive component I've got so far.

Mics really pick up a lot of handling noise too.

We could probably live with the hiss, but I'll never, not, notice it, and it will annoy me to no end.

I know some of you tried to talk me into higher end mics, champagne dreams on a Pabst budget.

 

[Lee]

Confirmed the microphone receiver was the problem. It's better, probably good enough for what it is.

Most folks claim ground loop problems are a hum sound not a hiss, but I read a few anecdotes of ground loop eliminator removing hiss, so I decided to start throwing parts at it.

That made a difference, more so at first. I can't reconcile why, but it knocked 80% of the hiss out first time I used it, then after powering it off and back on it got got a little worse. Not as bad as without the Hum Eliminator, but not as good as whan I first installed it, maybe 50-60% improvement.

I tried a different 15V wall wart for the wireless microphone receiver that some people on Amazon claimed to have helped their RF noise on some of their audio equipment. It actually made a hum and a hiss, WAY worse than the stock Samson wall wart.

I rigged up a DC noise filter. Back to back comparison with and without, it helps but very little. So little that I'm debating whether or not to even mess with 3D printing a housing for it.

And in all of my messing around I discovered quite by accident the biggest improvement and reduction in RF noise is determined by the orientation of how the Samson wireless microphone wall wart is plugged into the outlet. It's a basic switching transformer like millions of other electronics use, both prongs are the same size, it should be orientation agnostic. However, it turns out 80%+ of the noise is gone if I just plug the wall wart in 180° from what would otherwise appear to be the "correct way."

I snagged a 15V linear DC power supply off of eBay. I'll give it a try, if it doesn't make any difference, I think I've pretty well determined - It's as good as it's going to get.

 

[SomeGuy]

lol yup, shit wireless mics, lots of hiss and noise. No squelch adjustment? That is what old shitty mics would have to adjust noise floor. Could alternatively use a noise gate on it, but that isn't necessary on any decent mic.

 

[Lee]

lol yup, shit wireless mics, lots of hiss and noise. No squelch adjustment? That is what old shitty mics would have to adjust noise floor. Could alternatively use a noise gate on it, but that isn't necessary on any decent mic.

Only volume knobs on the receiver and a plastic Philips head gain in the battery tray of each handheld microphone, no squelch. The power button on the microphones doubles as a mute button, short press mute, long press powers off.

Something like this? There's a guy with a couple of these on Marketplace asking $40 a piece. That's a lot of knobs.

Behringer | Product | XR4400

www.behringer.com

Does the gate go between the source and the mixer or between the mixer and the amp?

 

[bgaidan]

The more knobs you have, the more people are going to fuck with them to "fix" the sound.

 

[SomeGuy]

Only volume knobs on the receiver and a plastic Philips head gain in the battery tray of each handheld microphone, no squelch. The power button on the microphones doubles as a mute button, short press mute, long press powers off.

Something like this? There's a guy with a couple of these on Marketplace asking $40 a piece. That's a lot of knobs.

Behringer | Product | XR4400

www.behringer.com

Does the gate go between the source and the mixer or between the mixer and the amp?

Usually gates go on the inserts on a channel, which is after the pre-amp but before the channel strip. Not sure the line mixer can do that. It's also not a great fix, all of my wireless gear is dead silent and I have zero need to use a noise gate with it.

 

[Lee]

The more knobs you have, the more people are going to fuck with them to "fix" the sound.

I've thought about that quite a bit.


The wall mount rack has a locking glass door. I'm going to put the key in one of these either on the wall next to it or on a side panel:

I'm probably going to 3D print covers for everything just to keep accidental knob knockers at bay.

I'm on the fence about how much more complication I'm going to add. I've already got a single gang, wall mount, remote volume knob and a VCA to be able to control volume from the main room. I have considered putting a keyed switch on the wall next to it to control a 120V relay that turns the whole system on and off. Just using the key to open the door and flip the switch on the power strip would be easier and if I have all the temptatious knobs covered, hopefully folks will keep their booger hooks off of them. Just tell whoever is using it the code to get the key, open the door, flip the red switch.

 

[Lee]

Usually gates go on the inserts on a channel, which is after the pre-amp but before the channel strip. Not sure the line mixer can do that. It's also not a great fix, all of my wireless gear is dead silent and I have zero need to use a noise gate with it.

Well I'd like to not add anymore to the stack of audio stuff than necessary, I only have a 12U and already have 5Us worth of second hand audio gear in it. I'd like to have room for future networking hardware still.

I'm sure it's just another Band-aid, but I've got one of these too. I was considering putting it between the mixer and the amp. My order of TRS cable ends got lost in shipping for a while, so I haven't tried that yet. Any chance a second hum reducer will knock out what the first one doesn't? I bought this one because I haven't had great experience with Pyle and Behringer seems to be a more well reguarded brand for this kind of stuff. I just got the Pyle version before the Behringer, and to my surprise the Pyle actually helped quite a bit, as I mentioned earlier. I should probably put the Behringer in place of the Pyle first to see if it makes an improvement.

 

[SomeGuy]

You don't have a hum problem, that's ground loop type issues usually....you have a hiss problem, which is noise in the actual signal. I doubt those little hum destroyer boxes will fix anything, they're usually just a transformer inside the isolates the input/output sides from each other.

 

[45acp]

So uh.... how far outside of the $500 budget are you?

 

[Lee]

So uh.... how far outside of the $500 budget are you?

A little bit. Not as bad as you might think. $663.13 as-is right now, it's fully functional and exponentially better than what they had. I'd just like it to be a little better. It's nice to want things. I'll probably spend another $40-50 in speaker wire. So call it a $700 PA system.

Power Strip: $27.19
Mixer: $32.63
Amp: $85.15
Wireless Microphones: $164.84
Bluetooth receiver: $20
Mono summing cable: $6.95
RDL VAC: $16.31
RDL Volume knob: $16.31
Spears (1st pair): $43.54
Speakers (2nd pair): $46.19
Speaker Mounts: $33.86
12u Server rack: $100
12p Terminal block: $9.99
24' shielded 18-3 wire: $8.99
Pyle Hum Eliminator: $24.99
Behringer Hum Destroyer (probably won't use): $16.20
DC Noise Filter: $9.99
15v Linear power supply (may not use): $12
4 pairs of XLR plugs: $9.99
4 pack of male TRS plugs: $13.04
5 pairs of banana plugs: $17.95
1 Female TRS plug: $7.60
20 pack of Phoenix connectors: $8.17