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Cheap diy amp module for surround speakers


RankStranger
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The right surround channel of my av receiver has died. ?

 

It’s a marantz sr5008 which is 7 x 100w all channels driven. It has pre-outs so my plan is to put an amp in to drive both rears but I have no money to spend on it at the moment. 

 

I was looking on eBay for one of those cheap and cheerful class t or d amps and I came across this https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F143327150308 

 

has as anyone used one of these or know if they’re worth the money or just junk? Is there anything else I could look at in a module or something that I can throw in a case and plug in to a power supply or something. I can solder but that’s about the limit of my expertise. I’m aiming to keep it under $100, if that’s possible. 

 

I had had the idea of rerouting the unused surround back channel amplifier but I wouldn’t know where to start with that or if it’s even possible. 

 

I’d be grateful for any input or ideas I may not have considered

 

thanks, Simon

Edited by RankStranger
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Hey Simon,

I've used three of these modules previously, two Sure 2x300watt for LCR duties and one 4x100watt for surround duties and built them into three separate enclosures with Meanwell power supplies. I replaced a Rotel RB-1092 and a RMB-1095 with these which were silly overkill in my HT. 

 

Pro's:

  • Sound good;
  • cheap
  • modular to some degree.
  • Meanwell power supplies are tough

 

Con's:

  • Fragile- I blew up a few amp boards by hot plugging them, the generation I had needed to be powered off before plugging in RCA's, this may or may not hold true today.
  • Questionable reliability - two lost power to their onboard fans so I had to add some PC case fans and mod the power supplies to suit. That was a hassle!
  • Need an enclosure really - to protect little fingers and house the PS and amp securely as one unit.
  • Quite some effort to build up into enclosures  - unless you don't mind wires and multiple boxes
  • Zero resale value.

 

They were a fun experiment but ultimately I went away from them and added a very nice sounding Yamaha AX-592 integrated to my system to run the L&R's when I switched from a preamp/processor to a HT receiver. I got this  Yamaha in great condition on Gumtree for $100 inc remote.

 

You may be better served by getting a pre-HDMI receiver with 5.1 analogue inputs and running your Marantz pre-outs into the analogue 5.1 inputs for your situation. These are a dime a dozen so to speak on Gumtree.

 

Good luck. 

 

Edited by Maz4bz
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Thanks for your reply, @Maz4bz

 

one of the main attractions is the size, I’m running out of room and thermal capacity in my cabinet, so a 2nd receiver is out. I did have a brief thought of running from the pre-out to the multi-ch in but that didn’t work and I’m ultimately surprised I thought it might.

 

it would make sense to run a better power amp for the front 2 channels and reroute the power but you can only do that to the surround back or zone 2 on my amp so that’s no good 

 

where did you source the power supply from. I had thought of just using a wall wart, is it worthwhile to use something better?

 

Thanks, Simon 

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@max4x

 

awesome post mate :thumb:  real down to earth of what happens when you go diy.  The ultimate thing about diy is not the costs involved but the learning curve and experience  you gain as a DIYer.   And because audio is subjective, a lot of these kits are “unheard” and you take the risk on SQ and reliability.

 

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Thanks for the compliments gents!

 

The Meanwell power supplies are also sold by Sure. All you need to do is match the volts of the board to the appropriate power supply (PS). Just understand that the board is only as good as the PS that supplies it in terms of output power. Don't skimp on the amps capacity of the PS or your amp will be throttled by it. Same applies to wall warts, just that generally they are have low amps capacity.

 

I found Sure very good to deal with. The first board that died they replaced free of charge, no questions asked or need to return freight the dead unit. I did all my business through their eBay presence.

 

As a final thought, I reckon one of these kinds of mini amps would be a better bet. Their internals are essentially the same, great features for future proofing but with a nice enclosure and power supply included.....

 

https://www.ebay.com/itm/US-Stock-SURE-2X100-W-Class-D-Audio-Bluetooth-Amplifier-w-Mean-Well-Power-Supply/143317234859?hash=item215e5f74ab:g:Kz8AAOSwXkJavurQ

 

 

Edited by Maz4bz
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13 hours ago, Maz4bz said:

Thanks for the compliments gents!

 

The Meanwell power supplies are also sold by Sure. All you need to do is match the volts of the board to the appropriate power supply (PS). Just understand that the board is only as good as the PS that supplies it in terms of output power. Don't skimp on the amps capacity of the PS or your amp will be throttled by it. Same applies to wall warts, just that generally they are have low amps capacity.

 

I found Sure very good to deal with. The first board that died they replaced free of charge, no questions asked or need to return freight the dead unit. I did all my business through their eBay presence.

 

As a final thought, I reckon one of these kinds of mini amps would be a better bet. Their internals are essentially the same, great features for future proofing but with a nice enclosure and power supply included.....

 

https://www.ebay.com/itm/US-Stock-SURE-2X100-W-Class-D-Audio-Bluetooth-Amplifier-w-Mean-Well-Power-Supply/143317234859?hash=item215e5f74ab:g:Kz8AAOSwXkJavurQ

 

 

Thanks for that. Yes I saw quite a few finished little amps like that. My thought is I’d rather spend as little as possible and get just what I need vs spending more on features I won’t use but it’s still an option to consider. I’m also not super concerned with SQ because these are just rears in a 5.1 system and it’s only a temporary solution (though I’m not sure how temporary)

 

is this the sort of thing I’m looking for? https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F232930029637

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41 minutes ago, RankStranger said:

I'm no electrician but that looks like a LED downlight power supply?

 

A quick search the Sure eBay store will get you LOTS of options. I did include a link to these in my previous post.....:rolleyes:

 

So for example, if you pick this 2x100 (that's more like 2x25 if you read the manual fine print) then you need a 36v PS. There are three there to choose from, you pay more for increasing output in watts (amps).

41 minutes ago, RankStranger said:

I’d rather spend as little as possible

I don't think you will do much better on these kits after adding in the PS. The mini amp will have some resale value. If my experience is anything to go by there is little to zero resale in these kits. 

 

Either way we are not talking mega bucks here, the convenience of the mini amp is what would take me in that direction. 

 

Good luck!

Edited by Maz4bz
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46 minutes ago, Maz4bz said:

I'm no electrician but that looks like a LED downlight power supply?

 

A quick search the Sure eBay store will get you LOTS of options. I did include a link to these in my previous post.....:rolleyes:

 

So for example, if you pick this 2x100 (that's more like 2x25 if you read the manual fine print) then you need a 36v PS. There are three there to choose from, you pay more for increasing output in watts (amps).

I don't think you will do much better on these kits after adding in the PS. The mini amp will have some resale value. If my experience is anything to go by there is little to zero resale in these kits. 

 

Either way we are not talking mega bucks here, the convenience of the mini amp is what would take me in that direction. 

 

Good luck!

You’ve helped a lot and given me a lot to ponder, Maz. Thanks very much for your input. You’re a great example of what I love about stereoNET

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Sooooo... I bought this instead ?

 

DA37BD05-4653-47DC-84E0-3355550C856D.thumb.jpeg.ec75a99fc825d1282cea01439e1e5797.jpeg

 

which was nothing like what I planned to do but... there you go.

 

in all fairness it’s probably not the best solution but i thought it looked cool and I honestly thought it looked smaller than it is (it’s half a metre wide). Regardless, it’s pretty dang cool-looking.

 

I probably should’ve check how well it plays with 4 ohm speakers because I’ve just now read that it doesn’t very well and my rears are 4 ohm so I’ll have to keep an eye on that or potentially swap them with some others I have. It also has din plugs instead of RCAs or bananas so I’ll have to re-terminate some cables or change the plugs on the unit. There’s also some threads and videos about re-capping online so I might try my hand at that, too.

 

If it turns out to be unworkable, I’ll pop it in the garage until I have my second system,  full-range speaker project finished and go to plan B for my rears (B in this case stands for “Bloody hell, what am I going to do now?”)

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The right surround channel of my av receiver has died. [emoji2959]
 
It’s a marantz sr5008 which is 7 x 100w all channels driven. It has pre-outs so my plan is to put an amp in to drive both rears but I have no money to spend on it at the moment. 
 
I was looking on eBay for one of those cheap and cheerful class t or d amps and I came across this https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F143327150308 
 
has as anyone used one of these or know if they’re worth the money or just junk? Is there anything else I could look at in a module or something that I can throw in a case and plug in to a power supply or something. I can solder but that’s about the limit of my expertise. I’m aiming to keep it under $100, if that’s possible. 
 
I had had the idea of rerouting the unused surround back channel amplifier but I wouldn’t know where to start with that or if it’s even possible. 
 
I’d be grateful for any input or ideas I may not have considered
 
thanks, Simon


i would have recommended the B&O ice module. all in one with Power supply built in. 50asx2 for around $120 or 125asx2 for $185

i too have damaged 3 boards by hot plugging or being careless.

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9 hours ago, misternavi said:

 


i would have recommended the B&O ice module. all in one with Power supply built in. 50asx2 for around $120 or 125asx2 for $185

i too have damaged 3 boards by hot plugging or being careless.
 

 

So, does that mean I just need to add a box and plugs to make a power amp?

 

The 50asx2 sounds interesting but I can’t see it anywhere for $120. Can you point me to a link?

 

Thanks, Simon 

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12 minutes ago, RankStranger said:

So, does that mean I just need to add a box and plugs to make a power amp?

 

The 50asx2 sounds interesting but I can’t see it anywhere for $120. Can you point me to a link?

 

Thanks, Simon 

https://www.ebay.com.au/itm/New-Icepower-Circuit-Amplifier-Board-Module-Ice50Asx2-Power-Amplifier-Board-E3R1/183813299690?hash=item2acc205dea:g:~6kAAOSwBApc3S3-


Yep. Box and connectors and you have a power amp. Or if your AVR has space inside you can install inside.

Or go to Ghent Audio and buy a pre drilled box for $75USD.

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6 minutes ago, misternavi said:

https://www.ebay.com.au/itm/New-Icepower-Circuit-Amplifier-Board-Module-Ice50Asx2-Power-Amplifier-Board-E3R1/183813299690?hash=item2acc205dea:g:~6kAAOSwBApc3S3-


Yep. Box and connectors and you have a power amp. Or if your AVR has space inside you can install inside.

Or go to Ghent Audio and buy a pre drilled box for $75USD.

Ah, cheers. That didn’t come up in my search for some reason. That might be a good long-term solution. I’ve heard a lot of ICE implementations that I’ve been pretty impressed with. I’m surprised you can get them at such a reasonable cost.

 

Do you know, are they the same modules that go into the Bel Canto/B&O/Rotel etc or do they just use the same tech?

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Ah, cheers. That didn’t come up in my search for some reason. That might be a good long-term solution. I’ve heard a lot of ICE implementations that I’ve been pretty impressed with. I’m surprised you can get them at such a reasonable cost.
 
Do you know, are they the same modules that go into the Bel Canto/B&O/Rotel etc or do they just use the same tech?

one of a few Bel canto does use the 125asx2 with their own input buffer.
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7 hours ago, RankStranger said:

Ah, cheers. That didn’t come up in my search for some reason. That might be a good long-term solution. I’ve heard a lot of ICE implementations that I’ve been pretty impressed with. I’m surprised you can get them at such a reasonable cost.

 

Do you know, are they the same modules that go into the Bel Canto/B&O/Rotel etc or do they just use the same tech?

oh 1 more thing, make sure your output impedance from your source/pre is LOW (below 200ohms)- these modules have  a low input impedance of around 4-8Kohm.
 

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23 minutes ago, misternavi said:

oh 1 more thing, make sure your output impedance from your source/pre is LOW (below 200ohms)- these modules have  a low input impedance of around 4-8Kohm.
 

Thanks. I’ll make sure I learn what that means before I do anything :)

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1 hour ago, misternavi said:


i couldn’t find what the pre amp output impedance of you marantz receiver was.

Thanks for checking. I really don’t have the budget for it at the moment anyway. I’ll be sure to check it with the distributors’ service desk if I decide to take that route down the track. Thanks again for all your help :) 

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On 07/08/2019 at 2:08 PM, RankStranger said:

I probably should’ve check how well it plays with 4 ohm speakers

Also, how much power do you need to drive your speaker?   (Sorry if I missed where you said that).

 

It's like you've asked "what type of fuel should i put in my car?" .... and nobody has asked "what car do you have?"  :|

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26 minutes ago, davewantsmoore said:

Also, how much power do you need to drive your speaker?   (Sorry if I missed where you said that).

 

It's like you've asked "what type of fuel should i put in my car?" .... and nobody has asked "what car do you have?"  :|

They’re m&k k4 tripoles which is the 15 years ago version of https://mksound.com/products/m-series/m4t/ with seemingly the same specs (though I don’t recall ever seeing the sensitivity published for mine. 

 

They don’t need heaps of power, even thought they’ll quite happily take a lot. Plus, they’re rears so I don’t need them to perform to the standard of say, the centre channel.

 

Also, current model Subaru Impreza ?

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Aaaaand... my rear right channel is working again. Just like that. So I’ve spend the last week stressing, researching, learning, and buying a vintage receiver for... nothing?

 

Of course not!. You guys have been great and I’ve learnt heaps. And I’m really looking forward to fiddling with the Armstrong to get it singing sweetly again.

 

Plus the Marantz might always s#!+ itself again so there’s that. 

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On 09/08/2019 at 12:28 PM, RankStranger said:

Plus, they’re rears so I don’t need them to perform to the standard of say, the centre channel.

Sure... but you need to them to produce the same volume as the centre channel.

 

So, your speakers are about as inefficient as they come....    If you know your peak SPL, then you can have a rough idea of how much power you need to have.

 

An issue with the cheap amplifier modules mentioned is that they may really only deliver a fraction of their rated power (read datasheet carefully).

 

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16 hours ago, davewantsmoore said:

Sure... but you need to them to produce the same volume as the centre channel.

 

So, your speakers are about as inefficient as they come....    If you know your peak SPL, then you can have a rough idea of how much power you need to have.

 

An issue with the cheap amplifier modules mentioned is that they may really only deliver a fraction of their rated power (read datasheet carefully).

 

Sure. I wasn’t looking for a perfect, long-term solution, just an adequate and cheap temporary one. Hopefully the fact that it’s come back on means it’s a either something simple or something I don’t have to worry about for a while

 

I’m aware. Back when I worked in electrical retail we used to call those ratings “xx watts JBIE” (just before it explodes)

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23 hours ago, RankStranger said:

Sure. I wasn’t looking for a perfect, long-term solution, just an adequate and cheap temporary one.

That's all I'm talking about.

 

The minimum viable product here is an amplifier which would drive your rears to the same loudness as the rest of your channels, without catching fire.

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