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DIY Bi-Amp setup for front 3 channels

18K views 66 replies 5 participants last post by  NBPk402 
#1 ·
I am going to give building an amp a try now. I just ordered a Bang & Olufsen ICEpower 50ASX2 SE 2x50W Class D Amplifier, and a B&O ICEpower 125ASX2 amplifier module. This will give me enough power to power 2 of my new speakers (bi-amped). Iam still looking for one more of each to finish off the amp, and an enclosure. I am hoping this turns out to be pretty easy to build. I need to still find the banana jacks, power connector, and a power button for this too. Am I forgetting anything? I will have to make up the wires for wiring too.
 
#3 ·
Still tinkering, eh Ron?! From this pic I found of the module's back panel, it seems this particular version also has a balanced input and a switch to toggle between AES/EBU and RCA input connections.



And here's the front panel. Nice enclosure, eh?
Louie, your links did not work for me.

How about power, is that covered? Those amp modules can be very capable, looking forward to your writeup.
 
#6 ·
I found 2 more amp modules, so now i have enough to do the front 3 channels bi-amped. I will try to arrange the modules so i can run all the channels in the Elan case (if I get it).
 
#7 ·
I meant AC power, but I am sure you thought of that, too.

Here is a thought, kinda along the perfectionistic way of looking at things.

A spec that is hard to find these days for most power amps is crosstalk, or channel separation, which tends to decrease with frequency and can impact SS&I at high (10 kHz) frequencies.

Best way to make it not an issue would be to do vertical bi-amping, where the two channels of an amp are used to power the two drivers of the same speaker. Don't know how that would mess up your plans and don't know how much audible difference it would make. Just a thought.
 
#9 ·
I meant AC power, but I am sure you thought of that, too.
ICEpower's feature sheet shows these modules are fully protected. I wonder if their recovery mechanism includes visual feedback. Are there any indicators that can alert the user to fault conditions? I imagine a non-functioning channel/driver would be a giveaway in a 2-way configuration, but might take awhile to detect depending on program material and playback volume. I'd prefer something a little more obvious like a power indicator changing from green to red, or better yet - flashing. Connecting the modules to a master fuse/breaker is beyond my area of expertise, and has questionable benefits for such well-protected devices. Still, I'd be more comfortable with an indication something is amiss - if for no other reason than to diagnose a problem.

Here is a thought, kinda along the perfectionistic way of looking at things.

A spec that is hard to find these days for most power amps is crosstalk, or channel separation, which tends to decrease with frequency and can impact SS&I at high (10 kHz) frequencies.

Best way to make it not an issue would be to do vertical bi-amping, where the two channels of an amp are used to power the two drivers of the same speaker. Don't know how that would mess up your plans and don't know how much audible difference it would make. Just a thought.
In my quest to obtain more performance from my stereo system, I crossed a path where I obsessed over channel separation. Long story short, I wound up with one monoblock per channel. No direct A/B comparison could be made - how convenient say the objectivists! - because stereo amp "A" was converted to mono. But I knew in my heart that the system sounded more like music than a assemblage of mechanical parts making musical sounds. Or so I believed. So if you believe, then you too can experience the difference low crosstalk can make (I jest, of course).
 
#11 ·
What would happen if I took 2 2x4 MiniDSPs, and mounted them inside the case...would I still need level controls or could I just use the gain in the 2x4s?
 
#14 ·
Wasn't that a great mini amp! If I don't win the amp I am looking to use as a donor, I am thinking of making a amp case out of Aluminum, and Ironwood. I really like some of the designs I saw where the amps were made out of wood/plexi/aluminum.
 
#15 ·
I BELIEVE the answer is - yes and no.

Both miniDSP 2x4 units will have gain which can be controlled by a remote, and both can be programmed to respond to the same remote, BUT, there is no gain readout (without USB connection to a computer) and keeping the two gains in sync while being changed by the remote is not something I have ried and I am guessing there might be circumstances where they might get out of sync. That would NOT be so good.
 
#16 ·
What i meant was to use the gain control via Windows, save it, unplug the USB, and let it go. Since I don't use a remote the settings should stay, correct?
 
#20 ·
4x10 is much more expensive though, plus I only need 6 channels total...2x4 is 2 channels more than I need too. I am going to order the kit version, and remove the RCAs.

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#22 ·
I will take some pictures as I progress on this new project. Right now all I have are a bunch of amp modules for the front 3 channels. I plan on getting 4 more amp modules next week, and also i need to order 2 MiniDSP 2x4s for the amp. I have a Elan 16 channel amp arriving next week that doesn't work. If we can fix it i will sell it, but if not it will be the enclosure for my amp build (I got a real good deal on this, but my friend thinks it is better to fix it and sell it for a little profit. I hope to be moving forward on this over the next 2 weeks, and I am hoping it will be a pretty quick build.
 
#23 ·
Some questions...
Would it be advantageous to add a large cap for each amp Module?

What would be the advantage?

What would the disadvantage be?

What should I use for wiring up the MINIDSP to the amp internally? Do I just take a RCAs, and cut it in half, solder the ends to the amp module, and the rear panel?

Would it be worth it to use a DIY Kimber Cable style braided wires for all the internal wiring?

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#24 ·
Okay, I'll take a stab at this based on some research, but I think we need an expert to chime in :R. Hope I don't belabor the obvious!

Some questions...
Would it be advantageous to add a large cap for each amp Module?
What would be the advantage?
What would the disadvantage be?
On first read, this reminded me of the caps car-audio enthusiasts add to support current draw from a vehicle's electrical system. With powerful or multiple amps, loud passages can cause enough draw to temporarily drop system voltage (ref this article). But outboard caps supply extra current up to their rated capacity. This is an advantage which smooths out current peaks in response to musical demands, keeping it dynamic instead of flat or distorted. A disadvantage is the risk for electrical shock. So what about the electricity in your home? Do we have enough info to calculate total current draw under max operating power (I=P/V)?

Would it be worth it to use a DIY Kimber Cable style braided wires for all the internal wiring?
It would be cost-effective if you use reasonable quality wire as in this DIY braided cable project. The 3-wire braiding provides for field cancellation and low inductance, while the wire gauge provides for low capacitance. And according to this article, Unshielded Twisted Pair (UTP) cable has advantages that include improved data transmission in EMC-rich environments and ease of installation. Those class-D amps have a whole lotta switchin' goin' on! But on the other hand, they're completely EMI shielded to provide a CE and FCC pre-approved design (Ref: pg.3 of ICEpower manual). It wouldn't hurt to wire everything internally with UTP, but I think it's unnecessary. What if you selectively wire only the sensitive signals with UTP? The trick then becomes how to identify them.
 
#26 ·
#28 ·
Thanks, I will keep looking. I liked the idea of it being a circle. Do they make adapters to a type b connector?

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#29 ·
#31 ·
I have the amp donor gutted now, and it looks like we can reuse the RCA jacks, after desoldering them from the circuit board.

Question...where do I find standoffs for mounting the boards, or do I have to make my own?

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#33 ·
I now have these on the way:

Breakout box:
7 SpeakOn 4 pole male mounting plates
3 SpeakOn 8 pole male mounting plates
1 1u rack mount plate with 8 holes for the Speakon plates
1 1u rack mount plate for the front plate which will get 2 holes punched for the 8 pole SpeakOn plates

Still need to get...

Amp:
standoffs
12v power supply for 2 MiniDSP 2x4s which will be internally mounted

The plan right now is to use the Elan front faceplate with Cumaru wood for the side panels, perforated stainless steel for the bottom, and plexi for the top of the amp case. The back plate will have 16 RCAs for the input, 2 8 pole SpeakOn plates, AC hookup, and power switch. The 8 pole SpeakOn plates will feed all of the channels to the breakout box...which will then split them up into one pair of speakers per connector. This should make it easier to wire for bi-amping the front 3 channels and also allows me to run wire to speakers in pairs (L+R, or L front + L rear). It def should clean up the back of the amp. The breakout box will also have a plexi top, Cumaru sides, and perferated bottom. I will post up pics as soon as I get all the pieces in, and arranged in the case.
 
#35 ·
#39 ·
I also ordered all the RCA jacks, (8) Speakon 4pole, and (8) SpeakOn 8 pole jacks, the metal standoffs, and the PS listed above. Hopefully all the parts will arrive next week so i can start laying these out. I also have submitted a design to Markertek for a rear panel that would have all the puched holes, and labeled (we will see if they will do a one off, and how expensive they are).
 
#40 ·
Parts are arriving daily for the build now. I own have all 8 8 pole Speakon cable ends, and 2 my addon box panels. The addon panels I have will be 4 Speakon 8 pole inputs, and 8 4 pole outputs. I am also working on having the rear panel El for the amp too.


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#41 ·
Lot of activity there! Can hardly wait to find out your impressions when it's all said and done. BTW, it's a small point but did you ever decide on the amp's internal wiring? At one point you were considering a Kimber type braid, IIRC.


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#42 ·
Lot of activity there! Can hardly wait to find out your impressions when it's all said and done. BTW, it's a small point but did you ever decide on the internal wiring? At one point you were considering a Kimber type braid, IIRC.


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I have the wiring kit for the modules...not sure if I will go that route as the wires might be too short. I will be using my MonoPrice 12 gauge wiring for all of my cables out side of the amp including the for SpeakOns that go to the 2nd box for distribution.
 
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