Need input buffer design or ideas for icepower 125asx2 in BTL mode. - Page 2 - diyAudio
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Old 29th July 2011, 09:06 AM   #11
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stokessed, thanks for information.

As StigErik has no problems running these with a miniDSP i think there'll be no problem with this input impedance. I'm going to build 2 (later +2 = total 4) subs controlled with one miniDSP.
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Old 29th July 2011, 11:06 PM   #12
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If you are building subs, you have no problems with the dropping input impedance at higher frequencies regardless of input circuit


Sheldon
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Old 30th July 2011, 02:22 AM   #13
toufu is offline toufu  United States
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Would a b1 buffer suitable here?
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Old 10th August 2011, 04:45 PM   #14
Tangman is offline Tangman  United States
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Hi Everyone -- long-time lurker and 1st time poster.

I've never built anything before unless it was made of wood, so there's my skill level. This site has always yielded good and/or interesting info which helped guide my hardware purchases, but I've never (yet) dived into an electronics project.

So, I don't know if anyone cares to help me with my ignorance (it's a big job!) but I'm wondering about the DIY possibilities of these 125asx2 modules. After reading the datasheet it seems easy enough to assemble a stereo version, but I'm confused about bridging them. I was under the impression it was a matter of a jumper to switch from SE to BTL, but That's obviously wrong. Is there a nutshell explanation someone can give me of what physically needs to happen to these modules to render them "BTL"? Does it take another version of the board entirely, or an add-on of some sort?
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Old 20th August 2011, 07:42 PM   #15
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Quote:
Originally Posted by Tangman View Post
Hi Everyone -- long-time lurker and 1st time poster.

I've never built anything before unless it was made of wood, so there's my skill level. This site has always yielded good and/or interesting info which helped guide my hardware purchases, but I've never (yet) dived into an electronics project.

So, I don't know if anyone cares to help me with my ignorance (it's a big job!) but I'm wondering about the DIY possibilities of these 125asx2 modules. After reading the datasheet it seems easy enough to assemble a stereo version, but I'm confused about bridging them. I was under the impression it was a matter of a jumper to switch from SE to BTL, but That's obviously wrong. Is there a nutshell explanation someone can give me of what physically needs to happen to these modules to render them "BTL"? Does it take another version of the board entirely, or an add-on of some sort?
BLT means that the two channels will have to work 180 derees out of phase. To get them to do this, you must build a phase inverter circuit and feed the output from this to one of the inputs. The other input should recieve the original signal directly.

You will only get one BLT channel pr. ASX2 board.

Warm regards
\\\Jens
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Old 3rd February 2013, 10:44 PM   #16
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I want to start my 125ASX2 project and want them to run in BTL mode. Can someone take a look to my picture i've modified if this wiring from a balanced source is correct? I'm not an expert in this kind of stuff:

Click the image to open in full size.
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Old 5th February 2013, 09:07 AM   #17
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Katarakt,

Yes, this should work fine :-)

BTW: I have designed a Phono -> Balanced converter PCB that fits the ASX2 series nicely.....

\\\Jens
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Old 5th February 2013, 03:35 PM   #18
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Great, thx a lot!

Phono to Balanced converter sounds great, do you have a picture? Is it small?
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Old 13th February 2013, 11:46 AM   #19
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Jens,
I'd also be interested in getting more info on your PCB.
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Old 8th September 2013, 11:21 AM   #20
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A few days ago i've finished my BTL mode signal header cable for my 125ASX2 with balanced input signal. Can someone tell me if this wiring is correct?

Click the image to open in full size. Click the image to open in full size.

(As i've measured Pin 6+7 GND is bind together on the 125asx2 mainboard). On the pic: pin1 is on the left side.

The balanced signal comes from my miniDSP balanced. Test was ok, looks like it's workig but if i drop the miniDSP output signal level to 0, or near 0, i hear a tiny bit of background noise that can be heard a few inches from the speaker. This backround noise has always the same volume. If i increase the music level you don't hear it but at very low music volume you can hear the background noise.

I've heard in BTL mode the 125asx2 should be dead silent? So maybe my wiring is wrong or the miniDSP gives some backround noise to the icepower? Input signal to miniDSP is unbalanced, output from miniDSP balanced to 125asx2.

Last edited by katarakt; 8th September 2013 at 11:24 AM.
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