500W of ICEpower for USD$100, deal or not?

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darkzyf

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Joined 2014
Hi everyone, I just received it and here're the guts:D It's indeed 125asx2!

only connect to desktop system with a brief listening, i prefer not to comment on how it sounds yet, but build quality is great and it seems have a preamp buffer built in.

thank you mga2009 for the great find!
 

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hifiamps

Member
Joined 2016
Bearman said:
So, is the 3.5mm input connected to the preamp and the differential input in the back not? Just curious since I just ordered one :)
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From the picture by darkzyf, it looks like the balanced 1/4" inputs connect to the preamp board powered from the AUX supply jack of the 125ASX2. In the 125ASX2 datasheet, it says that in BTL mode, Vin channel 1 needs an outboard inverting opamp (Figure 17). Also, in the online FA-500 manual it says in BTL mode: "Note that if you have a stereo source audio signal, the LEFT/RIGHT channels will be mixed into a mono signal. You can still adjust the volume of the LEFT/RIGHT mix by using the LEFT and RIGHT gain knobs on the face panel."
In the picture here by darkzyf it looks like there is another preamp board at the far end on the output side of the 125ASX2.
 
Nisbeth

Nisbeth

Member
Joined 2001
theslowdiyer.wordpress.com/
hifiamps said:
In the 125ASX2 datasheet, it says that in BTL mode, Vin channel 1 needs an outboard inverting opamp (Figure 17).
Click to expand...
Only if you want to use the same SE source as when you operate the module in SE-mode (look at fig. 17 and you'll see an SE-source).

BTL mode with a balanced source on a TRS plug does not need that inverter (at least when we talk about the "raw" module - not sure how these amps are wired).
 
H

hifiamps

Member
Joined 2016
Nisbeth said:
BTL mode with a balanced source on a TRS plug does not need that inverter (at least when we talk about the "raw" module - not sure how these amps are wired).
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The amp has two single ended inputs in stereo mode and in BTL mode the Channel one is the inverting input for a balanced input, correct? Thank you for clearing that up. It looks like I be pulling the modules from these.
 
M

menlobob

Member
Joined 2017
hifiamps said:
The amp has two single ended inputs in stereo mode and in BTL mode the Channel one is the inverting input for a balanced input, correct? Thank you for clearing that up. It looks like I be pulling the modules from these.
Click to expand...

Based on the manual here http://www.vocopro.com/products/pdf_manuals/featheramp.pdf it appears the preamp is used for both single ended and balanced connections and will mix a stereo signal down to mono in bridged mode.

I have both bridged and stereo 125 amps I built this spring that I can A/B test against these this weekend.
 
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