Need input buffer design or ideas for icepower 125asx2 in BTL mode.

[JensRasmussen]

Hi,

Chances are that the mini DSP (that I have no experience with) is a tiny bit noisy... even as few as 100µV of noise on the input of the amp will be detectable by ear.

What happens if you short pin 5 to 8? It should be very silent.

I'm building a box with 125ASX2 at the moment including a phono to balanced buffer.

Best regards
Jens

 

[katarakt]

Short pin 5 with pin 8? The red and white input signal? Does this damage the 125asx2?...i'm afraid to do this.

Maybe the miniDSP is a bit noisy, i don't know really, some say it is silent, somewhere i read it's noisy so i can't test the miniDSP somewhere else at the moment.

The other thing is, i've only 1v coming from my "pre-amp" yamaha rx-a3010, going through the miniDSP which gives this out to the icepower. The icepower needs 1,99v input sensivity as i know. So, how can i get the 1v transformed to 2v ???

 

[nFORCE]

A BTL module is add into 125ASX2

 

[DQ828]

I have built a sub and used the attached diagram to wire the 125ASX in BTL mode, the Sub gets it's signal from a MiniDSP that combines the L&R channels and the mono signal is sent to the sub via a single RCA cable. Even though I have wire the signal to the 125ASX as per the diagram once it get to the Sub, what I haven't done is invert the signal to one of the channels.

After reading through this thread I assume I should be inverting the signal to one of the 125ASX inputs?

Can anyone advised the best way to do this please.

 

[Zero D]

@ DQ828

See here http://www.diyaudio.com/forums/anal...quested-mini-buffer-preamp-3.html#post3908201

 

[recepky]

Hi
I am not familiar with electronics, but I want to use my two 125 asx modules in BTL mode with unbalanced input!

I have a DIY Tube Preamp (Glassware Audio - Aikido 12Vac) and I am using one of my modules in SE mode, my speakers are KEF LS50, I dont hear any high freq. drop out, but I feel some of the mid range and upper mid bass is weak.

My question is:

1-Do I need input buffer for BTL mode? (remember I have a tube preamp)

2-If I need input buffer, can you suggest any simple buffer or anybody sells it directly?

 

[Jonse]

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?

http://abload.de/image.php?img=btlwiring4psow.jpg

(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.

Hi,
Did you figure out the wiring and the noise from 125asx2 with minidsp? I am building my own amp with 125asx2 right now with minidsp as preamp. I have wired it the same way you did, and I saw Ghentaudio seems to do it the same way. I hope its right