Sonic Impact 5066 Parts List & Modifications

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Lostcause

Lostcause

Member
Joined 2005
Getting there then? Good:)
Just try and get everything on the input side shielded.... Look at the leads to / from the caps... very long and un-shielded.....

I would get rid of the ferrites on the output wires as well...... keep them short.

In a box that big you could create a front partition that totally isolates the input section maybe
 
gychang

gychang

Member
Joined 2005
thanks for all the suggestions.

Lostcause said:
Look at the leads to / from the caps... very long and un-shielded.....

I would get rid of the ferrites on the output wires as well...... keep them short.

In a box that big you could create a front partition that totally isolates the input section maybe
Click to expand...

Lostcause: I will correct the leads to caps/rid of ferrites and shorten the wires...

panomaniac said:
The only time was with a bad biascap. Maybe that's it?

Did it hiss before you took it apart?
Click to expand...

panomaniac: did not hiss before the "mod", which ones are biascap?

mustik said:
Would applying a piece of aluminium tape around the cable (and then another layer of insulating tape on top) qualify as a shielded cable?
Click to expand...

same question from me, can I shielded them using the aluminum+electrician tape?

gychang
 
S

Sharkythefrog

Member
Joined 2006
Easiest way is to "back the process" as far as I can see it as an almost freshmen in this without extremely good testing knowledge and facilities.

Disconnect your USB card - any differens?
If not turn everything of and remove it from the case again - still there or not. If it´s not there start to mount again. Start with input connectors - any differens? and go on.

If you still have the hiss after removing all the case mounted connectors etc. Start to disconnect cables from the board. As its no differens according to volume turn it down to zero.
Start with disconnecting input connectors etc.
 
Lostcause

Lostcause

Member
Joined 2005
mustik said:
Question about the suggestion to use shielded cables: Would applying a piece of aluminium tape around the cable (and then another layer of insulating tape on top) qualify as a shielded cable?
Click to expand...
Yes that will do it... I've done that myself with great results. I wrapped the wires with the foil tape then wrapped a bit of bare wire around that (leaving a good length protruding) and shrunk the lot. You can then earth the shield to the case for even better results...

;)
 
S

Sharkythefrog

Member
Joined 2006
Or just use a 75 Ohm antenna cable for each single wire in the construction. Connect the shield to its inside wire only on the "sending side" of the signal. Ex left input live will have the shield connected at the connector side, and it´s "zero" will have the shiled connected at the board side.

Much easier than building your own shield - better shield and better sound. (even if its not as good sounding as a four twinned cable).
 
Lostcause

Lostcause

Member
Joined 2005
gychang said:
which ones are biascap?
gychang
Click to expand...

That's the cookie ringed in green.....
 

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gychang

gychang

Member
Joined 2005
hiss on the modded t-amp

I shortened and shielded input wires, but the hiss comes on as soon as the unit is turned on, music sounds excellent, good solid base, but the hiss...

funny thing is when I turn on the unit without any music being played, when I turn the volume knob the hiss changes, and seems to lessen as I turn the volume knob. Can not tell if the hiss lessens as the music is playing though.

Any experts?, is this a defective pot? I am almost there...

thanks,

gychang
 
Pano

Pano

Administrator
Joined 2004
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It's a ground problem, pretty sure.

Hum that is level dependant on the volume control is almost always a ground problem. Hiss, too.

I know you have tried a lot of things, but it must be there somewhere. From your descriptions, it still sounds like a ground problem.
 
R

ricebox

Member
Joined 2007
Bringing up kind of an old post but I decided to start to mildly mod my SI T-Amp following this picture:

http://www.diyaudio.com/forums/attachment.php?s=&postid=783363&stamp=1133905808

My question is if i primarily use this amp with my ipod will I need a volume control? Can just just wire C4/C3 to the 2.2uf caps straight to the RCAs? I also noticed that in that picture it lists the resistors in between the caps and the RCAs as optional...what benefit will i get from installing new resistors?


thanks in advanced for helping this noob
:xeye:
 
Lostcause

Lostcause

Member
Joined 2005
I'm currently (on-hold!) doing the same thing.
You have two options:
1. Use the slightly inferior (sonically) headphone jack and use the ipods DSP volume control etc....
2. Use the line-out via the dock connector which I believe cannot be driven by the ipod volume (don't know for sure but that's what I've read), then use a volume pot between the ipod and amp.

The extra mod that I will be testing is DC coupling them without a pot or cap by linking the negative inputs to the bias pin. This is covered on another thread but requires at least one of the components (amp or ipod) to be battery powered (floating).

Good luck
 
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