diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Solid State (http://www.diyaudio.com/forums/solid-state/)
-   -   where is short wiring in an amp important/ not important ? (http://www.diyaudio.com/forums/solid-state/31530-where-short-wiring-amp-important-not-important.html)

sandro600 3rd April 2004 12:03 PM

where is short wiring in an amp important/ not important ?
 
Dont know if this question makes sense. But if I ask about specific examples it might be clearer.

Is length of wire from output transistors to speaker terminals on the back of the amp important ?

Is wiring length from chassis mounted volume pot to pcb ?

Or from the RCA input to the PCB/pot ?

what about within the circuit ?

Gainclone fans go to a lot of trouble to put the power supply caps right next to the chip. Does this apply to non chip amps ?

what about the length of ground wires/pathways?

Any explanations ?

Thanks

li_gangyi 3rd April 2004 12:05 PM

the gainclone has got the caps so near for decoupling purposes as the main chip itself is essentially a very powerful opamp...as for "normal" amps it is not so critical...but if the power supply is located quite a distance...sometimes some caps are needed on the board itself...if u know wad i mean...

leadbelly 3rd April 2004 09:35 PM

The short answer is that you should always make wiring as short as possible. If you have to make some runs longer, you must look into specifics of the amp design.

Depending on the amp, in some areas it can be critical. The reason GainClones are the way they are is the minimalist approach - super short feedback path to avoid extra components there to guarantee stability.

Do you have a specific amp design in mind?

sandro600 4th April 2004 01:44 AM

Quote:

Do you have a specific amp design in mind?
Yep , Rod Elliots P3A

some of my ideas ( i dont know if they are right) include:

from output transistors to speaker terminals on the amp should not matter since theres going to be a length of loudspeaker cable.
The portion of wiring within the amp represents only a small portion of the total length.

Ive read somewhere ,and cant find the reference now that emphasised making the connections from volume pot and pcb ultra short if possible mounting the pot onto the pcb but why I dont know. Indeed elliott sells pot extension shafts to achieve this.

If the tracks on a pcb are so close together can you not get unintended EMF going from one track to another ?

leadbelly 4th April 2004 03:08 AM

Quote:

Originally posted by sandro600
Indeed elliott sells pot extension shafts to achieve this.

That's it, follow the designer's recommendations above all.

Quote:

Originally posted by sandro600
from output transistors to speaker terminals on the amp should not matter since theres going to be a length of loudspeaker cable.
The portion of wiring within the amp represents only a small portion of the total length.

Careful now, the hardcore guys who bi-wire all the way back to the star-ground inside the amp might flame you :D

Quote:

Originally posted by sandro600
If the tracks on a pcb are so close together can you not get unintended EMF going from one track to another?
Not sure how this relates to your topic, but if you are wondering why traces can be so close and still avoid noise, etc., that is because the EMF pattern is very different for a plane than a round wire.

lucpes 4th April 2004 03:10 AM

Quote:

Originally posted by sandro600


If the tracks on a pcb are so close together can you not get unintended EMF going from one track to another ?

Negligeable.

The worst case of using wires would be from pcb to output devices. Had one B&O receiver that did just that and it was on the edge of stability.

Do not run signal input and output wires together and as a rule of thumb keep every connection as short as possible (just enough to accomodate enclosure placement) and for power supply /star ground/ and speaker out use the thickest wire possible (14ga will suffice) and solder when possible rather than using crimped connections. Keep all returns to star ground the same length though...


All times are GMT. The time now is 07:03 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2