In the seventies american cars had theire positive battery pole hooked on the chassis of the carbody.JBL had woofers in that time the red speaker connection as negative and the black connection as positive.When you hook those driver on a todays amp and don't turn the connection the cone will move inverse.I think that's why it is important how you wind your coil.
The most important thing is BMW850 didn't find his MKIII sound nice and after he rewind the coils he said the sound improved.There are some things we can't explain and maybe it's good to have some basic rules like how to wind your coil even if it's just for your peace of mind.
Last edited:
I have the coil on my MKIII on the right way wrapped as Patrick and Hugh Dean suggested and that is a whole improvement.
I had the coil wrapped the wrong way, see #1462
Patrick, thanks for the right solution
Dx Blame MHIII Hx: https://www.youtube.com/watch?v=AHp82_KWuTQ
Regards,
Rudy
Merry Christmas
I'd sure like to hear some technical explanation for why this would make any difference. I have used lots of commercially produced air core inductors (for example in xover networks) and have never seen one marked for polarity or any other indication that they need to be wired into a circuit with a particular orientation. The case of speaker coils is not analogous since they sit in the field of a permanent magnet that has a definite polarity. Air does not have a polarity and neither do resistors.
Steve
ASK
where can I get for this PCB layout?
-please, upload all information is the PCB, that looks great. -
where can I get for this PCB layout?
Thank you Vostro for taking the time to put together this information. I do understand the concept of emitter degeneration as a method of improving the linearity of an amplifier. There is however some debate about whether this applies to the VAS given its function as a transimpedance amplifier. There is also some evidence that emitter resistors in the VAS stage actually increase distortion. The attached link describes this research in great detail.
http://www.sg-acoustics.ch/analogue_audio/power_amplifiers/pdf/audio_power_amp_design_comments.pdf
Thank you again for your kind response.
So all the typing I did was unnecessary hehe.
Im no expert on this small details, so Ill only comment once, and leave it to the experts.
Even in the IPS which is voltage fed, there is noise introduced by the degredation resistors.
Pros and Cons.
I follow convention. But Debates will always be there.
Regards
hehe.Im no expert on this small details, so Ill only comment once, and leave it to the experts.
Even in the IPS which is voltage fed, there is noise introduced by the degredation resistors.
Pros and Cons.
I follow convention. But Debates will always be there.
Regards
I think all of the surrounding metallic parts are aluminum and therefore should not interact with the coils magnetic field. In any case it doesn't explain why the winding direction of the coil would matter.
I like my Hx so much! It's powerful, precise and punchy. It's my passtime to discover all of its subtelties and to learn on a real big fat amp how stuff works... That's why I decorticate it so much and I put it to the test so much, both sonically and on my test bench as well.
I think I've found what'S causing the dent on the downward slope that occurrs on my test bench. It seems to be caused by the VAS bootstrap. In the simulator, If I only put a CCS, the dent doesn't appear. If I put a bootstrap only, the dent is present. That dent is there while using the initial CCS/bootstrap configuration. For all the tests in simulation, I arrange to have the exact same 16mA at the VAS emittor, and to have 54mV bias.
"curious" Mart...
I think I've found what'S causing the dent on the downward slope that occurrs on my test bench. It seems to be caused by the VAS bootstrap. In the simulator, If I only put a CCS, the dent doesn't appear. If I put a bootstrap only, the dent is present. That dent is there while using the initial CCS/bootstrap configuration. For all the tests in simulation, I arrange to have the exact same 16mA at the VAS emittor, and to have 54mV bias.
"curious" Mart...
Last edited:
Can't explaine it myself but there is sound improvement and so it has to be noticeable on a scoop no?Sound improvement is only there if your winding direction is (wrong) maybe due fase shift?
Last edited:
coil winding direction
Not interaction with non-ferrous surroundings.
The other circuits may have a "directionallity".
If the on board coil "adds" the same directionallity then you get increased antenna/aerial effect when current values change.
If the on board coil "subtracts" from the on board circuit aerials/antennae then you may get less of feedback effect.
It is better to remove the coil from the board and instead insert it in the cable route leading to the speaker terminals.
I have been telling you this for years. Won't you listen?
Now back to the "The other circuits may have a "directionallity"."
After having located the coil OFF board, go back and design the PCB layout to minimise the feedback effects of the trace directionality.
One way to avoid this trace directionality is to ensure that all traces are paired as FLOW and RETURN.. This is the Low Loop Area philosophy.
It is this "rule" that is habitually ignored in all the DX amplifier layouts where the power inputs are on opposite sides of the PCB. The worst way to layout the Power Supplies !!!!!
Not interaction with non-ferrous surroundings.
The other circuits may have a "directionallity".
If the on board coil "adds" the same directionallity then you get increased antenna/aerial effect when current values change.
If the on board coil "subtracts" from the on board circuit aerials/antennae then you may get less of feedback effect.
It is better to remove the coil from the board and instead insert it in the cable route leading to the speaker terminals.
I have been telling you this for years. Won't you listen?
Now back to the "The other circuits may have a "directionallity"."
After having located the coil OFF board, go back and design the PCB layout to minimise the feedback effects of the trace directionality.
One way to avoid this trace directionality is to ensure that all traces are paired as FLOW and RETURN.. This is the Low Loop Area philosophy.
It is this "rule" that is habitually ignored in all the DX amplifier layouts where the power inputs are on opposite sides of the PCB. The worst way to layout the Power Supplies !!!!!
Last edited:
- Status
- Not open for further replies.