Offtopic from Gallery thread 
Hi,
New LM3886 at home !
Kit from Chipamp, ps (27 volts) with snubber, one safety loop breaker per side, direct input (no cap, no resistor), gain is 28, one output for bass amp..
Great sonics !!
Special thank's for Andrew T, Mark Whitney and Chipamp.
Phil.
Hi,
New LM3886 at home !
Kit from Chipamp, ps (27 volts) with snubber, one safety loop breaker per side, direct input (no cap, no resistor), gain is 28, one output for bass amp..
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Great sonics !!
Special thank's for Andrew T, Mark Whitney and Chipamp.
Phil.
Only if the center mounting bolts for the trafos go through the chassis. I suspect the two trafos are mounted to the aluminum bar and held with the two brackets to the chassis. No shorted turn there.
Once you get the new knobs, I hope you line them up so they're the same distance from the front panel. Very nice build otherwise.
~Tom
If the center of the mounting bolt goes through both the aluminum bracket and the chassis, you have a shorted turn. This will blow the fuse. If it doesn't already, it's probably because the coating on the chassis has prevented the short circuit. Once the bolts touch metal, the mains fuse will blow...
This is why you use the hardware that comes with the transformers...
~Tom
So this would be like a secondary that is shorted because the bolt, chassis and strap all go around the core like a secondary winding and are "shorted?" But given the distance from the core and if there is a load on another secondary winding, is this problem at all reduced? I've heard of problems related to "shorted turns" where there's close coupling but not a physical connection. I'm not particularly familiar with this problem so am wondering.
Read: Toroid and Solenoid External Field
Shorted turn:
~Tom
Shorted turn:
An externally hosted image should be here but it was not working when we last tested it.
~Tom
New mounting..
I even feel that I have more spl in low frequencies !
Thank's again.
Phil.
I even feel that I have more spl in low frequencies !
An externally hosted image should be here but it was not working when we last tested it.
Thank's again.
Phil.
Thank's all..
Perfect ? I'm not sure, but better of course.
So what is the best mounting ?
With nylon screw ?
I observe this way from Audiosector, on a wood plate :
http://www.audiosector.com/nigc_kit-users_guide.pdf
page 21..
Phil.
Perfect ? I'm not sure, but better of course.
So what is the best mounting ?
With nylon screw ?
I observe this way from Audiosector, on a wood plate :
http://www.audiosector.com/nigc_kit-users_guide.pdf
page 21..
Phil.
Tom: Excellent tech support. A solution for an important question.
---
"... I even feel that I have more spl in low frequencies ! ..."
(Hopefully everyone who pays attention here will look inside their older projects, as I just did, to make sure we have not made this same mistake.)
Last edited by a moderator:
The pulsing current through the turns of the winding creates quite large forces.
These forces turn on, turn off, reverse, turn on, turn off and repeat for each cycle of the mains.
Any turn or lamination that is not secured will vibrate, that is the noise.
A good transformer will be vacvac impregnated in transformer goop (maybe a special varnish).
This locks the turns and laminations together and massively reduces the vibrations and thus the noise.
These forces turn on, turn off, reverse, turn on, turn off and repeat for each cycle of the mains.
Any turn or lamination that is not secured will vibrate, that is the noise.
A good transformer will be vacvac impregnated in transformer goop (maybe a special varnish).
This locks the turns and laminations together and massively reduces the vibrations and thus the noise.
Hi,
@ mhouston , thank's..
@ AndrewT, than's for explanations..
@ troystg said :
"But also sometimes DC on the mains causes a noisy transformer."
I do not understand really how it would be possible ?
One member ask me about wiring.
For speakers, I used CAT5, 2x2 awg 24, connectors are rhodium plated, attach with screw
For audio, it's diy wiring, silver wire with natural silk sheath, except for low amp output made with litz wire. Audio connectors are pure copper with screws.
On pcb, wiring is soldered (tin with silver), cause I have no other choice..
Phil.
@ mhouston , thank's..
@ AndrewT, than's for explanations..
@ troystg said :
"But also sometimes DC on the mains causes a noisy transformer."
I do not understand really how it would be possible ?
One member ask me about wiring.
For speakers, I used CAT5, 2x2 awg 24, connectors are rhodium plated, attach with screw
For audio, it's diy wiring, silver wire with natural silk sheath, except for low amp output made with litz wire. Audio connectors are pure copper with screws.
On pcb, wiring is soldered (tin with silver), cause I have no other choice..
Phil.
It would be a power company supply to house grounding issue but sadly it happens. You can measure the DC voltage on your outlets.. IDEALLY there is NONE. If there is some check the house ground and or have the power company check the feed.
I have seen it twice in my limited years, both >50 year old homes in rural areas with very old transformers from the power company.
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