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Old 4th December 2012, 10:34 PM   #41
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Quote:
Originally Posted by Blink_PT View Post
Hello,

Thanks Jorge for your help, but I have some questions to confirm.

I made a little diagram of what you said, and I look like this:

The Amp GND of right and left (R1 and R2) and R10 will not connect GND PSU?
No, they will connect to the ground side of the RCAs, each to each channel.

About the big currents from the loudspeaker (from the minus output binding post) of course they must be connected to the 0 point between the capacitors ( or near it, like you have in the schematic)
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Last edited by Tube_Dude; 4th December 2012 at 10:37 PM.
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Old 4th December 2012, 10:47 PM   #42
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a bit away from the caps.
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Old 4th December 2012, 10:51 PM   #43
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Quote:
Originally Posted by AudioSan View Post
a bit away from the caps.
Yes! Better to make it closer...
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Old 5th December 2012, 12:11 AM   #44
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closer? not to the caps. thats a "dirty" ground.
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Old 5th December 2012, 03:52 PM   #45
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Quote:
Originally Posted by Blink_PT View Post
....................The big currents working in loudspeakers should not return to the center point of the capacitors?...........
Yes.
And the big Charging Pulses around the rectifier circuit MUST NOT be allowed to contaminate any other grounding Wire/Cable/Plate/Trace.

This advice MUST NOT be followed. It is wrong!!!!
Quote:
1- The wire from the loudspeaker return, the black output terminal, must be connected to the 0 of the power supply, near the electrolytic capacitors.
The Zero Volts between the Capacitors must never become the Audio Ground. Take a wire or trace from the Zero Volts connection to a remotely located Main Audio Ground. this link can be long or short or very short. It MUST be a link that DOES NOT pass charging pulses along the link.
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Last edited by AndrewT; 5th December 2012 at 03:56 PM.
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Old 5th December 2012, 04:53 PM   #46
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Everything remains the same ... but I must tell you that F5 had a very difficult childbirth that I will describe, because it can be related to some of the effects I have described...

I had everything set up (had not connected the network will F5), but a person (friend) had already built an F5 gave me some advice and told me not to connect any mass, neither the speaker nor the Amps.

I saw did not respect the scheme but believed, turned it on but nothing was heard, but I tried to narrow down Bias was all unstable, and then began to hear a sound but distorted sound that could not be the F5.


I disconnected and then ask understood what to do now! He told me to pull the same termitores ace of mosfetes washers, and repeated not to connect because no mass lay with floating masses!!

I pressed the F5 and after a few seconds a thermistor burned like a match, hung everything and went back to talk to the person counselor.

A person came to my house, Bias values ​​were at 0.50V but sound nothing suddenly he turns on a mass of amps, and the voltage increased to 2V at R11 and R12, the fuse blew, it was hot, a burnt R11 such high currents.

We changed the pots to the minimum values​​, put new resistance R11 and new fuse, but as it was very hot the F5 did not give any sound, I think that some of the internal device Mosfetes blocked.

We waited a few minutes and yanked, this time connected with the masses, but the tension in R11 and R12 on the right side of the plate which had burst and the thermistor resistance could not tune the Bias, 2V and kept us was always off.

We removed the card from the place and saw that a lane next to the pot and R11 had melted, the others were good, with a shunt put the card ok, and then everything is back to normal.

I commented this summary because there may be some correlation between some of these facts and this little speaker from 20cm to hum ...


Connections of grounds, I have done everything, now I can only do very little:

- Get another source or other capacitors

- Other PCBs Amps

- Mosfets replace the board that took the scalding, or even JFETs?


I leave here a summary of the measurements made you an hour with a Bias of 1.3 A:

- DC voltage on the speaker load

** Left = 0.02 V Right= 0.069 V


- AC voltage in the rails (after the bridge)

*** Left = 0.25 V AC Right= 0.63 V AC


The tension in my home network is 226V AC.

The pre service is in Rotel RA-1250

Thanks for reading all this.

Blink
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Last edited by Blink_PT; 5th December 2012 at 05:07 PM.
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Old 5th December 2012, 05:11 PM   #47
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[s]please remove that dreadfull white wire between the RCA grounds.[/s]
good, you allready did.

see attached file.
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Old 5th December 2012, 05:16 PM   #48
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this is NOT what i told you to do. this is the worst way to connect signal ground.
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Old 5th December 2012, 05:16 PM   #49
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Hi, Blink_PT

But you still have the hum? Even without interconnects, means, without nothing connected to the input RCAs?

I ask because i really don't understand it, from your last post.
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Old 5th December 2012, 05:19 PM   #50
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Hi,
Attached it is an updated in the wiring using one of the PS board picture. This is the way I will wire it. One thing I noticed it is that the ground do not make start point. Cable to too long. So I did some changes in the way I will wire it. I think it compared with the powerflux wiring.
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