The simplistic Salas low voltage shunt regulator - Page 550 - diyAudio
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Old 23rd October 2012, 08:41 PM   #5491
Salas is offline Salas  Greece
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In analogue it is as you describe in the first experience. About variations in digital I am not learned by application. Are there different brand/type diodes/capacitors in the two occasions you experienced so it could be a matter of synergistic or antagonistic subjective properties mix?
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Old 23rd October 2012, 10:05 PM   #5492
orelli is offline orelli  Italy
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No,all the other parts are the same; diodes, caps , Salas regs. I'm disappointed because I hoped the same upgrade with my BII, but it's an other story , I don't understood why.
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Old 23rd October 2012, 10:17 PM   #5493
Salas is offline Salas  Greece
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Normally the R core gives better mains isolation due to completely separate primary and secondary and much less cross capacitance than the toroid. It passes strict regulations for isolation in medical equipment and most models have electrostatic shield too. Its the yellow primary wire. Do you earth that along the mains earth to chassis?
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Old 24th October 2012, 08:21 AM   #5494
AndrewT is offline AndrewT  Scotland
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They both supply electricity.
They should perform the same if the transformer parameters are the same.

Maybe worth testing them to the procedure Gootee posted for us.

They we can see what differences there actually are.
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Old 24th October 2012, 11:10 AM   #5495
orelli is offline orelli  Italy
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I connected the yellow wire to a dedicated earth ground, but in this way sounded worse.
My system is completely disconnected to earth ground.
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Old 24th October 2012, 01:08 PM   #5496
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Quote:
Originally Posted by orelli View Post
I connected the yellow wire to a dedicated earth ground, but in this way sounded worse.
My system is completely disconnected to earth ground.
Wich version are you using?
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Old 24th October 2012, 06:34 PM   #5497
orelli is offline orelli  Italy
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1.2r
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Old 24th October 2012, 07:53 PM   #5498
Salas is offline Salas  Greece
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Can you see any differences when applying the R Core in the good subjective influnce and bad subjective influence circuits situation when having an oscilloscope on the raw dc rails watching filter capacitors charging cycle? It could have lower impedance as a Tx than your previous.
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Old 24th October 2012, 07:57 PM   #5499
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1.2r
Have you tested with a scope the reg?
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Old 25th October 2012, 01:00 AM   #5500
tpark is offline tpark  Canada
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To cut a long story short, that config you got will not work. Try this mix with the parts you described. R7 can be your trimmer.
I wish to apologize for wasting your time as the fault was in my unfinished circuit and not your regulator. AS you know my plan was to build a version of the B5 active crossover based on Nelson's design. I use Lowthers and the large woofer on an open baffle. My Lowther amp is a current amp based on the F3 and the gain is around 20bd and I have an F5 amp for the woofer. I have been using a version of the basic B1 buffer and need a bit more gain so planned on using the F5 design slimmed down as in the Burning amp 3 front end but with feedback of 50 ohms to give a gain of 14db. I use the Toshiba Fet's as mentioned in his article. This part of my design was completed. This will give 4 outputs. A direct line output for driving an amp directly, an output for headphones, an output to drive the high pass crossover and the last output to drive another F5 stage to give a gain of 20bd and do the low-pass crossover for driving my woofer. This latter stage will have an attenuator to allow for adjustment and the input to the first will have the volume control for the whole system. I had mounted the second amp fet's , cascode BJT's and the output fets but had not hooked them up. I did however puit in the .47 ohm source resitors to the output fet's and had the drains connected. I did not have any gate connections. The problem was that even though I thought this was open and would have no effect this output fet string was causing the oscillation. I opened the source resitors and the regulators are rock steady and the input first stage amp is running perfectly. I can usually get down to 1-2mv offset and it stays there so I am quite happy with this. I am not an engineer so can't explains why this should have happened but am happy to report the regulator was not the problem. I have made the changes though as suggested above and will put R6 back to the regulated side and probably will leave it as Salas suggested and leave the follower transistor out. I dropped R8 to 47 ohms to get the current up a bit to drive the Fet capacitance. Running about 3.5ma with this and seems very stable. Can't listen to it for a while as I have the other channel to build and then connect it all up. Thanks for you help though and you live and learn.
Tom
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