Carlosfm's Regulated PSU for GC

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To anyone who has a GC.. you gotta do a regulated power supply.. it's just literally breathtaking the results. The detail is so much better and the amp is much more transparent.. the bass is tighter too!!! And this is all with CHEAP No name caps on the lm3886. I haven't even gotten around to buying blackgates or equivalent! Don't forget to add the 0.1 uf caps between the transformer and the diodes, it makes a BIG difference. Thanks again Carlosfm for sharing your findings with the regulated PSU!

Take care,
300_baud
 
Thanks for posting, i'am glad about your experience ! :D

300_baud said:
Don't forget to add the 0.1 uf caps between the transformer and the diodes, it makes a BIG difference.
Exactly where should be placed this 0.1uF cap ?
Paralell to all of the power-diodes in the graetz ?
And where are the schematics of this regulated-PSU ?
 
Look at the following attachment, you'll see what i'm talking about.
 

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300_baud said:
To anyone who has a GC.. you gotta do a regulated power supply.. it's just literally breathtaking the results. The detail is so much better and the amp is much more transparent.. the bass is tighter too!!!

I sign below. :D
Glad you like it.
BTW, original idea to use LM338s with the GC is from Pedja.

Will said:
Just a slight off topic,
how come nobody has ever applied these sort of
regulation for the tube buffer GC ?

Fraz uses this PSU with his valve buffer IGCs.
Check the chipamp forum.
 
Yes, I use a regulated psu for the powerstage in my valve buffered amp.

Question: Why? There are already 7 regulators inside the LM chips?

Answer: What can this 7 regulators do, when the psu is sagging?

Answer 2: Nothing!

Solution: you could use a very big mains tranny (>300VA), or an >160VA tranny and a regulated supply.

Results must be nearby, imho.

National mentions several times in datasheets and application notes "a good psu".

Of course, this is the key. They use laboratory equipment for the measurement, regulated, for sure!

Franz
 
That means nobody has ever done it before.

I was referring to the use of this regulated PSU to power the valve's +/- 35v.

I'm using Pedja's regulator circuit since the beginning (for the 3875), just wondering what sonic benefits will I get if I whipped out another similar regulator for the valve stage.


regards,
will.
 
Dont forget, the valve buffer is running in class A, so nearby constant currents are flowing here!

The main advantage would be, when you design this psu adjustable by a trimmer pot.

This way you could choose the best working point for your valve by ears.

The second advantage would be the high PSRR. But: with a simple CRC filtering I have no hum coming out of my amp. Remember: you need just about 10mA for two channels.

Many people are already using regulated psu's for anode voltages, this is nothing new.

Franz
 
Warning!!!

I had a 60VCT transformer (not 30-0 and 30-0, but 30-0-30) and used this. it worked great until the i connected the two grounds and BANG..sizzle :att'n:
one of my electrolytics exploded, loudly, cought on fire for a moment, and sprayed acid juice everywhere including on me (and it was burning hot). It's tin lead was welded apart by the current, and it bellowed nasty smoke, i had to leave the workshop it stank so bad. My 10 amp regulator blew, so did one of the nice diodes, and my PCB has a black spot where the cap used to be, and was wet with acid. :bigeyes: :hot: :whazzat:
 
If you look at the schematic in the first few posts, its the "star" ground where the two sides of the supply meet to form a ground. I even tested the two 'ground' wires before connecting them, and it read 2.2 volts or something, i figured it was just a floating voltage that would be happy being joined, but no. It makes sense now, why the transformer HAS to have independent secondaries; otherwise, the negative and positive sides aren't truely isolated, so you cant really use two positive regulators like this. its okay, ill just get a negative regulator and start over (cheaper than a new transformer)

EDIT: i knew something very bad was brewing when i touched the gounds together (gave that small high current spark) because those wires i was holding started to vibrate slightly, and the transformer was humming in disapproval, then the big explosion verified my suspicion.
 
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