The (high-cap.) unregulated PSU for chipamps

[steenoe]

the RC snubber should be placed as close as possible to the diodes.

The film caps?? They are not meant to be Diode snubbers, but are
forming a Zobel network, that actually enhance the sound.
Don't ask me how it does that

Steen.

 

[carlosfm]

Sounds like fun, but we don't have to!
You have made all the hard work already



Well, your guidelines were followed all the way, I think.
And with great result, I might add!!
Here is a pic of the rearside of those amps, in case you care?
The binding posts were ordered from Taiwan, of all places!!
Very cheap, and very good quality. Can take a serious speaker-cable.

Steen.

Gorgeous work.
And those binding posts are familiar. An imitation of a german brand.

 

[jackinnj]

No, it should be placed as close as possible to the chips.
But it's not practical to use them on-board, and I think local bypassing is more important.
Small caps on the chips, as close as possible to the PSU pins.
The snubbers after the last big caps on the PSU.

Anyway, maby the snubbers will also work fine right next to the rectifier diodes.

On-Semi says to put them next to the diodes. The snubber compensates for the ringing caused by the transformer secondary inductance AND capacitance of the MUR860's --

 

[carlosfm]

The film caps?? They are not meant to be Diode snubbers, but are
forming a Zobel network, that actually enhance the sound.
Don't ask me how it does that

Steen.

You mean something like this?
http://www.diyaudio.com/forums/showthread.php?s=&threadid=39039&highlight=

Yes, in most situations it improves the sound.

 

[steenoe]

Excactly Carlos, I did read that once
Hat's of gents, this is major stuff
I must add that the chipamps I build have no hum, no hiss, no noise, at all! Even with the head stuck into the speakers!!
Only music

Steen.

 

[AGGEMAM]

Only music

Oh .. that's a relief .. for a second there I was wondering if you knew what the amp was supposed to do

 

[XELB]

Oh .. that's a relief .. for a second there I was wondering if you knew what the amp was supposed to do

LOL










Carlosfm,

this technic of the snubbers could be applied to any amplifier or only in this one ?


Let me see, you have change your caps for high capacity and you gain bass! Then, to gain detailed sound you installed a snubber for each cap ? (or it's for each channel)

 

[carlosfm]

Warning to the navigation

Guys, the snubber makes a very marked (and positive) effect to the PSU and the sound of the amp.
That you can listen immediately.
But let the new big caps -in for some days (I don't do less than a week) and you will .
Let the amp sing continuously for some days.
The big PSU I finished yesterday sounded very good but today it sounds deam gorgeous.
Actually, I'm beginning to figure out that this is better than an LM338 regulated PSU.

 

[XELB]

I'm using a STK 4152 II chip and the recommended PSU uses 2 caps of 10000nF and 2 resistance of 500 oms.

My amp is using 3300nF caps but I don't know the resistance values


So, if I change the PSU for the recommended one, should I install the snubber ?





See picture. It's the recommend PSU.

 

[wigginjs]

A question about capacitance, I'm looking for large capacitors that will still fit on the BrianGT/PD gainclone boards. Is 5600uF enough to yield this "magic" sound? Thats the largest 50V capacitor I can find that will fit on those boards. I can get as high as 8200uF if I look at 35V capacitors, but thats getting pretty close to the actual rail voltages...

Link tothe part I'm refering to

 

[falcott]

100nF film caps were also used on the pcb's. Have a look at the BrianGT boards used for this project.

Hi Steen, is this amp non-inverted?
Cheers

 

[steenoe]

Hi Steen, is this amp non-inverted?

Yes, Brians layout is non-invertid.

Steen.

 

[carlosfm]

I picked the wrong file, that schematic missed a black dot that indicates that the two snubber caps join at the ground point.
Small detail, but someone may be in doubt.
I know someone will ask (nevermind... already did).
Here's the revised schematic.

 

[demogorgon]

yes, i got a mail asking about that you know

funny how theese thing work..

btw: got my caps to day, 138.000uf 80v caps.. 12*1000 and 2*8200.

i altso picked up some lm317's, and disregard everything i'v ever said about TO-3 encloasures, they are beautiful!

now i just have to find a way to make those mosfets joine forces with the regulator.. 1.5amps i redicolusly little... i want more

 

[carlosfm]

btw: got my caps to day, 138.000uf 80v caps.. 12*1000 and 2*8200.

Is this artillery only for one amplifier?

 

[Alcaid]

...
btw: got my caps to day, 138.000uf 80v caps.. 12*1000 and 2*8200.
...

Lets see:
12 x 1000 = 12.000
+ 2 x 8200 = 16.400
= 28.400

that's 28.400uF not 138.000uF.

 

[carlosfm]

Lets see:
12 x 1000 = 12.000
+ 2 x 8200 = 16.400
= 28.400

that's 28.400uF not 138.000uF.

Either way, 1,000 or 10,000uf, the final value is not right.

 

[demogorgon]

Lets see:
12 x 1000 = 12.000
+ 2 x 8200 = 16.400
= 28.400

that's 28.400uF not 138.000uF.

Either way, 1,000 or 10,000uf, the final value is not right.

Bah!!

you guys are no fun, you know that??

damn..
12*10.000+4*8200 is the total amount of artillery available.
this should mount to a total of 120.000+32.800=158.000uf totally!

MORE THAN ENOUGH ANYWAYS!!

 

[carlosfm]

damn..
12*10.000+4*8200 is the total amount of artillery available.
this should mount to a total of 120.000+32.800=158.000uf totally!
MORE THAN ENOUGH ANYWAYS!!

You should use a soft-start circuit.
And even with some low value bleeder resitors I suspect the amp will continue to play for some minutes after swith-off.

 

[murat]

Do you think the idea might be relevant to solid state amps? Read first paragraph after "Power Supply Decoupling and Grounding" in Leach's power supply:

http://users.ece.gatech.edu/~mleach/lowtim/pwrsply.html

Is the usage of small caps there a similar idea?