LM338 regulated snubberized PSU for audio amplifiers

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
metalman said:
Let me see if the XGC likes it!


carlosfm said:
Do that, try it. :cool:

The only reason I want to parallel before the X (SuSy) circuit is the speakers will be rather low impedance... between 2 and 3 ohm I think very likely. ;) May dip below but I think I can keep it above 2. I also have a few of the LM3886 to mess with, and will likely wire up one with those before the LM4780's. There I can obviously go with this circuit as-is. Looking forward to it.

C
 
carlos, why dont you try a tracking pre-regulator version . It is a cheap way to get quite improved noise performance. since the pre regulator is referenced to the output of the main regulator. the main regulators input also benefits from the regulation of its output,. (and who knows maybe the snubberization as well :) ) and the error amplifiers in those things need as much help as they can get, they are about the quality of a 741!

i hope that makes some kind of sense.

you need to have a bit more of a voltage drop though.

you just need another 338, a cap and 2 resistors per rail.

its on page 12 of here
http://www.national.com/ds/LM/LM138.pdf
 
The LM338 reg Ic is more expensive than the LM3875 power IC !

:bigeyes:
:bigeyes:
:bigeyes:

Carlos,

Seems we also put the chipamp to its limitation now. Just wonder what next innovation you will contribute to this forum ;)

How about this:

- Parallel chip amps with IC driver/buffer
- Chipamp as driver to Mosfet power stage
- Integrated (Chip)amp with NOS DAC
- Chipamp with High WAF ** Important*
( WAF = Wife Acceptance Factor )

Hee hee hee :D
 
tiroth said:
LM338T is only USD$1.50 in quantities of 25 at digikey.

tiroth said:
LM338T is only USD$1.50 in quantities of 25 at digikey.

I pay around 1.5€ a piece here, but if I look next door they ask around 4€ each.
You guys have to look around for the best price, don't take for granted the first quote you get.
Sometimes to buy some parts I go to 3 different places.
The guys that have the LM338s at 4€ have some other parts that are cheaper than at other places.
Buying electronic parts is a science.:clown:
 
XELB said:
Carlos, you have 8 Ohms speakers. Don't you ?

Mine are 6 Ohms, and normally I test the amp with 4/2 Ohms speakers(this ones have 5 drivers but 98dB sensitivity).
Do you think 10,000uF per rail will work fine with this speakers?

I think 10,000uf will do, even for 4 ohm speakers.
Btw my speakers are 8hms, but not easy to drive.
You can ask to anyone who knows, has or sells Epos ES11 speakers (discontinued, ES12 later, M12 now) if it's easy to find a commercial amp that really makes them sing.
There are some, but $$$$$$.

Alcaid said:
Carlos
Secondary on T2 is shorted in the diagram.

No, it's not.
Go back to the first post again and check it out.
When I opened the thread and posted the schematic I saw that I had a reversed bridge (B2).
I corrected that and edited the post.
This was a question of minutes, maby you downloaded the first one.
The last think I want is to post a PSU that explodes in your faces.:eek:
:D

Nuuk said:
Yes, I'm going to try it as well. I'll sell the Krell to raise money for the extra parts! :D (Only joking Uncle Carlos but I will need to order the extra caps)

Nuuk, you have to make some stock at home.
I'm in a creative mood.:D :D :D
 
SvErD said:
Carlos, it's still shorted.

You are right.:xeye:
Who would spot that one?
Congratulations, you have just winned... an unshorted trafo.:cool:

PS: maby the moderators could replace the file on the first post?
Thanks.:angel:
 

Attachments

  • cfm lm338 regulated snubberized psu.png
    cfm lm338 regulated snubberized psu.png
    22.9 KB · Views: 3,454
I just finished my unregulaterd Snubberized PSU :D :cool:
Since here is 1:15 AM, I could not test it loud and clear… :xeye:
I will let the amp burn this night on and, in the morning, I will wake up everyone in the building! AH AH AH:devilr: LOL :dead:

I'am using an STK4152II chip for testing ;)



Next step, regulated PSU :D



Carlos, I that small store an 340VA-35V Toroidal transformer costs 40€ ( with instalation parts ).
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.