| digi01 |
scratch VER#1.0
pic review here.
the PCB boards size as big as my 3886igc
-digi |
|
|
| digi01 |
| the zip is protel99se project file,for free:D |
|
|
| digi01 |
modify 1:smash: :smash: :smash:
 |
|
|
| carlmart |
Before discussing pcb, it would be a good idea to know which schematic you are using and to put it on this thread.
Carlos |
|
|
| digi01 |
the pcb can mounting TO-200 or TO-3 types chip.
sch file: |
|
|
| carlmart |
| quote: | Originally posted by digi01
the pcb can mounting TO-200 or TO-3 types chip.
sch file: |
First of all provide protection diodes as is suggested on the LM317 datasheet.
Second, the output capacitors should be smaller, at least on the 338. Look at Carlos findings on how the 3886 sounded when the regulator used smaller caps. He put a film cap at the 338 output and a small 'lytic by the 3886.
If you are going to design a pcb, also provide pads for a resistor instead of a trimpot. After you set the voltage it might be better to use a fixed resistor.
Carlos |
|
|
| sek |
Hi Carlos,
| quote: | | the output capacitors should be smaller |
as stated in the LT108x datasheet, those ICs need a minimum capacitance at the output to ensure stability. It's good to provide an adjust pin capacitor too (as Digi has done), but this increases the required output cap size even further.
| quote: | | He put a film cap at the 338 output and a small 'lytic by the 3886. |
I think the circuit is safe with the 220uF for the LT108x. As for the LM388, nobody forces one to put a big cap in. But it's wise to provide the board space. ;)
Sebastian. |
|
|
| carlmart |
| quote: | Originally posted by sek
as stated in the LT108x datasheet, those ICs need a minimum capacitance at the output to ensure stability. It's good to provide an adjust pin capacitor too (as Digi has done), but this increases the required output cap size even further. |
There are very few comments to get use info about the LT108x chips on this forum. So I wouldn't risk going too high without trying and listening. Adjust pin cap is certainly good, and it's there where you can go high, not at the output. You will need protection diodes there, though.
In fact I think diode protection should be used between: input/output, adjust pin to to output, and output ground. Though the latter is not necessary if output cap is small.
| quote: |
I think the circuit is safe with the 220uF for the LT108x. As for the LM388, nobody forces one to put a big cap in. But it's wise to provide the board space. |
Providing space is nice if you have it, particularly because you can try film caps if capacity is small and go for better quality. On the 338 you should try first what people used here and seemed to work better: small caps. Then see what works better for you.
Carlos E. Martinez |
|
|
| digi01 |
oooop!!
modify 2 :smash: :smash: :smash:
thank you Carlos and Sebastian;) I have optimized some parts rooms.
H.B |
|
|
| digi01 |
main components mounting details:
U ,regulator chip
the board can mounting to-220 or to-3p types.
DIODE
each one,the foot distance is 400mil ,10.16mm.
C2
foot distance 300mil/400mil,7.62mm/10.16mm.
radius max=16mm
leg holes 2mm
can mounting common audio quality caps.
Rtrim
it is for setting the output voltage, the range is from 20V to 32V.
the board pads can moungting a resistor or a trimpot.as Carlos motions,after you set the voltage it might be better to use a fixed resistor.
;) |
|
|
| rabstg |
Hi dig1-
Please pardon my ignorance, but this circuit is for one side of the pwr rail correct? From the schematic it shows -V and grnd. Is there another circuit for the +V and grnd?
Also, is there a circuit for a single transformer and Bridge rectifier for both rails? I have use for both Ultimate pwr supplies with separate transformers and standard power supplies with a single transformer and BR.
Thanks, Troy |
|
|
| digi01 |
thank you mention it,my sch file has a little disturb about the DC out put label.
Bob03,your sch is right :D |
|
|
| carlosfm |
| quote: | Originally posted by Bob03
:cool: |
That's a good schematic!:cool: :cheerful: ;)
What software do you use?
Ah, you don't need the fuses on the secondary.
The fuse on the primary is enough.;) |
|
|
| carlosfm |
| quote: | Originally posted by digi01
revised sch |
I'm sorry to tell you, but with those output caps the amp will sound very bad.
Look at my schematic above, check the difference in value for the output cap, after the reg.:eek:
And you need a small cap before the reg too.
It's all there, I've tested it, I listened, I changed, listened again...
I see some schematics of this PSU on this forum that will make the GC sound worse than unregulated.:att'n:
I know, my thread is still closed...:rolleyes: |
|
|
| digi01 |
;) thank you carlos
This is two respects of a question.
my PCB design is to hold and accomodate different components while fully utilize the board room.as Sebastian mentiond.
the output caps C5* and C4,I just leave the enough room on the board.you can free play it when LM338 or LT1083 be used.
the same in value and room for the C2 .
H.B |
|
|
| Bob03 |
| quote: | Originally posted by carlosfm
Ah, you don't need the fuses on the secondary.
The fuse on the primary is enough.
|
I know;) :cool: |
|
|
| carlmart |
| quote: | Originally posted by carlosfm
Ah, you don't need the fuses on the secondary.
The fuse on the primary is enough. |
Completely agreed.
Not only enough, but if you have a failure of any kind on one fuse you will have half your supply at the output. That will not happen with a primary fuse, except if one regulator blows.
Carlos |
|
|
| carlosfm |
| quote: | Originally posted by carlmart
Not only enough, but if you have a failure of any kind on one fuse you will have half your supply at the output. |
Good point.:hot: :att'n: |
|
|
| Upupa Epops |
To Bob 03 : Fuse on secondary winding is nonsens.
To digi01 : If you have heavy devices such as 10 G capacitor, use screwing holes in every corners. |
|
|
| digi01 |
| quote: | Originally posted by Upupa Epops
To digi01 : If you have heavy devices such as 10 G capacitor, use screwing holes in every corners. |
thank you:) |
|
|
| neutron7 |
| quote: | Originally posted by carlosfm
That's a good schematic!:cool: :cheerful: ;)
What software do you use?
Ah, you don't need the fuses on the secondary.
The fuse on the primary is enough.;) |
it looks like he used circuitmaker 2000 and then pasted it into word or similar and added the text. then took a screen shot or save as image.
ooops stupid search made me revisit aincient thread..nothing to see here. move along. |
|
|
| derekyu |
can didi do one (PCB) with LM338 in TO3?
I cannot find one (LM338) with TO220 all over the city.:bawling: |
|
|
| slackman |
Hi,
same problem in Germany: you can't get the TO220 version - so i ordered samples. A lot cheaper than the TO3s. ;)
Michael |
|
|
| yusuf |
is it possible to get update protel version?
Thanks |
|
|
| digi01 |
| quote: | Originally posted by derekyu
can didi do one (PCB) with LM338 in TO3?
I cannot find one (LM338) with TO220 all over the city.:bawling: |
I think I can.I need find a international TO3 heatsink and build its footprint.
So user will easy to set up the To3 device.
| quote: | Originally posted by slackman
Hi,
same problem in Germany: you can't get the TO220 version - so i ordered samples. A lot cheaper than the TO3s. ;)
Michael |
P.S.
for small load,LM317 will do the job.
| quote: | Originally posted by yusuf
is it possible to get update protel version?
Thanks |
What you mean is my smt version?I think I have release it on my site.
Zang |
|
|
| gaborbela |
HI Zang
In here in Canada I can find LM338 regulator in TO220 case but all marked as a + regulator .
Can I use these in both chanel ?
Please let me know .
I would like to see If I can det the parts before I start a project .
Thanks for your ansver
Greetings |
|
|
| troystg |
| quote: | Originally posted by gaborbela
HI Zang
In here in Canada I can find LM338 regulator in TO220 case but all marked as a + regulator .
Can I use these in both chanel ?
Please let me know .
I would like to see If I can det the parts before I start a project .
Thanks for your ansver
Greetings |
Post 10 and post 15.
I had similar questions. |
|
|
| gaborbela |
Hello
Thanks for your help , I just realised I do not need the regulated power supply to the balanced preamp driver .
The balanced preamp driver has the own regulator .
Because both design is coming from the same source from Zang I was confused , I tought the power supply was designed for the balanced preamp driver but now is all clear .
Thanks one more time .
I want to use the balanced preamplifier to drive a bridged Zenquito amplifier . So I can use it in a balanced mode .
Greetings |
|
|
|
