Author Topic: gainclones diy anyone? (Read 385458 times)

Ron_21 · « **Reply #1710 on:** Oct 18, 2011 at 08:18 AM »

pin assignment of 7915

pin 1 - gnd
pin 2 - input
pin 3 - output

tama ba?

rustyns · « **Reply #1711 on:** Oct 18, 2011 at 12:11 PM »

Quote from: TonyT on Oct 18, 2011 at 06:57 AM

^can you post pictures?

either me mali ka sa iring or defective you regulator chip, saan mo binile yung regulator?

Sir Tony,

Ang una kong assumption was mali yung wiring ko. So sinubukan ko i-isolate ang problem. Nagtap ako ng isang wire from ground ng transformer at isa pang wire sa negative ng psu. Sinukat ko ang voltage: -35. Kinabit ko yung ground sa pin 1 ng 7915 and yung negative sa pin 2 ng 7915. sinukat ko ang voltage between pin 1 and pin 3: -26 talaga.

Sinubukan ko the same thing sa 7815, isang wire from ground and isang wire from positive ng psu. voltage:+35. Kinabit ko yung ground sa pin 2 ng 7815 and yung positive sa pin 1 ng 7815. voltage between pin 2 and pin 3: +15.

Both itong 7815 and 7915 sa DEECO commonwealth binili.

Thanks.

ATJr. · « **Reply #1712 on:** Oct 18, 2011 at 03:22 PM »

^you got a defective lm7915.....best to buy from Alexan...

markcrenz · « **Reply #1713 on:** Oct 18, 2011 at 08:26 PM »

you're pushing it to the limit. review the datasheet, absolute max voltage is 35 volts. try to insert a 10 ohm 1 watt resistor before each reg input. or install a small psu na lang. even a 200 mA transformer is enough.

ATJr. · « **Reply #1714 on:** Oct 19, 2011 at 06:37 AM »

^yup, an input limiting resistor or even 5watt zener diodes, about 04.7 ~ 12volts in series with the inputs really helps.....

JojoD818 · « **Reply #1715 on:** Oct 19, 2011 at 10:40 AM »

I would go with the dropping resistor or zener since you already have most of the parts. Or kung ambitious, capacitance multiplier or series pass muna before the 3-terminal regs pero kung sa sub mo lang gagamitin yan ok na yun resistor.

rustyns · « **Reply #1716 on:** Oct 19, 2011 at 03:06 PM »

Quote from: markcrenz on Oct 18, 2011 at 08:26 PM

you're pushing it to the limit. review the datasheet, absolute max voltage is 35 volts. try to insert a 10 ohm 1 watt resistor before each reg input. or install a small psu na lang. even a 200 mA transformer is enough.

Thanks sa suggestions sir. Hindi nagwork yung pagdagdag ng resistors. Try ko next yung maliit na transformer with 7815 and 7915 from alexan.

Rusty

rustyns · « **Reply #1717 on:** Oct 24, 2011 at 11:07 PM »

Quote from: markcrenz on Oct 18, 2011 at 08:26 PM

you're pushing it to the limit. review the datasheet, absolute max voltage is 35 volts. try to insert a 10 ohm 1 watt resistor before each reg input. or install a small psu na lang. even a 200 mA transformer is enough.

Sinubukan ko 220 ohm instead of 10 and it worked. Many thanks!

JojoD818 · « **Reply #1718 on:** Oct 25, 2011 at 11:41 AM »

Quote from: rustyns on Oct 24, 2011 at 11:07 PM

Sinubukan ko 220 ohm instead of 10 and it worked. Many thanks!

Remember to put an electrolytic capacitor (note the polarity) after that 220 ohm resistor.

jake052478 · « **Reply #1719 on:** Oct 27, 2011 at 03:36 PM »

Sorry for OT and for my ignorance

Just wanted to know the difference between the gainclone vs Dayton APA? anyone who tried to compare this two in SQ?

please i need feedback....

vimikay · « **Reply #1720 on:** Dec 17, 2011 at 04:40 PM »

Mga Sirs,
Matanong ko lang po uli kung saan ako makabili nang LM 3875 sa Raon or sa Cubao.
Eh, try ko rin na gumawa po sana. Tulungan niyo sana ako. Puwede rin niyo akong ma contact
sa e mail: [email protected] or [email protected] ...Salamat po.
Vimikay

ATJr. · « **Reply #1721 on:** Dec 17, 2011 at 05:39 PM »

sa newport electronics, sa raon, nasa 350 ang isang isa....

vimikay · « **Reply #1722 on:** Dec 17, 2011 at 08:31 PM »

Mga Sirs, ...Malaking pasensiya po sa kulit ko . Wala po silang stock daw na LM 3875, noong isang linggo nang nagtanong po ako sa Newport. Bigay niyo po kung mayroon pa po kayong alam na nagbibinta nang LM 3875 sa Cubao or sa Raon. Gusto ko rin pong masubukan makagawa nang gainclones na ampli...
Salamat uli sa inyo po... Vimikay

blackmoly · « **Reply #1723 on:** Dec 18, 2011 at 01:33 AM »

try mo alexan (raon) bro, dun ako dati bumili

jlester87 · « **Reply #1724 on:** Dec 18, 2011 at 07:41 AM »

Quote from: vimikay on Dec 17, 2011 at 08:31 PM

Mga Sirs, ...Malaking pasensiya po sa kulit ko . Wala po silang stock daw na LM 3875, noong isang linggo nang nagtanong po ako sa Newport. Bigay niyo po kung mayroon pa po kayong alam na nagbibinta nang LM 3875 sa Cubao or sa Raon. Gusto ko rin pong masubukan makagawa nang gainclones na ampli...
Salamat uli sa inyo po... Vimikay

try mo sa alexan, dun ko nabili yung sakin less than 300 yung price pero last year pa yun...

ATJr. · « **Reply #1725 on:** Dec 18, 2011 at 11:14 AM »

try mo rin sa Liamson or Eleshop baka meron....

vimikay · « **Reply #1726 on:** Dec 20, 2011 at 11:32 AM »

Mga Sirs,
Baka mayroon po kayong LM 3875 diyan na hinde niyo na gagamitin ay ibinta niyo na sa akin.
Balak ko kasi ay bibili nang mga apat(4) na piraso. Sakali lang ay bilhin ko na lang po sa inyo. Dating ko
po diyan sa Manila ay mga 28 nang December 2011 galing Bohol. At puwede po kayong mag email sa akin:
[email protected] or [email protected]. At puntahan ko po kayo at magkita tayo sa Metro Manila or malapit. Salamat po sa inyo at sana makagawa din po ako nang ampli ko na gainclone. Excited na nga ako.
Regards at Merry Christmas and a Happy New Year sa inyong lahat.
Alfie

vimikay · « **Reply #1727 on:** Jan 07, 2012 at 01:31 AM »

Mga Sirs,
Thanks a lot for your assistance. I was able to buy in Alexan(Raon) and
I will be starting to assemble my LM3875 soonest.
Again thanks a lot.
Regards and Merry Christmas and Happy New Year,
Alfie

squatt3r · « **Reply #1728 on:** Jan 17, 2012 at 08:55 AM »

mga bossing, would like to solicit additional feedback on this chipamp design from diyaudio. thinking of a gainclone project to pass time.

http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html

ATJr. · « **Reply #1729 on:** Jan 17, 2012 at 12:04 PM »

Quote from: squatt3r on Jan 17, 2012 at 08:55 AM

mga bossing, would like to solicit additional feedback on this chipamp design from diyaudio. thinking of a gainclone project to pass time.

http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html

gainclones are good sounding amps, jojod has sold plenty of those here, he calls it babyG....

if you want kits this a good place to get it....http://www.audiosector.com/

markcrenz · « **Reply #1730 on:** Jan 17, 2012 at 02:21 PM »

Quote from: squatt3r on Jan 17, 2012 at 08:55 AM

mga bossing, would like to solicit additional feedback on this chipamp design from diyaudio. thinking of a gainclone project to pass time.

http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html

unless you fully understand mauro's design, you're better off with a basic, proven gainclone.

squatt3r · « **Reply #1731 on:** Jan 17, 2012 at 07:25 PM »

thanks sir tonyt

what do you mean sir markcrenz? mahirap gawin yung kit ni mauro?

ATJr. · « **Reply #1732 on:** Jan 17, 2012 at 07:39 PM »

input op-amp ang pinagkaiba, the LM318 is a very fast op amp with high slew rate, are you making the board yourself?

the3886 then is used as a unity gain power stage......bandwidth is maximum at unity gain...

hmm....maybe it is good to find out how it sounds.....go ahead and do it.....

suggestion, provide a socket for LM318 so you can roll op-amps....

squatt3r · « **Reply #1733 on:** Jan 17, 2012 at 07:58 PM »

based dun sa thread sir tony merong kits being offered. i thought nakarating dito sa pinoydvd kaya nagsosolicit ako ng feedback.

JojoD818 · « **Reply #1734 on:** Jan 17, 2012 at 11:30 PM »

if you haven't made any, I suggest you start with the basic. anything with a gain of ~20 won't hurt your bandwidth unless you have an oscilloscope built-in on your ears.

or you can redo it and use an OPA637 with a minimum gain of ~5. the tricky/freaky thing about that design is decoupling, use a Salas shunt reg on the opamps if you're feeling a bit adventurous.

friendly advice, the opamp is direct-coupled and inside the feedback loop so watch out for input offsets or you'll end up with a constant DC output up your ass.

cheers!

squatt3r · « **Reply #1735 on:** Jan 18, 2012 at 09:23 AM »

sir Jojo do you offer your babyG as kits also?

JojoD818 · « **Reply #1736 on:** Jan 18, 2012 at 09:49 AM »

Quote from: squatt3r on Jan 18, 2012 at 09:23 AM

sir Jojo do you offer your babyG as kits also?

Unfortunately, I intentionally do not offer it as a kit sir.

You can ask tony if he has some spare from the group buys he joined in. There will also be a range of new boards available at diyAudio Store in the future.

ATJr. · « **Reply #1737 on:** Jan 18, 2012 at 10:46 AM »

i have no boards to sell, sorry...

jojo kailan nga pala magiging available yan sa diystores?

ano basa mo kay senor Carlos, para nga bang namamaalam na?

squatt3r · « **Reply #1738 on:** Jan 18, 2012 at 10:54 AM »

thanks sa mga inputs mga sirs.

JojoD818 · « **Reply #1739 on:** Jan 18, 2012 at 06:16 PM »

Quote from: TonyT on Jan 18, 2012 at 10:46 AM

i have no boards to sell, sorry...

jojo kailan nga pala magiging available yan sa diystores?

ano basa mo kay senor Carlos, para nga bang namamaalam na?

some of the guys are still on holiday mode, napasarap yata... pero I'm pushing them to haul ass at madami na ang naghihintay ng mga new boards eh...

wag naman sana siya namamaalam, laki ng contribution niya eh. baka dahil doon sa Blameless, though I'm still seriously considering to give that amp a place in the store. diba mas ok nga yun para madami tayo variety to choose from.