to all indian diyers

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
S

sekhar

Banned
Joined 2009
the method suggested by godfred is the best ....... add a few more turn and every thing will be ok ............ .... another method is to open up the secondary and rewind it again .... if u need help on winding or transformer design i & many others r there to help ............


regards
sekhar
 
shaan

shaan

Member
Joined 2009
Untill 2009 I had faced problem regarding finding high quality components here in Kolkata.

Now a days the story is different. More and more high end parts are getting into market here.

Last month I ordered 2SK1058 which I have been searching for about 3 years here with only mission-failed return. Last month's report was different. I did get my 2SK1058s within 24 hours of ordering. GGoD these FETs are damn expensive, I usually get my IRF FETs for INR25/- max; but these hitachi devices took me INR160/- per device. But I know that they are expensive, the fun part was in watching the shopkeeper's face while he was delivering me the FETs. He said something like this- "Goodness sir these transistors are damn too much expensive... i have never stocked such a costly transistor in my shop ever... Are you sure these are the devices you look for?" I clearly got him, he was unable to see a reason for a mere average diyer like me to order those parts... it's fine, and it's changing. In future I hope more expensive and premium parts like the high end opamps from Burr-Brown or NSC or vacuum tubes like KT88/EL34 etc will be readily available here... within six months or so...

BTW, I also got my Nippon Chemicon audio grade caps last months with those FETs.
 
shaan

shaan

Member
Joined 2009
sekhar said:
shann from which shop in kolkata do u order those stuff . i come to calcutta quite often may be i can also get some good parts.....


regards
sekhar
Click to expand...

I live in Konnagar. Ordered them in local shop.

Well, I personally bought 2SC5200s from Nahar Electronics... everybody in chadni market knows them for any high priced devices. They are good, coz, my local shop also got the 2SK1058s from Nahar. All the best.

sekhar said:
and shaan whr do u get ur amp cabinets made ????????????
Click to expand...

I buy them readymade, there are many shops there in chandni. Gemini Radio is a good source. But they seem to have limited number of designs and no supply for full aluminium cabinet. Hope this gets better soon. Anyway my purposes are met with the cabinets they have. Do you know a better shop? If you do please let me know.

Thanks.
 
S

srinath

Member
Joined 2010
Shaan - you build amps and sell them ?

I am getting buried in dead amps I am working on fixing. However, could you sell me an amp you've built, one tha tis high quality and 100-150 watt or so a channel. And it has to be able to use 110V 60hz, cos I am in US. PM me and we can discuss further.

Thanks.
Srinath.
 
shaan

shaan

Member
Joined 2009
srinath said:
Shaan - you build amps and sell them ?

I am getting buried in dead amps I am working on fixing. However, could you sell me an amp you've built, one tha tis high quality and 100-150 watt or so a channel. And it has to be able to use 110V 60hz, cos I am in US. PM me and we can discuss further.

Thanks.
Srinath.
Click to expand...

I do build amps and sell. But getting transformers for 110VAC Primary is almost impossible here in kolkata. I can help you with everything except the transformer.

I have quasi-complementary class-AB schematics that use 2SC5200 trannies and can drive 4ohm load to 150watts. I can provide them to you if you want. I use them myself, however, being an SE Class-A fan I use them only for my sub-woofers. For the Mid+High I use hot n' sweet class-A amps. Finally, I think you can get better help for all your amplifier related problems in US than with me, here.

All the best.
 
S

sudhir kumar

Member
Joined 2008
godfrey said:
The problem may be different to what you think.

If you make a supply like in the picture below, and the center-tap is not in the center, then you still get equal DC voltage on the positive and negative outputs.

The problem is that all of the current will be supplied by the winding with the higher AC voltage. The other winding will carry little or no current, so the maximum output current will be much less than it should be.

The ripple voltage will also be worse than it should be because the capacitors are only charged 50 (or 60) times a second, instead of 100 (or 120).

There may be a fairly easy way to fix the transformer, though.

Moving the center tap is almost impossible, but if there's a little bit of space left, you can add some extra turns of wire on top of the existing windings and connect them in series with the low-voltage side, to increase it's voltage and make it the same as the other side.

Sekhar designed and built a transformer not long ago. Perhaps he can help with advice.

Cheers - Godfrey
Click to expand...

Thanks for advice, adding some extra or unwind some turns will be fruitfull.
 
S

SoundLogic

Member
Joined 2010
Hi,
Quality speaker components are available in calcutta ,mostly tho they are of pro variety you are looking at RCF,JBL,FANE,P.Audio drivers.I usually order them from the master distributors in India.If you want to get the amp chassis made and screen printed you can contact Mr.Tarun Roy, 943317667 ,I believe he should be able to help you in this area .He should also be able to help you get your hands on some quality components but for the real high end stuff it might be a better option for you to import,mostly small shipments come through quite easily.partsexpress and madisound are two of the best sites that I have come across.
 
S

SoundLogic

Member
Joined 2010
if you plan to go to mumbai you can get your hands on B&C Speakers (used in the Geddes loudspeakers) ,they have a distributor in mumbai,you can also get peerless audio india (very good,home audio drivers-Jitu 09821161535).Fane is available at Narain audio 02223895376 ,good luck with your hunt!

Hth.
 
S

sudhir kumar

Member
Joined 2008
I used to make amplifiers on multipurpose pcb but it is very difficult.Kindly tell me some easy method to make pcb at home.Can i use screen printing for this purpose? I have read about the toner transfer method but not sure about its results.
If anybody have information about the availibility of power tranistors and mosfets(2sk1058) at any place in bangalore with expected price kindly inform me.
 
G

gmphadte

Member
Joined 2003
Easy method to make PCB at home

Draw the tracks using oil/enamel paint on a copper clad cleaned w/scotchbrite. The copper should be shining. Make a solution of copper sulphate about one to 10 parts in water. Take a plastic tray and put the board with copper up. Rock the tray up/down to agitate the solution.

U can see the open, unpainted copper dissolve.
Rinse thoroughly in water.

Check for hairline cuts on tracks. This can happen due to some hair/dust on the copper track.

Drill the board with 0.8/1.0/1.2/1.4 mm drill bits. size-as required by the component.

Take care when using copper sulphate. It will stain anything. So do this itching process outdoors, wearing reject clothes and gloves.

Enjoy.

Gajanan Phadte
 
Last edited:
  • Like
Reactions: 1 user
S

sekhar

Banned
Joined 2009
to sudhir kumar
u can very well use the screen printing method . I have used it ever since i came 2 work with electronics. Take a print out of the pcb layout on a translucent sheet with darkest printer setting then take this 2 a screen printing shop and ask them to print the pcb and the copper board with a paint that does nt dissolve in water and its done. Just etch and drill the board u r ready 2 rock.
And bout prices of power fets the irfs cost around 50rs and the 2sk /2sj cost around 160rs at my place

regards
sekhar
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom