These are available in Chennai at around Rs.160/pair in small quantities - you may be able to get better deals on full tubes (25 or 50 units) in more competitive markets like Mumbai.
The number of fake components is making it impossible to do any electronics project these days. Recently I bought BC548 from Vishal (SP Rd., Bengaluru) to use in a simple inverter switch, and was shocked to find it was taking ~1ms to switch! I replaced the transistor with an old piece I had and it immediately performed as the simulation indicated! Similarly I used a number of TL072's for a preamp circuit and was surprised to find the circuit consumed far more current than I anticipated. Further more it was somehow overloading the poweramp causing it to overheat and shut down. I wasted a LOT of time before I found that the TL072 were fakes. Each was drawing about 30 mA supply current instead of the few mA as per specs. I had to replace all of them, and learnt the hard way that IC sockets are a must these days 🙂.
Audio Poweramps: I have tried a number of them and I have found the best by far is the Leach amp. The instructions are foolproof, and detailed, the components (or near equivalents) are easily available, and the performance is outstanding! I have used it for a 5-ch amp, as well as subwoofer amp. The circuit works as advertised. Other amp circuits need tinkering and adjusting and not worth the trouble of several iterations of design and PC fabs.
vkj
I had a batch of BC560 that turned out to be NPN transistors. Some high-voltage ceramics turned out to be 35K resistors, so when used as Miller caps were leaking DC into the output.
The $14 component tester I bought on eBay is a lifesaver. I now test each component before inserting it. Use Chinese to catch the Chinese.
The $14 component tester I bought on eBay is a lifesaver. I now test each component before inserting it. Use Chinese to catch the Chinese.
Yup, it's a brilliant design using a PIC, but that was also shamelessly copied from an Open-Source HW design by a designer in Germany. A toast to the original designer!
@vkj: The TL072 is one of the least expensive opamps in the world, so which opamp would they have re-marked as the TL072? LM358 is BJT input. Same with the BC548 - dirt cheap. BC560 is harder to find, so there's an incentive to counterfeit.
Sadly I fell victim to this very logic 🙁. Actually the genuine parts I got from Amar arent that cheap. I bought 10 ea of TL072 and NE5532 and it cost me about Rs 700 (!). I forgot the exact price, but the 5532 were abt Rs 40-50 ea. When I howled in pain, the Amar prop. told me right out that the cheaper parts available in the other shops were fakes. No option but to agree. They are both marked with the TI logo but under a lens the markings on the fakes are a little smudged. Incidentally TI still makes 5532!
How can one carry a tester to SP Road and check every component? Its hard enough to get some elbow room in that melee!.
vkj
One of the colleagues told me this when he wanted to replace an IC which I told was faulty. He told me that in the south (don't recall the city) that you have to tell the number of pins the IC has and they will give you one. I just laughed.
Gajanan Phadte
Gajanan Phadte
Your friend hasn't been to the South ! He's just another redneck ! Maybe not even outside his town ! 😉
VKJ: Genuine TL072 and NE5532 cost about 180/- (10 pcs each)! Something very wrong about your pricing. From a bulk seller, but they will sell 10. Never realised that Amar charged whatever they felt like. Other shops aren't so bad. I did find that they WILL tell you if it is original or not. But you need to ask, most times !
Last edited:
Ashok: I think sometimes the vendors themselves are not quite sure of whether the parts are genuine or not. I bought several IRF3205's from Vishal and he assured me they were original but were fake. When I checked the cutoff voltage it was too high and as a result the device was not turning off. I discovered this after a LOT of unnecessary waste of time and money. Ceepee had the genuine ones which worked fine. I find Ceepee is more reliable, yes, he tells you if the part is dubious or not.
The problem with Vishal is that he does not stock many of these items but instead sends his boy to get them from somewhere. These procured components are dubious.
The only 100% reliable seller on SP Road I have found is Amar. So unfortunately we have to put up with the high prices and arrogant and lazy sales women 🙂.
vkj
vkj: You are probably right. It is really hard to determine if a part is good or not at the shop. Amar has a very poor attitude towards customers . Snooty is a good word I think !🙂
I got 10k rubycon caps at an exorbitant price a few years ago from amar, with a bill. 6 months later when I tried to use them, they were rulycons. Of course I had misplaced the bill. Stopped going to him after that.
That is certainly a shocker and disappointment. Looks like it is "buyer beware" with everyone. It is surprising that electrolytic caps which were previously made in India (Philips/Keltron/etc) are now being imported. Says something for "make in India" 😉.
On TWO occasions I have experienced brand new electrolytic caps exploded for no reason!
vkj
where can i buy some decent heatsinks in bangalore for amps, I searched on sp road and nearby and most of them sell like a 10-12 feet rail weighing some 20-25kg and costing some 10k.
Amar Radio sells smaller sections. If you don't want to buy from him, check out Cee Pee and Chetan.
Try Aluminium heatsink, Heat sink in bangalore, Heatsink stockist, Heatsink dealer, Heatsink supplier, Aluminium LED Heatsinks, Aluminium Reflector Sheets, Aluminium Caul board Sheet 2.5mm, Aluminium Plywood sheets, Aluminium Alloy Rods,plates in 2014, 7
They are in Bangalore and can give you any size you want. Email them for a quote.
Boy, that web link sure ended up rather long. The actual one is www(dot)perfectmetal(dot)in . Put in the dot and remove the '(dot)' !
They are in Bangalore and can give you any size you want. Email them for a quote.
Boy, that web link sure ended up rather long. The actual one is www(dot)perfectmetal(dot)in . Put in the dot and remove the '(dot)' !
Last edited:
"NAHAR EMPIRE", #339/1-4, Anantha Ramaiah Woolen Factory Compound,
Opp. Satellite Bus Terminal, Mysore Road, BANGALORE - 560 026, Karnataka. INDIA
Tel No : +91 80 2675 6936 Fax No : +91 80 2675 3163 Customer Care : +91 81052 55001
Email ID : info@perfectmetal.in Website URL : www.perfectmetal.in
Opp. Satellite Bus Terminal, Mysore Road, BANGALORE - 560 026, Karnataka. INDIA
Tel No : +91 80 2675 6936 Fax No : +91 80 2675 3163 Customer Care : +91 81052 55001
Email ID : info@perfectmetal.in Website URL : www.perfectmetal.in
There is a shop called Winner 'something' on SP road. It's past the main parts shops on the right on the 2nd floor. Narrow stairs going up.Look for the board saying Winner. Visible from the street. He has heat sinks too. They have a web site but I can't find it now. Guess someone on the forum has the URL.
Two good sources for anodized heatsinks are (a) Universal and (b) Texonic. Texonic has the larger sizes suitable for Power Amps. They have masked out surface for mounting but no holes so you have to drill the holes yourself. Universal has the smaller (3" wide) heatsink in length about 2'. You will have to cut and drill. Quite expensive!
One of the problems with predrilled, precut heatsinks is that they are distorted by the punching process, and the surfaces are no longer true. Also they dont have mask-out. You often have to file them down and make them true--not that easy!
vkj