Wow, thanks for that mango expertise! You know your mangoes man! I must try out the Himmanpasand. I have tried Rumani some time back (mishread it as "roomali" as in the roti
) Hopefully the mango crop will be good this year, tho I was told that many plantations have been converted to housing "development".vkj.
Where did you get the Styroflex/polystyrene caps? I recall they used to be freely available years back, but suddenly disappeared. Why did they fall out of favor? They were available in 1% tolerances. I went looking for them the other day for some active filter designs. UNiversal had a bunch of them and sold me the lot for Rs 40. Unfortunately most of them are "NOS", leftovers from '80s, many of them have the markings worn off, and leads missing, and to top it all the values I needed werent there. Waste.
I finally used the small polyester(?) caps aka "box" caps, but the min. value for these appears to be 1nF. 63V. Tolerance not mentioned. I recall they were once made by Erie. Incidentally Amar has some nice trimmer caps (20pf) but Rs 40 each!! CeePee has cheaper but not as nice ones for a lot less (forgot the price).
What is an I-V converter? Current to voltage? Recently my Denon DVD 2910 conked--SMPS driver burnt. Amazingly I was able to get this in SP road (TOP 244) for Rs 65!
vkj
That's a terrific deal, even if some of them don't work out. I paid between Re.1 and 2 *each* for the few values that I've seen at CeePee or Chetan. Styroflex fell out of favour when the sole producer of the bulk sheets, BASF, stopped making them in the '80s. The alternatives were metalized polypropylene and polycarbonate (also obsolete now), which don't perform quite as well and sound a bit more closed in most audio applications.
Tolerance is specified by a letter code:
M - 20%
K - 10%
J - 5%
H - 3%
G - 2%
F - 1%
and so on.
For low values from 1 pF to 1000 pF, the only viable option now is Class-1 ceramic, like the Philips plate-type 2222 series, Murata, AVX/Kyocera, Kemet Aximax/GoldenMax, etc. The COG/NP0 dielectrics are available up to about 220 pF, and N150, N750, etc., above that until a few 10s of nF.
Polyester is not recomended in the audio signal path, unless the DC voltage across them is very low, say 0 to a few volts. Under those conditions it performs OK. Panasonic ECQ Polyesters are available from sub-nF to a few uF.
The best box-types are polypropylene film/foil like the Wima FKP2/FKP3, and Evox/Rifa PFR or similar. I have bought some small stashes of these from CeePee and Chetan in the past, but they're now unobtainium. CeePee has one value left in 7.5mm FKP3,
and maybe something in PFR also.
The Wimas are available from Farnell online and others for princely prices like Rs.50 each and higher.
The better sounding DACs have tended to be current-output unbuffered DACs like the Philips 154x, etc. Typically, you need an inverting opamp in current-series low-pass integrating configuration to convert it to line-level voltage. The performance of this stage is critical - a good I/V can lift the performance of a mediocre consumer-grade CD-player into an entirely different league. I have found Class-A discrete stages with styroflex capacitors to be the best sounding upgrades here. This is a proven upgrade for Marantz CD-4000, 43/53/63/67 and few Marantz DVD players.
The thing that ruins the sound in a DVD player is the RFI/EMI from the SMPS. Unfortunately, the market went towards slim DVD players, for which an SMPS is the only option, and even the bulkier ones went with SMPSes around Y2000 time-frame.
Nothing much can be done about this, but some Marantz and Denon DVD players have some filtering to improve the PSRR. A discrete opamp upgrade to a Marantz DV-4400, for instance, takes it into fairly rarified territory.
TOPswitch converters have been available easily for years. However, if one failed in-circuit, then some other component would most probably have failed before it - most probably a P6KE-series transient-suppressor or similar, or maybe dried electrolytics. Denon has been cutting corners on electrolytics over the last 10 years. Once they were exclusively an Elna Silmic/Cerafine house, and now they use Samwha, Jamicon and other junk that I've never even heard off. I believe that the parent company Nippon-Columbia unloaded the Denon brand to some Indonesian or Malaysian entity, but I could be mistaken.
Check if your Denon has mostly red and brown Elna electrolytics. If so, you're lucky - that's an old-school Japanese build. Even so, the SMPS electrolytics will dry out and need to be replaced, preferably with solid polymers or Oscons if possible.
I went to Universal today to check out the polystyrenes, and I saw exactly what you saw - NOS caps with brittle and oxidized leads, missing text, etc. There were very few useful values - 68 pF and 1000 pF being two of them. I bought all 3 of the 1000 pF caps he had for Rs.15 - a minor rip-off, but this was just a small test purchase. I measured their values on an LCR meter, and they turned out to be 872, 918 and 965 pF respectively. They're not even 10% tolerance, but 20% ! A total waste for active filters, and in fact for just about any useful application - no joy there.
He did have a whole lot of gold RF connectors - SMA, BNC, and various others. Also spotted a 64 VA 24-0-24 Miracle toroidal trafo there for Rs.850 - a moderately expensive deal for some lower power applications like DACs, pre-amps, headphone amps or even a low-powered gainclone or Class-D amp.
@Gajanan: I've heard of the Mancurade (must be the same thing, Portuguese spelling), but never tasted one.
If I recall correctly, the caps on my Denon were choc. brown, but this could be wishful thinking
. Im pretty sure the failure was due to over voltage. The mains voltage here quite often goes as high as 265V! For some reason (possibly to save relays) my stabilizer does not cut off if the voltage is beyond its range. Ive found that the SMPS is the weakest link in most electronics gear today. My Nak. tape deck has never given any trouble besides a belt replacement. > 15 yrs old.I was a bit surprised to see the SMPS in the Denon. Here we have all kinds of fancy settings such as switching off the display to "avoid switching noise" and yet its powered by an SMPS! I guess this is some energy-saving regulation? I toyed with the idea of replacing it with a xfr (surprisingly the SMPS is followed by 78xx linear regulators). But it seemed too much work. And besides the Denon is awful at playing pirated/scratched DVDs. A waste of good money.
The corner-cutting isnt just Denon. I bought a Sony SR-660 and was quite pained by how badly it was made compared to a old Sony NS50P(?) that I bought years back. The latters only shortcoming was that it doesnt have a 5.1 audio output. The USB functionality of the 660 seems to me a me-too feature added hastily, and is barely usable.
I once bought the fancy Burr-Brown and Cirrus Logic DAC-set as well as the AD sample rate converter in the hopes of building the greatest DAC, but that was abt 10 yrs back
. In these days of MP3 and 5" retinas who wants ultra-pure Hi-Fi and 8' screens? Heck, even CDs are obsolete! It seems that the good old days of diy electronics are numbered .vkj
There was once a time not too long ago, when Bloreans would have mango trees in their gardens, and the braver ones among us would climb them for rich pickings. I remember on the way back from school we would regularly stop at what is now KSCA stadium to pick those purple "jamun" fruit from the trees that once existed there.
Today all we can do is try to avoid (mostly futile) mangoes that have been artificially ripened by that white powder.
vkj
Today all we can do is try to avoid (mostly futile) mangoes that have been artificially ripened by that white powder.
Very much true. Everybody is behind fast buck.
Your post reminds me of a similar incident.
On the way to Miramar beach from Panaji, there used to be vegetable fields and other side of the road was also barren and you could see the Mandovi river. Many of use would steal the tomatoes and run away towards the river.
Presently, nothing except concrete jungle.
Gajanan Phadte
Very much true. Everybody is behind fast buck.
Your post reminds me of a similar incident.
On the way to Miramar beach from Panaji, there used to be vegetable fields and other side of the road was also barren and you could see the Mandovi river. Many of use would steal the tomatoes and run away towards the river.
Presently, nothing except concrete jungle.
Gajanan Phadte
I've been reading frequently about the problems you guys in India are having in obtaining components. The mail system to India is pretty robust and reasonably reliable. If you ever need something that you cant buy locally you can simply ask one of us to send it to you. Unlike commercial suppliers - I don't try to make any money, just try to help out.
Tho Ive never met the guy I would have to say Im impressed too!
Heres an idea:
Most of the people buying stuff at SP road are no doubt from the electronic industry (such as it is), the other big crowd is the bunch of hapless students, taking their first faltering steps.
But occasionally (sadly, rarely) one does come across the genuine "addict". Tho I take down his (its always male
) contact details, it ends there.I think we guys shd organize a convention/get-together, like the Trekkies. It would be great to exchange ideas and just hang out with guys on the same wavelength. Anyone interested?
vkj.
Thanks, thats really quite kind of you! Tho its very possible you may end up regretting your offer
. Im sure theres a huge number of folks here who would need a good source of components.Do let me know how this would work. In particular, how do I pay you for your expenses? Besides the actual cost of comps, theres the shipping. SInce Digikey charges $60 min. for shipping, Im guessing that this is an expensive process.
Or we could ask Linuxguru to ship you mangoes in return. Juuust kidding
.vkj
Sure - it's been done a few times with good results. Check out the hifivision forums for various audio meets arranged in Bangalore and Chennai by the regulars - GeorgeO, Capt. Rajesh, Santhosh, Rajiv, and numerous other enthusiasts. So far, it's been audio-related, but it could be generic electronics or other stuff, if there's interest. It does take a fair amount of effort (and sponsors, venue, food, etc.) to organize a successful meet as well as host/liaison with out-station participants. It probably helps to get some hand-holding from the folks who have already organized meets.
@katieandad: There's no problem in offering parts for sale on a for-profit basis, either through the swap-meet or vendor forum, or directly through email/PM with willing buyers. There are lots of people willing to pay good money for authentic NOS parts (tubes, passives, transistors, opamps, etc.).
For instance, I could use Holco, Welwyn and Allen-Bradley resistors in some specific values, NOS Black Gates, and some specialty film/foil caps including polystyrene, polycarbonate and axial polypropylenes.
Speaking of NOS electrolytics, I recently found a pair of authentic Nichicon KG type-I Gold Tunes locally - but the electrolyte had dried out and I could feel the foil-roll shaking inside the can. A pity, because that is/was a premium electrolytic at an accessible price.
LinuxGuru,
Perhaps we can suggest it to the organizers. If you have their contact email I could send them an email and request. Is there a mailing list to find out when/where they meet? I dont visit these forums too often.
Re. parts: Not sure how the thing would work. First how to pay for the goods? I have never purchased anything in foreign currency, tho Ive been told that one can pay via credit card. But how does one send money to an individual? Second shipping via Postal Service entails clearing Customs. I did once ask a friend to get some parts from Digikey and ship them to me via FedEx. They cleared Customs (for a fee) and I paid them on delivery. It was painless, tho a bit expensive.
Once Citibank offered the services of some concern who would procure anything for you and get it over--all legit. Not sure if they are still around.
vkj
Here are a couple of links to threads about past/present events:
South India Audio Meet-2013
Is it time to do another workshop in Bangalore?
You should be able to read the threads without registration, but posting/PM will require registration and maybe a wait of a few days.
The simplest is to use a PayPal account. These days, it can apparently be opened from India and funded with a local credit/debit card, but YMMV. You can then use the balance to make small purchases over EBay, from individuals, etc.
Customs clearance is now much simpler than the golden age of socialism in the '80s when nothing would be cleared and you would get a show-cause notice for importing contraband, even if it was just half-a-dozen 2-cent BC550 transistors. Nowadays, the Postal Appraisal Department clears items quickly and usually charges very little (if any) duty on low-value imports below Rs.2.5k or so. The package is delivered straight to your address and the duty (if any) is collected by the postman, and a proper receipt is given on the spot - very clean and transparent compared to the past. The duty is also a nominal 10-15%, compared to the 365% duty + CVD on anything electronic pre-1985, which essentially killed value-added electronics manufacturing in India completely, and allowed the emergence of the Asian manufacturing hotspots like Indonesia, Malaysia, Thailand, Singapore, and the Chinese manufacturing juggernaut.
You can use the services of Borderlinx and other courier/clearance agencies if you wish, but it's no longer needed, at least in Chennai.
Thanks for that info, Linuxguru. I took a look a the Audio Meet thread AFAI could make out, it seems to be about audio gear, not d-i-y. I think I attended one such event way back, and it basically was a bunch of audio retailers setting up booths to showcase their products.
Re. the customs duty, Im not sure if that applies to Blore. (KA is the new Bihar
). As I mentioned, less than year back, I asked a friend to FedEx some parts to me. It was a tiny package, some video op-amps, value < US$ 30. FedEx charged me Rs 700 svc charge for customs clearance, and the customs duty itself was ~ Rs 1k (I forget the exact figures). But certainly it wasnt anywhere near 15%. So I ended up paying an extra Rs 2k (ie besides what Digikey charged). Others have also mentioned that they have to cough up lots of money for those free samples that you can order from the manufs. Another "memorable" incident I recall in 2004 was when my Velodyne speaker went bust and I ordered a replacement driver. This involved a number of trips to the airport and interrogation by some official, who was undoubtedly angling for a bribe. Finally the "clearance agent" paid him and then charged me! ~ Rs 9k those days.
The import flood that you mentioned is a mixed bag. I remember way back the awful quality of components such as resistors and caps. You have to have a "blade" handy to scrape every lead otherwise it wouldnt even catch solder. Real pain. In direct contrast were the A-B resistors that were available in the PSU R&D dept that I worked in then. IN fact you may notice that in your polystyrene caps
. When Philips got into the comps game, it was a real blessing.Most comps made indigenously are poor quality even today. Even a decent mica washer kit seems to be out of reach for our guys. I now find that thanks to the iron leads that are being used, soldering them once again has become a pain. Not just the electronics industry, but in general designing and manufacturing a quality product at a reasonable price is way out of the capability of our guys. And even more so is maintaining that quality.
vkj
Yup, but typically there will be lots of DIYers also at such meets, in addition to the plug-and-play crowd.
Ouch, '80s-style ripoff continues.
... a "blade" handy to scrape every lead otherwise it wouldnt even catch solder. Real pain. In direct contrast were the A-B resistors that were available in the PSU R&D dept that I worked in then. IN fact you may notice that in your polystyrene caps
... in general designing and manufacturing a quality product at a reasonable price is way out of ...
Yup, I remember the oxidized leads well. In fact, old habits die hard, so I still scrape every lead of most components before soldering. The real pits are those with several layers of dark grey oxidized tin, followed by blackish oxidized copper leads below. You think you're done when they're shining, but no - one touch of the soldering iron and they're black again. Rosin flux is of no use, one needs Sal ammoniac for this kind of junk.
However, now there are exceptions in local manufacturing. Watts, Thakor, etc. make very good resistors at a decent price. The sonic quality of some Watts CFRs is astounding - lush and full-bodied, reminiscent of classic Allen-Bradley, Kiwame, Beyschlag, etc.
PCBPower/Circuit Systems makes first-class PCBs in prototype quantity, comparable to the best in the world.
There are a few other legacy components which are pretty good, like Silver Mica.
Which reminds me - some fink bought 800 470pF/1000V El Menco Silver Micas (his entire stock) from one of the vendors I mentioned earlier, just a few hours before I went on a routine visit there. Just bad luck, and I don't use 470pF much in my designs, but I would have stocked up maybe 100 units for the rainy day if it had been possible.
Vishal (and prob. others) have something called "liquid flux". Is this the one you are referring to as the ammonia thing? Incidentally the enameled Cu wire guy opp. Vishal sells flux for Al. soldering. Very expensive!, but I did try it and it works, tho messy and corrosive, and very probably toxic.
I dont think anyone on SP road bothers where they get their CFRs from--cheapest is the way to go. How does one know who the manuf. is? If you want better stuff, the usual route is to go MFR.
Since you are evidently into audio, have you ever tried/built a good MP3 player? I bought a board from Pooja for Rs 130(!), but the quality is bad, there are some very audible "popping" noises, which are extremely irritating. The "docking stations" by the audio manufs are horribly expensive. It would be great to incorporate an MP3 functionality into a diy amp.
Another audio question: Is it possible to send digital audio (from say a DVD player) over long distances (~20 feet) via 75 Ohm cable and do the D-A conversion at the far end?
vkj
Liquid flux is a recent innovation, and generally meant for wave-soldering or hand soldering on plated surfaces in current use - Sn/Pb, lead-free, immersion silver or gold. It works great on clean uncontaminated surfaces, and produces shiny, concave solder beads. It's really mainly meant for solders to flow very smoothly and wet surfaces.
For terribly contaminated copper surfaces (with lots of oxide and other metallic impurities like aluminium, iron, etc.), ammonium chloride aka Sal Ammoniac was the only easily available flux that worked in the old days. It's a white slightly hygroscopic salt that used to be available from chemistry supply stores. It's harmless and non-toxic in solid form, but produces an acrid cloud of ammonia and hydrogen chloride at the moment of soldering. I don't know if Mangaldeep's aluminium flux is the same thing, but sal ammoniac works with some difficulty on aluminium surfaces also.
The spectacled guy in the same row of shops as Mangaldeep (the enamelled Cu wire store) is the Watts dealer and specializes in resistors. You can ask specifically for Watts and maybe a few other local brands from him. Most other shops will also give you Watts on request, but they source it mostly from the spectacled guy above. It's clearly marked on the paper tape, so there's no hanky-panky. The leads will be very soft tin-plated pure copper on almost any Watts resistor, except on some older stuff where they used tin-plated brass.
The problem with the cheap resistors is ferromagnetic leads or end-caps. The worst are those Fe-Cu (Fecuma) leads seen on cheap metal-oxide resistors, but nickel/kovar plating is also weakly magnetic and messes up audio.
Weakly magnetic end-caps now seem to be an unavoidable evil, even on otherwise high-quality imports like Panasonic ERX metal film and KOA CF carbon film. There are very few resistors now that are completely non-magnetic - Dale, PRP, Futaba, NOS Holco, Welwyn and some Shallcross non-inductive wirewounds come to mind. Of these, Dales are the only ones that occasionally show up locally.
I have one of those Rs.100 Chinese MP3 modules with remote as well.
I haven't tried it yet, just wanted the little IR remote actually.
For high-quality digital playback, the best options are moderately expensive: A linux-based Atom motherboard connected to a separate USB 2.0 audio DAC like the HiFiMeDIY Sabre ES9023 24/96 DAC.
Sure, you just need a DVD player with digital SPDIF coax output, and a DAC or an amplifier with SPDIF digital input. Many DVD players have SPDIF built-in, and some have optical output as well.
There are inexpensive modules that can convert the optical signal back to coax SPDIF digital, or slightly more expensive modules that have a DAC and can convert optical to 2-channel line-level analog audio.
The simplest option is any cheap Home Theatre receiver that has digital input - just about any Sony, Pioneer, Kenwood, Panasonic, Harman-Kardon, etc.