[INDIA] Group Amp project

[Pixo]

IRF India

These are some of the IRF distributors in India i pulled off the IRF site
I hope it helps

Hi-Rel Products Sales Rep
International Rectifier
#407, Prestige Centre Point
Cunningham Rd.
Bangalore 560052, India
Tel: (91) 80-2208 8025/26
Fax: (91) 80-2208 8028

Arrow Electronics India Ltd
5th Main, II Floor
Pusa Road
New Delhi 110 005, India
Tel: (91) 11-578 4629 / 3845
Fax: (91) 11-578 5751

Arrow Electronics India Ltd
311/312, Chintamani Plaza
Adheri-Kurla Road
Adheri (East), Mumbai 400 099, India
Tel: (91) 22 5692 5196/8/9
Fax: (91) 22 5692 1415
E-mail: rajeev.mhashelkar[at]arrowasia.com

Arrow Electronics India Ltd
No. 49, I Floor, Rama Archade
Hospital Road, Shivajinagar,
Bangalore 560 001, India
Tel: (91) 80-558 1520
Fax: (91) 80-558 0909

Future Electronics (New Delhi)
No. 1308/9/10, Ansal Tower
38 Nehru Place
New Delhi 110 019, India
Tel: (91) 11- 646 1414/1417
Fax: (91) 11-646 1418

Future Electronics
#710/711, Gateway Plaza
Hiranandani Gardens
Mumbai 400 076, India
Tel: (91) 22-570 2745
Fax: (91) 22-570 2743

Future Electronics
No. T 8&9, Gem Plaza
66, Infantry Road
Bangalore 560 001, India
Tel: (91) 80-558 7885/7886
Fax: (91) 80-558 7890

Kudamm Corporation
D-17 Kalkaji
Opp. Nehru Place Terminus
New Delhi 110 019, India
Tel: (91) 11-622-9093
Fax: (91) 11-647-9097

Intraco Limited
No. 579 2nd Floor
11th Main Road
5th Block Jayanagar
Bangalore 560 041, India
Tel: (91) 80-665 4545
Fax: (91) 80-699 1001

Cresta Instrument
9-A, Sitladevi Indl Estate
140, Sitladevi Temple Road
Mahim, Mumbai 400 016, India
Tel: (91) 22-446 4946/ 446 4801
Fax: (91) 22-445 7230

Advent Electronics Pte. Ltd.,
R-283, Greater kailish-1
New Delhi 110 078, India
Tel: (91) 11-629 4370/4372
Fax: (91) 11-629 4398

Advent Electronics Pte. Ltd.,
# 202, Lok Centre
Marol Maroshi Road, Andheri (E)
Mumbai 400 056, India
Tel: (91) 22-5675 6584
Fax: (91) 22-5675 6583

Advent Electronics Pte. Ltd.,
No. 85, Ground Floor
5th Main, 1st Cross
Domlur 2nd Stage
Bangalore 560 075, India
Tel: (91) 80-535 0357
Fax: (91) 80-535 1869

 

[tcpip]

Randy Slone amps... others are totally khush!

Remember, I was talking about Randy Slone designs? Well, I found this thread with lots of war stories about his amps. And apart from the OptiMOS design, which people seem to be really raving about, there's also the "Figure 11.4 design" mentioned in this post, which is the ultra-low-distortion schematic I'd mentioned earlier, with clear similarities to the Doug Self Blameless amp. The design is covered in Figure 11.4 of his book, "High Power Audio Amp Construction Manual."

Just thought I'd tempt you towards the Class B devil, seeing how all of you seem to be veering towards room heaters ... oops, Class A amps.

 

[Pixo]

Oops! went a little too long....... sorry!

 

[Rahul]

Hello! friends,

Sunil

Tnx a lot for info on IR distibuters. I am sure it will be of help if we go in for Amps based on these devices. I do remember giving a call to this Pusa road unit long time back but it might have to do with something else.

Tarun

For Linux PCB software keeps popping up every now and then I have not used it but its free from here:

http://bach.ece.jhu.edu/~haceaton/pcb/

Sprint is windows based.

This is really helpful that OPTI-MOS has a single sided layout already done this will be one big help if in future we decide to go ahead with this design. Will it be possible to mail me a scan of this PCB at
lkorahul@yahoo.com
I would be highly obliged and will try to learn something from this layout.
Tarun since I am already in middle of an amp project I will be grateful if you will just go thru the MOSFET mod of Harman Kardon Citation12 at Pass DIY under legacy section and give an opinion. I have been facing a very embarrising situation, every now then friend would request me for a good system for occassion and parties now I simply do not have anything to give them hence a powerful amp is also needed.

Ashok

I too feel JLH class A is one we should freeze for reasons
1) It is simple
2) Common availibility of components.
3)Simple PCB
4) Ultimate class of scheme.
5)Good performance and documentation.
PCB I can do at par any on the forum and even get them made here.
It is fully practical to go in for bulk purchase of heatsink from disposal. I frequently visit Agra and can select one suited to our needs. How else do you think I collected all these check here:

http://www.qrz.com/callsign.html?callsign=vu3wjm&bs=vu2

Same cannot be said of transformers as no two of them are similar one off its OK. Secondly our specs would vary from what is available.
Again we would need to decide on type of transformer torroidal or EI. If EI then I suggest looking for old 24V type defuct UPS 500VA are good ones for our class A project, multiple taps at mains input gives us some control over output voltage and yes they can be had for free. ( I already have one).

I did the magnet check on the MFR they failed all stuck, so did all CFRs and surprisingly even the Philips blue resistors.

All Ok abt the YLs ie young lady from 6-116 yrs young. Only ones I saw were at CR the campus restaurant. During Fox hunt we suggested giving hints like I see YLs all around , students said it will mislead as all will take it as Fox is definately out of campus.

Tnx for the 73 ( Regards) My 73 to you and family and 88s ( Love and kisses) no porn here all international telegraphic lingo.

Best wishes

Rahul

 

[Rahul]

Bunchful of extra 88s for the YL on boat. OOOOH LALA LA OLE O OOOH LA LA!

Good Times

Rahul

 

[corbato]

I too feel JLH class A is one we should freeze for reasons
1) It is simple
2) Common availibility of components.
3)Simple PCB
4) Ultimate class of scheme.
5)Good performance and documentation.

And it ain't uses no MOSFETS I've set my eyes on this version:

An externally hosted image should be here but it was not working when we last tested it.

There is another, more powerful version which I’m not keen because of the following reasons:
1. Multiple gain stages
2. Dissipating all that heat from 8 output + 4 PS devices will render my listening room very hot indeed.

Your opinion pls.

PCB I can do at par any on the forum and even get them made here

How about the above schematic?

Again we would need to decide on type of transformer torroidal or EI.

EI. No doubt about that. A dual sec 25volt, 5A transformer wont be very expensive. My last transformer was 350-ct-350 (250mA), 5 Volts (2A) and 6.3 V (3A) cost me around 550 bucks.

...as Fox is definately out of campus.

Yeh kya bandhu?? IIT K kya marubhumi mei parivartit ho gaya hai ?? Yeh to atyant hi chintaa ka vishai hai Sub apne karmo kaa fal hai bhai.

 

[corbato]

Bunchful of extra 88s for the YL on boat.

None that I can see in the India threads We do have a LID though. Thankfully he is back in his tree.

Hoping for eyeballs soon.

 

[Rahul]

Dear Ashok and others,

Yes this is the same ckt I also had decided upon. Let us hear from others. At this power level we need not worry much about heat and rightly you have pointed a 125VA EI will not be too big. While on subject of PSU I missed telling you from disposal we also get very good quality main filter caps I have usually bought 33,000uF -68,000uF 25-30V for my radio PSU but other ratings are also available ie lower uF and higher V. Again they are of best quality like Sangamo, Farnell, Cornell-Dublier, Sprague Italy etc. Cost in range of 30-45Rs. Ideal high end stuff.

I will start working on PCB just improvement on other designs. It can be made on vero board or point to point wiring but again we cannot expect every one to be equally deft with the soldering iron, a PCB would be helpful.

BTW 88s were for the kingfisher pic going between George and you. LID has been shut tight for time being.

Soory Pixo Thanks to you for the distributer list.

Regards

Rahul

 

[corbato]

Cornell-Dublier

Didn't know that Dublier guys are still around ! Have some NOS Dublier oil filled caps waiting for a proper tube project.

Resistors from RS have non-magnetic lead/end caps. But can we have a head count here. Just who else, besides you and me, is keen on JLH project.

 

[Rahul]

Hi! Friends

Its my majboori to make a good amp, Ashok here willing to join now I sincerely look forward to all your participation.
We now have inputs and some excellent sources that would enable us to achieve our target not only at a low cost but provide us with an ultimate high end equipment of a standard which is not available in mkt. Also the satisfaction of having done it with our own 2 hands.

I say lets do it We can make it work.

Regards

Rahul

PS: I still dont see any better options at comparable cost.

 

[Rahul]

Dear Ashok,
This one specially for you.
I have to make one. I will be making a couple of boards for my self and feel there would would be spare enough for few friends.
BTW I have to collect 2 HF sets that I have purchased so if things work out I would procure sufficient stuff for those interested in this project ie the heatsink and good quality caps.
Cornell Dublier is still in mkt, it appears it supplies to only top of the line companies like Tektronix, Hughes, Fluke, TRW Dallas and possibly NASA etc I did recieve some samples last year in relation to a defence project.

Ashok my judgement as Secy of UP radio org you qualify fully as a HAM how abt just fulfilling the formality of giving the exam and getting the ticket ie license.

regards

Rahul

 

[corbato]

Its my majboori to make a good amp[/qoute]
Mailing something for your on this.

not only at a low cost but provide us with an ultimate high end equipment of a standard which is not available in mkt. Also the satisfaction of having done it with our own 2 hands.

Amen to that
Boss. I think even two of us will make it a group build. So do you concurr that we should start ordering parts from RS? I may be having some of the 3055 or MJE devices from On Semi samples.

I will be making a couple of boards for my self and feel there would would be spare enough for few friends.

Chalo boss jald kaam shuroo karte hai

I would procure sufficient stuff for those interested in this project ie the heatsink and good quality caps.

Heatsinks will be particularly helpful, But do you think caps would be in good condition?

Ashok my judgement as Secy of UP radio org you qualify fully as a HAM how abt just fulfilling the formality of giving the exam and getting the ticket ie license.

Janaab aap to bahut bade fish ho !. I was very attracted to Ham as kid. Unfortunately, my family was not financially well off to support those kind of activities. By the time the cash was more plentiful I had other interests. But yes! Me and pal of mine (60yrs young) have been thinking of HAM for a while. Jsr had a thriving Ham community in younger days. Perhaps some of them are still around.

 

[tcpip]

JLH Class A it will be, then...

Boss. I think even two of us will make it a group build.

Hey guys, I'm in on it too, and so will Angshu be, I think. He's been keen on this one for some time. I have some questions:

• Is this the schematic of the most recent, refined version with the 2003 mods? I would like the most recent mods, for obvious reasons.
• Are we going to make the PSU PCB too? I hope so...
• Can we design the PCB, get two fabricated, build them, test them, before we make the mass fabrication? I think there'll be a demand for mass building, because PCBs are inexpensive (I'm getting rates of less than 50p/sqcm in Bombay, with solder masking and legend printing, for quantities greater than 25). At that rate, and for an expected smallish PCB, I'll probably opt for half a dozen myself, "just in case"
• I hope we'll use the MJ15003/4 devices? I'd really like that. Maybe George can even get us some devices if we order them right away and ask for them to be shipped to his brother's address. We'll have to decide amongst ourselves first, then check with George. He's agreed to get some other chips etc for me from there.

Angshu will be back in the loving embrace of his family today. From tomorrow, we can turn up the pressure on him and make him join in. He can even do PCB design and the like...he did the Blameless amp PCB in an afternoon, and it works!

Of course, I know the JLH will not satisfy the needs that all of us have for a more powerful amp, but I guess we'll decide that one as time goes by. Maybe we can even do the OptiMOS yet.

Tarun

PS: We should now demand that all of us Indian builders read the entire super-long thread on the JLH Class A which is there in the Solid State Forum... I'm sure it'll help to build a common ground for our discussions/designing.

 

[corbato]

Tarun:

Good u ain't watching the stupid match. 73/3 I give up.

Back to the amp.

• Yes this the most recent revision. Their is another, higher power version too. But not being thought of at the moment. Reasons are listed in an earlier post
• Yes
• Why not. A vero board job. I've heard the '96 version rigged up that way.
• Those MJ devices always make a better sub for the 2N3055. I got MJ's as sample from On Semi. And why should we trouble George? At least to me On Semi ships regularly. Now they have $20 handling fee of-course.

I trust Angshu had a close inspection of those Soft Dome Twits. Will be interesting to know his views.

In addition to that JLH thread, do visit this website.

 

[tcpip]

• Yes this the most recent revision. Their is another, higher power version too. But not being thought of at the moment. Reasons are listed in an earlier post
• Yes
• Why not. A vero board job. I've heard the '96 version rigged up that way.
• Those MJ devices always make a better sub for the 2N3055. I got MJ's as sample from On Semi. And why should we trouble George? At least to me On Semi ships regularly. Now they have $20 handling fee of-course.

Great. I'm certainly in on this, then.

BTW, I just got a quote from Balaji Hertz. If you want to build 50 PCBs, 2-ounce copper, 9cm x 4 cm, he'll charge less than Rs.25 per PCB, including legend printing and solder masking, and after including all applicable taxes. The prices that guys in the US and Europe pay are astronomical in comparison. We should build arrays of Gainclones just for decoration pieces, at these prices.

The JLH should be good! What power output can we hope to get with these devices and the latest mods? About the prototype, I was wondering whether we should actually make a couple of PCBs, and actually test that the PCB design itself is okay, before making the bulk set of PCBs.

Tarun

 

[roadkill]

Another design to consider?

Hi all,
MOSFET fans, here's a nice design to consider. I found it in Electronics World, while in Pune. The schematic's at my website, with a small change: the original asked for a single IRF640/9640 pair, the schematic shows two without any split gate drive resistors or source resistors. My bad... anyway, the version I've built used only one driver pair per channel. I later pulled them out and used an IRFP240/9240 pair (cost me Rs. 250 per pair). The amp works just GREAT, it's my preamp which gives me trouble (ground loop, and it's only marginally stable). I know, it's a mess, but I made it while in college, so I had to take a lot of shortcuts. Consider this design for something in the 50-100W range. Probably we can increase the output power by paralleling output drivers. IRFP240 seems to be genuine, and, well, it hasn't blown on me yet. And I do wake up the neighbours some time with some Massive Attack.
In case anyone's interested, I can put up a board for this amp, but it has holes only for IRF640/9640. I used this same board with the 240/9240 through soldered wires.

 

[Rahul]

Hi Friends,

Call it a gift from almighty I feel good vibrations wether I see a good design, a good project or a group of very dedicated and nice people. It is my good fortune that I find all of the above here.

Tarun :

Rs25 per board is very reasonable. You dont even get a kiddies project PCB for the price and here we talk of high end amp. I offer to pay up for all the 50 PCBs. Others joining simply pay the actual cost incurred and postage to their respective destination as when they join this way we will have something available for Indian DIYers for a long time. Tarun as far as PCB goes there are already many tested layouts it is simple matter to make one along the lines and of such a size will take only few hours. Other experienced members can guide us to suitable changes I for one fully willing to do the artwork. No trouble at all in providing the gerbers for the manufacturer. I do not recommend PCB for the power supply board as we already have the bridge rectifier and fiter caps off the board. Now it all leaves us with the two transistors and regulator if we go in for regulated PSU version , again a point we need to decide before we proceed ahead.

Roadkill:

I am happy the neighbours do wake up least, you may have to change ur ID here but more important that u are not whisked to the big guest house with many guards, huge gates .
Again I find this amp design very good (my vibrations) CCS for all stages, complimentry and not overtly complex. I am sure the performance is also good.
I have made Citation12 Mosfet PCB but yet to fire them up, hopefully in few days. It is much simpler and maybe in performance department too.

Ashok :

Hey we WON. Thanks for ur offer, more on that in direct mail.
The caps Ashok I had no trouble in radio use but again that is no audiophile stuff, basic communication quality 2.7Khz and that also in class AB.
Today I do the final check of all available layouts and then we proceed with our own. What do you say should I try to go in for a plug and play type layout ie RCA socket for input, SIL connectors 6 pin for power devices all on board. Those willing still have the option to solder all direct.
Even I have couple of original Motorola 3055s but we will have to seek more opinion on this as a group project.
I have trip pending to Agra what better excuse with all this going I am sure I can manage a suitable pair of heatsink to suit each requirement.
I would look forward to Guru Angshus advice. Hope he aint workin up to drive those domes.

HAM radio never too late my friend just take a plunge Main hoon na.

Regards

Rahul

 

[corbato]

Tarun:

At Rs. 25 /each you can’t be serious. Comom,,…I buy copper laminated board for Rs. 80/sqft. More power to you and your PCB guy.

The JLH site has a PCB layout for the revised amp. It looks a bit wasteful to me. However, if we are thinking in terms of redoing the layout, then caution must be exercised in respect of track width. Should be sufficient for high current draw.

Roadkil

Dude this is one MOSFET amp I may ever build. Not complex at all and the devices you mention are available. Just the right thing for a bass amp.

Rahul

Great we thrashed the pakis at Lahore.

I had almost given up on this one. We should win the finals too. Insha Allah.

Your point on whether we should have plug’n’play type pcb is something that has been bothering for a long time. I think I’ll compromise and go for simple solder posts wherever possible. The quality and fitting of connector we get in the market is just not upto audiophile standard. I’d have like gold plated contacts. And RCA directly into the PCS is strictly no no. Ours will be just one offs. While PCB connector will be very good on production line situation, I would not be happy with the possible degradation that may bring about.

I will also prefer to have PCB for the PS, because it will be a current boosted or capacitance multiplier design. And if I’d prefer to have individual PS for both rails and each channel. So we are talking about 4 separate PS boards. And I would definitely use Schottky’s instead of a simple generic bridge

And the BTW thanks to Tarun and Rahul for there work on the PCB department. I’m sure all of us will appreciate that very much.

 

[roadkill]

I am happy the neighbours do wake up least, you may have to change ur ID here but more important that u are not whisked to the big guest house with many guards, huge gates .

Huh?
Totally off topic, but my nickname was because the week I registered, I saw too many run-over animals on the road. I'm a huge dog fan So far, no moderator's complained, but if any do, I'll be glad to change my nick.

The White amplifier's design goals are quite diametrically opposite to what most "audiophiles" like. It uses a circuit which, open-loop, has a relatively high distortion. It then uses a high gain and NFB to obtain low distortion. The article claimed < 0.005% THD (if I remember right), which is far more than what I need. These he measured using a spectrum analyzer, the article includes THD plots and analyzer results.

And I don't mean to sound firangi but not all of us can understand Hindi very well, so if someone could add subtitles...

 

[Rahul]

Dear Roadkill,

Sorry if it offended in anyway. All was said in lighter ways, we all are perfectly happy with your nick. I do feel sad abt the facts and circumstances of your picking up the name. BTW I am a regular visitor for OKC Oudh kennel club shows.

Back to the amp In my opinion the the current boosted design is much better in comparison to capacitance multiplier one as it also offers voltage regulation a very important criteria considering the quality of mains supply in our country. The presets also offer precise tweeking to eliminate variations arising as result of transformer manufacture tolerences. Regulators are standard devices.

I feel we can do only one layout for the PSU pcb that will have provision for both LM337 and 317 rest of the circuitry has same configration in its complimentry form so we can use the same board seperately for both the supply rails.

Regards

Rahul