well is this kit good :S LM3886 Hi End Amp DIY Kit Component 68W Components New | eBay coz i have ordered it
The output transistors in the first kit you've mentioned in your first post seems to be fake as the price of the entire kit is almost as low as the 10 output genuine output transistors. Yes, genuine parts cost more, that is the price you need to pay for quality
they have a different number too.something like tta1943 and ttc5200.i will check later and post.
p.s.the lme49810 is original.
This is a TRUE story. [I know the teacher]
An American teacher,working in Nanjing China, walked into a small shop and saw IVORY brand soap selling for 3rmb {about 50 cents USD}. Normally imported soap retails for 12rmb. He was delighted to see imported soap for such a low price, and promptly bought.
Using the soap in the shower, he realized it was not IVORY at all - it was 'fake'.
He rushed back to the store, and declared to the shop owner, "This is Fake!"
The shop-keeper stayed calm, looked the foreign teacher in the eye, and said, "Of course it is. Are you so stupid to think you would get imported soap for only 3rmb?!"
Although i am a freshman here in this forum but i've been reading threads here for half a year b'coz i want to learn to build my own chipamp and DAC, i live Hong Kong, born under British Colony.
The kit you mentioned above i can get from taobao for less than 25bucks.(rmb148http://www.diyaudio.com/forums/members/kmossman.html), and those kits from ebay i don't see much different than i get from china and shipped back from us to hk especially those sellers get a large qty. discount from china and ship out from Hong Kong to worldwide. I do brought 3 sets of WM8741+WM8805 DAC, however it was beyond my ability to build the DAC from components.
I wouldn't say all kits from china/ebay are fake, obviously some of them are fake, but quite a large amount those ic's & capacitor are "recycled" rubbish(but worked) and imported from foreign developed countries. They de-solder it and sold to public, some of them went to ebay. Most of these process are done in Guangzhou and Fujian. There are shops in china DO sell genuine+used chips. But those electro cap's, some of them are mostly beyond there storage life as told by sellers in china. There is genuine chips all around, but you need to know WHERE to get them.
Kmossman is telling the truth. 3x sale price is a minimum on ebay.
Caveat emptor is golden rule when u try purchase stuff from this country. All of them are sold as-is. When in doubt, pick another seller.
i wonder if any experts here can help me out to pick a chipamp to build for my speakers?
I've been watching that kit myself, let me know how it works, I need a power supply before I order something which is why I am playing with the TDA2030 and 2050 boards
here are some pictures of my kit, first of all iam impressed, all the capacitors are legit, real wima and so on, and they hold up the capacitance well, so they aint used.
and the pcb has excellent build quality
https://www.dropbox.com/s/g2t6xilwyqwpfaa/Photo 2013-02-18 19 21 57.jpg
https://www.dropbox.com/s/1kqbd7lmnfjd68j/Photo 2013-02-18 19 25 42.jpg
https://www.dropbox.com/s/0qqfhzz9cxn2btc/Photo 2013-02-18 19 24 25.jpg
https://www.dropbox.com/s/eu08aw7tx8yd2ii/Photo 2013-02-19 05 39 26.jpg
and got good instructions aswell
and the pcb has excellent build quality
https://www.dropbox.com/s/g2t6xilwyqwpfaa/Photo 2013-02-18 19 21 57.jpg
https://www.dropbox.com/s/1kqbd7lmnfjd68j/Photo 2013-02-18 19 25 42.jpg
https://www.dropbox.com/s/0qqfhzz9cxn2btc/Photo 2013-02-18 19 24 25.jpg
https://www.dropbox.com/s/eu08aw7tx8yd2ii/Photo 2013-02-19 05 39 26.jpg
and got good instructions aswell
A question to mirmite.
Is the large toroid transformer mounted with metal brackets and a metal through bolt onto your chassis? If so than you will have a serious problem as this constitutes a shorted turn and it will overheat the transformer very quickly. This method of mounting is OK as long as plastic brackets or a nylon through bolt are used.
I thought I had better point this out as I had a similar problem many years ago.
Best of luck with the project.
Is the large toroid transformer mounted with metal brackets and a metal through bolt onto your chassis? If so than you will have a serious problem as this constitutes a shorted turn and it will overheat the transformer very quickly. This method of mounting is OK as long as plastic brackets or a nylon through bolt are used.
I thought I had better point this out as I had a similar problem many years ago.
Best of luck with the project.
ohh now i see, yeah there wount be a short in the transformer it aint a through bolt its two bolts on either side, and there are rubber mat on the bracket aswell.
only one last thing remains on my amplifier, its to connect the grounds, i have connected the ground from the power outlet to both of the chassis, shuld i connect the ground to the gnd of the output aswell ? or to any of the pcbs?
only one last thing remains on my amplifier, its to connect the grounds, i have connected the ground from the power outlet to both of the chassis, shuld i connect the ground to the gnd of the output aswell ? or to any of the pcbs?
sorry for the spamming, here is a schematic of my wiring on my xy kit, should i connect the gnd from the outlet to somwhere else except the chassi? or have i missed something
https://dl.dropbox.com/u/15996745/bajs2/well.png
https://dl.dropbox.com/u/15996745/bajs2/well.png
I can't speak for the kits, as I have only purchased assembled boards, but they have been very good.
I recently tried a pair of opa627 ICs, was skeptical figuring these would be easy to re part mark for a quick profit. The parts are great, even at a cost that was a small percentage of their cost here in the US.
Never heard of the leather car interior in Tijuana eh?
Different markets have different prices.
The center tap is what you would attach to the chassis. I usually investigate the outputs (while un powered)with an ohm meter to get a better idea of the configuration. That, along with the voltage readings will give you the whole picture. When you have correctly identified the two center taps you will find that they will have a fairly low ohm reading.
I recently tried a pair of opa627 ICs, was skeptical figuring these would be easy to re part mark for a quick profit. The parts are great, even at a cost that was a small percentage of their cost here in the US.
Never heard of the leather car interior in Tijuana eh?
Different markets have different prices.
The center tap is what you would attach to the chassis. I usually investigate the outputs (while un powered)with an ohm meter to get a better idea of the configuration. That, along with the voltage readings will give you the whole picture. When you have correctly identified the two center taps you will find that they will have a fairly low ohm reading.
Usually the centre tap connection is the ground.
You want the ground to be of the STAR type --- all ground wiring goes to one point. For many non-audio projects a ground bus bar works - grounds are connecting to a thick [copper] wire or 'bar'. But this can result in a potential difference, causing hum.
So use a STAR ground.
I just got 2 of this 300W boards similar to that of 400W mentioned in post #1:
LME49830 K1530 J201 300W Mono Power Amplfier Board | eBay
Quality upon inspection is perfect and components seem genuine and as advertised. If you have to do this on your own it will probably cost more than getting it as a finished product, the same as if you sum up the cost of any car full spare parts list will be much higher than buying it brand new. The retail price of a transistor is not the same if you get one than if you get 2 thousand units.
LME49830 K1530 J201 300W Mono Power Amplfier Board | eBay
Quality upon inspection is perfect and components seem genuine and as advertised. If you have to do this on your own it will probably cost more than getting it as a finished product, the same as if you sum up the cost of any car full spare parts list will be much higher than buying it brand new. The retail price of a transistor is not the same if you get one than if you get 2 thousand units.
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Bought IRS2092 kit, had some trouble first with 5 band and 4 band mixed resistors with unreadable color code...
Then dumped them in garbage... well i used most of them but still had to use some of my own.
Driver was fake, both output trans were fake...
It did not even start up, has some hiss on the output bu nothing when signal was applied..
Supply voltage was +-65V (good enuf) ;D
Bought new drivers and two IRFB4020 for 8€ total and it works like chaarrrmmm
Now waiting for LM4766 stereo amp i saw the supply rails to the chip were prety damn long but maybe adding some solder to them will affect the sound a bit better way.
Then dumped them in garbage... well i used most of them but still had to use some of my own.
Driver was fake, both output trans were fake...
It did not even start up, has some hiss on the output bu nothing when signal was applied..
Supply voltage was +-65V (good enuf) ;D
Bought new drivers and two IRFB4020 for 8€ total and it works like chaarrrmmm
Now waiting for LM4766 stereo amp i saw the supply rails to the chip were prety damn long but maybe adding some solder to them will affect the sound a bit better way.
Broad-brushing the notion that all kits, or other amp modules from Asia are worthless and/or dangerous is simply irresponsible. I've ordered many such kits and have had only 1 failure. OTOH, I did purchase a Sure IRS2092 based amp from Parts Express and it lasted 2 weeks before it started to fail and ultimately died and was relegated to the dust-bin of my used, but damaged modules. So a reputable dealer is not always a reliable benchmark. And to suggest that all kits from China will blow up in your face, is simply gross hyperbole. I have found on most of my modules that the parts are genuine and build quality excellent on professionally made PCBs, and I have been very happy with most of my purchases and more importantly, the audio results of the end product.
Has anyone tried this particular assembled amp module based on the TI LME49810 chip amp? On simple visual appearance it appears of quality build. Like to hear first-hand experiences with it. Does it sound good?
So a reputable dealer is not always a reliable benchmark. And to suggest that all kits from China will blow up in your face, is simply gross hyperbole. I have found on most of my modules that the parts are genuine and build quality excellent on professionally made PCBs, and I have been very happy with most of my purchases and more importantly, the audio results of the end product. Has anyone tried this particular assembled amp module based on the TI LME49810 chip amp? On simple visual appearance it appears of quality build. Like to hear first-hand experiences with it. Does it sound good?
All set Andrew.
Thread here:
http://www.diyaudio.com/forums/solid-state/241562-300-300-wrms-pa-lots-pictures.html
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