new ChipAmp.com website - LM4780 kit and more

DWong · 2004-09-29 3:36 pm

OK! I am really to order now!

Thanks a lot!

_henry_ · 2004-09-29 4:47 pm

i want one!!!

this is getting very2 interesting, such a reasonable price, hats off for u Brian, Peter, and Vikash for designing the web.

i lived in jakarta, so the only problem is we don't have a good toroid trannies.
what should i do?

btw, right now i'm building GM's jx92s design, i think the clone will do just fine with them, do they?

rnoble · 2004-09-29 5:52 pm

Henry,

You could try this place in Sydney

They do all types of trannies at very reasonable prices; and ship via courier, not sure how much they'll charge for you but they stock Antrim trannies, good quality trannies.

Or you could try partsexpress.

Cheers

_henry_ · 2004-09-29 6:06 pm

rnoble, thanks i'll try contact them

have u built the clone yet? with the antrim?

cheers

rnoble · 2004-09-29 6:40 pm

_henry_ said:
rnoble, thanks i'll try contact them

have u built the clone yet? with the antrim?

cheers

I'm in the process of doing it now (LM3875), received the Antrims yesterday, have my case all set up and am awaiting delivery of the amps from Peter and Brian, can't wait!

kepa1 · 2004-10-03 4:59 pm

to brian,

thank you for the new site and most of all for the pdf file; very interesting for someone who knows nothing about it all!

i'll probably buy a 4780 set for driving a 10" beyma driver...

see you later

wigginjs · 2004-10-05 2:52 pm

Just to clairify for the LM4780 kits...

The LM4780 chip has two amplifiers on a single die, correct? In the kits you are providing are these two amplifiers bridged or wired in parallel? If so, the output power is about 120W@8ohm? Would it be possible to provide a pic of the board layout including size?

Peter Daniel · 2004-10-05 3:22 pm

The layout and sizes are posted here: http://www.diyaudio.com/forums/showthread.php?postid=478317#post478317

The two amps are wired in parallel. A bridging board will be available later, allowing to use 4 amps in parallel/bridged configuration.

The power available, from parallel configuration, is presented in those graphs (depending on supply rails): http://www.diyaudio.com/forums/attachment.php?s=&postid=482889

kleung · 2004-10-05 3:33 pm

Peter or Brian, will your shop offer any other than Chip amps. Reason I ask is that I missed out on the PCB group buys on the X and the Aleph and I do not feel buying it overseas. Since Brian designed nice PCB's for them, will you guys supply them as well in the future?
Regards.

BrianGT · 2004-10-05 4:37 pm

kleung said:
Peter or Brian, will your shop offer any other than Chip amps. Reason I ask is that I missed out on the PCB group buys on the X and the Aleph and I do not feel buying it overseas. Since Brian designed nice PCB's for them, will you guys supply them as well in the future?
Regards.

I have provided the Aleph layout to others already. I am willing to provide the output files to anyone who wants to get them made for their own not-for-profit use.

As for the Aleph-X boards, I never finished assembling my prototype pcbs, as the Chad's boards looked great, and people seemed more interested in them.

As for the site, I will not be offering any boards based on the Aleph boards, due to the IP issues. I am willing to provide help if someone wants to organize a group order for them. I don't have time to do it myself, as I do have a full time job, and spend my spare time mailing out the gainclone kits.

If you want to try to organize a new AlephPCB group order, create a new thread and see if you can generate interest for it. I get a few mails a month asking for boards.

--
Brian

wigginjs · 2004-10-05 8:09 pm

Really good. I was about to place an order for the LM3875 kits, but I'll be happy to try these new kits. I suppose a 25V transformer (25*1.414 = ~35VDC) would work well with these amps? Recommended VA rating for the transformer (~200VA?)? I suppose that these chips will need a significantly larger heatsink that the 3875s?

Peter Daniel · 2004-10-05 8:17 pm

m0tion said:
I suppose a 25V transformer (25*1.414 = ~35VDC) would work well with these amps? Recommended VA rating for the transformer (~200VA?)?

This should be fine (especially when using one such transformer per channel, but not neccessarily).

Those chips idle on a warm side, but the heatsink does not get hot, like with class A amps. Any reasonable size will be OK.

fireman · 2004-10-05 8:30 pm

Peter,

How about those Avel-Linberg 2X28.4 V toroids from ApexJr. Are they underpowered for the job at hand ?

I'd really like to build a 5 channel HT amp so using 5 of these would be very interesting for me ($$$).

Peter Daniel · 2004-10-05 9:04 pm

150VA per channel will work for HT, but I'm not sure if 28.4 V AC on secondaries isn't too high. It may produce 40V DC (or even more than that if you mains voltage is on higher side) and this is the max rating for the chip. It may be pushing it a bit too much.

I would rather buy one toroid first, and see what I'm getting after rectification.

troystg · 2004-10-05 10:07 pm

Jean-Pierre & Peter-

Use the one from Apex.jr and use the LM338 regulator.

I am doing just that for a 5 + 1 amp with 6 torids. All but the sub torid are regulated. Drop the voltage to 30-33 VDC and have a "toite"(please excuse the Austin Powers quote) pwr supply.

As for unregulated, I would do as Peter suggests and try one first.

Thanks,

Troy

fireman · 2004-10-05 10:21 pm

rabstg said:
Jean-Pierre & Peter-

Use the one from Apex.jr and use the LM338 regulator.

I am doing just that for a 5 + 1 amp with 6 torids. All but the sub torid are regulated. Drop the voltage to 30-33 VDC and have a "toite"(please excuse the Austin Powers quote) pwr supply.

As for unregulated, I would do as Peter suggests and try one first.

Thanks,

Troy

Would you mind sharing more information with this forum ? I am quite "green" in chip amp and this kind of stuff. The only thing I actually built, well I'm actually still building it (still waiting for some parts to finish the case), is Brian's LM3875 chip amp. I'd really like to see how you implemented the regulator chip.

You might want to start a new thread in order to avoid hijacking this thread.

troystg · 2004-10-05 10:26 pm

No need to elaborate, digi01 says it all here:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=38636&highlight=

Let me know if you have any problems with the link.

Thanks again,

Troy

troystg · 2004-10-05 10:37 pm

Here is the finished PCB.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=39816&highlight=digi01

I have mine sitting in the post office right now. They tried to deliver and I was out of town so I need to go pick them up.

Thanks,

Troy

fireman · 2004-10-06 12:03 am

rabstg said:
Here is the finished PCB.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=39816&highlight=digi01

I have mine sitting in the post office right now. They tried to deliver and I was out of town so I need to go pick them up.

Thanks,

Troy

Thanks for the info. The PCBs have already been ordered. If I use the part values suggested by digi01, will this get the voltage low enough for the LM4780 ?

Also, I just received an email from Steve from ApexJr and he said that he has a good stock of those toroids so if others are interested...

troystg · 2004-10-06 1:31 am

Hey Jean-Pierre-

"If I use the part values suggested by digi01, will this get the voltage low enough for the LM4780 ?"

Yes it will work as designed however I suggest you adjust the regulated voltage to around 30 VDC so the regulator does not have to work too hard.

Thanks,

Troy

new ChipAmp.com website - LM4780 kit and more

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