Commercial Gainclone kit- building instructions - Page 31

Peter Daniel · 15th November 2008, 12:26 AM

Yes, you can connect the speakers and the source.

You can connect heatsink to Earth ground (isolate the LM1875 chips)

afunkymonk · 15th November 2008, 05:43 AM

Quote:

Originally posted by Peter Daniel
Check the fuse.

Thanks. Some mothers do have them...

Measuring the power supply without the amp boards connected, both measure approx 25VDC across both pos and neg.

Voltage at the wall is approx 216VAC

Now I have connected the amp boards, both amps read approx 29V and 33V across positive and negative respectively.

The chip gets pretty hot pretty quickly. I have changed the pcu heatsinks for pieces of aluminium sheet measuring 4" x 8" x 1/8" which hopefully will dissipate heat better.

Tested amps through two four ohm speakers from a pc speaker system using ipod as a source. Barely audible badly distorted sound from both amps. What to check next?

Thanks as usual

Matt

Peter Daniel · 15th November 2008, 06:03 AM

Are you sure you didn't mixed up resistors on amp PCBs?
The values should be according to schematic here: http://www.diyaudio.com/forums/attac...amp=1210693738

bestbier · 15th November 2008, 02:29 PM

Can I really hear the difference between the Premium LM3875 and Classic LM3875 Kit?
I mean, they are the same but use different (pricy) components.

And what about their PCB used with "common" components? Would such a version be a bad expierence?

Peter Daniel · 15th November 2008, 02:38 PM

Only you can answer that: some people hear the difference, some not. When in doubt, I usually recommend to start with standard components and upgrade later, when you feel it might be worth it

What do you mean by 'PCB version with "common" components'?

bestbier · 15th November 2008, 05:32 PM

I mean ordering the PCB only, and filling
it with standard components.

Peter Daniel · 15th November 2008, 05:55 PM

That should work too.

bestbier · 15th November 2008, 09:52 PM

Well, to be honest I have more faith in your kit. And it saves me time and shopping for the right parts.

Anyway, I ordered your classic kit this afternoon (Wester-Europe time) and hope I can build this beauty soon. :-D

northernsky · 16th November 2008, 04:18 PM

My first chipamp works and sounds fine. Thank you to everybody, it should be impossible without the help of this thread

Renato

bestbier · 16th November 2008, 10:28 PM

About the transformer. What is the minimum VA (Watt) and minimum/maximum Volt?

15th November 2008, 12:26 AM	#301
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Yes, you can connect the speakers and the source. You can connect heatsink to Earth ground (isolate the LM1875 chips) __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

15th November 2008, 06:03 AM	#303
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Are you sure you didn't mixed up resistors on amp PCBs? The values should be according to schematic here: http://www.diyaudio.com/forums/attac...amp=1210693738 __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

15th November 2008, 02:38 PM	#305
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Only you can answer that: some people hear the difference, some not. When in doubt, I usually recommend to start with standard components and upgrade later, when you feel it might be worth it What do you mean by 'PCB version with "common" components'? __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

15th November 2008, 05:55 PM	#307
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	That should work too. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

15th November 2008, 02:29 PM	#304
bestbier diyAudio Member Join Date: Nov 2008	Can I really hear the difference between the Premium LM3875 and Classic LM3875 Kit? I mean, they are the same but use different (pricy) components. And what about their PCB used with "common" components? Would such a version be a bad expierence?

15th November 2008, 05:32 PM	#306
bestbier diyAudio Member Join Date: Nov 2008	I mean ordering the PCB only, and filling it with standard components.

15th November 2008, 09:52 PM	#308
bestbier diyAudio Member Join Date: Nov 2008	Well, to be honest I have more faith in your kit. And it saves me time and shopping for the right parts. Anyway, I ordered your classic kit this afternoon (Wester-Europe time) and hope I can build this beauty soon. :-D

16th November 2008, 04:18 PM	#309
northernsky diyAudio Member Join Date: Feb 2008	My first chipamp works and sounds fine. Thank you to everybody, it should be impossible without the help of this thread Renato

16th November 2008, 10:28 PM	#310
bestbier diyAudio Member Join Date: Nov 2008	About the transformer. What is the minimum VA (Watt) and minimum/maximum Volt?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Commercial complete Gainclone kit for a beginner?	gychang	Chip Amps	365	4th October 2011 08:19 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read