DIAMOND DIFFERENTIAL INPUT POWER AMPLIFIER EBay kit

janusz · 10th March 2011, 02:14 AM

Hi,

I have just purchased this kit. I believe it's pretty fast and somewhat resembles older Sansui PA with differential diamond input.

Is there anyone who has built it?
It might be beneficial to share experiences and discuss potential modifications. The kit is is not expensive - $100 for two boards and all parts including on board speaker protection.
Output devices are njw3281/1302.

PA's diagram is attached. W2 and R28 are deleted, R16=220ohm now.
All comments invited.

cheers,

Tony · 10th March 2011, 02:32 AM

can you post the links?

ptempel · 10th March 2011, 02:39 AM

Maybe this is the kit?

Diamond differential power amp kit spk protection pair! - eBay (item 220630577557 end time Mar-28-11 02:36:27 PDT)

Looks nice and has speaker protection.

janusz · 10th March 2011, 02:54 AM

That's the same kit but I got it from tubeshunter as his kit has otput transistors included

link:
2 X DIAMOND DIFFERENTIAL INPUT POWER AMPLIFIER KIT! - eBay (item 380247429645 end time Mar-27-11 19:02:03 PDT)

cheers,

alexcp · 10th March 2011, 09:29 AM

On the schematic, should R22 and R23 be connected to "OUT" rather than to "IN-"?

AndrewT · 10th March 2011, 09:31 AM

I can't find a diamond arrangement.
I can see a cascoded VAS.

AndrewT · 09:38 AM

Quote:

Originally Posted by alexcp

On the schematic, should R22 and R23 be connected to "OUT" rather than to "IN-"?

I don't understand.

I see it now, the two schematics are different.
The first shows and extra connection from R22, 23 to -IN that is not shown in the second schematic.

janusz · 14th March 2011, 09:06 AM

What about lifting R22 and R23 from the nfb line? Acciphase and Sansui have these floating. Most modern amps have these floated. I do not know if there is any advantage having these connected to the nfb line. What do you think?
Has anyone got this amp?

cheers,

forr · 09:54 AM

Not very similar to Diamond Sansui's circuit, below, which has not a complementary input stage but nevertheless gives a push-pull VAS.

janusz · 15th March 2011, 12:10 AM

Forr,
I was talking about a somewhat different Sansui amp. This one:

cheers,

10th March 2011, 02:32 AM	#2
Tony diyAudio Member Join Date: May 2003 Location: Palatiw, Pasig City	can you post the links? __________________ http://www.electronicslab.ph/forum/i...?topic=32688.0

10th March 2011, 09:31 AM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I can't find a diamond arrangement. I can see a cascoded VAS. __________________ regards Andrew T.

14th March 2011, 09:51 AM	#9
forr diyAudio Member Join Date: Dec 2004 Location: Next door	Not very similar to Diamond Sansui's circuit, below, which has not a complementary input stage but nevertheless gives a push-pull VAS. Last edited by forr; 14th March 2011 at 09:54 AM.

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10th March 2011, 02:39 AM	#3
ptempel diyAudio Member Join Date: Jul 2008	Maybe this is the kit? Diamond differential power amp kit spk protection pair! - eBay (item 220630577557 end time Mar-28-11 02:36:27 PDT) Looks nice and has speaker protection.

10th March 2011, 02:54 AM	#4
janusz diyAudio Member Join Date: Oct 2004	That's the same kit but I got it from tubeshunter as his kit has otput transistors included link: 2 X DIAMOND DIFFERENTIAL INPUT POWER AMPLIFIER KIT! - eBay (item 380247429645 end time Mar-27-11 19:02:03 PDT) cheers,

10th March 2011, 09:29 AM	#5
alexcp diyAudio Member Join Date: Jun 2009 Location: Florida Blog Entries: 28	On the schematic, should R22 and R23 be connected to "OUT" rather than to "IN-"?

14th March 2011, 09:06 AM	#8
janusz diyAudio Member Join Date: Oct 2004	What about lifting R22 and R23 from the nfb line? Acciphase and Sansui have these floating. Most modern amps have these floated. I do not know if there is any advantage having these connected to the nfb line. What do you think? Has anyone got this amp? cheers,

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