C-Audio Pulse 2x1100 - identifying mods |
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Haschatan
New Member Joined: 06 May 2021 Location: Merseyside Status: Offline Points: 3 |
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Hello All, Sorry for hijacking the post. I recently bought a C-Audio 4x300. It did have already the inductor mod done. I have changed the resistors on the four amps from 75ohm to 100ohm, i have ordered the 0.0047µF capacitors, and it already had the proper IGBTs and driver transistors for the IGBT. The only mod who will be left is the pulse transformer. I am wondering if it is difficult to wind it up or if i should not hesitate to make it? i have never wound a transformer. What are the risks if i leave the old pulse transformer? And while i am here, the IGBT are the old NGTG50N60. How long do the IGBT last? While the board is off, i could change the IGBTs if needed. Thanks a lot for your help. Regards.
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ceharden
The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
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Speak to SimonP (see previous posts) for a ready wound transformer. Otherwise I think I have a few of his transformers around. I used to wind them myself, then Simon got a batch done and saved me the effort.
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simonp1100
Young Croc Joined: 01 September 2008 Location: Bristol Status: Offline Points: 1103 |
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enclosed link for Pulse Transformer.
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kedwardsleisure
Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4938 |
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They aren't a wearing part, just leave them be. |
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Kevin
North Staffordshire |
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Haschatan
New Member Joined: 06 May 2021 Location: Merseyside Status: Offline Points: 3 |
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Thanks a lot for your answers guys. My C-audio 4x300 is going to be ready for many years now
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ceharden
The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
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You're not after any more Pulses are you? 😉
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M4trix
Registered User Joined: 23 June 2009 Location: Croatia Status: Offline Points: 445 |
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Speaking of which, @ceharden, What are the values of those two bodged yellow caps ? 0,0047uF/100V ? Nothing 'bout them in service bulletins. |
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ceharden
The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
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It's a good question. To be honest due to the lack of full information it's not a mod I've ever done. They appear to be Miller caps across the transistors doing the Vbe clamping (current limit) so I'm assuming they are there to reduce the sensitivity of the current limit to high frequency signals.
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simonp1100
Young Croc Joined: 01 September 2008 Location: Bristol Status: Offline Points: 1103 |
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Yes i think this is correct & this mod came out just after Crown took over the C-Audio brand & used it in the XS series etc. I also do this mod on any C-Audio Pulses i get in for service / upgrade.
Edited by simonp1100 - 07 August 2021 at 12:19pm |
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kedwardsleisure
Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4938 |
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the later crown-badged pulses (silver face) have the caps built into the pcb
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Kevin
North Staffordshire |
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M4trix
Registered User Joined: 23 June 2009 Location: Croatia Status: Offline Points: 445 |
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Guys, your conclusions about the caps were right. I've found the Crown's XS schematics with all mods included. |
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