Need schematic KEF 25B sub amp SP2298

cyclecamper · 15th December 2011, 02:31 AM

I need a schematic for a KEF 25B subwoofer plate amplifier model SP2298.

Or a replacement plate amp cheap.

cyclecamper · 15th December 2011, 05:44 PM

This is about 100 watts, mono (transformer couldn't do more than that). Looks like 4 large tab/screw output devices, and 1 small device thermally coupled to the heat sink. There's a lot of heat discoloration around the crappy little power supply diodes, but that could be symptom rather than cause (or neither).

cyclecamper · 05:51 PM

Maybe I'll just close up the hole with a plate and make it passive, but I have no mixer or mono amp nor small bridgeable amp, and the voicecoil is not a dual coil.

The surround is intact, but it feels like the type of foam that gets a bit sticky before it crumbles completely. Stamped frame. I'm not impressed.

I guess what I have is one bass-reflex box for a 10". Just what I never wanted. And I paid $50 for it. There's another on eBay with the exact same problem (blows fuse), but then shipping makes it unreasonable. Unless repairing the pair on amps would become cost-effective.

cyclecamper · 6th January 2012, 07:14 PM

Anybody want to fix it for me for a reasonable fee?

cyclecamper · 10th February 2012, 06:06 PM

Any good ideas?

cyclecamper · 27th February 2012, 06:13 AM

Getting desperate. I no longer have the equipment to do this myself, but I suspect I could replace the powersupply rectifier diodes and all the output tansistors for much less than getting a new plate amp.

cyclecamper · 15th March 2012, 05:10 PM

Anybody got "connections" to get the schematic for this plate amp from KEF?

cyclecamper · 21st March 2012, 08:47 PM

Nobody?

River'd In Audio · 26th March 2012, 12:50 PM

Can you post the static ohms of your driver. Mine must be shorted because it checks at .2 ohms. I have not been able to locate any source of a schematic. Mine is blowing the AC use. Mine also has the discoloration on the board at the diodes.

15th December 2011, 02:31 AM	#1
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Need schematic KEF 25B sub amp SP2298 I need a schematic for a KEF 25B subwoofer plate amplifier model SP2298. Or a replacement plate amp cheap.

15th December 2011, 05:47 PM	#3
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Maybe I'll just close up the hole with a plate and make it passive, but I have no mixer or mono amp nor small bridgeable amp, and the voicecoil is not a dual coil. The surround is intact, but it feels like the type of foam that gets a bit sticky before it crumbles completely. Stamped frame. I'm not impressed. I guess what I have is one bass-reflex box for a 10". Just what I never wanted. And I paid $50 for it. There's another on eBay with the exact same problem (blows fuse), but then shipping makes it unreasonable. Unless repairing the pair on amps would become cost-effective. Last edited by cyclecamper; 15th December 2011 at 05:51 PM.

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15th December 2011, 05:44 PM	#2
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	This is about 100 watts, mono (transformer couldn't do more than that). Looks like 4 large tab/screw output devices, and 1 small device thermally coupled to the heat sink. There's a lot of heat discoloration around the crappy little power supply diodes, but that could be symptom rather than cause (or neither).

6th January 2012, 07:14 PM	#4
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Anybody want to fix it for me for a reasonable fee?

10th February 2012, 06:06 PM	#5
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Any good ideas?

27th February 2012, 06:13 AM	#6
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Getting desperate. I no longer have the equipment to do this myself, but I suspect I could replace the powersupply rectifier diodes and all the output tansistors for much less than getting a new plate amp.

15th March 2012, 05:10 PM	#7
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Anybody got "connections" to get the schematic for this plate amp from KEF?

21st March 2012, 08:47 PM	#8
cyclecamper diyAudio Member Join Date: May 2010 Location: was Chicago IL, now Long Beach CA	Nobody?

26th March 2012, 12:50 PM	#9
River'd In Audio diyAudio Member Join Date: Oct 2009	Can you post the static ohms of your driver. Mine must be shorted because it checks at .2 ohms. I have not been able to locate any source of a schematic. Mine is blowing the AC use. Mine also has the discoloration on the board at the diodes.

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