Schematic for the "Phonic powerpod k12 plus" with class D power amp?

[Tubis]

The swedish distributor sent me a schematic but its not the right power amp on the schematic. The schematic shows an analog power amp with 12 transistors but in the mixer sits a class D one with four transistors. The distributor then replies that this is the only schematic available for that model. Phonics doesnt answer my mail.
Schematic with the class D power amp anyone?

[blindboybenton]

Don't know the amp but on bm amps site where there are thousands of schematics there is a k16. Guitar Amplifier Schematics and more

[doctor]

The swedish distributor is right. K12 Plus has switchable power supply and two linear power amps.

[Tubis]

There is a PWM signal going to a PCB card with an IRS20955 driving two IRFB4227 per channel and output filters, then going to the speaker jacks. The power amp on the schematic is nowhere to be seen. The swedish distributor just said that the schematic they sent me is the only one available. They didnt say anything about the circuit.

[blindboybenton]

Have you checked out the k16 looking at pictures of both. The k16 looks the same but more channels it's on the bmamps site

[Jazz P Bass]

Here is a 'standard' Class D amp using the IRS20955.




Some really good info here from International Rectifier on their take of a Class D amp.

[nickb]

BBB:I suspect the "plus" versions are class D whereas the others are not. Therefore the K16 schematic is not much use as far the the power amp is concerned.

Tubis: So, what is the problem? If it the power amp then that's lucky for you since in many way Class D amps are much easier to fix than most others There is the part the generates the PWM signal, usually very reliable, a gate driver, a IRS20955 in this case, and the output FETS. The failures are usually in the last stage. Yank the FETS and bench test them. If one is bad replace them both.

[Tubis]

I have the "plus" schematic. That is what they sent me. Not the one you can find online. The problem is I will not start digging in without a correct schematic under the presumption that it is the output tranistors. Been down that road before and if its not i have spent all that time and there is a customer that have to pay for me fiddling around. In Sweden we have very high cost for repair jobs because we are taxed very hard and everything is very expencive. I only do easy guitar amps without a schematic.

[nickb]

Oh well, so much for my guess. I recently been around the same loop where they kept sending me an incorrect schematic. it was finally correct on the forth attempt and only then after they contacted Engineering to get it.

[doctor]

It seems like new version. Can you upload this schematic?
If it is too large, you can place it in the dropbox.
Thank you in advance.

[nickb]

It seems like new version. Can you upload this schematic?
If it is too large, you can place it in the dropbox.
Thank you in advance.

I was talking about a different amp. My point is you need to persevere with them.

Edit: See comment by G1 below - he was right