has anyone had a CLASSE AMP CA300 modded

I have upgraded the IEC power inlet and output binding posts of my CA-300 but that has been it. The input buffer OP amps may be worth upgrading. Also bypassing the +VE and -VE rails at of the output transistors as in the CA-301 versus only two points in the CA-300. Replacing the stock rail fuses with premium ones may also realize some improvement. These were eliminated in the CA-301, so it stands to reason the fuses must have some sonic influence.

PM me if you need schematics, etc. While these can be obtained from the Classé service dept., note that there are several issues with the original schematics. They have a few errors, which I pointed out to them at the factory, the document quality is not that great, and some parts, including the OP amps are not identified. I obtained the parts numbers from the factory, and have schematics that I updated and improved using Photoshop. The updated schematics have all parts identified, are very legible, and have the errors corrected.

http://img.villagephotos.com/p/2003-5/191557/2009226

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hi Glen,
this is great news ...i will pm
john

The heatsinks on the CA300 ring like a chime. Try to dampen the fins. When I had this amp, I used some thick mdf wood panels and brass weights across the top of the fins to damp out the ringing. This cleaned up the sound to a remarkable degree. There are likely more elegant solutions available. BTW the DR8's didn't exhibit the ringing fins. Of note, the transistors are mounted to the back plate of the offending fins hence the degradation caused by the ringing.

thanks Rhljazz

If this ringing is a problem in the CA-300, it should also be a problem with the CA-200/CA-400/CA-301/CA-401, since they all use virtually the same style heatsinks and transistor mounting method.