K8040 questions


I would like to purchase 4 of the K8040 mono blocks for driving my speakers using bi-amping. But before buying, I’d need some additional information about them. (I can’t afford to buy 4 for these amps just for testing if it works).

The speakers I need to power with these amps are customized Canton Ergo RC-L (serious audiophile speakers with well designed crossovers). Their nominal impedance is 4-8 Ohm. While the impedance never exceeds 8 Ohm, the impedance minimum is 2,8 Ohm between 2 and 3kHz. Otherwise the impedance is fully optimized, flattened and therefore absolutely not critical for the amp. The SPL is about 88 dB@2,83V@1m. The crossover frequency is at 300 Hz, so the more-solicitated amp powering the woofers will not have to deal with the 2,8 Ohm frequency minimum mentioned. Only the amp dedicated to the mid/hi-section (which will need to deliver less output power as it is the mid/hi-section) will be confronted to the 2,8 Ohm impedance.

In the technical specs of the TDA7293 MOSFET IC the K8040 kit is based on, the minimal impedance mentioned is 4 Ohm. Nevertheless, it is worth mentioning that I never had problems driving my speakers with even standard-class consumer-hifi amps, also designed for only handling loads higher than 4 Ohm. Do you think powering each of these speakers with 2 of these amps (bi-amping) would work well even at high listening volumes?

Would it be possible to obtain the 3D stability diagrams for the K8040 (output voltage relative to load impedance and electrical phase)?

Is the amp always working in class A/B does it switch to class-A when only a few watts of low output power are needed?

Correct me if I am wrong: If I understood the schematics right, the opamps (all IC except theTDA7293) are not used at all for processing the audio signal and therefore it makes no sense to replace these with some Burr Brown or Analog Devices audio-grade ones?

Thanks for your advices and help

best regards,


It is a class AB amp. The op-amps are not part of the audio circuit.
Sorry, no graphs. We’d assume it will work fine and we never had problem caused by speakers which occasionally drop below 4 ohms, but I’m sure you’ll understand we cannot guarantee anything without actually testing it ourselves.

thank you for your help!