I have for sale a pair of very clean Soundstream Reference 405 amplifiers that were recently serviced and modified by Eric from Eric's Amplifiers in Georgia to provide a class A bias on channels 1 through 4. As you can see the amps are very clean. Only reason I'm not using them is because I decided to go with an all-in-one amp+dsp (Helix). I have $500 in each amplifier ($300 purchase, $200 service and modification) so they are each $500 or $1K for the pair plus actual shipping costs. I accept Venmo or PayPal, if you use goods/services the fees have to be added on top of the purchase price. Happy to provide references. Amps are located in El Dorado Hills, CA.