I look after a CCA 3000DS that has had IPA retrofitted with a 3CX400A7, rather than a pair of 4CX250B's. The tube I am running is getting a little soft, and I am looking for a source for a replacement. Apparently, this is not a very common tube, as the only one we have been able to locate was over $780. Does anyone have a NOS one that is no longer needed, or a suggestion for a supplier that has a reasonable price point? Thanks.