It's good to hear that your amp is working nicely and that you're not experiencing any issues with hum or performance. While the orientation of transformers can sometimes affect certain aspects of an amplifier's performance, it's not always a critical factor, especially if the amp is working well and producing the desired sound.
However, the orientation of transformers can have some impact on electromagnetic interference and potential noise issues, which is why many amplifier build guides provide specific instructions on their placement. Transformers are designed with careful consideration of their orientation to minimize electromagnetic interference and hum.
geometry dashSince you mentioned that your amp is currently working well without any discernible hum or noise, and that vintage hiwatt amps also show similar transformer orientations, you might be in a situation where the orientation isn't causing significant problems for your specific setup.
If you're concerned about the orientation of the transformers but you're hesitant to make major changes, you could consider monitoring the amp over time to see if any issues develop. If you continue to experience good performance with no noticeable problems, it's possible that the current orientation might not be causing significant issues for your specific amp design and setup.
However, if you do encounter any hum, noise, or other performance issues in the future, you might want to revisit the transformer orientation and consider making adjustments as needed. Ultimately, the decision should be based on the overall performance and sound quality of the amplifier. If you're unsure, consulting with experienced amplifier builders or technicians might provide you with more specific advice based on the details of your setup and design.