Although the thread is quite old, I still want to answer because it seems that nobody cares.
The Tramp amp does not have an effect loop built-in. However, it may be possible to install one by modifying the circuit of the amp. This would require some technical skills and knowledge, and it may void the warranty of the amp. Therefore, it is not recommended to do it yourself, unless you are confident and experienced in amp modification. You may want to consult a professional amp technician or builder for advice and assistance.
geometry dashAlternatively, you may consider using a different amp that has an effect loop, or using pedals that work well with the front end of the amp. The Tramp amp is designed to have a vintage-style tone and response, and it may sound better with pedals that are compatible with its character and headroom. You can experiment with different pedal orders and settings to find the best sound for your amp.