Merlin Super Bam serial #3746 that I'm not using as I've upgraded to a Master Bam. It's in nice shape and does improve the overall performance . More refined and a fuller overall sound that, I find , is more relaxed. It just sounds better. The caps are easily upgraded to improve the performance even more. This is the battery / ac version. Will need a battery service ( due every 3-4 years according to Rich at Signature Sound ). He charges around $100 for that service. Or find out about doing it oneself. I've taken $100 off what I paid for it to allow for this service.