MIG100B Bassov Blues Boy. Not really sure what that means but this is the bass version of Sovtek MIG100. Has that old bent transformer thing going on from being dropped.
Chassis shot of this beast. Still going strong but just needing new power tubes, which is normal every handful of years. Looks like someone either replaced or added some cathode bypass caps. Not sure because I have never seen a schematic of MIG100B but MIG100 schematic in general is a good reference.