The Bambino was a feature set definition that was quite a job to accomplish. Design an amp that had all of the qualities of a larger amp, but at a much lower volume level. Include features to set it apart from all the other 5 watt tube amps in that market. It had to satisfy the bedroom player, but also satisfy Obeid’s ears and high standards of product design. Obeid was actually one to revive that market segment in the 90’s with the VC-508. Before that amp, there was very little market velocity in the 5 watt tube amp arena. Now you can’t go anywhere without falling over 4-5 different variants, not to mention the high end boutique manufacturers.
Single ended amplifiers are completely different animals than larger push pull designs, so Obeid wanted to start with a push pull deisgn. Triode designs were discarded early on because they just didn’t have the “aliveness” of a pentode. Obeid dug into his stash of tubes from the LA-2A clone (see tech bomb la-2a) and found his answer, the 6AQ5. Readily available and inexpensive on the NOS market, the 6AQ5 power pentode uses a miniature 7 pin socket and a 12 watt dissipation, so size and power were covered. The initial results were very promising so the power amp design was settled upon.
The speaker load box and headphone outputs were a concept bouncing around for a long time. Notebook sketches from SLM days were used to define the back panel features. No one had a headphone jack on a small tube amp, but ss amps had headphone jack as a standard feature. The load box concept had been around for a while, but no-one had put it all together (ding ding light bulb). Obeid incorporated this type of “re-active” load and speaker simulator, and headphone drive-ability to the Bambino. The ability to use the amplifier silently is one of the standout features that set it apart.
Take all the above requirements, and then add Stack Mode concept to it and now the amplifier is complete. Two independent vintage voiced signal chains, and a third modern series combination offered the flexibility for the preamp. This was a concept worked out in the Stack Mode story (link to blog) on the mutt brown amp (pic). The combination of all these features made the Bambino quite a challenge for Obeid to design, but a challenge he was up for as seen by the rave reviews and wonderful reception by the marketplace.