The Difference with My Mods

Akai / Roberts Monoblock Step by Step Conversion:

I have lot of folks reference other mods done to these Akai/Roberts monoblock Amps. Some folks add fancy transformers, remove feedback caps that open up the frequency response and lots of other little tweaks to the mostly stock units. Most of these folks leave the original wiring in place and even reuse the 50 year old capacitors. I don't do that. All my units are stripped down to bare parts, cleaned, refurbished and then reassembled from the ground up with ALL new wiring and electrolytic capacitors. I think of my amps as little hotrods. While most guys are rolling heaps out of garages and giving them a quickie tuneup, I am doing a ground up restoration and modification. Think of the wiring and caps like the old wiring, hoses, belts, gaskets, and tires on an old car. They are partly rubber and organic, just like the electrolytes in the filter capacitors. Would you drive a car on 50 year old tires and feel safe? They may work, but they will tend to fail on you at the WORST time. One this that bugs me with these tape machine donor amps is that they have a lot of circuitry devoted to tape functions. The energy and chassis space that is freed up from removing the erase circuit for example, give me an ability to add a line amp to the tweaked 6267 Preamp circuit. I reuse the super high quality dog bone resistors from the original amp, but again they have been taken apart gently, cleaned and reassembled with a minimum path, shielded cables, and a sophisticated ground system that minimizes hum and noise from the power supply. All stuff even the heaviest tweaked stock unit doesn't have! Look at the pics of the process from raw donor to skeleton, to fully rebuilt electronic sculpture. Here is a visual progression from donor to finished two unit. I did a whole run of six amps here. I prefer doing 4-6 a a time to combine steps and more efficiently build and troubleshoot. It takes me 3-4 weeks to finish all 6, doing about two a week. Each takes about 12-20 hours total time, so two of these make a nice chunk of my work week.