Instrument/Amp/Studio Equip. Repair

Modifying a Hammond Model A organ to run without a Leslie or with the new Studio 12.

An old Standel Imperial amp head came into the shop. It's one of the hybrid models with potted modules in the preamp and a tube power amp section. These are hard because the potted modules are different than the schematic available online. First, I found that the power supply had major incorrect modifications. Replaced capacitors and rewired correctly. Once that was fixed I was able to find that the Normal channel was working fine but the Vibrato channel was not. That problem was isolated to the Vibrato module. I had to slowly grind away the potting and compare it to the later schematic. I had to change transistor, capacitor and resistor values to make everything work properly. In the process I found the power tubes needed to be replaced and the phase inverter tube was the wrong value. Replaced the two-prong power cord with a regular three prong version. Put in an speaker impedance switch. Everything working then shipped off back to the owner.

This is a minimalist repair of a 1962 Gretch Double Anniversary 6117. Rain leaked into the place where this guitar was stored. There's nothing I can do about the fogging in the finish without a total refinish job. The client has minimal money so this is a labor-only job. Strings rusted off. Bridge is frozen with rust and pickups are rusted up as well. The pots and jack are in bad shape. The nut is covered with rust from the strings that rotted out. The tuners are rusted and one of them has some funky screw that doesn't even fit. Frets are badly worn but I have to leave them alone.

Here are a couple Oktava MC012 microphones that I modded for someone. Mods included resistor changes and FET/capacitor upgrade. After the mods, the mic turns from just an okay mic to an excellent sounding mic that sounds great on drum overheads, guitars, etc.

These are two Nady tube microphones that I modded to be U47 clones. One uses an EF14 tube, which is very close to the original, and the other uses and EF800, which is in the same general tube family. Pretty hard stuffing the EF14 in the short body, much easier with the EF800. The one with the EF14 has an M7 capsule made by BeesNeez, while the other has a K47 clone capsule made by Equinox. The original U47 circuit was recreated and the power supply was modified for the proper voltages needed. Installed the U47 style transformer made by Cinemag. Finished off with a hammered grey paint job on the bodies. Great sounding miss with interesting sound differences due to the component choices.