Tube Amp Schtuff

03/08/2025

Perusing the Federal AM864 to drop some new filter caps in when I discovered two wires that were not actually grounded - as in the person in the factory decades ago totally missed soldering these to ground. Probably sat in a shelf for decades cause it never worked properly. No wonder it’s so clean…mind blown 🤯

03/03/2025

Prepping this guy for a test run!

03/03/2025

02/28/2025

Another Altec 438 on the bench for some minor upgrades!

This is one of several Altec 438A Preamp/ Compressor units that came in for a filter cap replacement and upgrade to silicone recitifier diodes. Ended up swap...

02/25/2025

Prepare to have your mind blown by the complexity and shear size of this 1941 RCA Consolette! If you have no clue what I'm talking about, have a little watch and learn some history behind this amazing, highly engineered piece of analog tube amplification. The mission is to bridge the connection between the stand alone power supply and the console. There are terminal strips in both the power supply box and the console that are designed such to make the console flexible for signal routing a myriad of configurations. More pics from under the hood to come!

This here is not just a cool piece of gear, this a time capsule representing an era of analog technology that just does not exist anymore. This is Part 1 of ...

02/24/2025

Got a “quickie” in this week 🙂. I like the projects, but a simple fix = immediate gratification.

02/23/2025

Pulled the selenium rectifiers from these old Altec 436 compressor units. Over time, these components don’t pass the DC like they used to. The result is the VU meter doesnt adjust to “0 db” cause it’s not seeing enough voltage from the power supply. Upgraded to silicon rectifiers and increased the value of the voltage drop resistors as you get a higher DC from the new diodes which has the opposite effect of raising the VU meter beyond the “0 db” mark.

02/22/2025

Got this Pultec EQ H2 on the bench for a 3 pronged AC cable replacement. You can see it’s gonna be a little project to install given the location under the hood. Will end up taking out the power switch and lamp assembly for sure. Figured I’d take a few snaps whilst under the hood. You can see, not a lot of components - it’s mostly tubes and transformers. I dig the frequency selector switches are selecting between taps across the one transformer. Overall, very clean inside.

02/21/2025

Diggin' way back into the early 50's to bring you a Masco MA-17 PA amplifier! The mission: turn this guy into a guitar amp😎. Just a quick tour on the Masco and what I've got done so far.

Up on the bench is an old Masco MA 17 PA amplifier. The plan is to convert this to a guitar amplifier head. Just recreated the circuit with new components, b...

02/20/2025

Check it! Check it! The Federals are here!