5F2a completed, and working....

After faffing about with a Chinese tube amp for a while, and increasing my understanding about how amps work, I decided to build a 5F2a Princeton, from a kit supplied by Modulus Amps.

The build went well, and was completed over a period of three days, with the amp working first time. (No smoke, sparks or explosions!)

The build was done to the Modulus layout, with the exception of the 68K Grid stopper resistors, which were changed to metal film, mounted on the input jacks and connected to the preamp tube by shielded cable. (Shield grounded at the jack end) I read somewhere that this was a good idea!

The amp is temporarily housed in a cab with a 12” speaker. I’ll get a cab built for it soon, but it may get a 10” speaker. Not decided yet. I’m currently trying to figure out if a slab of hardwood I have will be big enough for the box. Cardboard templates being produced.

Only minor issue is a slight amount of hum, so I may do some wiring adjustments to see if it makes any difference.

 

Thanks for the compliments. I'm quite pleased with the result!
Yes, first build, although I've done soldering on a few occasions for other purposes. I then rewired the heater wires on my Chinese amp, so that gave me some practice working inside a box!
I had originally planned to build a Harvard, and have collected a lot of the components for that. I then decided it might be better to practice on a kit first.

It was just an idea to hold them tight together until I got around to terminating them. Just seemed to tidy things up.

I'm a novice guitarist, with old ears, but it sounds fine to me. I've been playing around with the settings, and different pickup settings just to see what they do!

Modulus recommend sticking with their layout, so I'll leave it as-is for the moment. I may try some of the other ideas in the future. (Elevated centre tap, split preamp/power ground etc etc.)

I need to go back and concentrate on practicing, rather than building. Although the temperature in my workshop has now risen enough tto start thinking about woodwork......

 

Yes, that's the one.
The hum is just low background, so not an issue at the moment. It starts the instant the power is switched on, before anything heats up, so I'm thinking its just PT noise. I'll try sometime with all the valves out and see what effect that has.

 

Some further progress with this project.
Cab now nearing completion.
This was built from an old wardrobe side panel which was, I believe, mahogany.
Cab size was based on the online 5E3 dimensions, but scaled down slightly to suit the size of panel that I had.
A couple of minor joinery issues, but nothing that needs covered in fabric!
Next crucial decision is what colour/type of grill cloth? I was thinking oxblood, without the gold stripes, but open to suggestions.

 

Cab now completed.
Fitted with a Jensen 10" C10R Ceramic Speaker.