5E3 Prototype Two

I have taken what I learned from Amp one and have begun to build amp two.  The chassis is bigger, the layout is proper and I am much happier with the way the holes for tubes and transformers worked out. I will be using a 5E3 Board from Hoffman Amps and this will make for a much more organized build.

5E3 Feaver 3 001

5E3 Prototype 2

This chassis is from a Canadian chassis maker called Seaside Chassis Design from the East coast and I am quite happy with the work they have provided. It came stock and I did all the drilling to my liking.

 

 

 

Top and Rear

Top and Rear

Top and rear view is nothing that unusual. Transformers are twice the size for this project with the HT at 312 VDC and the OT in the 18W class. I will still use 2 6V6 and 2 12ax7 tubes with a 5Y3 rectifier stage.

 

 

One thing I will really need to invest in is a set of Greenly Socket Punches for holes. At this point I am using step drill in the drill press and I am less than impressed with the quality of some cuts. I suppose I will get better at drilling but in the meantime this is going to have to do.

 

Initial assembly

Initial assembly

Starting to add some hardware, and begin to see how things all come together. Sockets fit in ok, pots and jacks are in fine with much more room to work. I will not have as much trouble wiring up this project as there is more room inside.

 

 

 

Circuit Board Progress

Circuit Board Progress

Here is some more progress on the circuit board. On this amp I am using current technology turret board and new current era components. Except for a few caps and the odd resistor. I am happy with this progress and I had to make some revisions to the circuit to match my chassis but not much else.

 

 

Installed Transformers

Installed Transformers

At this stage, I installed the power transformer and the output transformer. The power transformer is a 315-0-315 CT transformer that is from a Hammond organ of some sort and I think it will do the job nicely. The OT is a 22W rating that will be more than enough to handle this output. I have been using a Workmate 225 as a bench for amps. It works really good as the table splits in the middle allowing me to flip the chassis over and have the transformers go below the table. I had considered making a bench working jig but this Workmate works even better.

 

Bottom

Bottom View

Wiring from the Transformers exits through grommets in the traditional way. I will not wire them until I have finished the filament wiring.

 

 

 

I have completed this amp and perhaps have more images to follow. It turned out much better than the first amp. Voltages were right in the appropriate ranges and the sounds from this amp are clean and consistent. Heat from the amp is reasonable and I don’t think that it was ever working to maximum with that big output transformer and the larger than normal Power Transformer.  Lots of capacity before some distortion was evident which resulted in a clean sound.

Completed this amp on July 31 2013 and it was delivered to a customer.

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