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Henry Scott Yocum Memorial Amplifier Build


ToolShedAmps

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It's been awhile since I've posted to the forum for various reasons. However, I thought this would be an appropriate vehicle to allow those interested to see the construction of an amplifier from start to finish..... the ToolShed way.

 

As many of you may know, shortly after the pilgrimage we unexpectedly lost a great addition to our extended Klipsch family, Henry "Scott" Yocum. He was a jovial, kind-hearted, Klipsch lover that I came to know during the several months he was in my queue. We had half a dozen hour-long conversations about everything from music, speakers/amplifiers to food. He will be greatly missed. The amplifier that will be constructed on this build thread is his. Built exactly as he wanted it, with the exception that it will have his name etched into the top plate where the name of the amplifier normally goes. Hopefully, once completed, his family will listen to it through his beloved K-Horns and the music will touch them as it did him.

 

So, if you have interest, tune-in as I'll be posting pics as well as text to walk y'all through this build over the next few weeks.

 

Godspeed Scott.....

 

Matt. 

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OK, a brief description of Scott's amplifier is in order before we begin. His amplifier will be a variation of my PWK Special Edition Euphoria Stereo 45 amplifier. His will be a Two-stage, Triode-Strapped Pentode (E180F/E280F/D3a) driving a 2A3 Triode. It will be tube rectified via GZ37 or 5U4g. DC filament heaters for the driver stage and AC heating for the 2A3's. I am including top-plate mounted "hum" pots for the 2A3 filaments for the very 1st time so that Scott's family can even elect to swap in some of the very inexpensive Chinese tubes and have a means of balancing the heater rails. Additionally, as gobs of power is unnecessary to drive K-Horns, we had elected to use a pair of my very favorite output transformers with a 5K primary winding which will yield approx. 4 watts RMS into the typical Klipsch 8 Ohm load.

 

For the DIY'ers among you, I will publish the schematic for the circuit and power supply "as built" at the end of the thread.

 

As per usual, every amplifier begins with the wood base. Scott had decided on the "standard" Klipsch 2Tone flavor of Curly White Oak and Black Walnut. I'll post pics this evening.

 

Cheers!

 

Matt.

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Hey all, as promised, here are a few detailed photos of how my amp bases are built in house. The base dimensions are 12" X 9 1/2" X 3 1/4". Comprised of 16 separate pieces, the 5/8" sides and front/back are "finger" joined and glued. The 8, 1/2" X 1/2" cleats are glued 1/8" from the top and bottom of the frame allowing for a reveal for the top and bottom plates to sit flush. When dry, finally the 4 glue blocks for the feet are glued in. When all is dry, everything is sanded from 100 grit all the way to 380 grit. NOW the fun starts! Every amp base has 8 coats of pre-catalyzed lacquer applied with 400 grit block sanding between each and every coat. After the last coat is applied and allowed to cure completely (2 days) the base is rubbed out with grey then white Scotchbrite pads. The last step is waxing the bases with Black Bison "dark" paste wax (this is the step represented by the photos), allowed to dry for a few days prior to buffing on my wheel with carnuba wax.

 

The next installment will address the 1/8" (3mm) 6061 Aluminum plates, how I cut them to dimension and mill them.

 

Cheers!

 

Matt.

IMG_1658.jpg

IMG_1663.jpg

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22 minutes ago, richieb said:

I'm waiting to see how you go about acid etching the face and top plates. Being very familier with the process on an industrial level I'm curious how you go about this at the "cottage" level. Should I assume etched stainless?

 

Hi Richie, 

No, actually it's 6061 Aluminum, not stainless steel. And that process will be highlighted following the next installment. I do use fairly benign chemicals, however, when combined and the aluminum plates are added the witches brew becomes fairly violent (I don't recommend anyone try this at home). ;)

 

Matt.

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Guest wdecho
7 hours ago, ToolShedAmps said:

Hey all, as promised, here are a few detailed photos of how my amp bases are built in house. The base dimensions are 12" X 9 1/2" X 3 1/4". Comprised of 16 separate pieces, the 5/8" sides and front/back are "finger" joined and glued. The 8, 1/2" X 1/2" cleats are glued 1/8" from the top and bottom of the frame allowing for a reveal for the top and bottom plates to sit flush. When dry, finally the 4 glue blocks for the feet are glued in. When all is dry, everything is sanded from 100 grit all the way to 380 grit. NOW the fun starts! Every amp base has 8 coats of pre-catalyzed lacquer applied with 400 grit block sanding between each and every coat. After the last coat is applied and allowed to cure completely (2 days) the base is rubbed out with grey then white Scotchbrite pads. The last step is waxing the bases with Black Bison "dark" paste wax (this is the step represented by the photos), allowed to dry for a few days prior to buffing on my wheel with carnuba wax.

 

The next installment will address the 1/8" (3mm) 6061 Aluminum plates, how I cut them to dimension and mill them.

 

Cheers!

 

Matt.

IMG_1658.jpg

IMG_1663.jpg

Being a woodworker I can really appreciate that wood and quality of build. Great job Matt. I should say woodworker at heart, more heart than woodworker now. 

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