BUILD: Fender Hot Rod Deville -> Point To Point Dumble

[sds1]

A friend gave me his Fender Hot Rod Deville 4x10 and asked me to build him something.

The Hot Rod Deville is a 2x12AX7, 2x6L6GC fixed bias powered amp rated at 60W with nearly 500VDC on the plates.

I recently serviced an amp that was largely based on the D'Lite kit by Brown Note Amplification but with a Princeton chassis and power/output section. Great amp! So I suggested the D'Lite for this project and it was well-received.

The D'Lite is D-Style with same gain staging as the ODS but with a simplified preamp. I found the D'Lite schematic over on Amp Garage. I've found a couple of mistakes in it so far, unfortunately, but comparing to a real Dumble schematic will keep me out of trouble.

I used KiCAD to put together a schematic for this project, merging the HRD's B+ and bias circuits into the bigger D'Lite schematic:

 

[sds1]

These conversion projects can be painful in that there is a tremendous amount of up-front work on a one-off project. One of my goals for this build was to see how fast I could get it done. I thought maybe if I forgo the circuit board and all of the intricate layout involved there I could save some time. Throw in some terminal strips and just build an amp. How bad could it be?

I still spent approximately one hour in DIYLC basically throwing each component into the layout and organizing it linearly from left to right, as quickly as possible. I also needed DIYLC to generate a BOM for me so I could go shopping. This is not the initial DIYLC because I've used it to mock up layout since:

I ordered all parts from AES and Mouser. For this build I wanted to see how much I could buy off of Mouser. The only passive electronic components I got at AES were the Orange Drop 6PS series polyesters.

 

[sds1]

Finishing up terminal strip installation. These terminal strips are $0.35 a piece at the local surplus store. I installed 23 here, at 2 screws per terminal strip I drilled 46 holes thru steel chassis by hand to get this done. Could have been easier!

 

[sds1]

Some initial work on the power section:

 

[sds1]

I had to go back to DIYLC to get the LTP phase inverter layout to work for me:

Oh, check out that gap in the chassis cutout for the noval socket. Having converted a Blues Jr previously I knew that was coming and anticipated machining a nice adapter plate to compensate. But then I realized I could mount off center... It's not pretty but it's solid and it saved me a day off hassle.

And a current progress shot:

Today I'll work on V1/V2 and then on to the front panel wiring.

 

[Bill Moore]

Very nice!
There's a fellow in Texas the has converted a lot of those to "tweed era" builds.
http://www.tjadamowicz.com/amps/home.html

 

[Outlaws]

Nice work. I have ordered orange drops from Mouser before. These a different type?

 

[sds1]

Very nice!
There's a fellow in Texas the has converted a lot of those to "tweed era" builds.

Thanks! The modern Fenders are of lower build quality and make nice donor amps. So I reckon he does good business with that.

Nice work. I have ordered orange drops from Mouser before. These a different type?

Thanks! The 6PS series are 600V polyester and Mouser doesn't seem to carry them. Looks like they have some other similar OD's though? I don't quite know the differences, I'll have to look into that more.

 

[clintj]

I like your style. Very ambitious, and very good looking so far.

 

[Dacious]

The only reason for using turret boards or fibre boards is productioning for semi skilled labour. If you can read a schematic it should be 'easy'.

 

[sds1]

I like your style. Very ambitious, and very good looking so far.

Thanks! That's high praise.

Some progress shots below. Pretty much all components are mounted and final hookups are remaining. I fashioned a relay board with regulated 5V DC supply and 2x onboard relays out of solderable prototyping FR4. It's a little janky to work on but the finished board is solid.

 

[sds1]

The footswitch jack is a Switchcraft 14B, which is TRS with switches on both the tip and the ring. The switches will engage the corresponding panel switches. My preference is that the corresponding boost/OD panel switches be disabled when the footswitch is plugged in.

You can use transistors in lieu of a switched jack to accomplish the same.

The relay power supply is floating and must not reference the chassis, therefore the jack is installed using isolation washers on both sides of the chassis.

 

[coldengray]

This is great stuff, I am inspired to gut my friends dead Hot Rod Deluxe and do something similar.

 

[Urshurak776]

This is really cool. Did you make your own chassis? Or cabinet for it?

 

[sds1]

This is really cool. Did you make your own chassis? Or cabinet for it?

Thanks! No, that's the original steel chassis and it will go back into it's original black tolex 4x10 cabinet. Just a gut swap.

 

[FenderLover]

Your friend is lucky to know you. That's a very cool build!

 

[tele_savales]

Looks awesome. I was playing drums in a few bands in Colorado around 2005, and my guitarist got a Deville. Then another player we knew got one. Finally, I was like "Why does everyone keep buying these things? they're terrible!"

 

[John How]

I have an original blues deluxe (40w 1x12) that is more amp than I need...haven’t used it in probably 15 years...last time I hauled it out it had some scratchy pot noise but a little squirt of cleaner and a few twists cleared that right up...I should probably sell it but I guess it could be a donor as well. Though it would still be way more amp than I need...yeah, I’ll sell it...your build is inspirational though...looking good!

 

[sds1]

Assembly complete, about to fire this thing up:

 

[coldengray]

Awesome work, very inspiring. Let us know how it sounds.