First tube amp build: Fender Deluxe AB763 style amp (no reverb).

[mikepukmel]

First draft BOM, with some notes pages

First shot at a bill of materials for a Fender Deluxe AB763 chassis build.
Took advice (thanks!) read across the schematic, writing values down.
Then, on another page of the spreadsheet, sorted and got counts.
Another page for big ticket items like transformers, cabinet.

Decided to get components close to original values since I don't know beans about engineering yet. Also, use orig components
that fit into particular slots in the original design eyelet board, like ceramic disc caps.

Rough estimate about $1,100.00 USD for this build, using good components. This is a rough estimate, I'll be bargain
hunting.
Next step is to get closer on suppliers and get a few web shopping carts together with shipping costs. Wahoo, here we go!

FenderDeluxe_AB763_BOM_03182017_NO_ORDER_CARTS_rev1.xls

[mikepukmel]

Any amp builder/fixer out there buy one of these?

Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC

sounds very reasonably priced.

[Leo_Gnardo]

Any amp builder/fixer out there buy one of these?

Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC

sounds very reasonably priced.

Heck of a deal, just don't stress it past 3 amps. Buy a couple more things & get free ground shipping. Fuse and meter, I'm impressed. Here at LG's Lab I gotta have a big variac 10 amp, never know what kind of big gear is gonna show up. But if you're dealing with small amps only that's a great find!

[mikepukmel]

Heck of a deal, just don't stress it past 3 amps. Buy a couple more things & get free ground shipping. Fuse and meter, I'm impressed. Here at LG's Lab I gotta have a big variac 10 amp, never know what kind of big gear is gonna show up. But if you're dealing with small amps only that's a great find!

Thanks Leo! After poking around on ebay and such, I never thought I could find one cheap enough for my little amp builds and other small project.

[eschertron]

The Hammond 291BX has 330 0 330, which is close to the 325 on the Fender schematic. Now Im second guessing (47th guessing) whether this is the best transformer for the job due to the voltage issue.

I didn't look at the 291BX, but if it's like the other current offerings it'll have taps on the primary for 115VAC and 125VAC. Smart on their part!

[eschertron]

The only thing keeping me from ordering more duplicates of some parts is that I think...

I certainly wasn't suggesting that you accurately see into the future! It was more of a suggestion that if you are buying, say 3 each of 100k resistors, go ahead and get 10 for a price break. Common-value parts like that will be used in almost any 'next' build, whatever it is. When I buy coupling caps, control pots, etc., I'll get some extra in the case I burn something up, or want to breadboard/prototype some other idea I come up with. Rare or expensive parts, not so much

[mikepukmel]

I certainly wasn't suggesting that you accurately see into the future! It was more of a suggestion that if you are buying, say 3 each of 100k resistors, go ahead and get 10 for a price break. Common-value parts like that will be used in almost any 'next' build, whatever it is. When I buy coupling caps, control pots, etc., I'll get some extra in the case I burn something up, or want to breadboard/prototype some other idea I come up with. Rare or expensive parts, not so much

Thanks eschertron!

[mikepukmel]

I didn't look at the 291BX, but if it's like the other current offerings it'll have taps on the primary for 115VAC and 125VAC. Smart on their part!

Oh thanks for the tip, I will check out their data sheets.

[eschertron]

Oh thanks for the tip, I will check out their data sheets.

Had a minute to look at Hammond's offering. Seems the 'vintage' PTs have a primary rated at 120vac, no taps. Of course, 120vac kinda splits the difference in the line voltages over the years, and may not be too bad for what you want to accomplish. Just thinking about it (not very hard, mind you) I'd say their 330-0-330 rating is close to - but actually lower than - what a vintage tranny rated at 325-0-325 would be putting out connected to today's outlets.

[mikepukmel]

Chassis arrived today, three days early. Haven't had a chance to unbox it, but should check that its the right thing and no damage.
No turning back now.

This is the chassis I got. $65.00, includes faceplate and shipping.

Deluxe Reverb-style Amp Chassis with Faceplate Blackface Silverface RI | eBay

store is

zachmdhunter on eBay

[mikepukmel]

Got some time today to measure up the chassis, make sure the parts fits the holes before ordering.



So far so good. The Hoffman eyelet board is a little wider than the fender, either that or the chassis grommet holes are not in the same spot as the fender chassis. No big deal, the grommet holes will be just a little under the edge of the eyelet board, where the period fender chassis had the grommet holes just outside the edge of the board viewed from the top. Maybe will have a local shop trim 1/8" from the edge of the board.

So far, chassis and board look to be very good quality.

[Leo_Gnardo]

My that does look good. Your board will be on standoffs, no? Perched a bit above the chassis. In cases I've had where the pass-thru holes come up under the board edge, I break out the Dremel and carve away some semi-circles where necessary, to let wires pop thru without having to make radical bends

[mikepukmel]

My that does look good. Your board will be on standoffs, no? Perched a bit above the chassis. In cases I've had where the pass-thru holes come up under the board edge, I break out the Dremel and carve away some semi-circles where necessary, to let wires pop thru without having to make radical bends

Yes, definitely standoffs, Leo. I have looked around, found metal and plastic, probably go with metal. Thanks for the tip on dremeling where the chassis holes are, will do that! Times like this, I wish I had a small cheap drill press. Could hog out a little with a forstner bit. Maybe pick around craigslist for one.

Measured up the transformer hole, the 'stock' Hammond 291BX will fit the power transformer body hole and mounting bolt holes. (wheew!)

The 8 pin tube socket holes were cut for Belton 8 pin tube sockets 1.18" chassis holes, which is nice. The 9 pin holes are standard 0.75", fit all the tube sockets I have found (belton and other cheaper ones).

The only thing Im not absolutely sure about is the power cord strain relief hole. Lots of strain reliefs on th web but they don't all state the dimensions of the required holes.

[mikepukmel]

Leo I just noticed your location as Dogpatch on hudson. I grew up in Poughkeepsie, NY, we called that <some rude words> on the hudson (not repeatable in polite company!). For us, our drinking water came out of the hudson, and we were one of the towns affected by the big GE plant up north dumping PCB's into the hudson way back when.

[Leo_Gnardo]

You'll want to run a vacuum hose near any dremeling, the board dust is nothing you want to inhale.

One of the standard power cable nylon strain reliefs is Heyco 6NP3-4, I get 'em by the 100 from Mouser. Also, your local Home Despot typically has a selection, you could bring in your chassis, find one that fits & buy that.

Leo I just noticed your location as Dogpatch on hudson. I grew up in Poughkeepsie, NY, we called that <some rude words> on the hudson (not repeatable in polite company!). For us, our drinking water came out of the hudson, and we were one of the towns affected by the big GE plant up north dumping PCB's into the hudson way back when.

I thought you might have a mid Hudson connection. A couple decades ago (80's) there was a reporter for the local paper named Pukmel. First name I forget - Gary? - so did his editor. He had a weekly column, said when his editor wanted to see him, he just yelled out "PUKMEL ! ! !"

Poughkeepsie still draws river water for public use. They went the wrong route on "purification" some years ago, put in a system that added some half ass chemical, chloramine, that other cities had previously tried and declared unfit to continue. That's the way things go around here. I'm sure somebody pocketed a fortune on that deal. There's still a standing warning to strictly limit eating fish from the Hudson. Although the river has recovered greatly from its condition 60 years ago (THANK YOU PETE SEEGER ! ! ! ) it's still not safe. And now the Coast Guard wants to approve allowing barges full of crude oil from Canada to use the river as a parking lot while oil futures traders buy & sell contracts on them, IOW make lots of cash for the rich folks while endangering the environment for us normal folks. I'm sure it will get full approval from . . . well that's a matter for another thread so we'll send the rest of it there, shall we.