Dolly amp, v2.0

Redboy

a few good watts

• Oct 27, 2008

• #1

I've been wanting to build something into one of these boxes for awhile. It's a Hammond extruded aluminum enclosure, 7 inches square and a little more than 2.5 inches deep:

 

Last edited: Dec 28, 2021

Redboy

a few good watts

• Oct 27, 2008

• #2

I tend to get a little goofy about the planning process. Like, more than "measure twice" goofy... maybe even a little obsessive.

I found that Visio is a great program for laying this stuff out.



Stick it on with spray adhesive...




...and start choppin'!

 

Last edited: Dec 28, 2021

Redboy

a few good watts

• Oct 27, 2008

• #3

I'm trying something new this time - the goal is to have fewer screw heads on top.

 

Last edited: Dec 28, 2021

Redboy

a few good watts

• Oct 27, 2008

• #4

Here's the chassis, nearly finished. I used a step bit and a file for almost everything. Worst part was hoggin' through the center "rib" along the backside, where the IEC and power switch come in.

 

Last edited: Dec 28, 2021

Dan ʕ•ᴥ•ʔ

Peanut Head

• Oct 27, 2008

• #5

Nice work! :yes: Wish I had more free time to do something like that.

 

ejfud

Audio Pinhead

• Oct 27, 2008

• #6

Nice work Nate!

 

Redboy

a few good watts

• Oct 27, 2008

• #7

Thanks fellas! Celt, this is a bit of a time suck. :yes: It's my favorite part of this hobby, though.

Test fit some stuff:

 

Last edited: Dec 28, 2021

Redboy

a few good watts

• Oct 27, 2008

• #8

I was working on the kitchen table for awhile. That will probably never be allowed again. Ever.

Anyway, here's the proof!

 

Last edited: Dec 28, 2021

Redboy

a few good watts

• Oct 27, 2008

• #9

Progress shots. This ended up being "modular," which was nice for the build process.

 

Last edited: Dec 28, 2021

Squidward

Scrappy Mod

Subscriber

• Oct 27, 2008

• #10

Very nice work!

 

Redboy

a few good watts

• Oct 27, 2008

• #11

This is a second reincarnation of an Olson console amp. Schematic is pictured above, and my first clone build is documented here.

Cableguy Bill somehow got ahold of the first build, so I had to build another.

EDIT for missing resistor values

Off pins 3/8 of 12AX7 to ground is 2.2K

Connected to pin 2 of EL84 is 1K​

.

 

Last edited: Jul 21, 2010

von.ah

Schultze!

• Oct 27, 2008

• #12

mein gott, that is beautiful. thumbs up to you, sir.

 

Squidward

Scrappy Mod

Subscriber

• Oct 27, 2008

• #13

One minor thing, and it's not worth re-doing now. I like to put my small signal tubes as the last tubes in a chained heater. Then they only see the current they draw, not the additional load of a power tube later in the chain. Less current means less possibility for noise at a critical part of the circuit, etc.

 

Redboy

a few good watts

• Oct 27, 2008

• #14

von.ah said:

mein gott, that is beautiful. thumbs up to you, sir.

Click to expand...

Beautiful in an ugly, industrial sort of way... right? That's what I'm shooting for here.

Squidward said:

One minor thing, and it's not worth re-doing now. I like to put my small signal tubes as the last tubes in a chained heater. Then they only see the current they draw, not the additional load of a power tube later in the chain. Less current means less possibility for noise at a critical part of the circuit, etc.

Click to expand...

Thanks for the tip - I'll take it to heart. The first one I built was nearly dead quiet, once I got some heater noise handled... I wonder if that was part of the problem? :scratch2:

But you're right, I'll try to live with it at this point.

 

cableguy

In Twang We Trust

• Oct 27, 2008

• #15

Awesome Nate....

 

wajobu

Boing Boom Tschak

• Oct 27, 2008

• #16

Looks great Nate!

 

doucanoe

Registered Audio Abuser

• Oct 27, 2008

• #17

Looking good Nate!


I'm glad to see you keeping your skills honed. For purely selfish reasons of course

RC

 

Redboy

a few good watts

• Oct 27, 2008

• #18

doucanoe said:

Looking good Nate!


I'm glad to see you keeping your skills honed. For purely selfish reasons of course

RC

Click to expand...

Heh! :yes:

The aluminum they make this box of is a pleasure to work with. It cuts and files easily and fairly cleanly. I can see putting together a whole system of components crammed into these little boxes. That would be cool.

A technical/ tactical question for the pros out there. The PS uses the four-part multi cap you see in the pics, and another smaller value cap that I'll need to fit in somehow. My plan is to secure the smaller cap vertically next to the larger cap. Question is about how to secure it - could I tape it with electrician's tape to the larger one, or should I use zip ties? Glue? Things might run a little warm in the box, so there's the concern.

 

DENNYDOG

Addicted Member

• Oct 27, 2008

• #19

Come on now Nate, electrical tape? You need to use Duct tape!

It looks like the project is coming along nicely. How much do you think you will have tied up in this with trannies, tubes and all the other little pieces?

 

Redboy

a few good watts

• Oct 27, 2008

• #20

DENNYDOG said:

Come on now Nate, electrical tape? You need to use Duct tape!

Click to expand...

Of course! What was I thinking?! :stupid:

It looks like the project is coming along nicely. How much do you think you will have tied up in this with trannies, tubes and all the other little pieces?

Click to expand...

I don't have an exact figure, but I think you could build this amp with these parts (except maybe tubes) for under $200. With different parts, maybe less - there are cheaper resistors out there, for sure. Hard to beat the Edcor iron at this pricepoint though, and that's a majority of the cost of this project - around $90 shipped for the power and output trannies used here.