Building an Amp Order of the assembly steps

[Sonny ReVerb]

Here's the one I built out of pine. Easy build and it works great. It tilts and locks in position. The plans were from one of the guys over at the 18W forum.

[img900]http://img189.imageshack.us/img189/8665/cradle101.jpg[/img]

[img1581]http://img692.imageshack.us/img692/5140 ... cradle.jpg[/img]

[Wayne]

Stacks of old textbooks are what gets pressed into service at this budget-concious shop - usually books about solid state electronics

W

[M Fowler]

I can't use an amp cradle drives me nuts.

I get a new carpet pad every once in a while from Menards and work on top of that.

[Joost]

.....
9) first fire up, orient OT for least humm, install and wire (use current limiter)
...

Seriously? Does the OT orientation make a difference noise wise?

[Structo]

Yes it does.

Look up the "head phone" method.

Electromagnetic lines of force are generated around transformers.
When they are near another transformer they can "induce" voltage in the form of hum in the other transformer.

[amplifiednation]

There's some great information in this thread I'm going to bump it so I don't have to search for it again! Great stuff for those of us that are about to undertake a Dumble build. Funks steps are nicely explained and make perfect sense, and i think we all know he has the experience to back it up!


The amp cradle plans are great too!

[groovtubin]

Good approach - but you left out the last step:
17. cry/curse/swear/wimper when it sounds like crap

I'm not familiar with that step.

neither am i!

[Homebelly]

Great pointers one and all!

If the first timer doesn't all ready have one, I suggest as a first step to build an amp cradle.

It really helps working on a chassis.
Maybe not at first since you are flipping that box around a lot but for wiring and working on a built amp they are indispensable.

I think I copied AmpDoc's cradle when I built mine but later had some other ideas.

The locking arms are great so you can have the chassis at any angle you wish.

And since the chassis is really an unbalanced load due to the transformers having the cradle hold the chassis securely is key.

Thanks for that..
I can scrap the plans i have been table napkining for a while..

[noworrybeefcurry]

Funk-

Im sorry if this is a bit of a newbie question, but what is the "death cap"?

[martin manning]

... but what is the "death cap"?

Brandon (AKA Funk) has sworn-off TAG as far as I know. The "death cap" is the 0.05uF switchable from one mains supply leg to the other. This was a common feature on Fender designs dating from the 1950's to reduce noise. If the cap shorts and the switch is in the wrong position, the chassis is connected to the mains, hence the name.

[jlatrace]

I go about things a totally different way, Having built 20 of these in the last 12 months, I really think I have it down to a science, It goes together easily, and takes less than 30 hours start to finish this way. I start from the outside walls, and things along the floor and build up and in:


1. Mechanical assembly with screws, threaded stand-off's, tube sockets, Terminal Strips, and ground lugs first. If you install the transformers first how do you get the screws in that are under the transformers? why do you want to build with all that dead weight? leave them out until it's time to wire them so that your chassis can be easily manipulated

Build your boards, and connect all the leads to the boards with an addl 1-
2" of lead just in case, since the screws are already there, hold your boards in place to make sure you get long enough leads BEFORE you clip

2. Install relay supply board, route wires along the back of the chassis- these are the longest runs of wirein the amp. Install and wire footswitch jack, manual/pedal switches, also wire up the voltage regulator and pilot lamp on the "Lamp end".

3 Install Bias supply/ rectifier board, and bias pot. Route wires along the relay switch leads, bind together with zip ties, leaving an area unbound to attach the output of the bias pot to the preamp board later.

4. Install OT and Choke, Wire power tube sockets: Screen grid leads first, plate leads, cathode resistors(or wire if you don't use 1ohm's to ground), pilot lamp power assembly, screen resistors, grid stopper resistors & Bus, attach OT plate leads.

5. Install FET board with Power lead(leave extra length for routing).

6. Route shielded wires: If you are using coax solder the shields to the back of their respective pots, if you are using foil shield Install the pots and ground bus. Wire the input jack.

7. Wire the switches, pots, and PAB relay, Install leads from Relay board grounds to Manual/pedal switches

8. Install the preamp board with flying leads attached, Wire from v1 toward power tubes, then wire the other side of the board starting with the grid leads/ bias supply lead(routing it along the back of the chassis) Wire presence, then master volume. Wire shielded leads for OD Drive and volume, wire tone control leads.

9. Wire channel relay

10 Install power supply board and wire (all leads should be in place by this time and just need to be attached) and wire stand-by switch.

11. Wire Up OT Secondary (This step can take place anytime after v2 and v3 are wired with plate, grid, and cathode leads) Impedance selector, and speaker Jacks.

12 Mount PT and wire B+, Bias Supply, Grounds, and filament LEads.

13. Install twisted filament leads

14 Install power cord and wire Power switch, and fuse holder ( I don't EVER wire the death cap, if you choose to it is your perogative)

15 Install fuse

16. Check all Grounds, and leads for continuity, take your time and go over each lead to make sure it is wired correctly.

17. Plug into a current limiter or variac and fire it up

18 If everything is good, fire it up at full AC and check voltages

19. If everything is good, Install tubes, bias, and give her a listen!


More than 50 ways to skin a varmit far as I can tell!

[212Mavguy]

I'm really sorry to find out that the Funk is not here more, also Dogears. I learned a ton from their posts, and loved the "no punches pulled" writing style.

I learned what the word "Blencowe" meant here, bought his preamp book. Then was gifted a copy of O'Connor's work on top of that recently. They complement each other well, with O'Connor IMO being the easier read.

The posts of TAG members are solely responsible for what I have learned since joining. I'm SO grateful. I'm not quite ready to tackle a D-build yet, but In the last two months I have completely gone through three old Sound Projects PTP/terminal strip vintage amps, Harmony H-306-A, Harmony H-420, and a Lectrolab R600C, which all behave and sound like boutique amps now only because of what I've learned here. And since these amps all have little collectable value they are not sacred cows when it comes to circuit mods. Qtone's thread about vintage parts was a wake up call, I collect and use vintage tubes exclusively in my amps already.

This thread is a godsend for a first time D-build, dunno if it is gonna get that status, but it's a personal "sticky" for me anyway.

Thank you all.

[crbowman]

I'm really sorry to find out that the Funk is not here more, also Dogears. I learned a ton from their posts, and loved the "no punches pulled" writing style.

I miss those guys as well. Between the two of them, that's a TON of expertise we've lost and I know that the vast majority of folks here greatly appreciated their input. I KNOW I did!