2 watt Trainwreck Layout

[mehfuzhoss]

Hello folks,

I am starting to build a low watt trainwreck as per ax84 4 4 0 layout. i found few errors in the layout. Please advise -

https://imgur.com/E4nyA1r
https://imgur.com/TEnD2Nr

caps 18 is mentioned twice; once in the preamp board, close to V5. and on the vr4 pot. Should i get 500pf/500v for all three places (two for bright cap, volume, 1 for preamp board) ?

C16 (100pf/500v) is in the bill of material but not seen in the layout. is C16 not used ?

Thank you.

[Synchu]

I am not very well acquainted with the AX84, but I did low wattage Rocket build (SE EL84 based - https://ampgarage.com/forum/viewtopic.php?f=1&t=31462 ), by simply following the big brother layout posted here and adjusting few things. It's a "garage" style build with what I had lying around but sounds great.

The 500pF (C18) on the board should be the coupling cap after the first gain stage and the one at the Vol control should be C16 (100pF bright cap).

As I am always adjusting these to taste and suite my guitars and cabs, can't remember what I ended up with

Niki

[mehfuzhoss]

Thanks

[mehfuzhoss]

the pilot lamp that i ordered seems to have to have no 1m resistor connected. it is hard to see inside the red lamp cover. should i connect a resistor to one of the wires?
lamp i used is this one : https://www.amplifiedparts.com/products ... quare-120v

the PT 269JX has these wires:
- 2 green goes to 6SN power tube through the 5 watt resistors
- 1 red/orange stripe connects with C1 cap
- 2 red connects with the preamp board's diodes

Now I am left with 1 black, 1 white and 1 grey wire. where does these wire connect to ! plz help.

[MakerDP]

Have you searched the AX84 forums for answers to your questions you are having? This amp has been built many times over there and discussed quite thoroughly in the forums there.

[mhuss]

When in doubt, check the manufacturer's data!
https://www.hammfg.com/files/parts/pdf/269JX.pdf

White is common, gray is 120v, and black is 125v (the AC/mains side of the transformer). If you're in the US, I suggest using White and Black for the AC connection and taping and stowing the gray wire.

[Colossal]

Mr. Huss!

[pompeiisneaks]

He's back!

~Phil

[stephenl]

Attached is the Cliff Chappell's 4-4-0 from AX84.

I built one of these way back. Crazy loud for a 2W amp. Pretty cool little amp.

I never loved the triode output section. I ended up rebuilding it with a big bottle PA and power scaling...