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haha, well, i've gotten everything wired up and there's a few problems.

well, the main problem really is that it doesn't really do anything. The tubes light up, and it makes some little crackling noises when the master volume is turned all the way up and i poke the eyelets with a metal probe, and i managed to make it buzz once that way.

from what i've been able to determine judging by where various pokings make things happen or not happen, i've figured this...

probing any of the connections for the first 12ax7 makes nothing happen.
the second 12ax7 seems not to do anything either unless i probe where it connects into the phase inverter tube.

the third ax7 seems to make a few litlte popping sounds when i poke around the various eyelets it's attached to.

so, I have some questions ... I seem to get voltages everywhere, but i'm not quite sure what voltages are supposed to be where... is there a chart that tells me what voltages i should expect to see at various points?

the only voltage that strikes me as particularly suspect is the wire coming off of pins 8 and 3 of the first 12ax7, measures zero volts with respect to the chassis ... is it supposed to be like that?

also, what exactly does the "V3" wire attach to? as far as I can tell, it attaches to pin 6 on the second 12ax7, but the layout diagram is really vague at that one spot.

any help or suggestions would be great I just can't quite figure out where the problem could be

I am assuming you are working on a Lightning.

Which layout are you looking at. The one I have has a short piece of line missing connecting [C-7 (.01 uf) and R-13 (1.0M)] to pin 7 of V-3. The layout stops short of pin 7 ending on the center pin of V-3.

The second stage of V-2 is used as a cathode follower stage feeding the signal from Pin-8 into the tone control circuitry and then to the PI on pins 7 and 2 of V-3.

FYI Pins 3 and 8 of V-1 on my lightning read 1.4v. Make sure your scale on your meter is set low enough to read this small voltage.

I just noticed those two connections john mentioned in the layout had gotten disconnected. Ouch, I fixed them and reposted the new layout.

The schematic is correct.

whiteshade, see if this makes it go.
Check all the high voltages on all the tubes. Make sure you have the correct value resistors from hi voltages to the EL84s pin 9. i.e. 100 ohm.

Layout is posted in the links/lightning project

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

the resistors going to the power tubes are definitely right; they've got 100ohm written right on them so even *I* wouldn't be able to screw that one up

in any event, it's still not working

* i had the v3 wire attached to the right place, as per the corrected diagram, i guess i picked the right one afterall

* however, I had messed up part of the phase inverter; i had the wire that was supposed to be going i think to pin 7 (I'm writing this at work now so i dont fully recall) going to the weird little center pin.. i don't entirely know why i did that, but when i looked at the revised layout i realized I was wrong, heeh.

so, i still only get some vauge little crackling noises when i probe various places.. beyond that, no hum (except for a verrrrrrrrrrrrry minimal hum that i can just barely hear even with my ear right up next to the speaker) which is probably just pt hum being picked up by the ot, and no squeal, or anything... and probing the first preamp tube seems to not have any effect whatsoever. I tried replacing that tube with another one just to make sure it wasn't that, but to no avail.

Anyway, I guess i'll have to go through the revised schematic again and make sure I didn't mess up any other wiring, and then i might hook a probe up to my crappy old discman and see if i can inject some signals in.

Any other suggestions? Any ideas what could conceivably make the amp essentially make no noise whatsoever other than some slight crackle? Is there some "standard screwup" that i might have made?

I'll also have to dig out the schematic and figure out what points should have what voltages... everything *seems* to have reasonable voltage, but i dunno.

*sigh*... i would have preferred some ear shattering squeal and/or floor rumbling hum rather than this ominous silence, hahaha

Before I fire up an amp,

I trace every wire on the layout and hightlight it to make sure they are exactly where they are supposed to be.
Then I run with no rect tube and test AC voltages and heater voltages;
Then I run with rect & no tubes and check dc voltages;
Then I run with the tubes, look for smoke or hot parts make sure they all light up and check dc voltages again;
Then I plug in a cable to open up the input and touch the tip and generate some hum.

Try this, don't make any assumptions, test the continuity with a resistance meter from the board to the part and from any of the off board parts - highlight the connection on the layout. If everything is fine, and voltages are fine, it should at least squawk! or hum when you plug in a cable to the input.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps