trinityamps.com

I was doing some continuity checks across the board and I noticed that the underboard connection on the bottom left of the board (as seen on the layout) had gotten pushed out when i put the ground wire in, so i reconnected it and WE HAVE SOUND!

right now the level is very low and sounds a bit overly distorted, but that's something i can work with!

ok it's definitely a lead dress problem now

when i move all the various wires inside around it the volume goes up and down a lot, and i can just barely hear a high pitched whine which changes depending on the wire placement...

i'm on the home stretch

That whining sound probably means that you have a little bit of oscillation going on there. That's a lead dress issue. But, the low ouptut I think is due to something else...

_________________
PJM

http://www.diyguitarist.com

ok my voltages seem like they're really low...

v0 is -336
v1 is -208
v2 is -304
v3 is -253
v4 is -313

the point at the first filter where the output from the tube rectifier connects and the input to the choke goes measures -335

the pt secondaries measure 275 on both sides... which seems reasonably close, especially as my wall current is 117, so if the transformer is expecting 120 then i could see it losing a few volts..

anyway... 208 volt v1? how on earth can that be over 100 volts off?

there's definitely a problem here

any ideas?

Not sure why the voltages are low, but it sounds like you're onto something there. Are you sure that you hooked up the power supply correctly? Also, are you sure that your power transformer can give you the amount of current that you need for your circuit?

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PJM

http://www.diyguitarist.com

I'll double check the connections but i'm fairly certain it's right...

it's pretty simple so i'd be surprised if I screwed it up..

I gave Heyboer the full requirements for the transformer, current requirements, voltages, and everything, and they made it for me so I would assume it's correct!

anyway.. time to check more wiring

Ok, I figured you probably did your homework on the PT specs, but thought I'd check. It sounds like something is wrong in the B+ power supply. It sounds like your starting voltage off of the PT is in the ballpark, but something goes awry after that. Maybe you got a dodgy filter cap or something?

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PJM

http://www.diyguitarist.com

haha, i bet that's one suggestion that stephen will be quick to hope is wrong


*cough*

im gonna reflow all the connections on the ps .. lets see what happens

If the volume changes when you move stuff around, you likely have a cold solder joint or two. I'd touch up the most crowded solder joints first, starting with anything that runs to ground. Then check the leads to your controls.

Hope you work it out. Sounds like you're close.

-n

Good point, I was going to mention a possible cold solder joint, but I forgot about it.

_________________
PJM

http://www.diyguitarist.com

cold solder joints was my first guess, and i reflowed most everything and now the sound stays the same no matter what I move around...

I just can't figure out why the hell the resistor between V0 and V1 is dropping over 100 volts ... how on EARTH?

considering that V1 is attached to the two 100ohm resistors which connect to the screen grids of the el84 ... that doesnt really make any sense at all, haha

i've checked all the ground continuities and everything seems to be earthed fine...

i have no idea what could be wrong now ...

Have you verified that all the tubes are good? Did you measure the resistor between V0 & V1 to see what value it really is? Maybe you have a mis-marked resistor or something. I still think something fishy may be going on with your filter caps...

EDIT: Oh, I see you fixed it. Never mind then. I was going to post a link to a thread on the AX84 forum that was a very similar situation with a Lightning build!

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PJM

http://www.diyguitarist.com

yes, paul, it was simlar situation because it was MY situation, hahahahhah


i was banging my head against the wall for a while so i cross posted onto ax84 as well

Oh, well, that explains a few things.

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PJM

http://www.diyguitarist.com