Another Wreck (almost) alive.

[LeftyStrat]

I've finished up my Wreck, but I'm having a strange problem I have never encountered before. I have a high pitched whine coming, not from the speakers, but from inside the chassis.

My voltages seem okay:

B1 404
B2 362
B3 289
B4 272
B5 259

V1P1 190
V1P3 1.7
V1P6 171
V1P8 1.3
V2P1 242 (?)
V2P3 2.8
V3P1 188
V3P3 34
V3P6 189
V3P8 34

V4P3 404
V4P4 345
V4P5 -33
V4P6 362
V4P3 404
V5P4 344
V5P5 -33
V5P6 362


I thought v2 plate seemed odd being large than the plate on the pi, but the chart glasman posted has his higher as well. But it seems my pi plates are too low.

The whine starts high when the standbye is flipped, and descends as the voltages settle.

Anybody got any ideas?

[LeftyStrat]

Doh!

I wired up the output of the OT to the switched side of the cliff jacks (good thing I didn't fry it). Once I had that corrected I had to switch my OT primaries.

I'm off to play.

[LeftyStrat]

[Legin]

I shall listen out for you as I fly over Seattle on the way to Vancouver on the 31st

[LeftyStrat]

Or look for the mushroom cloud...

This thing is seriously on the threshhold of total destruction.

[MooreCowbelle]

Or look for the mushroom cloud...

This thing is seriously on the threshhold of total destruction.

That sounds ... great!

who's up for a Sea-Tac amp fest?

[philmanatee]

Count me in for a SeaTac ampfest, hopefully I'll be firing up within the next 2 weeks. I'm really excited to hear mine and compare it to some others. The few clips I can download with my phone hookup are pretty impessive. Phil

[LeftyStrat]

Count me in. I still need to tone this one down a bit. It's like the whole chassis is microphonic. I'd like to hear it in a bigger room with a 4x12. I'm using an Avatar 2x12 w/ G12H30's right now. And I have to stand at the other end of the basement to keep my strat pups from squealing.

[MooreCowbelle]

Lets keep the Sea-Tac amp fest idea on the back burner for now. I need to get my build done...I may cast the net on 18watt and even AX84 to see who else might be interested...

Lefty, you may want to do a search on a discussion that Nigel (Legin) and Paul Ruby had on this board regarding "split load" - Nigel used this technique to tame the volume a bit. I plan on doing it as well. It is a simple modification to the V2 plate resistor (splitting the load between two resistors). It is supposed to act like a 'fixed' MV.

[dobbhill]

I installed the split load on the second stage with 82k and 22k resistors and a switch to select full of split load. It works well. I also have a 100k pot on top of (in series with) a 56k to ground before the 3rd stage that acts as variable shunt. It attenuates some and doesn't affect the sound much.

[MooreCowbelle]

I installed the split load on the second stage with 82k and 22k resistors and a switch to select full of split load. It works well. I also have a 100k pot on top of (in series with) a 56k to ground before the 3rd stage that acts as variable shunt. It attenuates some and doesn't affect the sound much.

Sounds interesting. Do you have a quickie diagram for those mods?

[Legin]

+1 on the 82K/22K split load, it works well and seems transparent.
Nigel

[Allynmey]

I installed the split load on the second stage with 82k and 22k resistors and a switch to select full of split load. It works well. I also have a 100k pot on top of (in series with) a 56k to ground before the 3rd stage that acts as variable shunt. It attenuates some and doesn't affect the sound much.

do you use a .1 cap after the switch and before the grid?

Allynmey

[JimiB]

legin,
Did you attach the 22K to the plate or the 82K?
Also is yours on the 2nd gain stage or the 3rd?
thanks\

[Legin]

Mine is on the third stage with the 82K to the plate and 22K to B+, it allows me about 1/4 turn of the volume before my nose starts bleeding.