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I have started to go through the initial checkout on my newly completed Plexi build.

Transformer voltages tested correct and all filament voltages tested correct.

After putting in the rectifier tube, got the expected pulse from my dim bulb tester as caps charged and then nothing.

I measured my B+ with just the rectifier tube at 418 vdc.

What is unexpected is measuring 415 vdc at pin 1 of each of the tube sockets. I know they should be high with no tubes, but I believe this is too high.

I have been tracing everything and checking grounds, but so far nothing is jumping out at me. Any suggestions?

Thanks,
Christian

Well after reviewing some other posts it appears that the plate voltage this high is normal until tubes are installed.

Unfortunately, I went ahead and installed the rest of the tubes and received a steady and bright glow from my dim bulb tester. It appears I have a short somewhere.

More tracing and testing to go......

I put all tubes back in to take a reading of B+.

When taken off standby, it appears that the red indicator light slowly goes out.

Also, B+ now measures at 170 vdc . with all tubes in

the search continues.....

Short somewhere

Post some pics

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Thanks for the assist kurtlives......here are the build pics.

I was thinking about re-flowing the solder on all my turrets to start, but if this is acting more like a short not sure if that is the place to start.

I removed the preamp tubes ( V1-V3) and left the power tubes and rectifier in.

When power switch flipped, there was a delay in the indicator light coming on (just a split second, but never noticed before), and my dim bulb tester seem to be indicating a draw, as it was lit.

When I flipped the standby, indicator light goes out. B+ measures at 205 vdc.

I am checking for shorts between socket pins and continuity on all leads but so far nothing.

I feel like this is going to be a really silly error....

Time to do. a circuit trace.

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

I went through a complete trace again and I have a question regarding the signal wires and cliff jacks.

In reading some other trouble shooting posts it is warned about the signal wires shorting to ground.

If I attach my black lead to chassis, and then check the signal wires at the cliff jacks with red probe, I am getting continuity ( short?)...is this right?

Each of the 4 signal wires at the cliff jacks will buzz to ground with my meter.

Here are some shots of my cliff jacks. Also redid V1 to place resistors closer to socket. The scorched green wire on the one cliff jack was me not paying attention with heat gun....

I place a guitar cable in each jack and checked each for continuity from tip to 68k grid resistor - all worked

I guess I am stuck....I re-flowed solder on all my connections....scratching my head on this one.....

I had a similar issue last weekend starting up a TMB v6...
I was also using a dim bulb tester and found that with all the tubes in, and using a 60 watt bulb, that the bulb was lighting up, but, not bright... the voltages were very low and I thought that I might have an issue with wiring...

I went through all the wiring and could not find anything wrong....

I bypassed the dim bulb and went directly to the wall and then measured the voltages and they seemed to be more in line with what i was expecting....
And the amp sounded great...

I was wondering if maybe the dim bulb was not allowing enough current through the transformers to power up correctly... I am not sure if a higher wattage bulb would have made a difference... Is the dim bulb test only good to test wether or not you have a dead short, or can it be used for running the amp under true operating conditions...
I am not to sure, but, maybe someone else can let us know...

Take care,
Andrew

Hmmm....now that you mention, I believe I had that same experience with my tramp build. Couldn't get the right voltages until I bypassed the tester.

I have a 40w bulb in the tester, could it be preventing everything from firing up properly?

Andrew - your suggestion brought me across the finish line!

I guess, once I saw everything act as it should on the 40w dim bulb tester with the rectifier in place, I should have either took it off the tester, or better yet put in a higher wattage bulb to allow more current? ( this is a question for someone much more knowledgeable than me).

Anyways, bypassed tester and went right into wall. Plugged in all tubes and bingo!

My first thought was " hmmm, not quite as quiet as my tramp" , but then it's working and did a quick check and everything seems to be working great! Even got some nice tones through the old 12" speaker I am using as a test.

I did the voltage measurements and I believe all is in order - voltages across the preamps seems low - but maybe someone can confirm good.

Thanks everyone for chiming in on this!
Christian

B+ all tubes in 368
V1
Pin 1 142
Pin 3 1.0
Pin 6 145
Pin 8 1.0

V2
Pin 1 157
Pin 3 1.18
Pin 6 268
Pin 8 156

V3
Pin 1 204
Pin 2 55
Pin 3 86
Pin 6 204
Pin 7 54
Pin 8 84

V4
Pin 3 12
Pin 7 357
Pin 9 340

V5
Pin 3 12
Pin 7 354
Pin 9 340

V6
Pin 1 312
Pin 3 366
Pin 7 313

What should my expectations be in terms of amp quietness? Keep in mind I have been spoiled by my Tramp build.

When I turn the amp on (no guitar plugged in ) and off standby, I can tell it's on (faint hiss from speaker) when TMB volume is turned up around 3. Normal channel appears to be a little noisier as I can tell amp is on around 2 or so.

Again, I am right up on speaker, couple of feet away cant even tell. Just curious if this is normal for the design or do I have some signal trouble shooting to do?

Two more observations since I have had a chance to play all morning:
1. This is a loud amp ......definitely either consider VRM or plan on pedals for those higher gain tones - not a problem for me as I like a clean tone with maybe a little dirt, which leads me to
2. Seems to have plenty of nice clean headroom with a great tone!

Overall I am all smiles... I am 2 for 2 on great amp kits (Tramp and Plexi) from the team at Trinity....thanks guys!

I haven't compared my 18Ws directly to my Tramp but the amp isn't all that noisy.

It may be a bit nosier than the Tramp being a higher gain design. You may have a noisy tube, keep in mind you have three 12AX7 that could be dodgey compared to a Tramp's single 12AX7.

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I picked up a 300 watt bulb at home depot this weekend and when i use this bulb, it does not light up at all....
I guess the 60 Watt is just not enough....

Andrew

Congratulations on your success!! Pretty normal to have some hiss with carbon composition resistors. Could definitely be a noisy tube to.

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