Trinity 5e3 Build. Please Critique

[Cruisin Home]

Did you check hv at every tube? Also heater voltage at every tube? Make sure your speaker is connected properly before goin any further

[Cruisin Home]

Not as forgiving as forgetting bulb. You will blow your ot.

[guycalleddave]

so honestly this part is probably the most daunting. So I've poked around a few times with the meter. What ranges are normal as I continue? i'm nervous about killing myself (not really, but the thought does cross my mind).

Any where you know that give a detailed description of how to go about this part. I mean I think i just check the v's at each tube point, but i really really want to be comfortable before really getting into it. like i said i think i know what i'm doing, however I just want to be careful.

[guycalleddave]

also yes i have the extension cab to my valve junior plugged in.

[Cruisin Home]

A little fear understandAble at first. U will be ok just dOnt touch circuit with hands until discharged. Put black DMV lead on ground and touch the red lead to point u want to measure. Most of time set dvm to 500vt dc range. If measuring heAters or line in use ac setting. Some DvMS will autorange.

[Cruisin Home]

Always measure voltage on the positive side of the big caps after you turn off and unplug from wall before touching. If high voltage present you can discharge by making a discharged with small resistor. Make leads off resistor and insulate with shrink tubing. Clip one lead to ground and touch other to cap.

[EdMax]

Originally Posted by guycalleddave

So I'm just took my first measurement. Without tubes i'm getting a ready of 113 at multiple points at the board. I was confused, but since I have a Sovetek 5y3 and now an NOS RCA, I figured i'd throw the sovtek in there to see what happened. Well it glowed and off pin 4 i got a reading of 363 which sounded reasonable from what i remember reading in other build forums. Am I ok to start taking other readings? I really can't operate the amp until my replacement tube socket comes in.

Also I'm going to be adding a VVR probably today or tomorrow, installing it where the power switch is now, and placing a off/stand by/on switch where the standby is now.

VVR upgrade;

Personally I would;
1st, confirm proper operation of the amp.
2nd, put a few " hours" on it before attempting it.
Make sure no potential errors exist prior to installing.

I have done loads of VVR conversions and personally I really like the feature but that said, I have seen several novice builders run into issues installing it due to really simple technique errors.

[Cruisin Home]

Ditto re vvr

[guycalleddave]

...I have successfully installed a vvr into my Epiphone Valve Junior for what it's worth.

So when taking readings, I go every pin? with or with out tubes?

[Cruisin Home]

Tubes out: take readings on all tube sockets of the heater pins(ac). Then measure dc volts on the output pins. Should see volts high 300s on output tubes 150ish on preamp tubes.
Tubes in: see what happens. Be ready to pull power cord. Report back.

[guycalleddave]

Which constitutes an output pin? Just each lug that has a wire attached to it (minus the ones with the heater wires)?

[Commodore 64]

Rock Mumbles helped me troubleshoot my 5E3. I don't have a rectifier tube in mine, so I dunno what to look for on that thing. But this should get you started:

Plug the amp into a speaker. Turn it on.

Stick the black probe on your common grounding point. Put your left hand in your pocket.

With your right hand, put the red probe on:

6V6 voltages (measured referenced to ground):
Plate pin 3
Screen pin 4
Cathode pin 8

12A_7 voltages (measured referenced to ground):
Plate pin 1
Cathode pin 3
Plate pin 6
Cathode pin 3
pin 2 on V1 should give speaker noise.

For the Heaters carefully measure between pins 2 and 7 on the 6V6 or between pin 9 and pins 4&5 on the 12AX7's. You need both hands and both probes, one probe on each pin in the pair, this is AC. Be careful.

Report back with numbers.

My Fluke auto-range DMM was a godsend, so I didn't have to keep flipping the dial.

[guycalleddave]

just out of curiosity, what type of readings should I be getting for normal anticipated operation?

[Commodore 64]

I can tell you my readings...but my circuit is likely a bit different.

Standby Sw.: 378
6v6 Pin 3 376
6v6 pin 4 325
6v6 pin 8 21.9
12AY7
pin 1 118.4
pin 2 speaker noise
pin 3 1.95
pin 4 21.99
pin 5 22.0
pin 6 120.9
pin 7
pin 8 1.95
pin 9 22.0

[keithb7]

My Trinity 5E3 voltages taken last week:

V1: EHX 12AY7
Pin 1 131.2 (120)
Pin 3 2.038 (2.0)
Pin 6 121.6 (123)
Pin 8 2.04 (2.0)

V2: Groove Tubes 12AX7
Pin 1 162.2 (167)
Pin 3 1.26 (1.1)
Pin 6 205.9 (175)
Pin 8 46.4 (45.2)

V3:JJ 6V6GT
Pin 3 368 (380)
Pin 4 336.2 (338)
Pin 8 21.46 (22)

V4:JJ 6V6GT
Pin 3 369.6 (382)
Pin 4 336.7 (339)
Pin 8 21.45 (22)

V5: NOS Tung-Sol 5Y3GT
Pin 4 352V (384)
Pin 6 351V (384)
B+ 374.2 (400 new production 5Y3, NOS less)

[guycalleddave]

so to discharge the caps, let me just review this one more time before I go switching things.

I have an aligator clip to ground. I have a resister on the end of said clip. I touch the positive ends of all three caps, wait a few seconds, check with meter, and I'm good right?

[hackworth1]

Just one positive lead on a Filter Cap will be sufficient, but leave your clip on it for ten seconds or so. All the caps will drain thru the one. But they will take longer to drain with a resistor in the circuit.

Those caps can sting you, but nothing is as powerfully shocking as the high voltage connections when the amp is powered up.

A good jolt that way will earn your respect. I know I do.

For example, there's high voltage at the poles on the standby switch that is waiting there to bite you.

[guycalleddave]

so if i need to remove the tube socket will draining the caps be sufficient?

[guycalleddave]

so when measuring the rect voltage the meter would reach 399 than go back to 0, and now it's not really measuring anything. Did I break it?

[rogb]

Originally Posted by guycalleddave

so to discharge the caps, let me just review this one more time before I go switching things.

I have an aligator clip to ground. I have a resister on the end of said clip. I touch the positive ends of all three caps, wait a few seconds, check with meter, and I'm good right?

No leave the drain resistor clipped on while the amp is powered down, the caps can refresh themselves and release the voltage, even if you think they have discharged.

Never forget, one hand measuring, - lead clipped to ground (or the other wire when measuring the AC heaters), other hand in back pocket. It is so easy to slip off a pin and get a short.

Obviously you need to disconnect the drain resistor before you pwere up.

To Hackworth 1: If you think that getting a 400-500v DC shock is a good lesson, then you shouldn't be touching HV parts. This is very bad advice, if you have a weak heart and the charge goes across the chest, say from one hand to the other, you will learn possibly your last lesson.