5e3 build problems

[Scottfishel]

I’ve completed my first build (well, I guess it’s not complete yet). I ran into a couple of issues that were causing no output, did some modifications, and I now have sound from the guitar on all inputs with no hum. Pfhew:)

What I have now, though, is really bad distortion at breakup, and breakup way to early. It almost like it clips at a really low level. I did incorporate robrobinette’s master volume mod, but other than that the circuit is identical to the Weber layout. The master increases and decreases, and I believe the other standard volume controls do as well.

This isn’t a too little headroom kind of issue. It sounds like ****.

I can’t seem to find anything in chat rooms on this. Where so I start?

[PRR]

Welcome!

Voltage readings, all plates? If one looks odd, also get the cathode voltage.

[dude]

Maybe take the Master Volume out and get the amp working properly first, follow PRR's advice, then reinstall MV after stock Weber layout is  working ....?


al

[Scottfishel]

Ok. So I started taking readings and noticed most were a bit off and then noticed that I wired the v1 bypass cap backwards.  Unfortunately I don’t have an extra at the house so I’m going to have to swap it tomorrow. Is it possible that this is (my only) issue, or did I really mess things up?

[PRR]

Just take the cap out. Gain will be down but otherwise does it play fine?

[Scottfishel]

So I’ve continued to work on this, but haven’t had any success.  I did remove the cap that was wired backwards, with no difference.  I then removed the master volume and added the original resistor, again, no difference.  I went through and measured all or the reisitors on the entire amp and they appear to match.  I have noted that when I’m probing, I often hear static, notably at b+1,2 and 3.  Last, I took readings at all pins, which is below.  Any ideas?  There is certainly some variance from the expected voltage chart, but I’m not sure how much is expected.  Any help is greatly appreciated.
V4
1 empty
2 fil
3 359
4 326
5 .5
6 .06
7 fil
8 21

V3
1 empty
2 fil
3 352
4 324
5 .1
6 .09
7 fil
8 21


V2
1 157 - crackle
2 null - hums
3 1.34
4 fil
5 fil
6 186
7 25
8 61
9 fil

V1
1 168
2 null - hums
3 1.33
4 fil
5 fil
6 165
7 null hums
8 1.32
9 fil

B+1 361
B+2 327
B+3 248

[shooter]

V2
1 157 - crackle

try re-flowing that connection and re-tensioning the pin cup

[Scottfishel]

Ok - super novice question - what does re tension the pin cup mean?

[shooter]

the female part of the tube socket, most can be "squeezed" tighter for snugger fit, crakling at the plate (big voltage) can cause little arc's, loose wire, bad solder, loose tube pin, it gets little more complicated if that's not it

[sluckey]

I don't see any red flags with your voltage readings. Let's see some hi-rez pics.