Well...it started out good....

[martin manning]

See below. I suggest you go over your solder joints carefully.

Preamp Tubes Installed:
V4
1: 228DC (Note - loud ground sounding pop when i touched this pin...repeated several times) (note this is good- you are passing signal from here on out)
2: 1.5DC (this should be ~0 look for a wiring error or bad solder joint)
3: 1.67DC
4: 3.297AC
5: 3.297AC
6: 169.1DC
7: 167.2DC
8: 166.1DC
9: 3.294AC

V3
1: 124.3DC
2: .9DC
3: 1.958DC
4: 3.26AC
5: 3.26AC
6: 249.4DC (supply voltage)
7: 122.8DC
8: 125.5DC
9: 3.25AC

V2
1: 124.6DC
2: .0DC
3: 1.999DC (should be exactly the same as all V1 and V2 pins 3 and 8)
4: 3.263AC
5: 3.263AC
6: 254.8DC (too high- should be ~same as all pins 1 and 6)
7: 0.3DC (should be ~0)
8: 2.34DC
9: 3.31AC

V1 (good except pin 2)
1: 137.9DC
2: .3DC (Should be ~0)
3: 2.336DC
4: 3.278AC
5: 3.278AC
6: 130.6DC
7: 0DC
8: 2.333DC
9: 3.304AC

[Structo]

Yep, Martin has it.

Make sure your color codes on the resistors match up to the schematic or layout.

This is a common error even a pro can make.

For example, a 47K verses a 470K or 47R.

This is one of the reasons I measure all components with a VMM before soldering.

I tape the component to a heavy stock paper with the actual measurement and the color coded spec.

It keeps you from using a wrong value component in the wrong place.

Good Luck!

[big mac daddy]

thank you for the replies i will look into those areas now.

[martin manning]

The soldering on the board looks pretty good from what I can see, so check concentrate on those connections where the voltage looks odd.

[big mac daddy]

good to know the soldering isnt terrible! i am gonna go follow completely and redo the connections where you recommend.

[big mac daddy]

hell yeah. thank martin manning! resoldered each of the joints (both ends traced the connections) on the suspect voltage pins....back to full power and fantastic tweed sound! thank you all for your assistance...hope someday I can add to this as you all do - next up? a fender 63 reverb unit. (triode kit)

thanks so much

[big mac daddy]

here are some pics of the finished amp....ill keep on as I build the reverb if it helps.

[big mac daddy]

so a question - how do i know what the voltages were supposed to be? I mean I know a few pins (heaters, grounds and such)....just trying to become more educated and self sufficient thanks!

[Phil_S]

It's very nice looking amp. Let's get the insides fixed!

If you want to educate yourself, there is a big sticky with suggested reading at the top.

For tube spec sheets: http://tubedata.itchurch.org/index.html find your tubes here and examine the diagrams. A triode tube (usually for preamps) has a plate (or anode), grid, and cathode. 12AX7 is a dual triode -- two tubes in one bottle. Most typically (but not always), you'll find high voltage on the plates, about 0V on the grid, and small voltage (about 1V, usually less than 2V) on the cathode. Learn to associate the pin numbers with the structures in the tube. After a while things will start to make sense. For example, pins 1 and 6 are the plates and you should expect voltage in range of ~100-300, depending on the circuit. This is very approximate. It takes a while to get acclimated and well oriented.

Also, pay close attention to safety first!

[menger66]

Glad to hear you got thata amp singing, you might look for a real fender schamatic they have voltages remember tube amps are + or- 20% if its sounding good im sure you're all good, That amp really looks great mark

[big mac daddy]

thanks all...it will not be my last build. when I started building guitars I thought it would be a nice one for me....now I have 12 (6 built by me). Tube amps were the next extension of my hobby....I look forward to learning as I go!

[drew]

next up? a fender 63 reverb unit. (triode kit)

If you haven't already bought that, you might want to think about a ReVibe instead - if you're going to go to the trouble of building a standalone tube reverb, might as well get trem too.

[big mac daddy]

ya know i saw that after I had already bought the triode kit.....had mojo build a matching cabinet ( while they still have the free custom upgrades thing happening). Long term I may build a tweed vibrolux that matches my reverb....

btw if any pix of guitar builds are welcome I'll sedn some up....i get it though - the amp garage says it all. thanks all - been jamming through that twin all night...unreal tone machine

[Structo]

Here is a nice 5E8A schematic with typical voltages.

[big mac daddy]

Thank you for that Structo!