Well, I finished the amp this past weekend and decided to fire it up last night. I had a friend come over to help. He’s built a few amps and would know where to stick the wooden probe if there was a problem. The entire startup process to about 4 hours. I made three major mistakes in the build
1. I forgot to connect the group of resistors on the PT board to the cement resistor. Just simply couldn’t get a bias reading with out it. 
2. Once I connected the cement resistor I noticed that I still wasn’t getting a bias reading on either power tubes (pin 5). After about 45 minutes analyzing and probing, I realized that I incorrectly connected the bridge wire underneath the preamp board from the bias pin. DRAT! Not good, for this mean that I had to unsolder the preamp board from the chassis. ALL of the lead connections to the pots and to the valves had to be undone. There went my pretty lead dress/ straight and beautifully bent wires. Grrrrrr.
3. After taking about an hour fixing the second issue, we fired up the amp and finally got bias readings. Success. I probed around with the meter and all seemed ok, so I plugged in my guitar to see if there was sound. OH there was sound….a loud obnoxious amounts of hiss and hum. What was very interesting was that the volume, treble, mid, and bass pots did nothing to the tone or volume. The amp was louder than crap, and sounded ridiculously bad. My friend said it sounded like the pots are being grounded incorrectly. So we probed around the pots for a while checking every connection and such. He thought it may be the bright switch, so I took it out of the system. Didn’t help at all. Took readings of all the pots and noticed that the volume pot was not reading correctly at all. We both thought it got fried somehow. So…………….I pulled the pot. Again, another procedure of pain and ugliness. Got the pot out and took another reading. What the heck, it now reads just fine….1meg. Whatever……I frustratingly put it back in the system. There goes my nice wiring job on the pots. Got it all back together, except the bright switch. I’m looking at this thing and thought, “what a piece of crap. I’ve pulled this thing apart and now it looks like crap.”
We kept looking at the preamp board and connections to the valves, looking back at the schematic. All of a sudden the issue just kind of highlighted itself. On valve 1, I had pins 1 and 6 crossed-connected to the preamp board. I was basically bypassing the tonestack. GEEZ. I looked at my work hours trying to find errors and simply couldn’t find any. Oh well.
After all that, it finally worked as expected. All the pots worked. This amp is a monster. Hardly any clean tones. Can’t turn it up past 8 oclock without it breaking up. Even so, the overdrive tones are awesome. All the sustain and drive I would ever want. Very cool.
The most difficult part of the build was figuring out how to get two 18 gauge stranded wired into a tiny pin whole (…better for a camel to go through an eye of a needle than to thread to 18 gauge stranded wires….).
A couple of issues: There’s a ton of hiss. Sounds like a steam pipe pissing out a leak. And there’s is a modest level of hum. The hum is present with the volume all the way off, and yet does not increase as the volume is increased. It kind of gets masked by the hiss as the volume increases. Any help here would be great.
Anyway, I very much appreciate Ron, Dana, Allyn, and Pete for being patient with my novice questions!
I hope these reading make sense. They don't seem right...at least in what I've read here on the forum:
b5: 278
b4: 294
b3: 312
v1: p1-208 p6-178 p9- neg1
v2: p1-266 p3-2.5 p9- neg1
v3: p1-190 p2-24 p3-38 p6-205 p7-23
v4: p3-402 p4-396 p5-neg29
v4: p3-402 p4-396 p5-neg29
These pictures were taken before I tore it all apart fixing my mistakes.
[IMG:800:477]http://i209.photobucket.com/albums/bb15 ... ress/2.jpg[/img]
[IMG:800:571]http://i209.photobucket.com/albums/bb15 ... ress/4.jpg[/img]
[IMG:800:600]http://i209.photobucket.com/albums/bb15 ... ress/3.jpg[/img]
[IMG:800:600]http://i209.photobucket.com/albums/bb15 ... ress/1.jpg[/img]
[IMG:800:600]http://i209.photobucket.com/albums/bb15 ... ress/5.jpg[/img]
[IMG:800:428]http://i209.photobucket.com/albums/bb15 ... ress/6.jpg[/img]
