New ROCKET, from a newbie :)

[RJ Guitars]

James,

It is very cool that you got this amp put together and that it sounds good. There was a bit of magic in that group build effort, great sounding amps for sure.

I'll bet that I've had a dozen people email me these past couple years and ask me why they only get 3 volts on the heater wiring. It's pretty simple once you think it through but it can make you question yourself until you understand it. A lot of folks don't like to post their work which is cool, but I appreciate you putting this out there for us.

Looks like you have done some really tidy work, the amp looks great. The treble pot should make a big difference... I don't see any issues at a quick glance but you'll know it when you find it... maybe a bad pot.

What cabinet are you using for this amp? I get lots of bottom end out of my build - usually refer to her as "the fat bottom girl" so I run an open back cab with a pair of 10's and I never run the bass full on... great sounding amps!

rj

[DocJames]

Hi RJ,
Yes, thanks for putting that build group together. I was a while in the making, but I thoroughly enjoyed the experience. I'm plotting my next build right now. Yeah, the amp has a booming low end, I don't turn it up that much. I do find though, that as it goes more into distortion, I want more of the low end, as the breakup is more on the high end. It evens it out more.

So I rechecked all the connections, and there was a bad solder joint coming off the treble pot. I re-flowed some solder into that, and it did the trick. The thing I'm finding, is this amp is loud! lol. I love the distortion but I can't get to it without the whole block noticing . I've contemplated putting in a switch to cut it down to 2 el84, but I've heard bad things about doing that, if I remember correctly.

Is Dana still making the VVR's? I've tried e-mailing him a few times. I think that would be the best option.

James

[DocJames]

So I need a little help. I've noticed since the initial fire up that the hiss lvl has increased incrementally. I was a little disconcerted, but left things alone in the meantime. All of a sudden, yesterday, I started to get a loud hum, at roughly the same lvl as the input volume. Turning the base pot completely off tames this down somewhat. Am I looking at a bad ground? I had accidentally turned on the amp with the cab disconnected. Would one time have possibly killed a tube?

I checked voltages. All pretty close to normal normal, but I'll post them when I get home.

[angelodp]

Did you try and play the guitar through the amp while the amp had no speaker on it. After 30 secs or so it well have done damage to the OT.

[DocJames]

I didn't play through it without cabinet. I think I had even left it in standby and noticed before turning it all the way on. I had disconnected the Lamp on the front, and was changing it to a difference one. That was the only alteration that I had done to the amp prior to the hum showing up.

Voltages are:
B+1: 294
B+2: 283
B+3: 214
B+4: 189
B+5: 185

Still getting 6.3V AC to all the heaters. Everything looks the same. I thought That somehow the grounding disconnected, but I can't see any difference. Chopsticking around doesn't cause any type of difference.

I've thought of just ripping out of the board and re-wiring it all. I don't really like the wire that I ended up using. I hate to say it, but it was a radio shack purchase . I don't think that's really the cause, however, of why this thing is humming all of a sudden.

[angelodp]

Have you checked that your pots and jacks are tightened to the chassis. How about tubes, can you change them out. Try pulling out one tube at a time and see if it quits.

A

[fishy]

Grounds would be my first port of call. In my experience, all ground points measure less than 0.5ohms.

Tubes are notorious for causing problems and it would make sense to remove them from the equation.

Don't forget to check the input jack wiring also.

[statorvane]

I have had similar experiences that have always (knock on wood) been bad solder connections rather than tube problems. Still the first thing to try is tube swapping. I'm guessing the OT is ok.

The way I have found bad solder connections it to chopstick the amplifier wiring. I have found that bad or marginal solder connections can reveal themselves as microphonic wiring so to speak. Reflowing the suspect joint fixes it.

[DocJames]

ok, spent a good part of the day re-wiring, changing the grounding scheme, and just cleaning things up. I no longer get the hum anymore. However, the volume of the amp is significantly lower then it was before. The voltage chart is also a little different (I'll post that up as well). I've looked over my connections twice and don't notice anything glaring. Here's some gut shots to see if anyone can notice something that I've missed.

[DocJames]

Here's the voltage chart.

James

[Cliff Schecht]

Luckily I have a Rocket build sitting 3 feet from my bed. From what I can see your pins 1 and 3 on your first tube (V1) are flipped and pins 2 and 3 on V2 are flipped. Switch those around and I bet your Rocket takes off .

[Ian444]

I think the wiring on V2 is OK, could be the photo, I don't think those wires cross? Anyway, we'll have to start calling you Eagle Eyes Cliff!

[DocJames]

Great eye's Cliff. I quickly switched the pins on v1 to there proper position and...... now I have no sound, lol. I'm going to let that puppy sit for a few hours, maybe a day, and get a fresh set of eyes on it again.

[Cliff Schecht]

I think the wiring on V2 is OK, could be the photo, I don't think those wires cross? Anyway, we'll have to start calling you Eagle Eyes Cliff!

Ok I see this now. I was staring at this build last night after a night of drinking so it's no surprise a wire or two crossed in my mind . New pics and a new voltage chart might help us find other issues..

FWIW I think your B+ will drop down to the correct levels (within whatever percent) once you fix the issues with your preamp. Also it's hard to tell because I can't zoom in enough on the pictures but it looks like your 9.1k dropping resistors are only 1/2W, these should be 2W minimum (I'll use 1W after B+3.

[Fischerman]

In addition to the wires on pins 1 and 3 on V1 being reversed, it also looks like the plate load resistor for V1a on the board is 10K and should be 100K (should be brown/black/yellow). You should have the B+ for that stage connected to one end of that 100K (the end closest to the pots).