The Dilbert Principle: aka. My amp's done/Pics

[Bob-I]

The Dilbert principle is simple "Everyone's an idiot" not all the time but at times we all do things that are stupid enough to qualify us as idiots.

To start, I put the bias caps in with the negative leads to ground. Why was I only getting -5V? Why is my lightbulb limiter so bright? 2 hours later I found the shorted caps and replaced them with a new pair. Dilbert #1

Next why this terrible hum? Checked all grounds, moved some to various locations to check for lowest hum, still unusable. Grounding the gtid of V1B helps, PI input even more. WTF?

Put the scope on it, nope not 60Hz, it's 120Hz.. damn, no CT on the heaters. Put in the 100/100R's and powered it back up. Dilbert #2

Now WHAT??? No noise at all, picked up the guitar and wow, it's working but 0 hum. It's so quiet I thought that there was no output at all.

Next step, move my test cab out of my room so I can bring in a real cab, test various tubes, this Funk chassis and board set is a work of art. This amp's got tone that'll deflower a virgin at 100 paces.

[jelle]

Bob,

Great job. And not even smoke... The amp should be that quiet.

Have fun!

Jelle

[Bob-I]

Bob,

Great job. And not even smoke...

I'm not so sure on that one. I left the room and hit the power with a remote. I skeered to turn amps on.

[jelle]

Me chicken too....

First startup I use a variac and measure all the way to see if those voltages are tracking well.

Safety is something to consider.

This game you can loose only once, my friend.

Take care,

jelle

[Bob-I]

I'm joking about leaving the room of course, but I use a light bulb limiter. I knew something was wrong when the light bulb was at almost full brightness. The caps didn't smoke, but I measured the bias voltage and figured it was drawing about 70ma. I'd guess those 100V caps lasted about 10 seconds with -60V across them.

[phalanges]

Quote: Now WHAT???
Seems like I say this more than I used to.

[Normster]

Too funny, Bob. Glad it's not just me.

My favorite "repeat" offense...go through the whole startup routine, no sound...oops, forgot to plug in my relays.

[JamesO]

Good job, Bob. I hope mine turns on eventually, too

[Structo]

[IMG:392:46]http://i23.photobucket.com/albums/b392/ ... ead9al.gif[/img]

Gut shots please!

[Bob-I]

[IMG:392:46]http://i23.photobucket.com/albums/b392/ ... ead9al.gif[/img]

Gut shots please!

Agreed. I'll get some later this weekend.

[moj067]

That's a nice build, is guess it's all worth it now.

[Bob-I]

Too funny, Bob. Glad it's not just me.

My favorite "repeat" offense...go through the whole startup routine, no sound...oops, forgot to plug in my relays.

LOL. I could see that. I usually test that the relays work before I apply the standby switch.

This is my 3rd Funk chassis build, and this one's MINE. I like this 90's HRM tone best so it's staying that way. There's something about those 4 bottles buring that really sounds great, even at lower volumes. I suspect that the lower impedance of 4 tubes is the difference. I'm running Chinese 6L6's in it now and it sounds great. I'll try some other tubes later.

After I'm confident that I have the correct components installed, I'm going to silicon all the preamp components down and see if there's any difference.

I'm not seeing why there's 2 LED DC feeds to the footswitch, one should do it. I'm going to try to do a 3 button FS so that I can switch the Mid boost.

Also the jazz/rock switch is a waste so I'm looking for something to do with that slot. It's Jazz/rock now but that can change easily.

[tonelab2]

Stunning work Bob-i
lightbulb limiter is THE must have tool for techs

[fabiomayo]

When I build pedals, I always (I mean ALWAYS) forget to plug OpAmps
or transistors in. That's just crazy...

Thanks for the pics of your beautiful build.

Are those parallel wires going to each tube your heaters?
How's that working out?

[mat]

Great looking build ! Congrats !!

If I see right You didn't twist the power tube heater wires much. What is the story behind that ?

Would be very nice to hear a clip of the amp

Thanks,