pix of Custom built guitar amps/cabs

[tubelectron]

I thought grounding the input jacks was the first thing anybody ever did to a Danelectro.

Not even needed ! 

T

[Ben N]

I thought grounding the input jacks was the first thing anybody ever did to a Danelectro.

Not even needed ! 

T

What, no noise?

[thomasha]

Finished a 5672 PP build:

https://www.instructables.com/Push-pull-Tube-Amplifier-Using-Subminiature-Tubes-/

[stallik]

It's March. Time of year for the power tube in my WF-55 to fail and me to make what's become a diary entry on this thread.

Right on cue, it started popping & crackling so looked round the back and, sure enough,it's glowing blue. Replaced it and all is fine. Then I decided a picture might be useful so grabbed the old tube out of the bin and shoved it back in.


Had believed that the blue glow signified an issue but maybe not? It certainly didn't glow blue when it was new. I can't see any red plating. Anyway, no popping so far with the 'bad' tube. It's working and sounding fine. Let's see how much longer it lasts...

[bluebunny]

That blue is pretty wild.  Has Kate been photoshopping your pictures?

[stallik]

That's straight off the iPhone. Mind you, the sensors in most phones extend well beyond human vision - that's why they're great for testing remotes

Pic was handheld, long exposure stabilised by the little green men who live in the phone.

Wish I had access to that technology when I was a young pro photographer. How the world moves on...

[Phend]

Neat photo stallik, suitable for framing.

[davent]

Neat fun toys now but really nothing has changed, it still all comes down to the skills of the person with the toys, whatever the toys may be.

Cool picture!

[PRR]

Blue glow on the inside surface of the glass is harmless. Stray electrons (normally normal) and impurities in the glass.

The stray electrons *may* vary with bias. Does that amp (WTF is WF-55?) act like its voltages are unstable? Do your lights flicker? When poltergeists visit??

Blue glow in the space between electrodes is normally gas-glow which is normally run-away fatal.

[bluebunny]

For Paul: WF-55 is a 5F1-alike from Ampmaker in the UK.  I built one of these too.  Nice little amp.  Not running blue just yet...

[stallik]

Amp maker has now closed its doors indefinitely but the website hangs on atm

[stallik]

Found last years JJ 6L6GC in my glass recycling bin so grabbed it for the following photo shoot.

Without doubt, my iPhone sensor magnifies the vibrance of the blue glow. In this montage, the NOS Brimar 6L6GC clearly shows some glow which is (almost) invisible to the naked eye. Pictures are taken in very dim ambient lighting conditions - in full room light, even the filaments are as dim as a Toc H lamp

Hardly a diagnostic tool but fun anyway


Noticed that the grid resistor (originally a 1 watt 10k and raised to a 2 watt version last year?) is discolouring again. This probably has a bearing on all this so I'll order a 5 watt replacement as recommended by Willienille 4 years ago 

[PRR]

...the grid resistor (originally a 1 watt 10k and raised to a 2 watt version last year?) is discolouring again.

The screen grid resistor? 2 Watts in 10K means 14mA which means you are beating the snot out of that 6V6. I know that's a great sound. But if you need it reliable (playing for rent) I'd think about 5K 2W there and change up the 100r for 470R 5W (similar to cathode resistor) to drop plate-abuse and buzz/hum.

[stallik]

Thanks Paul. The resistor I'm referring to is R11. I've temporarily replaced it with another 2w 10k (5w version should arrive next week)

Made a modification this morning before seeing your post. R9 (Cathode resistor?) was 330r and Ive replaced it with a 470r. This lowered the plate dissipation from 17.7w to 14.7w Not sure if this will help the tube longevity or whether I have a different issue which is beyond my paygrade to diagnose

I'm using a 6L6gc and have linked pins 1 and 8 on the tube socket as well as increasing C3 to 22uf/63v as per the kit build instructions