6080 Doesn't Light Up...

[buldogge]

He guys...I just bought someone's abandoned Crack project, checked it over, passed all resistance tests...but...the 6080 filaments do not light up.

The 12AU7 filaments are lit (side note...one LED is brighter than the other).

The only deviations from the build manual that I found on the checkover (and have corrected) was the ground wire from 12 to headphone jack was at the exterior lug instead of the interior lug AND the (2) 2.49K ohm resistors were to the interior ground lug instead of the exterior ground lug.

Any suggestions on where to proceed...

TIA
-Mark in St. Louis

 

[Doc B]

Do you have 6.3VAC across the heater pins (pins 7 and 8 of the 6080 socket) with the amp on and the tubes in place? If so, turn off the amp, pull the tube from the amp and check for an open heater filament by measuring the resistance from pin 7 to pin 8 on the 6080 itself. If it is good it will read some small value of ohms. If it is open it will read infinite, for example OL or some flashing display on your meter.

 

[buldogge]

Do you have 6.3VAC across the heater pins (pins 7 and 8 of the 6080 socket) with the amp on and the tubes in place? If so, turn off the amp, pull the tube from the amp and check for an open heater filament by measuring the resistance from pin 7 to pin 8 on the 6080 itself. If it is good it will read some small value of ohms. If it is open it will read infinite, for example OL or some flashing display on your meter.

Thanks Doc...I haven't checked voltages yet...BUT...I have corrected the first issue...

The previous owner had the Octal facing the wrong orientation (180degs out)...both tubes are now lit.

Hopefully it goes smoothly from here.

While I have your attention...Do you recommend adding the ground wire across the (3) exterior tabs on the phone plug, as mentioned in several threads...?

TA
-Mark

 

[Paul Birkeland]

I would get the kit up and running before progressing to modifications. 
-PB

 

[buldogge]

I would get the kit up and running before progressing to modifications. 
-PB

Hey PB...The kit is up and running (and sounding great)...I have tried HD700s, HD650s, and AKG K240Ms.

While the AKGs are harder to drive, and very "mellow", they do sound quite nice on the Crack...I had not used/listened with them, in awhile.

Waiting on a few Russian tubes to try, and will shortly try a 6SN7 upfront (picked up the USA made adapter), as I have a few from my modded LD MK III.  I would also like to pick up a 5998 (or maybe just a 6AS7G, given current prices).

Lastly, I have the Speedball kit sitting here (was included in the sale)...How long do you guys recommend running the Crack stock before diving into the Speedball??

TA
-Mark

 

[Doc B]

Give it a month to burn in and for you to get the stock sound embedded in your databanks. Then you will be better able to evaluate the sound of the upgrade.

 

[buldogge]

Give it a month to burn in and for you to get the stock sound embedded in your databanks. Then you will be better able to evaluate the sound of the upgrade.

Will do Doc...Thanks.

-Mark