AudioFanMan
Active Member
Wound up crazy lucky, snatched an EICO 667 in absolutely mint condition. Still has the blue protective film on it !!!
Replaced the usual suspects (drifting resistors and old electrolytics) and all calibrated perfectly...
I also added back to back diodes across the meter, plan on another mod or two... have more parts on order to do them and also to build the eico 615 adapter....
While the parts are in route, I figured I needed to get a grip on what I need to know to test KT120's...
I hoped the EICO 666 tube chart had a KT88 to work off of, but I could not find ;-(
Also hoping to extrapolate what I learn to be able to apply to the KT150 and 300B....
Im hoping someone here has been through this already and can offer sound advice.
I found a spreadsheet with some additional EICO 666/667 tube data.
TY Gene Dunn! The layout alone would have taken me forever to come up with!!!
The KT120 datasheet has the following...
The Eico can test at 180V, the neg bias adjustable to -15v and that's showing me 65'ish mA of plate current.
Next I filled in the last two rows....
I believe since the EICO tests using AC, the 65ma should be multiplied by 0.6366 giving an indicated 41.3ma on the EICO
I feel like Im still missing something.. No, wait. I know Im missing more than something lol...
Anyone familiar with the KT120 and 667 (or 666) care to chime in so far ?
In addition to the unknowns for me above....
In my amp, both pins 1 and 6 (unused) are tied to the cathode, while pin 4 (2nd grid) is tied to the UL tap by way of 1.2k ohm resistor....
There is an "triode" option to tie B+ and g2 through a 100 Ohm resistor....
I would think we would want to mimic operating conditions while testing, since we really cant with the 667 what should I expect with g2 left wide open in any situation ?
Replaced the usual suspects (drifting resistors and old electrolytics) and all calibrated perfectly...
I also added back to back diodes across the meter, plan on another mod or two... have more parts on order to do them and also to build the eico 615 adapter....
While the parts are in route, I figured I needed to get a grip on what I need to know to test KT120's...
I hoped the EICO 666 tube chart had a KT88 to work off of, but I could not find ;-(
Also hoping to extrapolate what I learn to be able to apply to the KT150 and 300B....
Im hoping someone here has been through this already and can offer sound advice.
I found a spreadsheet with some additional EICO 666/667 tube data.
TY Gene Dunn! The layout alone would have taken me forever to come up with!!!
The KT120 datasheet has the following...
The Eico can test at 180V, the neg bias adjustable to -15v and that's showing me 65'ish mA of plate current.
Next I filled in the last two rows....
I believe since the EICO tests using AC, the 65ma should be multiplied by 0.6366 giving an indicated 41.3ma on the EICO
I feel like Im still missing something.. No, wait. I know Im missing more than something lol...
Anyone familiar with the KT120 and 667 (or 666) care to chime in so far ?
In addition to the unknowns for me above....
In my amp, both pins 1 and 6 (unused) are tied to the cathode, while pin 4 (2nd grid) is tied to the UL tap by way of 1.2k ohm resistor....
There is an "triode" option to tie B+ and g2 through a 100 Ohm resistor....
I would think we would want to mimic operating conditions while testing, since we really cant with the 667 what should I expect with g2 left wide open in any situation ?