SoundOfSound
Super Member
If the UFOs are good leave them in. They are much better build quality than those little plastic transistors.
What brand of COGs did you use?
What brand of COGs did you use?
If the UFOs are good leave them in. They are much better build quality than those little plastic transistors. . . .
i cant remember a single ufo transistor dying . i also think they look cool and look well made too . think i have some new ones knocking around some-place .
When I re-did my AU-555A, every flying saucer I pulled, I think there were six, had an hFE under 100, I think one was 40. That's a reason to change them.
me too, I pulled the first just to check for pin out and the Hfe was pretty low, but I am wondering what the original rating was?
Beautiful work. What's the reason for the NP muse caps ? Feedback caps ?
What are these cog ceramics for the signal - is there a mouser part number ?
PS. My impression of the UFO's are not that they are failure prone, but rather noisy.
+ 1 - the 1845's I used in a 505 resto averaged a 15% reduction in gain compared to the 871.
I did keep the 1845 though and the amp sounds very very nice. No strain or lack of bass whatsoever, so that part of the equation may be case by case.
@ Rob, do you know where to get the 1815 with suffix L - looks like digikey only carries Yta version with a gain range much lower than the 1845 ?
nice job ..i got to look for those transistors today to see the gains .but in my infinite wisdom i have moved them so cant be found yet.
I've never regretted pulling a flying saucer transistor. They may look cool, but after replacing mine in a 555a, 999 and 6500, the amplifier did sound better to me. I also had some crackling symptomatic of a failing transistor in a 6500 that went away once those transistors flew away.....
Are you going to replace those trimpots also, or do you think there is no need? I personally only do it when they contribute to noise at the outputs (from not holding their value properly) or where you get wildly fluctuating values on adjustment....