Adcom GFA-555 from New York for a "Check Out" Testing the Transistors and Capacitors. Part 2 of 2

[@barryg41]

Good quality work Steve. 👍

[@digitalwoodshop]

Another Excellent Video.

[@g.fortin3228]

Very nice one ! I think i'm going to be looking for one of these. simple nice design. add a protect circuit and done.

[@meltyblood]

Awesome video, thanks.

[@shaharyarsheikh6878]

best adcom test vdo . thanks .

[@lassiterdominguez2879]

Great vids thank you for your clean presentations. Do u have a reference or cheat sheet for why u rated thos ohm readings acceptable vs their capacitance ratings? becuz yes i too dont want to take them out. Lol. Ty again. Im not doubting u i just dont have ur knowledge.

[@tomb375]

Amazing Job!! As always. Thank you. How does it sound?

[@norcal715]

It sounded awesome. No distortion at all and a rich full analog sound.

[@RanTausi]

@@norcal715 Thanks a lot for this great video, Now please make a video on the GFA 555 MK2 ❤

[@jeffvara1184]

I very much enjoyed theGFA-555 videos. I happen to have one on my bench right now - apologize in advance for all the questions: One side has 8 vdc offset at the speaker terminals (on dim bulb) I suspect a bad output transistor on that side. I believe it is an 2SB554 and will pull/test them all (any tips on procedure?) I'm curious how you would approach replacing one bad output transistor on a unit like this (assuming it's just one) If I can locate a replacement 2sB554, is it ok to replace just one transistor at a time?

[@norcal715]

I would definitely replace all 4 (or all 8 on the bad channel preferably) in at least the positive, or negative stages as a "matched set"

[@diyelectronics5375]

can you explaine the video why so important the HFE matching? what is HFE and what is fuction?

[@norcal715]

HFE is the gain or amplification of the transistor, in a multiple transistor amplifier stage you don't want one transistor to have too much or too little gain in respect to the other transistor(s), so they will be balanced and share the load equally.

[@inothome]

Is that how you would read that reading of 15.91 mF? That's really 15,910mF? Looks like 15.91mF which would be 15,910uF?

[@inothome]

Yeah, I edited my reply, got all confused with m, u and p. lol