Adcom GFA-555 serviced and set the BIAS
Vložit
- čas přidán 19. 08. 2024
- Power output: 200 watts per channel into 8Ω (stereo), 600 watts into 8Ω (mono)
this is a Power Amplifier, easy enough to work on, no frill but it PACK's in POWER....check my video and enjoy.
PLS Subscribe to my channel, Thank You!
#adcom, #adcom GFA-555, #Adcom GFA
*Important Note: most of my video's that are on my channel may involve high voltages that could cause harm to yourself or even death...If you follow my video's and try repairs yourself, you are doing so at your own risk!!!
PLEASE be careful!!!
That amplifier is so nice and clean wish I had one.
Gracias, saludos desde Venezuela
That's a fine looking amplifier inside as well as out.... Too bad they are discontinued.
They're still in business, some made in Scottsdale Arizona and some out of Taiwan.
There's nothing to these amps aside form huge transformer, caps and lots of output transistors
There's a very good electronic project (by Mr. Nelson Pass), which delivers a fidelity sound with almost every speaker.
Which is how most high end amps are made. Youre a genius.
I have the identical amp which I just refreshed… caps, micas, etc. However, you have a film cap sitting on top of each large capacitor. My amp doesn’t have those. Can you elaborate a bit?
I have seen the same amp being worked on by other techs on youtube,and there are no caps across the capacitor terminals,but have seen the same thing on some other brands.
Merci beaucoup Joe de partager vos connaissances à propos des amplificateurs. J’apprends plein de trucs que je ne comprenais pas avant. 🔌🦾
Please show the hook up points for checking the bias. I have one of these beasts, and while it sounds very nice, I want to give it a tune up due to it's advanced age.
I'll send you the bias adjustments...what's your email address
Great video. Thank you so much!
I have 3 Adcom amps : a 555; a 545 and a 535 with signal controlled by an electronic crossover.
Those amps power sub woofers, mid-range and tweeters respectively.
I also have an Adcom gfp-565 preamp feeding the components.
I have some issues that required that the volume be turned to zero when switching sources or a loud thump would result.
I was changing songs on the CD player with the volume up and a loud thump blew out my left speaker midrange.
Any ideas on why this would happen? I’m going to rebuild everything including the preamp.
If the thump happens when you change source in the preamp GFP-565, I think you have to clean and de-oxidize the source switch contacts in the preamp. To do this, open the preamp and use a professional contact cleaner (not oily, no classic WD-40 or similar) on the switches, they are on the board (one for listening source, the other select the source for recording).
If the thump happens when you change song in the CD player, that could be a player issue. What CD player are you using?
(From an happy owner of a GFA-555 II 😉 )
@@util2 Thanks for the info.
The CD player is a 300 disc sony. Yeah, not high end, but it sounds way better than my highly rated and expensive Rotel. I keep the Rotel hooked up so I can pop a disc in and out without the hassle of dealing with the carousel.
@@jeffreylonigro1382 So, can you infer that the cause of the thump is the Sony ? I think it's possible, especially when the Sony changes the CD.
@@util2 Hey buddy, I appreciate the help.
There are a couple things going on. If I change sources on my Adcom GFP-565 preamp with any volume at all, you will get a nasty thump. I didn't think to turn the volume down when switching tracks on the CD player, and that blew the speaker. I'm not sure if these are isolated problems, or the same problem.
I am just learning to work on vintage audio. I am an electrician who built a Harley in his bedroom at 17 years of age. I have a high aptitude for mechanical and engineering applications. I'm 61 and could see myself really getting into this vintage repair stuff just to save this beautiful old equipment and pass it on.
I've tested the DC output on the speakers and there is basically none. My three electronically crossed over Adcom are vintage 80's and they've probably never been recapped, so all the electrolytics need to get replaced. That's a good starting point. I will also set the bias on all amps. I do have service manuals for all my equipment.
Any other advice would be very appreciated. I'm a newbie.
@@jeffreylonigro1382 Hi Jeffrey, I'm Dany from Italy, I'm IT technician with electronics competences and love for music and Hi-Fi.
As I wrote, and you have just confirmed, if you hear the nasty thump when you switch the audio soruce using the selector on the GFP-565, the cause is almost surely the electrical switch inside the GFP. So you have to clean and de-oxidize the source switch contacts as I described in my first answer.
Try this procedure, using a not oliy cleaner spray can. I can suggest you to clean all the switches and potentiometers inside the GFP. The spry must reach the inside of the component and you have to rotate or move it multiple times to clean the contatcs. As I see in a GFP-565 internal photo, you have to clean 7 switches and 2 potentiometers (treble and bass). The volume and balance are ALPS closed potentiometers, if you ear noise moving them, you have to remove them, open and clean or change with similar.
Pleas, let me know how the contacts cleaning procedure went. 😉 Bye
Oh man i got a gfa555 that could use some attention one of the rca inputs on the back is broke i fixed it temporarily and man does it sound nice but i lost the pice of rca i was using idk but if it was to be looked at for that id like it looked over completely to make sure shes tip top is this something you do for hire sorry first time seeing you
Hi Josh
I do work on then , I'm not sure where you are located
@VintageAudioFever I'm in Wisconsin brother
im in Moncton NB Canada@@joshuajames1067
@VintageAudioFever well hello my northern friend God bless
@VintageAudioFever I'll need some time but can probly figure something either way
Wondering if you take customer work and where you are located? I have an adcom 7607 that I purchased that doesn't turn on. Would like to have it repaired and/or refreshed. Can't find anyone near me that's familiar with these or will work on them
I'm in moncton NB Canada ...the thing about shipping..it is very expensive
@@VintageAudioFever damn, ok. Thanks for the response though. Maybe I'll poke around a bit and see if I can spot something out of whack
@@danny51577 yes....maybe you will find something that will jump at you ....maybe a easy fix...let's hope so
@@VintageAudioFevergreat video , would love to see the same video but with the GFA555 MK2. I am from Israel, I have acquired a new old stock of this , very rare. Happy weekend ❤
You really need to speak up it was extremely difficult to hear your voice.
I had the same problem,had to turn the Vol right up and at the end the music was really loud when he tested it,lucky I wasn't wearing head phones.
@@johnbravo7542You guys both need your ears checked