adcom 555
hi i have to ask this question again i have order the 15032/33 but they have 3 pins coming out of them the ones in the amp have only two what am i missing here the 2dd525 and 2sb595 are no longer available do i just leave the collector pin standing ?????? and use the base and emitter would someone please tell me whats wrong here thank you
hi i have to ask this question again i have order the 15032/33 but they have 3 pins coming out of them the ones in the amp have only two what am i missing here the 2dd525 and 2sb595 are no longer available do i just leave the collector pin standing ?????? and use the base and emitter would someone please tell me whats wrong here thank you
Hi djk,
My gosh that's funny. Now watch him buy a fullpak!
Hi changsecho,
Firstly, make sure you have purchased the metal tab types. Then, as djk said ...
Those parts you will order are improved substitutes for the originals from a voltage / current perspective.
-Chris
My gosh that's funny. Now watch him buy a fullpak!
Hi changsecho,
Firstly, make sure you have purchased the metal tab types. Then, as djk said ...
Cut the center pin off flush with the bottom of the case if you can. If you leave the pin hanging out, it may get bent and short later on.
Those parts you will order are improved substitutes for the originals from a voltage / current perspective.
-Chris
adcom 555
hi everyone want to thank you for clearing up that fact on that driver transistor it;s up and runing now sounds great and lots of power i would like to get some output on whether i should change all the transistors in the driver board if so are the transistors made my on are they good ones also would adding on 22uf 100 volts capacitors to the power outputs capacitors give me more bass i;ve seen here on the post where they have added them you all have been much help thank you very much
hi everyone want to thank you for clearing up that fact on that driver transistor it;s up and runing now sounds great and lots of power i would like to get some output on whether i should change all the transistors in the driver board if so are the transistors made my on are they good ones also would adding on 22uf 100 volts capacitors to the power outputs capacitors give me more bass i;ve seen here on the post where they have added them you all have been much help thank you very much
Hi changsecho,
I will now repeat myself from an earlier post . Okay ?
Your posts are difficult to read and it is wasting my time trying to read them. Please have some respect for others that read what you have to say.
Now, how many parts were bad? What were the part numbers?
You don't really get more bass by increasing the filter caps unless you are driving the amplifier hard into a low impedance load. What are the speakers nominal impedance and how many per channel are you using?
-Chris
I will now repeat myself from an earlier post . Okay ?
Your posts are difficult to read and it is wasting my time trying to read them. Please have some respect for others that read what you have to say.
Now, how many parts were bad? What were the part numbers?
You don't really get more bass by increasing the filter caps unless you are driving the amplifier hard into a low impedance load. What are the speakers nominal impedance and how many per channel are you using?
-Chris
"What most people don't realize is that there are already bypass caps mounted on the output boards"
I know on the later ones there are, but not all have them.
Adding bypass caps when there are none makes the bass sound tighter. Bypass caps get rid of the 'mud', and many people will perceive that as less bass. If you think you need more bass you need a tone control.
I find bypass values in the range of 22µF~100µF sound best. The GFA 585 came with 100µF.
These caps are also among the first to wear out, they seldom last more than 7~10 years.
I know on the later ones there are, but not all have them.
Adding bypass caps when there are none makes the bass sound tighter. Bypass caps get rid of the 'mud', and many people will perceive that as less bass. If you think you need more bass you need a tone control.
I find bypass values in the range of 22µF~100µF sound best. The GFA 585 came with 100µF.
These caps are also among the first to wear out, they seldom last more than 7~10 years.
Opened the cover and saw 2 47uF/100V caps (one for each channel) on the output board. Since this amp is close to 20 years old (the psu caps have a date of 1986), may be time due for a recap? ApexJr has the Hitachi 22,000uF/100V for $15ea, a little higher than the original 15,000uF, it shouldn't cause problem, right?
adcom555
hi all i have my adcom 555 up and running and i thank you all for your help.but i have another question i;m greatfull for your input.do you think i should replace all the transistors in the driver board if so what band do you suggest nte-on-fairchild ????.also if i put disc capacitors on the power caps would this give me better bass what size.if so what values would you suggest to use thank you
hi all i have my adcom 555 up and running and i thank you all for your help.but i have another question i;m greatfull for your input.do you think i should replace all the transistors in the driver board if so what band do you suggest nte-on-fairchild ????.also if i put disc capacitors on the power caps would this give me better bass what size.if so what values would you suggest to use thank you
Hi changsecho,
NTE? What is it really? Date code? Batch number? PRICE!!!!!!!!!
Fairchild? Please, tell me why you would install devices that the circuit was not designed for, or completely unknown parts? I am kinda shocked here. No good audio tech uses NTE or anything but original parts or suitable substitutes. Only TV techs and industrial maintenance guys use NTE because they do not understand how linear circuits work.
You can check the matching of the input pair and replace with a matched pair if you understand how to match those devices. If not, you had better leave well enough alone. Output transistors require matching. This isn't a "would be nice if" thing, this is a "must be done this way" thing. If you don't know how, same advice as above. Even applying heat sink grease seems to be an art (not really) because of the number of units I see with this improperly done. Hmmm, that means they were serviced and they failed again. There must be a connection here.
I normally don't do this, but I recently repaired a Citation 22 that came up from the 'States. Not working. It failed very quickly. So here is a picture of the channel as I removed it from the unit.
-Chris
Edit: Notice the obvious fake part, it had the right number.
You have just lost your right to own a good piece of equipment. I'll send you my address for delivery of your Adcom amplifier.
NTE? What is it really? Date code? Batch number? PRICE!!!!!!!!!
Fairchild? Please, tell me why you would install devices that the circuit was not designed for, or completely unknown parts? I am kinda shocked here. No good audio tech uses NTE or anything but original parts or suitable substitutes. Only TV techs and industrial maintenance guys use NTE because they do not understand how linear circuits work.
You can check the matching of the input pair and replace with a matched pair if you understand how to match those devices. If not, you had better leave well enough alone. Output transistors require matching. This isn't a "would be nice if" thing, this is a "must be done this way" thing. If you don't know how, same advice as above. Even applying heat sink grease seems to be an art (not really) because of the number of units I see with this improperly done. Hmmm, that means they were serviced and they failed again. There must be a connection here.
I normally don't do this, but I recently repaired a Citation 22 that came up from the 'States. Not working. It failed very quickly. So here is a picture of the channel as I removed it from the unit.
-Chris
Edit: Notice the obvious fake part, it had the right number.
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