Modifing the GFA-555 PowerAmps - diyAudio
Go Back   Home > Forums > Member Areas > Introductions

Introductions Welcome to the DIYaudio Community. Introduce yourself here so we can get to know you better!

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th December 2008, 08:59 PM   #1
diyAudio Member
 
Join Date: Dec 2008
Default Modifing the GFA-555 PowerAmps

Looking for any help or advice in modifing the GFA-555 PowerAmps.
  Reply With Quote
Old 25th December 2008, 02:16 AM   #2
diyAudio Member
 
Join Date: Jun 2007
The simplest mod is to bypass each PS cap with a smaller cap (22 to 47 uF). This will make the bas a bit tighter or more solid. It is not a large effect but it is an audible improvement. Some of the later series 2 versions may already have this done.

If you are more ambitious, then a larger transformer is in order. The stock one is about 700-750 VAC ( I forget the voltages). For about $125 or so, you can get a transformer that is over 1.2k VAC.

If you are even more ambitious, then regulation on the front end would be a good step. I have not tried this yet, so I have no specifics for you. It would require modifying the boards.

Even with the just the first step (bypass caps) the amp will be improved. The cost is less than $10 and the PS caps are not mounted on the board (unlike the GFA 545), so it is easily performed. You can use bipolar electrolytic (for crossover use), if you think you might mess up on the polarity.

These sell for $300-350. Add $10 in caps and this becomes a very competitive amp

Good Luck!
  Reply With Quote
Old 25th December 2008, 03:30 AM   #3
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Mike,
Welcome to DiyAudio!

There are many threads on building these amplifiers up. Use the search function and read some of these threads. Even if the model number is different, many things will still apply.

Remember too, these amps were well engineered. Therefore, the parts are all pretty good quality already. If you wish to change the power transformer (something I do not recommend) try other things first. Also, define what you want to achieve and work towards that end.

Finally, these are now old amps. They do need some TLC to perform as they did new. You may find this is all you really need to do to be honest with you.

-Chris
__________________
"Just because you can, doesn't mean you should" my Wife
  Reply With Quote
Old 27th December 2008, 04:01 PM   #4
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
Hi and welcome to the forums.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
modifing a CDP-X3000 SPDIF to AES/EBU jouch Digital Source 1 18th March 2005 10:02 PM
help with modifing a H/K A500 amp sweet Tubes / Valves 15 23rd February 2005 06:40 PM
Lynx Poweramps Cap Bank led_zeppelin Solid State 11 13th July 2004 10:06 PM
Lynx Poweramps Project Help!! led_zeppelin Solid State 4 13th July 2004 10:01 PM
Great poweramps bossman2 Solid State 0 31st December 2002 03:34 AM


New To Site? Need Help?

All times are GMT. The time now is 03:32 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2