pioneer a 88x can it be tweeked ?? - diyAudio
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Old 22nd November 2011, 08:47 PM   #1
paul.42 is offline paul.42  United Kingdom
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Default pioneer a 88x can it be tweeked ??

Pioneer A88X Schematic.zip
hi all iwas woundering if anything can be done to this amp,op amps caps etc..
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File Type: zip Pioneer A88X Schematic.zip (932.8 KB, 67 views)
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Old 23rd November 2011, 10:17 AM   #2
paul.42 is offline paul.42  United Kingdom
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Default opamps

going to try the opamps first,will try opamp2604.
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Old 23rd November 2011, 11:12 AM   #3
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These are pretty nice amps, nonswitching outputs high current output capable and sound pretty good. Considering the age of the amp I would recommend you rather start with replacing the caps especially the ones in the power supply circuitry and the main rectifying caps. After that you could also have a look at the caps in filtering and coupling circuitry depending on what was originally used and if you have access to a scope the compensation ones too. A bit of a warning, be very becareful as to not damage the nonswitching IC, will be very hard to replace.
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Old 24th November 2011, 08:15 AM   #4
paul.42 is offline paul.42  United Kingdom
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Quote:
Originally Posted by homemodder View Post
These are pretty nice amps, nonswitching outputs high current output capable and sound pretty good. Considering the age of the amp I would recommend you rather start with replacing the caps especially the ones in the power supply circuitry and the main rectifying caps. After that you could also have a look at the caps in filtering and coupling circuitry depending on what was originally used and if you have access to a scope the compensation ones too. A bit of a warning, be very becareful as to not damage the nonswitching IC, will be very hard to replace.
could be a plan,would you change like for like or change any of the values of the caps.and would you change caps in the signal path to wimas,ive heard of some people doing this before.
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Old 24th November 2011, 10:44 AM   #5
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Like for like is a good idea but in the case of the rectifying caps Id probably go a size or two up, that is space permitting on pcb. Pioneer usually used better than standard caps so Id get some good ones for replacement. Since youre in the UK and can easier purchase, have a look at BNC slitfoils, excellent power supply caps.

Wima polyprops are very good yes, but this again is size permitting, these caps are much larger, otherwise go with high quality electros. It also depends on what you want to spend to restore the amp.
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Old 29th November 2011, 06:55 PM   #6
paul.42 is offline paul.42  United Kingdom
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op amps fitted,big difference in sound.
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Old 29th November 2011, 07:05 PM   #7
Mooly is online now Mooly  United Kingdom
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That's good to hear.

Did you go for the OPA2604 ?
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Old 29th November 2011, 09:26 PM   #8
paul.42 is offline paul.42  United Kingdom
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Originally Posted by Mooly View Post
That's good to hear.

Did you go for the OPA2604 ?
yes i did,i cant believe how much the sound has changed,its more detailed for sure.very pleased..
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Old 22nd June 2015, 07:09 PM   #9
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Originally Posted by Mooly View Post
That's good to hear.

Did you go for the OPA2604 ?
would this op amp still be the one to use...or are there other suitable ones that can be used??

Last edited by paul armstrong; 22nd June 2015 at 07:35 PM.
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Old 23rd June 2015, 06:30 AM   #10
Mooly is online now Mooly  United Kingdom
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Wow, that was all a long time ago.

The 2604 is still as valid today if you like the sound. The other one to try would be the LM4562. Pretty much as good as it gets as regarding being transparent but you may/may not still prefer the 2604 at the end of the day.
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