NEED HELP for Pioneer A400x mods
Hi every one, I am new to this forum, I am working on a A400x at the moment.
For the dc coupling I used WAMA 3.3uF MKS4 non-polar. On power supply, i used a high speed rectifier bridge and 0.1uF WAMA bypass on every filter caps. I also added few 100uF/50V Panasonic FC and WAMA MKF on V+/V- of each transistor.
After the mods, rectifier replacement improved the quality of the bass a bit, WAMA give very nice high end, however the whole image became too bright.
Is there anyone have experienced on mods A 400 or A 400x?
Q1: how can I avoid the sound become too bright?
Q2: how can I get better bass control?
Q3: if I increase the bias current, does the 2SA/2SK driving pair needs a heat sink?
Q5: A400 originally 20mA on each power transistors, I am going to boost up to 100mA. Would that give me a warmer sound and better bass control?
Thanks very much!!!!!!!!!!!!!!!!!!
Hi every one, I am new to this forum, I am working on a A400x at the moment.
For the dc coupling I used WAMA 3.3uF MKS4 non-polar. On power supply, i used a high speed rectifier bridge and 0.1uF WAMA bypass on every filter caps. I also added few 100uF/50V Panasonic FC and WAMA MKF on V+/V- of each transistor.
After the mods, rectifier replacement improved the quality of the bass a bit, WAMA give very nice high end, however the whole image became too bright.
Is there anyone have experienced on mods A 400 or A 400x?
Q1: how can I avoid the sound become too bright?
Q2: how can I get better bass control?
Q3: if I increase the bias current, does the 2SA/2SK driving pair needs a heat sink?
Q5: A400 originally 20mA on each power transistors, I am going to boost up to 100mA. Would that give me a warmer sound and better bass control?
Thanks very much!!!!!!!!!!!!!!!!!!
Did a few small mods on my A400X.
Input caps changed to 4.7uF Nichicon ES and maybe Black Gate N or NX would work well here.
The main power supply caps were changed to 10000uF Nichicon Gold Tune.
Caps for op amp were changed to 100uF Nichicon Fine Gold. Tried a few different op amps such as OPA2134, 5532, AD826 but the original M5220 sounded the best. The other op amps may have needed some different power and by-pass caps but wasn't worth playing with.
The mods have seemed to give a bit more drive all round and more control in the bottom.... deeper may be?? ... a tad more clarity but no other noticeable changes. For the few dollars, was worth it.
Input caps changed to 4.7uF Nichicon ES and maybe Black Gate N or NX would work well here.
The main power supply caps were changed to 10000uF Nichicon Gold Tune.
Caps for op amp were changed to 100uF Nichicon Fine Gold. Tried a few different op amps such as OPA2134, 5532, AD826 but the original M5220 sounded the best. The other op amps may have needed some different power and by-pass caps but wasn't worth playing with.
The mods have seemed to give a bit more drive all round and more control in the bottom.... deeper may be?? ... a tad more clarity but no other noticeable changes. For the few dollars, was worth it.
thanks every one!
Hi, thanks for the replys. here is the link to A400 and A400x manual: http://www.hifiengine.com/manuals_type.php?man=Pioneer&mod=A400
Hi, thanks for the replys. here is the link to A400 and A400x manual: http://www.hifiengine.com/manuals_type.php?man=Pioneer&mod=A400
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