Hi Dani,
Happy new year to you and all others too.
If I take it apart again I will make some pictures.
It is still playing and I am still wondered about the sound that is coming out of it, certainly compared with the unmodded version.
I started this journey because I was curious about the MA12070.
Conclusion so far: the MA12070 is very revealing, it lets you hear everything. But also that the A20 is crippled by the pre-stage by using bad caps.
For my part out of the box, I was a little skeptical ...
2 months later .... I am convinced.
This MA12070 takes a long time to open, it is not the same now.
Like what the rodage .... Is not a utopia.
Happy New Year everyone ! 🥳 🥳 🥳
Thanks amigo )
Looking forward to get the pictures )
The MA12070 is a fantastic chip with a huge potential for sure ! Would like to something like the PA5 with some Infineon chips inside )
Took the 100uF panas out again and placed KZ 220uF (luckily I bought a couple of these), really big although...
Less impressive at first sight, but more open soundstage, less highs (surprisingly), much more relaxed.
But these caps are brand new and have to burn in first.
But definitely not that 'throw in your face' like with the panas. Probably most people would prefer this above the panas sound.
And clearly the caps on this position have a big influence on the sound of the A20.
But wait a week to see how it really sounds.
Less impressive at first sight, but more open soundstage, less highs (surprisingly), much more relaxed.
But these caps are brand new and have to burn in first.
But definitely not that 'throw in your face' like with the panas. Probably most people would prefer this above the panas sound.
And clearly the caps on this position have a big influence on the sound of the A20.
But wait a week to see how it really sounds.
Okay, we seem to make progress... Today I finally received the letter from Hificollective, so I could start with swapping some capacities.
Just for trial I soldered some Nichicon KZ as input caps, which were already better than the the stock ones. Now, with the audio note Kasei NP in place it's again much better, as the Nichicons in my ears cause some harshness in the high frequency. This is completely gone now, and the amp became much better than it already is. I also exchanged those 100 micro Farad at the NJM chip, this time for those Nichicons, because it had them at hand.
Last week I did something very unreasonable and bought a Gustard X26pro Dac, which I didn't like too much tbh. Now everything falls into place, there is a big soundstage, with lots of air and tonal subtleties, all harshness gone.
Those AN caps are highly recommended, they are neutral with a hint of warmth and are not in the way of music.
Silmics were also fine, however a bit colored and more romantic.
This amp has such a potential....
Just for trial I soldered some Nichicon KZ as input caps, which were already better than the the stock ones. Now, with the audio note Kasei NP in place it's again much better, as the Nichicons in my ears cause some harshness in the high frequency. This is completely gone now, and the amp became much better than it already is. I also exchanged those 100 micro Farad at the NJM chip, this time for those Nichicons, because it had them at hand.
Last week I did something very unreasonable and bought a Gustard X26pro Dac, which I didn't like too much tbh. Now everything falls into place, there is a big soundstage, with lots of air and tonal subtleties, all harshness gone.
Those AN caps are highly recommended, they are neutral with a hint of warmth and are not in the way of music.
Silmics were also fine, however a bit colored and more romantic.
This amp has such a potential....
Question is, if this are the KZ's or the AN's just masking something?
These caps besides the NJW1194 having such a big impact on the sound quality is something I don't like. An implementation without such a device would be better. Maybe in the end just place fixed resistor dividers over it to get rid off it?
If you ask me to describe the sound of the amp now, I would say it sounds like a superb transistor radio. It is still far too much leaning towards the high's and too thin. My guess is this a problem of the end-stage. I still miss the mid frequencies.... This did not change by changing the caps and opamps of the pre-stage.
If we can make the thing sound like a mature amp we have something fantastic.
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I would have seen some Elna Silmic II in the place of the KZ.
Any chance to try the Japanese Toshin Kogyo série here ? :
Post in thread 'Sabaj A20a modification... worth the effort?' https://www.diyaudio.com/community/...fication-worth-the-effort.377038/post-6898727
Sometimes this hobby can be rather disturbing....this amp in my system sounds everything but thin, very balanced from top to bottom, now has a nice tonal quality, even more on the warm side.
I cannot even imagine this amp sounding like you describe.
How is that possible?
Sometimes this hobby can be rather disturbing....this amp in my system sounds everything but thin, very balanced from top to bottom, now has a nice tonal quality, even more on the warm side.
I cannot even imagine this amp sounding like you describe.
How is that possible?
I'd like the chime in regarding those AN caps - I do not feel that they mask anything - I have also used them in various positions of my preamp - replacing those green Nichicon bipolar caps - and the difference (in added detail, cleaner timbres of voices, instruments) was not subtle.
And having heard the Sabaj on different speakers I would not at all agree that it sounds thin, lean etc. - go figure whatever the reason for that impresson might be....
.
And having heard the Sabaj on different speakers I would not at all agree that it sounds thin, lean etc. - go figure whatever the reason for that impresson might be....
.Hello @Jogi , could it be possible for you to summarize your final modding setup for the Sabaj A20a please ?
I'm struggling to keep track of what you did at the end.
I'm going to see if I can mod the AO200 in the same way, as these two units have a LOT in common.
Unfortunately the AO200 has a less powerful PSU and I don't think it has the room to put a bigger one... I don't think I need a lot of power for high volume but I would guess that it also give more punch and overall dynamic, what do you think ?
I'm struggling to keep track of what you did at the end.
I'm going to see if I can mod the AO200 in the same way, as these two units have a LOT in common.
Unfortunately the AO200 has a less powerful PSU and I don't think it has the room to put a bigger one... I don't think I need a lot of power for high volume but I would guess that it also give more punch and overall dynamic, what do you think ?
Yes, these amps look like twins. So I replaced the 6 22uf input caps, 4 22uf caps between the opamps and the merus
chips, and the 2 100uf at the NJW chip.
And the opa1612 are replaced with opa1656, which was the biggest upgrade, followed by the 6 input caps. Those 2 steps would be absolutely enough tbh.
I still have the meanwell supply here, but am too lazy to put it in.
When working at it, use proper tools, once the traces on the PCB are damaged, it can be the end of it...
chips, and the 2 100uf at the NJW chip.
And the opa1612 are replaced with opa1656, which was the biggest upgrade, followed by the 6 input caps. Those 2 steps would be absolutely enough tbh.
I still have the meanwell supply here, but am too lazy to put it in.
When working at it, use proper tools, once the traces on the PCB are damaged, it can be the end of it...
Thank you Jogi !
I will do my research to choose the correct specs for these caps and place an order at digikey or mouser.
I tried to collect informations to change the PSU but, with the AO200, I'm fairly limited with the room inside the box and I don't think any 300W PSU will fit (meanwel RPS and EPP), I would've like to put something like 400W but it won't fit for sure.
And with 300W PSU, even if it would fit, the specs show that it only give 200W in passive cooling mode, so I don't understand what would be the benefits here, maybe you could clarify this for me.
Plus the fact that the DC output connectors terminal are only M3.5 screws instead of proper JST VHR and I don't know how I would manage to connect the PSU to the board.
I will do my research to choose the correct specs for these caps and place an order at digikey or mouser.
I tried to collect informations to change the PSU but, with the AO200, I'm fairly limited with the room inside the box and I don't think any 300W PSU will fit (meanwel RPS and EPP), I would've like to put something like 400W but it won't fit for sure.
And with 300W PSU, even if it would fit, the specs show that it only give 200W in passive cooling mode, so I don't understand what would be the benefits here, maybe you could clarify this for me.
Plus the fact that the DC output connectors terminal are only M3.5 screws instead of proper JST VHR and I don't know how I would manage to connect the PSU to the board.
I'm in France and on Hifi Collective I get the AN for approx 10€/µ for the 63V which is a huge price for me ... (maybe you are talking about the 16V ?)
I'm wondering if there is a better quality priced caps that would do the job really good here
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