Someone previously wrote: "...the smaller DC blocking caps in the signal path will cause a loss of low end when they start going bad..."
Last time I checked, the Aleph 3 is a directly coupled design. There are no caps in the audio path outside of the support circuitry. Also, I question changing the values of at least some of those smaller caps, as the actual purposes they serve are different in the different areas. For example, C-103 is to bypass noise, per NP. Not sure where NP is in all of this.
The audio path goes thru a resistor, mosfet, resistor, mosfet, resistor and to the spkr output. The rest of the circuitry is support, including a form of advanced feedback that includes ghost loading reaction.
Last time I checked, the Aleph 3 is a directly coupled design. There are no caps in the audio path outside of the support circuitry. Also, I question changing the values of at least some of those smaller caps, as the actual purposes they serve are different in the different areas. For example, C-103 is to bypass noise, per NP. Not sure where NP is in all of this.
The audio path goes thru a resistor, mosfet, resistor, mosfet, resistor and to the spkr output. The rest of the circuitry is support, including a form of advanced feedback that includes ghost loading reaction.
do we agree that I can to disagree ?
C101 and C103 ( ref. Aleph 3 Service manual schematic ) are in signal path , at least in my book
all other are , say , filtering caps
these two are already over-sized in value , so no big fuss in decreasing them to 50%
off course - leaving them in original value is still better
C101 and C103 ( ref. Aleph 3 Service manual schematic ) are in signal path , at least in my book
all other are , say , filtering caps
these two are already over-sized in value , so no big fuss in decreasing them to 50%
off course - leaving them in original value is still better
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Sure, I'll disagree with Zen Mod, as in fact, this is a directly coupled design. Perhaps you misunderstood my POV, since caps that off of the feedback loop, yet are not coupling the signal from the output to the input, are not necessarily in the audio path; at least not directly as far as amplified signal that travels directly from input to output. Having owned an A3, I claim a strong interest, a reasonable familiarity with its operation, configuration and most certainly, its extraordinary performance.
I previously provided the actual audio signal path, which is stands as correct. You may follow along with the schematic, if that would help you trace the path that I outlined as directly coupled with no coupling caps present, from the A3's input jack to output binding post; a total of three resistors and two mosfets. Any remaining circuitry is power supply related including CCSs, parametric support, and a special form of loading that enables a variable form of feedback.
Zen previously wrote: "through C101 and C103 you have signal flow ; C102 have sort of other role"
I might partially agree with a portion of your former statement above, although it would be limited to this: Audio signal flows through those caps via the feedback loop, yet these don't couple the signal to the input. C101 does have audio signal flow but not as "coupling" since it's technically a bypass cap; the same would be true for one of the other caps.
The audio signal that goes through C101 goes directly to ground. Please refer to the schematic to verify this fact. I will provide a more detailed explanation for those who might be unfamiliar: After the audio output is both attenuated and isolated by a total of 11K through two resistors, C101 bypasses that portion of the (attenuated) audio signal to ground, so this is a bypass cap that enhances the function of the diff. pair.
I previously provided the actual audio signal path, which is stands as correct. You may follow along with the schematic, if that would help you trace the path that I outlined as directly coupled with no coupling caps present, from the A3's input jack to output binding post; a total of three resistors and two mosfets. Any remaining circuitry is power supply related including CCSs, parametric support, and a special form of loading that enables a variable form of feedback.
Zen previously wrote: "through C101 and C103 you have signal flow ; C102 have sort of other role"
I might partially agree with a portion of your former statement above, although it would be limited to this: Audio signal flows through those caps via the feedback loop, yet these don't couple the signal to the input. C101 does have audio signal flow but not as "coupling" since it's technically a bypass cap; the same would be true for one of the other caps.
The audio signal that goes through C101 goes directly to ground. Please refer to the schematic to verify this fact. I will provide a more detailed explanation for those who might be unfamiliar: After the audio output is both attenuated and isolated by a total of 11K through two resistors, C101 bypasses that portion of the (attenuated) audio signal to ground, so this is a bypass cap that enhances the function of the diff. pair.
think whatever you want , that's your basic right .
I will continue to think that even caps in feedback are in signal path ;
on the other hand , in many circuits , even PSU caps are in signal path
I'm not saying that that's bad , just claiming a fact , per se .
anyway - did you ever tried to replace or bypass that cap in Aleph CS modulation ?
it's clearly audible , when you make a change
same case - when you place shortie instead of that cap in feedback node - it's audible change , and for my ears positive .
if signal is not flowing trough them , change in sound will be impossible .
I will continue to think that even caps in feedback are in signal path ;
on the other hand , in many circuits , even PSU caps are in signal path
I'm not saying that that's bad , just claiming a fact , per se .
anyway - did you ever tried to replace or bypass that cap in Aleph CS modulation ?
it's clearly audible , when you make a change
same case - when you place shortie instead of that cap in feedback node - it's audible change , and for my ears positive .
if signal is not flowing trough them , change in sound will be impossible .
Thanks for the discussion (even it is still beyond me at this point, but I will try to get it eventually). 
I am very interesting in whether the change of those small cap values has + or - impact to sound. All the small caps were 220uF but now replaced by 470uF, so they are more than doubled.
Sonic-wise, after a about 50 hours of burn in now, the improvement on bass remains and it is the biggest improvement easily appreciated. The tremble and midrange are also changed but more or less in a mixed situation. The slight treble edge is gone, but at the same time the "air" feeling or the vividness/freshness is reduced a little bit. The midrange is still a little bit recessed and dry (but seems to be better after some burn-in). So I am observing its change.
Therefore, I am tempted to see how the SQ changes if I switch back to the original values of those small caps. Comments?
(I wonder if people put sockets for those caps so we can change them on the fly to see the change of SQ)
Thanks!
I am very interesting in whether the change of those small cap values has + or - impact to sound. All the small caps were 220uF but now replaced by 470uF, so they are more than doubled.
Sonic-wise, after a about 50 hours of burn in now, the improvement on bass remains and it is the biggest improvement easily appreciated. The tremble and midrange are also changed but more or less in a mixed situation. The slight treble edge is gone, but at the same time the "air" feeling or the vividness/freshness is reduced a little bit. The midrange is still a little bit recessed and dry (but seems to be better after some burn-in). So I am observing its change.
Therefore, I am tempted to see how the SQ changes if I switch back to the original values of those small caps. Comments?
(I wonder if people put sockets for those caps so we can change them on the fly to see the change of SQ)
Thanks!
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there will not be change if you decrease value of these caps from from present one ;
I hope you put some nice 10nF (and upwards , to 220nF) MKC (polycarbonats) across them , as bypass ?
I think that I told you to do so , previously .
that way you'll gain some speed up - clearer sound .
I'm finding 10nF MKC of benefit , even bypassing Black Gate , put in C103 position ;
I hope you put some nice 10nF (and upwards , to 220nF) MKC (polycarbonats) across them , as bypass ?
I think that I told you to do so , previously .
that way you'll gain some speed up - clearer sound .
I'm finding 10nF MKC of benefit , even bypassing Black Gate , put in C103 position ;
you know what to do then ........
send it to Authorized Facility for Proper Disposal of PL Products
Sorry, Zen-mod, I cannot afford the shipping costs for proper disposal. I guess I will have to torture myself and keep listening to the Aleph 3!you know what to do then ........
send it to Authorized Facility for Proper Disposal of PL Products
I'd like to report back to the SQ of recapped Aleph after the cap burn in (maybe >100 hrs).
I still have not got the bypass caps in yet since I am still collection parts for thee projects now. Dispre II (active preamp), DCB1 (buffer), and Lighter Note (Passive volume control).
Back to the Aleph 3's SQ. I did not keep close tracking on the burn-in hours. Interestingly, just now the vividness of treble has been back. And it is not too bright at all. So I have no complain on treble. The midrange may be still slightly recessed. More focus on it would be great. However, I also found out such midrange issue may be due to my preamp/Aleph 3 combo. I reported in another thread that the midrange focus was improved quite a bit by directly go from DAC to Aleph3. So I have go after DCB1 and Lighter Note because of this.
On the other hand, my current active preamp still give more punch and attack. I suspect that the large amount of digital volume control when I go direct DAC to amp may degrade the resolution (losing bits). Therefore, I'll report back when I put Lighter Note in the chain.
I still have not got the bypass caps in yet since I am still collection parts for thee projects now.
Dispre II (active preamp), DCB1 (buffer), and Lighter Note (Passive volume control).Back to the Aleph 3's SQ. I did not keep close tracking on the burn-in hours. Interestingly, just now the vividness of treble has been back. And it is not too bright at all. So I have no complain on treble. The midrange may be still slightly recessed. More focus on it would be great. However, I also found out such midrange issue may be due to my preamp/Aleph 3 combo. I reported in another thread that the midrange focus was improved quite a bit by directly go from DAC to Aleph3. So I have go after DCB1 and Lighter Note because of this.
On the other hand, my current active preamp still give more punch and attack. I suspect that the large amount of digital volume control when I go direct DAC to amp may degrade the resolution (losing bits). Therefore, I'll report back when I put Lighter Note in the chain.
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Bypass caps
Wow, it has been three months before I had chance to work on Aleph 3 again.
There was too much things happening in work.
During this period, I feel while A3 has much refined SQ, better focus, and darker background. There was something missing in the treble/mid that the vividness or liveliness is gone. And the mid sound like a little recess and not engaging.
And I didn't have much high expectation with bypass (sorry for the lack of faith), so I wasn't really excited in taking A3 apart to add the bypass cap.
I had 100nf Vishay MKC and 10nf Kemet film cap at hand. The lead spacing of MKC is too big for the existing cap, so I opt to use Kemet first even MKC is much more expensive.
Anyhow, I had a quick listen after adding 10nf to C101 and C102 (which are now 470uF). To my surprise, the sound has been changed quite a bit. The mid range now has much more body and is bold at front. It seems my seat has been moved several row closer to the stage. It is a positive change to me since the music is much engaging now.
I was really surprised. Now I look forward to play with 100nF MKC after I get familiar with this new voice of A3.
Wow, it has been three months before I had chance to work on Aleph 3 again.
There was too much things happening in work.
During this period, I feel while A3 has much refined SQ, better focus, and darker background. There was something missing in the treble/mid that the vividness or liveliness is gone. And the mid sound like a little recess and not engaging.
And I didn't have much high expectation with bypass (sorry for the lack of faith), so I wasn't really excited in taking A3 apart to add the bypass cap.
I had 100nf Vishay MKC and 10nf Kemet film cap at hand. The lead spacing of MKC is too big for the existing cap, so I opt to use Kemet first even MKC is much more expensive.
Anyhow, I had a quick listen after adding 10nf to C101 and C102 (which are now 470uF). To my surprise, the sound has been changed quite a bit. The mid range now has much more body and is bold at front. It seems my seat has been moved several row closer to the stage. It is a positive change to me since the music is much engaging now.
I was really surprised. Now I look forward to play with 100nF MKC after I get familiar with this new voice of A3.
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CL-60
And this time I took another IR temperature measurement on the thermistor CL-60. It was well in the 250 deg F or 120 deg C range. That is the reason why the pad under it was so hot. From what I read, it is normal to be hot ( <175 deg C ). Still, I would like to know if my measurement was in the right range? And it seems the pad on PCB (not the CL-60) can use some heatsink to prevent thermal damage.
Or we just like it become black?
And this time I took another IR temperature measurement on the thermistor CL-60. It was well in the 250 deg F or 120 deg C range. That is the reason why the pad under it was so hot. From what I read, it is normal to be hot ( <175 deg C ). Still, I would like to know if my measurement was in the right range? And it seems the pad on PCB (not the CL-60) can use some heatsink to prevent thermal damage.
Or we just like it become black?
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