I changed the LT1963 cap to a WIMA FKP02 10nF I had around. I also put a wima MKS4 100nF between V+ and V- of op-amp. I think it slightly improved but it is still less bass than on my Piano DAC.
Will try the new op amps I have ordered and if I am not happy probably try the Audiofeel op-amp. Do you mean the OPM401 MK2 which seems to be the OPA301 but with offset adj.? Only problem is the height which makes it difficilt to fit in a small case...
Will try the new op amps I have ordered and if I am not happy probably try the Audiofeel op-amp. Do you mean the OPM401 MK2 which seems to be the OPA301 but with offset adj.? Only problem is the height which makes it difficilt to fit in a small case...
I was thinking the plug-in op amp may be a lot easier than a transformer or tube output, and yes, it would be the 401 model, and not the "2401"like I had stated earlier.
The original purple Elna capacitors never worked well on mine, but I swapped them out pretty early, that may make a difference too perhaps, if you haven't already that is.
With the current discreet op amp, I have placed a tiny 4.7uf silmic ars right on the pins for the op amp, under the board. I had done that at the same time I had added the extra caps on the regulator outputs, so that may be a part of the improvement also.
There has never been a lack of detail with this board, even when new however, definitely a good one to work with. With a little patience it can be very good as I'm now beginning to hear.
I had to router a pocket out of the lid to my case, since the op amp was just 1mm too tall...
The original purple Elna capacitors never worked well on mine, but I swapped them out pretty early, that may make a difference too perhaps, if you haven't already that is.
With the current discreet op amp, I have placed a tiny 4.7uf silmic ars right on the pins for the op amp, under the board. I had done that at the same time I had added the extra caps on the regulator outputs, so that may be a part of the improvement also.
There has never been a lack of detail with this board, even when new however, definitely a good one to work with. With a little patience it can be very good as I'm now beginning to hear.
I had to router a pocket out of the lid to my case, since the op amp was just 1mm too tall...
The description of Audiofeel is very confusing with many models and model changes. It seems 2401 is for feedback resistors bigger than 1k Ohm (I guess this is the case on our board if not taking the cap in parallel to it into account). The 401 (and 301) seem to be for feedback resistors less than 1k Ohm and for voltage up to 5V only...but it has better slew rate and higher output current than 2401..mmhh
The purple ELNAS were changed from the beginning to Panasonic FM. I have Organic Polymer FP Elkos right beside the OP amps with a very low ESR of 7mOhm - this should give a stable power supply to the op amps.
I am also happy about the performance in Mid and High-range of this board. Somehow there is some kind of "airness" the Piano does not have. If the bass would be a little more punchy I really could live with it. Trials with other OP amps showed already that this really seems to be a matter of the choice of this op amp component.
The purple ELNAS were changed from the beginning to Panasonic FM. I have Organic Polymer FP Elkos right beside the OP amps with a very low ESR of 7mOhm - this should give a stable power supply to the op amps.
I am also happy about the performance in Mid and High-range of this board. Somehow there is some kind of "airness" the Piano does not have. If the bass would be a little more punchy I really could live with it. Trials with other OP amps showed already that this really seems to be a matter of the choice of this op amp component.
I agree that the descriptions of those parts can be a lot to dig through, probably why I wound up with "almost" the right part.
Those Panasonic FM should be great there, but I must say that I have not had good experiences using the polymer-type capacitors in any analog circuits. You might try some regular electrolytic if you have some around.
I got a good deal on some that were very low esr like yours, and then had to get some more that were in the 22uf - 47uf range just to keep the esr up enough to prevent any interactions due to too low of esr. This was for the digital decoupling on the xmos, and on the Ak4495 chip.
Those Panasonic FM should be great there, but I must say that I have not had good experiences using the polymer-type capacitors in any analog circuits. You might try some regular electrolytic if you have some around.
I got a good deal on some that were very low esr like yours, and then had to get some more that were in the 22uf - 47uf range just to keep the esr up enough to prevent any interactions due to too low of esr. This was for the digital decoupling on the xmos, and on the Ak4495 chip.
..maybe that is why your op-amp runs so hot as you say? Probably the 2401 would be the better choice?
If I will buy the descrete op-amp I will have to replace the FP caps anyway due to lateral space problems...than I could test some other caps as well. I first will wait for receiving the AD823 and OPA2227 - maybe they work fine under this condition already.
From the Linn streamer tuning Guru Mr. Dr.Volk (his reports are shown in the German Forum "Aktives-Hoeren") I now that the LM49720 need a almost "Zero" Ohm PSU to work well - that is why I put this caps there as he also does in most of his mods. The cap between the V+ and V- do almost the same and avoid swing behaviour.
Nevertheless nobody tried the transformer on AK4495 so far?
If I will buy the descrete op-amp I will have to replace the FP caps anyway due to lateral space problems...than I could test some other caps as well. I first will wait for receiving the AD823 and OPA2227 - maybe they work fine under this condition already.
From the Linn streamer tuning Guru Mr. Dr.Volk (his reports are shown in the German Forum "Aktives-Hoeren") I now that the LM49720 need a almost "Zero" Ohm PSU to work well - that is why I put this caps there as he also does in most of his mods. The cap between the V+ and V- do almost the same and avoid swing behaviour.
Nevertheless nobody tried the transformer on AK4495 so far?
I think this discrete op amp is biased a little hot, sounds great, would imagine the 401 is the same. Maybe not a good thing if you don't have a way to add a fan or leave the case open I suppose.
Well if the lm49720/solid cap combo works then you should be all set hopefully. They don't use film caps with the solid type do they?
Well if the lm49720/solid cap combo works then you should be all set hopefully. They don't use film caps with the solid type do they?
Hello phase,
no, just solid caps for V+ and V- to ground. I could not realize a decrease in performance adding the film cap. But I remember they also put a serial resistor of 100 Ohm (if I am not wrong) between psu and cap to decouple it.
Eldam, what do you mean? What would be the negative effect?
no, just solid caps for V+ and V- to ground. I could not realize a decrease in performance adding the film cap. But I remember they also put a serial resistor of 100 Ohm (if I am not wrong) between psu and cap to decouple it.
Eldam, what do you mean? What would be the negative effect?
Well I hope that works with the lm49720, if so it would explain what I did wrong when I had used it.
The damping resistor is a good idea too. I noticed that the literature from akm shows a 1m damping resistor across some of the supply pins (vref). I may give that a try after everything else has been sorted out.
The damping resistor is a good idea too. I noticed that the literature from akm shows a 1m damping resistor across some of the supply pins (vref). I may give that a try after everything else has been sorted out.
Ordered one set of this and it is on the way, meantime, does anybody can really get 768K sample rate from (U8) the board in the real life? that become my main concern while wait for the shipment.
4495, yes, it is 768 supported, same with 4490, that is out of question, but the XMOS side, it is possible since diyhk has one set of 768 supported with U8 under customized driver.
Any experienced user can give an answer?
4495, yes, it is 768 supported, same with 4490, that is out of question, but the XMOS side, it is possible since diyhk has one set of 768 supported with U8 under customized driver.
Any experienced user can give an answer?
Sorry I don't know the answer to the xmos question, but I hope it was determined by now, and you have the board up and running too.
There was an arcam dac that used the lm49720 and solid polymer capacitors for V+\-.
I have a clone version of this but am using different parts.
The "audiofeel" discreet op amp description mentioned that the feedback R should be less than 1k for the 301 that I have. The 4495 board has 5800r, so that would explain my heat.
Thanks for that, I didn't spend much time on that, was trying to order in a hurry...
There was an arcam dac that used the lm49720 and solid polymer capacitors for V+\-.
I have a clone version of this but am using different parts.
The "audiofeel" discreet op amp description mentioned that the feedback R should be less than 1k for the 301 that I have. The 4495 board has 5800r, so that would explain my heat.
Thanks for that, I didn't spend much time on that, was trying to order in a hurry...
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Hi Guys,
Is anyone can help me to point the 7-pin connections to activate the XMOS USB card with two rows of connections, I have purchased it to my AK4495 DAC board that has 7 pins in it and still can not figure out how to connect it correctly. The other XMOS USB card ( 7 pin) is suitable to the DAC board.
Here is the picture link: Shared album - Mykhailo M - Google Photos
Many Thanks in advance.
Is anyone can help me to point the 7-pin connections to activate the XMOS USB card with two rows of connections, I have purchased it to my AK4495 DAC board that has 7 pins in it and still can not figure out how to connect it correctly. The other XMOS USB card ( 7 pin) is suitable to the DAC board.
An externally hosted image should be here but it was not working when we last tested it.
Here is the picture link: Shared album - Mykhailo M - Google Photos
Many Thanks in advance.
I have AKM AK4495 DAC board and was looking to upgrade some parts that really effect the sound quality. Including Op-Amps what other parts are on the signal path that make sense to change? Here is the picture: Shared album - Mykhailo M - Google Photos
From the Caps marking I think they are:
A.
They are polypropylene film capacitors numbers:
1). one is 6800pf 100v
3). number 3 is 1500pf 630v and
2). number 2 is 100nf (100,000pf ) 100v
Problem number 2
The output volume quite low using LME49710.
What resistors need to be removed completely and bridged with a peace of wire that goes to (Op-Amp) Leg No: 2 inverting - input (Negative feedback) ? Are they on the left hand side a pare next to a green cap or a pare of blue ones?
Thanks
From the Caps marking I think they are:
A.
They are polypropylene film capacitors numbers:
1). one is 6800pf 100v
3). number 3 is 1500pf 630v and
2). number 2 is 100nf (100,000pf ) 100v
Problem number 2
The output volume quite low using LME49710.
What resistors need to be removed completely and bridged with a peace of wire that goes to (Op-Amp) Leg No: 2 inverting - input (Negative feedback) ? Are they on the left hand side a pare next to a green cap or a pare of blue ones?
Thanks
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Hi Sure, Here is the link (if opens in French just translate it in English) https://www.audiophonics.fr/en/diy-dac/diy-dac-akm-ak4495-ak4118-kit-32bit384khz-dsd-p-11126.html
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I might try leaving number 3 parts alone, look like they may well be film/foil already. You can see what brand/model they are and search the data sheet to find info on a parts construction.
I would try to find some similar parts for the number 1 replacement, then maybe after that, look at the number 2 parts, are decoupling for the op amp power, may be ok as is. For decoupling like that, often a .01uf of better quality will sound better, sometimes not...
But that’s just my approach, and I don’t know of any resistors to bypass on this one.
If the four large electrolytic caps are in series with the dac output, then this may be either a board once designed for an ak4490, or a re-badged ak4490, or something else. That was something that was done with the earlier dacs that isn’t required on the ak4495 and newer chips.
That’s a pretty large looking Sanyo Oscon near a regulator, while I’m a big fan of those, I have noticed that much larger than 100uf can resonate or ring easily, from too low esr. I only use 47uf near chips for digital supply only, use maybe a rubycon khz for the regulator(220uf/16v).
I would try to find some similar parts for the number 1 replacement, then maybe after that, look at the number 2 parts, are decoupling for the op amp power, may be ok as is. For decoupling like that, often a .01uf of better quality will sound better, sometimes not...
But that’s just my approach, and I don’t know of any resistors to bypass on this one.
If the four large electrolytic caps are in series with the dac output, then this may be either a board once designed for an ak4490, or a re-badged ak4490, or something else. That was something that was done with the earlier dacs that isn’t required on the ak4495 and newer chips.
That’s a pretty large looking Sanyo Oscon near a regulator, while I’m a big fan of those, I have noticed that much larger than 100uf can resonate or ring easily, from too low esr. I only use 47uf near chips for digital supply only, use maybe a rubycon khz for the regulator(220uf/16v).
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