Hi Sunsun,
unfortunately as Nino pointed out earlier UTO is no longer available at partsconnexion so cheapest available seems to be one from diyhifisupply for $150...
unfortunately as Nino pointed out earlier UTO is no longer available at partsconnexion so cheapest available seems to be one from diyhifisupply for $150...
Ah, I see. Thank you in pointing this out.
In this case, it is more expensive than before because the 2.2uF were included before. Anyway, you don't need those caps.
In this case, it is more expensive than before because the 2.2uF were included before. Anyway, you don't need those caps.
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Hi Sunsun check out the lampizator site he does tube kits but also tells you how to make your own tube kit.
Lots of information about tubes and dacs on his site.
Hi 730user, the link is directed to a clone Musical Fidility tube buffer X10-D which is very interesting. It is only a buffer without gain and I don't know if it is possible to connect to AK4399 output and generate sufficient gain to drive the preamp. However, it costs peanuts and I just bought one to try it out. Besides using it for DAC, I think this could also generate some tube-taste for my jFET phono preamp too. Let see.
Dave, I hope Lampizator can have a tube amp for balanced out DAC (like AK4399) converting to SE output. Yet, I cannot find such in his shop and besides, his price is similar to that of UTO. I hae been using UTO for 5 years and it never disappointed me when connected to different DACs.
Dave, I hope Lampizator can have a tube amp for balanced out DAC (like AK4399) converting to SE output. Yet, I cannot find such in his shop and besides, his price is similar to that of UTO. I hae been using UTO for 5 years and it never disappointed me when connected to different DACs.
Hi,Sunsun22
Looking forward to your impressions. 🙂
I do more interested in the external oscillator. Should I put on the board and at what frequency quartz is used
Looking forward to your impressions. 🙂
I do more interested in the external oscillator. Should I put on the board and at what frequency quartz is used
Hi 730user
I suppose you have the second version 2xAK4399 DAC with the AK4118 receiver?
As to my knowledge the crystal on the PCB is only used for detection of the sample frequency of the incoming signal, for displaying the right frequency on the display. The master clock is still derived from the spdif signal by the PLL, i.e. the clock of your source/transport.
You could try to replace the master clock on your transport with it, but replacing the clock on the DAC won't improve SQ.
regards, Nino
Hi,Sunsun22
Did the jfet mod Sj74/2sk 170, really good. Old HDAM Jfets were matched around IDSS 3 mA, new Jfets around 6-7,5 mA are there any negatieve effects to do this (higher IDSS)? Can the circuit around the ex opamps improved to match better with the HDAMs?
Anyone experimented with the rectifiers? I use IXYS DSEP 9-06 CR now, background "blacker", less echos (can't describe it), less live like (positiv).
Thanks in advance
Did the jfet mod Sj74/2sk 170, really good. Old HDAM Jfets were matched around IDSS 3 mA, new Jfets around 6-7,5 mA are there any negatieve effects to do this (higher IDSS)? Can the circuit around the ex opamps improved to match better with the HDAMs?
Anyone experimented with the rectifiers? I use IXYS DSEP 9-06 CR now, background "blacker", less echos (can't describe it), less live like (positiv).
Thanks in advance
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Actually, I wanted to change the diodes to Schottky, but then I found that they already mounted Schottky type diodes.
I see your diodes are soft recovery fast types. Which rectifier bridge did you replace, the +/- dual rail or the +5V rail(s)?
spare parts
The HDAM supplier said it is OK to choose GR grade Idss. I don't have 2sj74 at 3~4 mA (although I still have around 400 s2j74GR on hand but they were not being measured) therefore I just picked BL grade at 6mA. They sound much better than the original jfets.
The rectifiers make a difference too. I use BYV27-200 for my phono amp and once, I changed them to MUR860 that I have good result in my previous TDA1541 DAC but I returned to BYV27-200 after a week because the difference is significant. After this, I only use BYV27-200 in my DIY projects wherever possible.
I have completed to solder all SMD components on my newer version dual AK4399. The next thing to do is to solder the through hole components. The rest would be simple because I will be using UTO as tube output but I don't have sufficient supra regulator on hand to make a true comparison between the earlier and newer dual AK4399 versions.
There are 4 sets of rectifiers in the kit. Two sets for +/- rails for opamp, 1 set for dual AK4399 and receiver together and 1 set for display and MCU. I believe you can use whatever available for the display and MCU group. I am working to provide separate rectifier group for the analog supplies of AK4399 and receiver, can anyone give me his opinion/impression does this makes a difference?
I used to purchase spare parts from taobao but I stopped about four/five years ago because most of them; if not all, were fake. I have a locky_z curve tracer that I found the K1520/J200 have big difference between those I purchased from taobao and japan - this holds true for my K170/J74 too. I believe buying second hand spare parts could be safe but I found sellers in taobao even re-mark second hand spare parts - I have a batch of fake second hand K389/J109 too, not to say those resistors and capacitors. Do you believe OPA627 is selling at 1/3 of what it cost in Mouser, Digikey, RS-Online in China? Do you believe you are having real spare parts from those kit suppliers in China?
In China, most spare parts you buy are fake except one thing for sure - fakes are real fakes.
The HDAM supplier said it is OK to choose GR grade Idss. I don't have 2sj74 at 3~4 mA (although I still have around 400 s2j74GR on hand but they were not being measured) therefore I just picked BL grade at 6mA. They sound much better than the original jfets.
The rectifiers make a difference too. I use BYV27-200 for my phono amp and once, I changed them to MUR860 that I have good result in my previous TDA1541 DAC but I returned to BYV27-200 after a week because the difference is significant. After this, I only use BYV27-200 in my DIY projects wherever possible.
I have completed to solder all SMD components on my newer version dual AK4399. The next thing to do is to solder the through hole components. The rest would be simple because I will be using UTO as tube output but I don't have sufficient supra regulator on hand to make a true comparison between the earlier and newer dual AK4399 versions.
There are 4 sets of rectifiers in the kit. Two sets for +/- rails for opamp, 1 set for dual AK4399 and receiver together and 1 set for display and MCU. I believe you can use whatever available for the display and MCU group. I am working to provide separate rectifier group for the analog supplies of AK4399 and receiver, can anyone give me his opinion/impression does this makes a difference?
I used to purchase spare parts from taobao but I stopped about four/five years ago because most of them; if not all, were fake. I have a locky_z curve tracer that I found the K1520/J200 have big difference between those I purchased from taobao and japan - this holds true for my K170/J74 too. I believe buying second hand spare parts could be safe but I found sellers in taobao even re-mark second hand spare parts - I have a batch of fake second hand K389/J109 too, not to say those resistors and capacitors. Do you believe OPA627 is selling at 1/3 of what it cost in Mouser, Digikey, RS-Online in China? Do you believe you are having real spare parts from those kit suppliers in China?
In China, most spare parts you buy are fake except one thing for sure - fakes are real fakes.
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Hi,Sunsun22
I read the datasheet AK4118. This chip has the ability to work off the clock signal source and from the built-ak4118 generator. Instead of quartz can connect the external oscillator.
As is done in the double 4399 I do not know. But Comrade lomonosov to connect an external clock from the audio-gd and marked changes in the sound.
About counterfeit chips. I ordered a lot of operational amplifiers with taobao. And had only one case of faulty goods. But I very carefully chose the seller. By the way have Veylianga opamp not worth buying. About 90% of electronic components in the world is produced in Asia.
And about the price - data clone HDAM stands on taobao $ 8 and on ebay - 50.
I read the datasheet AK4118. This chip has the ability to work off the clock signal source and from the built-ak4118 generator. Instead of quartz can connect the external oscillator.
As is done in the double 4399 I do not know. But Comrade lomonosov to connect an external clock from the audio-gd and marked changes in the sound.
About counterfeit chips. I ordered a lot of operational amplifiers with taobao. And had only one case of faulty goods. But I very carefully chose the seller. By the way have Veylianga opamp not worth buying. About 90% of electronic components in the world is produced in Asia.
And about the price - data clone HDAM stands on taobao $ 8 and on ebay - 50.
Newer version of Dual AK4399
I finished the newer version today. There are a few differences between this version and my previous DAC: -
1. I do not have Dexa regulators for the receiver therefore I am using the provided LT1963-3.3 for digital, analog and buffer supply of the receiver. My previous version is using separate Dexa regulators for digital and analog supply.
2. The DAC chip output is connected to 12K resistors as provided, not the Vishay 2K 0.1% in my previous version.
3. The capacitor after LT1963-3.3 is Panasonic OSCON 220uF while the older version is using Rubycon ZA 330uF.
Other than the above, most of the parts are similar.
The immediate impression is higher density in mid and lower ranges. Vocal is becoming more airy bearing in mind this new PCB is just being finished. I think it will further improve over time. It seems the LT1963 is doing a good job because without separating the power supply for analog and digital, the background is very clean already. Anyway, I will try to use separate regulators for digital and analog later because I am moving home that my workshop will be in serious disorder in the next 20-30 days.
I will try to use 12K resistors from the DAC chip in my previous version when I have time and change the crystal to; perhaps, 1 ppm TCXO at a later stage.
I finished the newer version today. There are a few differences between this version and my previous DAC: -
1. I do not have Dexa regulators for the receiver therefore I am using the provided LT1963-3.3 for digital, analog and buffer supply of the receiver. My previous version is using separate Dexa regulators for digital and analog supply.
2. The DAC chip output is connected to 12K resistors as provided, not the Vishay 2K 0.1% in my previous version.
3. The capacitor after LT1963-3.3 is Panasonic OSCON 220uF while the older version is using Rubycon ZA 330uF.
Other than the above, most of the parts are similar.
The immediate impression is higher density in mid and lower ranges. Vocal is becoming more airy bearing in mind this new PCB is just being finished. I think it will further improve over time. It seems the LT1963 is doing a good job because without separating the power supply for analog and digital, the background is very clean already. Anyway, I will try to use separate regulators for digital and analog later because I am moving home that my workshop will be in serious disorder in the next 20-30 days.
I will try to use 12K resistors from the DAC chip in my previous version when I have time and change the crystal to; perhaps, 1 ppm TCXO at a later stage.
Attachments
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Hello Sunsun22,
It seems you figured out direct-output from mono configuration. How did you solve the problem? Did you get ground from different point? Have you enough gain with UTO?
Sunsun22 said:
I think you should more likely to use a XO which specified as "Low Phase" distortion. I'm not sure that TCXO's are so good with this spec.
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Hi,Sunsun22
Did the jfet mod Sj74/2sk 170 now i get around 2 V dc offset,potentiometer didn't change anything,with the old jfet configuration no problem. Any suggestions?
Regards.
Did the jfet mod Sj74/2sk 170 now i get around 2 V dc offset,potentiometer didn't change anything,with the old jfet configuration no problem. Any suggestions?
Regards.
risperdal: this DAC plays even without opamps but of course distorted with low gain, don't know if it's normal...
Hi Risperdal,
It is normal because sound goes via resistor used in negative feedback of the LFP filter (RR6 or LR6. See schematic diagram in post #107, page 11). Level of sound on channel without HDAM might be lower than in the other channel but it is depends on impedance of your amplifier which is normally quite high.
Hi Sunsun22,
As it was absolutely correctly mentioned above by Nino: "crystal on the PCB (with AK4118) is only used for detection of the sample frequency of the incoming signal ...". Consequently using better TCXO won't make any difference in sound quality.
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