The filter "feeds" 3 lm317, thru a 3300µF on the board
The underside wiring is to connect // lm317 5v regs
The center lm317 has the "hardest" job to do, it provides the analogue power to the dac.
A 22µF tantal decoupling Radj is underside , and 2 x 140µF // at the output, to lower impedance. Special care to tantalum cap with polarity !!!
R.C.
The underside wiring is to connect // lm317 5v regs
The center lm317 has the "hardest" job to do, it provides the analogue power to the dac.
A 22µF tantal decoupling Radj is underside , and 2 x 140µF // at the output, to lower impedance. Special care to tantalum cap with polarity !!!
R.C.
For me the best improvement is when you listen to small jazz band , more details appears, bass strings vibrations , cymbals ..
I think mods really worth, I've tried to minimize "pricey" components, even if Solid Tantalum are not cheap, but in "another world" for decoupling (recommanded in lm317 datasheet).
Another step would be to build one independant Shunt PSU, feeding Dac Analog Vcc ...and to buy a pair Jensen JT11P1
R.C.
I have both the "big" one and the smd version and I'd like to test the trannies mod.
Once done, is it possible to connect the DAC directly to an amp or a pre-amp is definitely needed?
If possible, what type of pot shoudl I use? 10k? 50K? 100K?
Is there any other mod suggested beside the tranni on the digital input? Any cap replacement (os-con or so) in the digital supply?
Once done, is it possible to connect the DAC directly to an amp or a pre-amp is definitely needed?
If possible, what type of pot shoudl I use? 10k? 50K? 100K?
Is there any other mod suggested beside the tranni on the digital input? Any cap replacement (os-con or so) in the digital supply?
As far as mods, the field is wide open. Some are just getting around to PS mods.
As far as the output level and interfacing, if low impedence (600ohm) output trafos are used, a 10k pot will work fine. If 10k trafos are used then you might have trouble using any pot, your amp input impedence must be very high, such as a tube amp or jfet front end. In any case, use short interconnects, there isn't a lot of current available.
As far as the output level and interfacing, if low impedence (600ohm) output trafos are used, a 10k pot will work fine. If 10k trafos are used then you might have trouble using any pot, your amp input impedence must be very high, such as a tube amp or jfet front end. In any case, use short interconnects, there isn't a lot of current available.
The filter mod looks interesting....Thanks Ciu
1. there's one reservoir cap on the main board...are you doing that purposely?
2. I found few TIP122 in Farnell pretty much the same in parameter...can you tell me the one that used here...?
3. Since rectification done in a new mini board, do we need to remove the old N4007 diode on the big board or just leave it there..??
4. Is the tantalum the best??? How bout poly caps...?? lytic..???
5. Any picture of wiring on the underside of the big boards (filter // lm317 5v regs) ?
Hello
Just have a look to Posts #2218 and #2219
May be, you would get answers.
Tantalum are recommanded by Texas, LT, for a better impedance to high frequencies (CF. lm317 datasheet) . I've followed these recommandations.
Try to find a small dimensions 280µF poly cap, I'm interested...
R.C.
Is there a PS I can get from digikey (Hammond?) that would be very similar to the kit PS in how it is implemented? It would be cheaper (and maybe better?) than getting the kit PS by quite a bit (for me at least, $20).
I have been emailing with Bill, but I just don't understand much. I was going to try using a Hammond 229 series split bobbin, but is looks like it will take some additional circuits to make it work right. I don't know how to make stuff up like that. I need it spelled out. I need to just get started with something. Not interested in mods yet.
Would a Hammond 166 be a more direct swap?
I have been emailing with Bill, but I just don't understand much. I was going to try using a Hammond 229 series split bobbin, but is looks like it will take some additional circuits to make it work right. I don't know how to make stuff up like that. I need it spelled out. I need to just get started with something. Not interested in mods yet.
Would a Hammond 166 be a more direct swap?
I am truly sorry that you aren't able to follow my advice. There has to be a basic knowledge level of electricity to begin changing things. I recommended that you purchase the power transformer with the dac board because of your knowledge level. It was not meant in a denigrating way, just realistic. Small steps. Use GOOGLE, Wikipedia, learn.
Best, Bill
Best, Bill
And I'm not trying to be annoying, just frustrated. Trying to be frugal and learn at the same time.
Well, here is the main problem with using a single 15-0-15 trafo. 15vac rectified to dc is about 21vdc, the digital regulator circuits are 5v so they have to get rid of 16vdc at whatever amount of current is passed through the regulators. If it is 500ma then the excess power is 8watts, and I don't know if the heat sinks are big enough to comfortably handle that. You will have to try it, and if they get too hot you will have to either use a smaller voltage trafo, use another preregulator circuit to cut the voltage down to 10v or so before the board connection, or use a fan, or put bigger heatsinks on the regs. It's not a good idea to start with, digital and analog circuits should not be powered by the same windings. Digital circuits are loaded with noise. It is a compromise that is not necessary, when you can get another trafo for the digital section at Radio Shack for 10 bucks.
Best, Bill
Best, Bill
Hi all
I am experiencing a problem with my DAC's left channel output. It is considerably lower than the right channel. There is faint music coming through together with a faint hum. It was working fine a while ago but I have been away and not used it for a while.
I am using UTC A-20 output transformers which seem to be ok. The problem occurs if I use the transformer RCA's or direct from the PCB RCA's via the op-amps so it seems the fault is with the DAC chip (CS4398) ? Does this sound likely?
Sound is provided via the on board S/PDIF connection on my PC motherboard.
Has anyone else had problems like this? Any advice would be greatly appreciated.
Thanks
Rich
I am experiencing a problem with my DAC's left channel output. It is considerably lower than the right channel. There is faint music coming through together with a faint hum. It was working fine a while ago but I have been away and not used it for a while.
I am using UTC A-20 output transformers which seem to be ok. The problem occurs if I use the transformer RCA's or direct from the PCB RCA's via the op-amps so it seems the fault is with the DAC chip (CS4398) ? Does this sound likely?
Sound is provided via the on board S/PDIF connection on my PC motherboard.
Has anyone else had problems like this? Any advice would be greatly appreciated.
Thanks
Rich
Hi Rich,
It really isn't likely, but anything is possible. Are you sure you have eliminated the other possibilities, such as a bad interconnect. Have you swapped the cables at the preamp. Check all your solder jobs and use your meter to make sure you have continuity from the chip output pins to the resistors on the board that feed the signal to the opamps. The board traces are not very robust and can be easily damaged. If you are not using resistors in line with the trafos primaries you possibly could have damaged the 4398.
It really isn't likely, but anything is possible. Are you sure you have eliminated the other possibilities, such as a bad interconnect. Have you swapped the cables at the preamp. Check all your solder jobs and use your meter to make sure you have continuity from the chip output pins to the resistors on the board that feed the signal to the opamps. The board traces are not very robust and can be easily damaged. If you are not using resistors in line with the trafos primaries you possibly could have damaged the 4398.
Thanks Bill, will check for continuity tonight.
I have Riken 510 ohm resistors in line with primaries with 1nf polyester caps across and 1.2k resistor with 1nf across secondaries. I was going to play with changing to Kiwame but will need to sort this out now!
I swapped amplifiers and amp connects and the problem is certainly with the source. unfortunately I do not have another 75ohm S/PDIF lead and have no other S/PDIF source (soundcard) other than the PC motherboard so cannot rule these out yet.
I'm thinking that at some point the primary leads from left and right channel that are attached to the board must have touched while powered up causing a short?
Shame as I have just recieved my Modushop cases and was ready to finish the job.
I have Riken 510 ohm resistors in line with primaries with 1nf polyester caps across and 1.2k resistor with 1nf across secondaries. I was going to play with changing to Kiwame but will need to sort this out now!
I swapped amplifiers and amp connects and the problem is certainly with the source. unfortunately I do not have another 75ohm S/PDIF lead and have no other S/PDIF source (soundcard) other than the PC motherboard so cannot rule these out yet.
I'm thinking that at some point the primary leads from left and right channel that are attached to the board must have touched while powered up causing a short?
Shame as I have just recieved my Modushop cases and was ready to finish the job.
Just tried it with a CD player and the problem is still there. So I think I have fried the DAC chip.
I have contacted Ian Ma and will get another CS4398 chip board and might get a DIR9001 while I'm there! $30 for a new DAC isn't too bad.
Does anybody know how much he charges for the DIR9001 board?
Need to be more careful...
I have contacted Ian Ma and will get another CS4398 chip board and might get a DIR9001 while I'm there! $30 for a new DAC isn't too bad.
Does anybody know how much he charges for the DIR9001 board?
Need to be more careful...
Actually I tried the USB awhile ago and couldn't get it to work. So I gave up and left it as I was more than happy with the S/pdif.
I remember reading that the selection jumpers on the PCB are not correct according to the manual.
Could someone give me a run down on configuring the USB input correctly?
Many thanks
Rich