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DAC-ASH (dac-end 2 up date)

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#341
I also have a AN DAC2.1 kit before, the DAC broad have no jumper, and without any filter network, only have a IV resistor parallel with a 820pF cap directly connected to the AD1865N current output!
I think you should shorted the pin1-2 to get out of phase.
Which IV trans you used? AN or sowter?
If the DAC ASH compare to the AN DAC2.1 kit, I found that the DAC2.1 better than the DAC ASH, I think the secret is the IV trans used in DAC2.1!
Actually we can build the clone AN's DAC with the DAC ASH digital broad, I have the 2.1B or 2.1C schematic, also have the PCB of the power supply and the linestage of the AN kit too, so it is very easy to setup.
 
#342
Oh no! You think the AN DAC 2.1 sounds better. I'm downgrading? 😱

I'm using Jensen transformers. I've been bugging Peter at AN for good I/V's for years and could never connect with him. The Jensen's sound pretty good and are at a good price.

I've screwed around with the AN board for many years and it always sounds better and more natural than other dacs I've had. I run my own output tube section that's choke loaded. So the only thing left of the AN was the board itself. As ancient as they are the AN dacs always sound natural.
 
#343
I feel that the AN's kit DAC2.1B have a more wide open sound and sure a deeper bass, I think the tube regulation of the DAC2.1 make them have a smooth and netutal sound!
Yes you can source the AN's IV trans from HiFiCollective or even the Parts Connexion, no need to contact Peter!
 
#344
Are you using the same tube stage and I/V trans as the AN? I'm not using the I/V board nor the tube stage from this project. Just the board.

I know. But Peter promised me so nice silver I/Vs that he's been holding for me. Otherwise unaffordable.
 
#347
ben-jam-in said:
lucylu,

Let us do the heater circuit seperately from the HV circuit. So un-hook the HV supply from the board and cap off the wires for now.
If you have soldered a wire to connect the point marked +F to +6.3 undo it. (This jumper connects power from the heater power supply part of the circuit to the actual tube heaters and the relay) First you want to subsitute a load for the filament heaters, to check the circuit is working properly and adjust the voltage with the trim pot to 6.3v. When you have both the heating functioning and the HV circuit functioning you will connect +F to +6.3, and put the tubes in.

I am using the 6h30pi tubes. I connected 3, 1R2/10W resistors in series for a total of 3.6 ohms. Connect one end of the resistors to +F and the other to the point marked GND, on the tube side of the R32 resistor. This will substitute a load for testing. power it up and adjust the voltage to 6.3v. Be careful your load resistors may get hot, and be careful your LT1084 and heatsink may overheat. ( you mentioned your supply voltage was over 9v, check it again with the load, because it may be to high, the LT1084 will get very hot). Power it down and let it cool if things get hot between tests if you have to.

see post #1032 in the OLD THREAD DAC end. There is also a lot of other useful info in that thread.

Ben
Click to expand...

Ben That all sounds easy and i understand no problem,will get resistors in a day or so .After that and i asume hv is ok or not ? as i checked volts with tubes in the other day. i could power up both and fingers crossed

Thanks john
 
#354
Any member in the U.S. with a scope that would be wiling to let me send them this board? I spent all weekend with it and honestly cannot find the problem without a scope.

I've built many Audio Note digital boards and never had this issue so hopefully its something very simple that a scope will show. Please PM me if you are willing to spread some holiday cheer by helping a member. 😀
 
#357
Yes, Quanghao offered to fix it. But that means a couple months. Vietnam mail is very slow. This is my main dac so I would have to rebuild the old one while I waited.

Better to get any advice or best if someone in the U.S. would lend a hand.
 
#358
Hi phrarod,

I've checked all the voltages per pin for you today, found some different from yours.
For CS8414
pin 1 0.027V; pin2 0V; pin3 0V; pin4 4.998V; pin5 4.998V; pin6 4.998V; pin7 4.998V;
pin8 0V; pin9 1.658V; pin10 1.661V; pin11; 2.498V; pin12 2.448V; pin13 0V; pin14 0V; pin15 0.833V; pin16 0V; pin17 0V; pin18 4.998V; pin19 2.277V; pin20 0.583V; pin21 0V; pin22 4.998V; pin23 0V; pin24 4.998V; pin25 0V; pin26 0.305V; pin27 0V; pin28 0V

For 74HC04
pin1 2.498V; pin2 2.514V; pin3 0V; pin4 5.028; pin5 0V; pin6 5.028V; pin7 0V
pin8 5.028V; pin9 0V; pin10 5.028V; pin11 0V; pin12 5.028V; pin13 0V; pin14 5.028V

For AD1865N-K
pin1 -5.038V; pin2 -1.232V; pin3 -3.828V; pin4 -0.002; pin5 0V; pin6 0V; pin7 -0.002V
pin8 -3.595V; pin9 5.028V; pin10 0V; pin11 2.513V; pin 12 2.447V; pin13 0V; pin14 2.5V
pin15 0V; pin16 0V; pin17 4.615V; pin18 0V; pin19 0V; pin20 0V; pin21 0V;
pin22 -3.827V; pin23 -1.251V; pin24 5.082V
 
#359
Hi la1209! I really appreciate all your help. Receiver looks ok BUT the 74H looks much different. Pin 6, Pin 8, Pin 9, pin 12 on yours is all 5vdc. While I do not have that.

Are you sure about pin 17 of the 1865 being positive voltage?

Other than that it looks like there's a problem at the 74H chip. I swapped out chips as I have a couple. These are hard to blow. Could it be something on the board or PSU?

Guys?
 
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