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DAC Kit - what else do I need? #2

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thanks martin.

in that case i've got 4.8V ish. what do i need to do to get 3.3V? i must admit i'm painting by number a bit. Rich might be able to shed some light. He set it up for 3.3 uae before he sent it, all i had to do was install the 1.2k and 820 ohm resistors. have i missed a step? i've had a good look through the fle manual and can see these two resistors control the output value. I can do the math, is it as simple using any two values thatgjve the correct multiplier? or does one of them need ti be a set value? or am i missing somthing else?

got a mate coming for a dac off on friday so want it all working!

Rich, any chance you might get a moment to desolder those boosters?

ta
 
in that case i've got 4.8V ish. what do i need to do to get 3.3V? i must admit i'm painting by number a bit. Rich might be able to shed some light. He set it up for 3.3 uae before he sent it, all i had to do was install the 1.2k and 820 ohm resistors. have i missed a step? i've had a good look through the fle manual and can see these two resistors control the output value. I can do the math, is it as simple using any two values thatgjve the correct multiplier? or does one of them need ti be a set value? or am i missing somthing else?
ta

Your using just one green led?
You got the resistors the right way around, off the top of my head 1.2K / 820R will give about 3V3 or 5V0 depending on wich way around they are, asuming your using a single green led.

You got a picture?

Tony
 
Your using just one green led?
You got the resistors the right way around, off the top of my head 1.2K / 820R will give about 3V3 or 5V0 depending on wich way around they are, asuming your using a single green led.

You got a picture?

Tony

Not near a camera at the moment but what you are saying makes sense. Just one green LED, I had discovered that I could just use 2 IN4007 diodes in series instead of this to give me the correct multiplier, but what you say about the resistors makes total sense, can't figure out why I didn't see it when I was messing with different values in the equation last might. Oh well.

I have them as per the circuit diagram in the flea manual at the moment ( 1k2 connected to L1 and k820 to the ground plane. Swapping them will give me the 3.3 (well 3.28)

Thanks!! I'll try this and if it doesn't work i'll do the picture and see what you think.

Stefan
 
Not near a camera at the moment but what you are saying makes sense. Just one green LED, I had discovered that I could just use 2 IN4007 diodes in series instead of this to give me the correct multiplier, but what you say about the resistors makes total sense, can't figure out why I didn't see it when I was messing with different values in the equation last might. Oh well.

I have them as per the circuit diagram in the flea manual at the moment ( 1k2 connected to L1 and k820 to the ground plane. Swapping them will give me the 3.3 (well 3.28)

Thanks!! I'll try this and if it doesn't work i'll do the picture and see what you think.

Stefan

It does get all a little too confusing at times, its often easy for an on looker :)


IN4007 is a noisy bugger, better with an led.

Once you have it working you could search out the double red led flea bodge in this thread which works great for 3v3 on the flea and allows the feedback resistor chain and capacitor to be removed for perhaps a little more finess. One of Martins little tweaks

tONY
 
great, got 3.28 v. i'll get the teddy regs finished tommorrow and assuming they work a couple of days to put it together before a weekend dac off!

Rich any chance of the boosters?
 
Got one of the STR's done and working ok, i'll finish off the other one tonight and hopefully start putting it all back together. Starting to get excited!
 
hmm, strange one this. I've hooked up the 2 str's to the generic rectifier and they both work, small sigh of relief! but the LED on the +ve one only lights very dimmly, I had tested this board when Rich first sent it and the LED was as you would expect. Should I worry about it or not? As I said the output of the reg is where I want it. Thoughts pls.

Stefan
 
Help!!

Got a big problem, I tested the STR's hooked up to the generic rectifier and they were just fine. Voltages exactly where i expected them to be.

This evening I put it all in the box and connected it to the DAC. The traffo now only puts out 3 ish V and gets very hot. What has gone wrong? What things do I need to test?

Looks like my DAC off on Friday night is off!!

Stefan
 
I notice that Gigaworks are offering the kit again, with a DIR9001 as standard.

Guess their plan to market the DAC as a complete finished unit didn't fly.
 
Help!!

Got a big problem, I tested the STR's hooked up to the generic rectifier and they were just fine. Voltages exactly where i expected them to be.

This evening I put it all in the box and connected it to the DAC. The traffo now only puts out 3 ish V and gets very hot. What has gone wrong? What things do I need to test?

Looks like my DAC off on Friday night is off!!

Stefan

Stefan,
could be a short circuit or perhaps a shorted turn if your trafo is a toroid.

Place your components on some cardboard or some other insulator and try again.

Regards
fs
 
It was weeks ago I posted my problem, all my fellow gigadac bodgers have defected to the buffalo! I've not touched it since I posted, got a little disheartened. I'll come back to it tonight I think. It's an r core traffo, can they get shorted turns?

Sent from my Desire HD using Tapatalk
 
Ah, sorted it. The power transistors weren't properly insulated from the case! The metal work on a couple of the holes was a bit burred and was cutting through the insulation material. Should have checked the continuity before I powered up. Live and learn I suppose. Still there seems to be no other damage so i'll put it back together tomorrow and see how it sounds.

Sent from my Desire HD using Tapatalk
 
Great, got it working. There is definitely more detail now and transient are faster with less distortion on the leading edge of guitar picks. There is more 'blackness'. Not sure it hasn't lost some drive though. Will have to listen a bit more........Thanks for all the help so far guys, hope you're all enjoying your new buffalo's.

Stefan
 
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