using Holco?
The spacing on the board is .4 inch and Holco 1/4 w are kinda fragile about tight bends on their end caps, so there is a possiblity there is one resistor damaged. check the IV and Vref R for value. The Vref and both IV most be to spec and the values I sent, any substitution will likely not perform properly. There is about a 30 ohm range for lowest distortion on the Vref above or below the spec'd value. 2.49 needs 1.37
The spacing on the board is .4 inch and Holco 1/4 w are kinda fragile about tight bends on their end caps, so there is a possiblity there is one resistor damaged. check the IV and Vref R for value. The Vref and both IV most be to spec and the values I sent, any substitution will likely not perform properly. There is about a 30 ohm range for lowest distortion on the Vref above or below the spec'd value. 2.49 needs 1.37
I have built a DacKit, and it sounds extremely good, regardless of price. When building the kit I noticed that the kit used a bare wire to connect two points under the receiver. If you use this bare wire, check that it does not make a short with some of the traces it crosses. It is extremly close to some of them!!
Thanks!!!!
Hi Scott, Bequerel,
Thanks!! This will give me some more ideas to check when I get my hands on my DACKit tomorrow.
I'll check the single wire link (which was the first item to be installed) the best I can, as it's under the receiver, but I will measure the resistance to see if there is a dry joint. Likewise the resisitors. My plan is to select the next point downstream / upstream from each lead so I am checking the integrity of both the solder joints as well as whether there is any lead damage.
I did use a mix of Holco H8s and RC55Ys. Although I used a lead forming tool to try and bend the leads once (and quite near to the resistor body), on more than one occasion I had to redo the bend (I wanted the markings all facing up - a little sad, eh!
).
Finally, I will double check that the IV and VRef Resistors are 2.49 and 1.37. I did order these parts specifically from Farnells after a bit of a supply hiccup, but, like all the resistors, I trusted that they did what they said on the body!!!
I'll get my multimeter!!
Thanks very much - Although it's been a bit of a challenge, I am learning a vast amount about this hobby from only one project!!!
Cheers
Jon
Hi Scott, Bequerel,
Thanks!! This will give me some more ideas to check when I get my hands on my DACKit tomorrow.
I'll check the single wire link (which was the first item to be installed) the best I can, as it's under the receiver, but I will measure the resistance to see if there is a dry joint. Likewise the resisitors. My plan is to select the next point downstream / upstream from each lead so I am checking the integrity of both the solder joints as well as whether there is any lead damage.
I did use a mix of Holco H8s and RC55Ys. Although I used a lead forming tool to try and bend the leads once (and quite near to the resistor body), on more than one occasion I had to redo the bend (I wanted the markings all facing up - a little sad, eh!
).Finally, I will double check that the IV and VRef Resistors are 2.49 and 1.37. I did order these parts specifically from Farnells after a bit of a supply hiccup, but, like all the resistors, I trusted that they did what they said on the body!!!
I'll get my multimeter!!
Thanks very much - Although it's been a bit of a challenge, I am learning a vast amount about this hobby from only one project!!!
Cheers
Jon
Schematics
A very similar DAC scema is available at
http://www.geocities.com/rjm003.geo/rjmaudio/diy_dac.html
HTH
Jon
A very similar DAC scema is available at
http://www.geocities.com/rjm003.geo/rjmaudio/diy_dac.html
HTH
Jon
Success!!!
Scott, JP, Bequerel,
well, all advice taken and acted upon.
Success!!!
It was a dodgy joint on the 1.37K VRef resistor. I was measuring across the components to check the values, then from the next point along the circuit to check the joints. The 2.49K parts were testing fine with the negative probe on the ground track. The 1.37 wouldn't register. A quick bit of work with the Soldamop (and it was horrible stuff I mopped up!! ) and then a resolder with the Draper 60/40 (I started off trying to use the silver loaded stuff - I will use it on the gold connectors and silver wire in future, but not on the main board - What a PITA!! ).
Multimeter read spot on!! Plugged the bare board in and, hurrah!, it works!
Interestingly, the output is so powerful that the Arcam only needs to be cracked-open to get a decent sound. There was a bit of background hiss, but selecting "direct" to bypass the tone controls sorted most of this out.
Well, as you can guess, I am really pleased with the result.
A big thank you for all the advice and support. Especially to Scott who was generous with his advice even before I had started the project.
Well, eveyone is going to get a big surprise tomorrow!!
Thanks again!!
Jon
Scott, JP, Bequerel,
well, all advice taken and acted upon.
Success!!!
It was a dodgy joint on the 1.37K VRef resistor. I was measuring across the components to check the values, then from the next point along the circuit to check the joints. The 2.49K parts were testing fine with the negative probe on the ground track. The 1.37 wouldn't register. A quick bit of work with the Soldamop (and it was horrible stuff I mopped up!!
) and then a resolder with the Draper 60/40 (I started off trying to use the silver loaded stuff - I will use it on the gold connectors and silver wire in future, but not on the main board - What a PITA!! ).Multimeter read spot on!!
Plugged the bare board in and, hurrah!, it works! Interestingly, the output is so powerful that the Arcam only needs to be cracked-open to get a decent sound. There was a bit of background hiss, but selecting "direct" to bypass the tone controls sorted most of this out.
Well, as you can guess, I am really pleased with the result.
A big thank you for all the advice and support. Especially to Scott who was generous with his advice even before I had started the project.
Well, eveyone is going to get a big surprise tomorrow!!
Thanks again!!
Jon
Attachments
DacKit Sound
Hi Andrea,
First listening seems to be fast, but with more emphasis on the mids and lows than I was expecting. The deatail is there, but is more in the background than the foreground. The soundstage does seem deep and well-defined. Of course, there is plenty of running in to do, and I expect the sound to change through the process. We'll be conducting some AB testing when it has had a chance to settle down. The output level appeared to be very high at first - had the amp turned way down for a quiet-ish volume - but this has now settled down.
There is a background hiss that was very much attenuated when I defeated the tone controls on the Arcam amp (with the "Direct" switch). Overall, it sounds very nice and I am combing the CD collection for some decent recordings to try out (it's amazing how poor some production is nowadays!!)
I am delighted that I can top up the battery using the CSI Airflow battery conditioner I used to use when I had an old classic car. This has been sat in the box for a couple of years and now has a decent job to do (thank goodnes - it wasn't cheap!!).
The bottom line is that this has been a really SUCCESSFUL project. I have had plenty of questions along the way, and a problem to solve that was caused by my inexperience with a soldering iron!! The good news is that the DAC is working well, but the best news was that I have learned a whole load of stuff in the process!!!
I recommend the DacKit if you haven't built one already!
Cheers
Jon
Hi Andrea,
First listening seems to be fast, but with more emphasis on the mids and lows than I was expecting. The deatail is there, but is more in the background than the foreground. The soundstage does seem deep and well-defined. Of course, there is plenty of running in to do, and I expect the sound to change through the process. We'll be conducting some AB testing when it has had a chance to settle down. The output level appeared to be very high at first - had the amp turned way down for a quiet-ish volume - but this has now settled down.
There is a background hiss that was very much attenuated when I defeated the tone controls on the Arcam amp (with the "Direct" switch). Overall, it sounds very nice
and I am combing the CD collection for some decent recordings to try out (it's amazing how poor some production is nowadays!!) I am delighted that I can top up the battery using the CSI Airflow battery conditioner I used to use when I had an old classic car. This has been sat in the box for a couple of years and now has a decent job to do (thank goodnes - it wasn't cheap!!).
The bottom line is that this has been a really SUCCESSFUL project. I have had plenty of questions along the way, and a problem to solve that was caused by my inexperience with a soldering iron!!
The good news is that the DAC is working well, but the best news was that I have learned a whole load of stuff in the process!!! I recommend the DacKit if you haven't built one already!
Cheers
Jon
Re: DacKit Sound
Well, the "background" detail is about the same impression I had with mine (I've actually built one, based on Doede's DDDAC).
For now I only tested it at 7.5V but I expect things to change playing with Vcc...
Cheers
Andrea
jonclancy said:Hi Andrea,
First listening seems to be fast, but with more emphasis on the mids and lows than I was expecting. The deatail is there, but is more in the background than the foreground. The soundstage does seem deep and well-defined. Of course, there is plenty of running in to do, and I expect the sound to change through the process.
--zip--
I recommend the DacKit if you haven't built one already!
Cheers
Jon
Well, the "background" detail is about the same impression I had with mine (I've actually built one, based on Doede's DDDAC).
For now I only tested it at 7.5V but I expect things to change playing with Vcc...
Cheers
Andrea
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