MANY thanks for running those numbers for me Bill - greatly appreciated. Have to say as a layman in electronic theory (I'm no more than an experienced 'solder by numbers' enthusiast really) all those terms and number crunching seem like some kind of magic/secret art to me haha! I'm glad there are people on here who are willing to help the electrically uneducated 
I'll get those parts ordered and report back.
Thanks again!
P.S. Just to confirm that's a 47nF cap you're talking about for the primary? Ta
I'll get those parts ordered and report back.
Thanks again!
P.S. Just to confirm that's a 47nF cap you're talking about for the primary? Ta
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Well I connected up the Digitec transformers today, and I am getting (potentially) great sound, but with barely ANY bass
The wires to the transformers come direct from the AK4396 (the chip AK4393 was professionally replaced for me).
On each primary are 10R resistors, with a 0.047uF cap between the + and - points.
On each secondary is a 1K resistor/1n2 cap between the + and - points (The 'Jensen filter').
Anyone any idea where this bass has gone to?
Mucho thanks
- John
The wires to the transformers come direct from the AK4396 (the chip AK4393 was professionally replaced for me).
On each primary are 10R resistors, with a 0.047uF cap between the + and - points.
On each secondary is a 1K resistor/1n2 cap between the + and - points (The 'Jensen filter').
Anyone any idea where this bass has gone to?
Mucho thanks
- John
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Removed the primary filter - had a listen. Then the secondary filter - same in each instance: still no bass.
I guess that leaves those 10R loading resistors or - worse - the AK4396 chip is either damaged in some way, or isn't capable of driving the Digitecs perhaps?
Any suggestions would be gratefully received
- John
I guess that leaves those 10R loading resistors or - worse - the AK4396 chip is either damaged in some way, or isn't capable of driving the Digitecs perhaps?
Any suggestions would be gratefully received
- John
Try caps
As a simple test, take everything off and install some good 2.2uf - 3.3uf caps to couple the signal straight out. I run mine direct out into 4k stepped attenuators with the best sonics of everything I have ever tried as a source so there is no problem with any normal load. Try that and if it doesn't provide some of the best digital sound you have ever heard, then something is definitely wrong with your chip or supply. The AKM chips are very fragile to heat when replacing.Removed the primary filter - had a listen. Then the secondary filter - same in each instance: still no bass.
I guess that leaves those 10R loading resistors or - worse - the AK4396 chip is either damaged in some way, or isn't capable of driving the Digitecs perhaps?
Any suggestions would be gratefully received
- John
Thanks for your reply
So I just connect each L + & R + wire to the caps then to the outputs, and what about the - wires from the DAC?
Do I need to connect together the minus and ground pins on the output XLR sockets if I do this?
I really hope the chip isn't broken I did get a professional to do it. I was also extremely careful when soldering the wires to the pads vacated by the 11k resistor group.
The sound isn't distorted at all, just no bass at all, and fairly quiet. Tried the output transformers with no filters and still the same.
Once I know what to do with the - wires from DAC I shall try the caps.
Thanks,
John
So I just connect each L + & R + wire to the caps then to the outputs, and what about the - wires from the DAC?
Do I need to connect together the minus and ground pins on the output XLR sockets if I do this?
I really hope the chip isn't broken I did get a professional to do it. I was also extremely careful when soldering the wires to the pads vacated by the 11k resistor group.
The sound isn't distorted at all, just no bass at all, and fairly quiet. Tried the output transformers with no filters and still the same.
Once I know what to do with the - wires from DAC I shall try the caps.
Thanks,
John
Rca
Is your volume control RCA in, single ended? If so, to make this test easiest, just cap couple the left and right + output of the dac chip to the center pins, take the original audio ground and then just leave the minus leg floating open for now.Thanks for your reply
So I just connect each L + & R + wire to the caps then to the outputs, and what about the - wires from the DAC?
Do I need to connect together the minus and ground pins on the output XLR sockets if I do this?
I really hope the chip isn't broken I did get a professional to do it. I was also extremely careful when soldering the wires to the pads vacated by the 11k resistor group.
The sound isn't distorted at all, just no bass at all, and fairly quiet. Tried the output transformers with no filters and still the same.
Once I know what to do with the - wires from DAC I shall try the caps.
Thanks,
John
Hey Sendler it works!!! Just running the outputs through a pair of fairly cheap SoniQs 4.7uF caps. Doesn't sound too bad actually!
Thanks for that suggestion
When I had the thing apart again I checked continuity of all the wires I soldered onto the vacant 11k resistor group pads to the DAC legs and all was fine, no shorts.
I guess this means for some reason the AK4396 doesn't like driving the Digitec transformers? Or could the chip still be partially damaged? I really would prefer to use output transformers at some point, but I guess the Digitecs are out. I'd still like to try and figure out why it didn't work well - I hate mysteries
Thanks again,
- John
Just running the outputs through a pair of fairly cheap SoniQs 4.7uF caps. Doesn't sound too bad actually!Thanks for that suggestion
When I had the thing apart again I checked continuity of all the wires I soldered onto the vacant 11k resistor group pads to the DAC legs and all was fine, no shorts.
I guess this means for some reason the AK4396 doesn't like driving the Digitec transformers? Or could the chip still be partially damaged? I really would prefer to use output transformers at some point, but I guess the Digitecs are out. I'd still like to try and figure out why it didn't work well - I hate mysteries
Thanks again,
- John
Input
What is the input impedance of the transformers?
Hey Sendler it works!!!
Thanks for that suggestion
When I had the thing apart again I checked continuity of all the wires I soldered onto the vacant 11k resistor group pads to the DAC legs and all was fine, no shorts.
I guess this means for some reason the AK4396 doesn't like driving the Digitec transformers? Or could the chip still be partially damaged? I really would prefer to use output transformers at some point, but I guess the Digitecs are out. I'd still like to try and figure out why it didn't work well - I hate mysteries
Thanks again,
- John
What is the input impedance of the transformers?
Unfortunately I do not know any details, and are something of a mystery in that regard. They were obtained from Franz in this thread (Post 278 onwards):
http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac-28.html
They worked fine with the CS4398 DAC. Odd.
http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac-28.html
They worked fine with the CS4398 DAC. Odd.
Transformers
Pano had some nice O-Netics transformers for sale if you wanted to give up on the junk bin trannies and go right to the best.
.
http://www.diyaudio.com/forums/swap-meet/161380-fs-dac-output-transformers-onectics.html#post2086571
.
I would also order 3uf worth of Dayton foil caps or Obbligato caps to compare.
If you know that your volume control already has a cap on the input, you don't need another cap or a transformer. You can send the signal out from one leg of the dac chip with nothing blocking it.
Another great option that becomes feasible with the reduced level of running direct is to eliminate the volume control and connect the dac chip straight to the amps using digital volume control. With my amps gain optimized for my speakers, this provides the best sonics by far and I haven't even changed my laptop to an ASIO player yet.
Pano had some nice O-Netics transformers for sale if you wanted to give up on the junk bin trannies and go right to the best.
.
http://www.diyaudio.com/forums/swap-meet/161380-fs-dac-output-transformers-onectics.html#post2086571
.
I would also order 3uf worth of Dayton foil caps or Obbligato caps to compare.
If you know that your volume control already has a cap on the input, you don't need another cap or a transformer. You can send the signal out from one leg of the dac chip with nothing blocking it.
Another great option that becomes feasible with the reduced level of running direct is to eliminate the volume control and connect the dac chip straight to the amps using digital volume control. With my amps gain optimized for my speakers, this provides the best sonics by far and I haven't even changed my laptop to an ASIO player yet.
Unfortuntely I cannot afford any new transformers at the momoment. I do have a pair of UTC-A20s, but they're being used with the Gigaworks 24/192 CS4398 DAC at the moment, and are too big to fit inside the Behringer's chassis anyway.
I may do as you say and try some different caps. Whilst sounding fairly good at the moment it's sounding nowhere near as good as the CS4398 with those UTC output trannies at the moment. At present I cannot see what all the fuss is about this DAC. Perhaps it sounds better as it burns in? Only had 2-3 hours on it so far.
Bill: Interesting - I would try that but whipped out the trannies yesterday to try the caps. I only have a finite amount times I can solder/desolder the extremely fine connecting wires too they're so delicate and break easily. Also I don't want to risk unsoldering/resoldering to the pads near the DAC chip as it's apparently extremely easy to heat damage. I'll see how I go with the caps, and if still not 100% happy I'll give the trannies a go with the 500R resistors for loading. Just wish I could find some solid information on the Digitecs. All I really know is that they're 1:1 and that's it really. Perhaps I should just use the caps for the time being, then get some Lundahls at a later date which - from what I have seen - definately work with the AK4396 DAC, not to mention they're a known design.
Cheers,
- John
I may do as you say and try some different caps. Whilst sounding fairly good at the moment it's sounding nowhere near as good as the CS4398 with those UTC output trannies at the moment. At present I cannot see what all the fuss is about this DAC. Perhaps it sounds better as it burns in? Only had 2-3 hours on it so far.
Bill: Interesting - I would try that but whipped out the trannies yesterday to try the caps. I only have a finite amount times I can solder/desolder the extremely fine connecting wires too they're so delicate and break easily. Also I don't want to risk unsoldering/resoldering to the pads near the DAC chip as it's apparently extremely easy to heat damage. I'll see how I go with the caps, and if still not 100% happy I'll give the trannies a go with the 500R resistors for loading. Just wish I could find some solid information on the Digitecs. All I really know is that they're 1:1 and that's it really. Perhaps I should just use the caps for the time being, then get some Lundahls at a later date which - from what I have seen - definately work with the AK4396 DAC, not to mention they're a known design.
Cheers,
- John
Cs4398
That's interesting. I will have to try something with the CS4398. Are you using the same digital source and cable for the comparison?
That's interesting. I will have to try something with the CS4398. Are you using the same digital source and cable for the comparison?
Yes absolutely, exactly the same components.
At the moment it sounds "OK" - but there's no emotion/passion coming through in the music. It doesn't make me want to listen. Sounds a little 'black and white' if that makes sense?
The SoniQ caps I am using at DAC output are not 'the best', but they're certainly not bad by any means. All I can think of is it just needs more burning in time.
At present I actually preferred the original AK4393 with stock output stage.
At the moment it sounds "OK" - but there's no emotion/passion coming through in the music. It doesn't make me want to listen. Sounds a little 'black and white' if that makes sense?
The SoniQ caps I am using at DAC output are not 'the best', but they're certainly not bad by any means. All I can think of is it just needs more burning in time.
At present I actually preferred the original AK4393 with stock output stage.
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I use the A20s with the Jensen setup which I think is 249R on each leg of the primaries from memory, but this is with the CS4398 Gigaworks DAC. Seems to work very nicely indeed. I wouldn't be able to use those in the Behringer as they're far too big. The Digitecs fitted perfectly.
Do you reckon those Digitecs might work OK with a 500R on each primary then? Perhaps I'll try that tomorrow as I really don't like how it sounds at the moment. Curiously uninvolving sound. If you move your head slightly away from the speakers 'line of sight' it very quickly sounds sort of 'hollow' or 'out of phase' sounding too. Odd sound to describe. Perhaps 'sat upon' is a better description. Perhaps the AK4396 needs both of its outputs used for best sound, rather than just the + through a pair of caps? It certainly does NOT sound like the 'Miracle DAC' it's cracked up to be at present.
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