GUSTARD DAC-R26 Balanced Decoder R2R+1Bit Dual Native Decoding Music Bridge

[rodthebod]

not heard about twisting power cables before, think I'll keep that for signal cables

further mods

removed clock and bluetooth cables, wonder if clock cable was acting as an antenna as removal made a difference and those adding an external clock say the right cable is important

also removed the optical connection, something we did to the squeezebox touch as it just creates noise, just picked away at it with pliers until it was gone leaving 3 connections on the board, which I snipped

swapped the 2 white mains power connectors which means the wires for the transformers are no longer crossing and the transformers can be fully separate and further away from each other. Removed the metal screen plate to allow the dc cables to remain separate, think there might be some loss of shielding, but the transformers are further away now, might look at adding shielding back in or cutting holes for the dc wires in the original plate.

Shall look at boxing in or mounting the transformers so it's more robust, but sounds mighty fine.

Concerning twisting power cables, I have made many power cables up for my equipment over the years, twisting brings massive benefits in rejecting RF, helping to prevent noise from entering the power supply in the first place, it just seems like a good place to start. Using external earth around the hot and cold wires in a helix configuration also brings benefits.

Sbgk, I'd try twisting those cables whilst they are out and easily accessible, it would be great to get some feedback on the difference.

 

[Jake2]

Shame to remove the optical connection - in my experience optical is the best input of all when playing CDs especially using a glass connection rather than plastic. Similar to the fmc connection for internet streaming in isolating electrical noise. Of course maybe you don't like CD, but for me this is the best sounding of all sources!

Yeah I'd never permanently remove the optical input, I use it with an Ifi s/pdif iPurifier 2 - sounds excellent.

Those are some pretty aggressive mods (apart from the clock and BT cables I've played around with), not sure I'd ever do em, but interesting to observe.. to hear what works, especially with power. Maybe something I can leverage in a lighter touch way.

 

[sbgk]

Shame to remove the optical connection - in my experience optical is the best input of all when playing CDs especially using a glass connection rather than plastic. Similar to the fmc connection for internet streaming in isolating electrical noise. Of course maybe you don't like CD, but for me this is the best sounding of all sources!

it introduces it's own noise though and if it's not being used then it's always on creating noise for everything else

 

[sbgk]

Shame to remove the optical connection - in my experience optical is the best input of all when playing CDs especially using a glass connection rather than plastic. Similar to the fmc connection for internet streaming in isolating electrical noise. Of course maybe you don't like CD, but for me this is the best sounding of all sources!

spent plenty of money on CD players over the years, playing wav files from memory is what I do these days, though still have CDs and vinyl, for that matter

 

[sbgk]

Yeah I'd never permanently remove the optical input, I use it with an Ifi s/pdif iPurifier 2 - sounds excellent.

Those are some pretty aggressive mods (apart from the clock and BT cables I've played around with), not sure I'd ever do em, but interesting to observe.. to hear what works, especially with power. Maybe something I can leverage in a lighter touch way.

I'll put it back together and see if it goes back to being a muddled sound, think they possibly bodged the transformer installation, the way the power cables crossed and dc cables were squashed in between the transformers bent back on each other is hardly having a totally separate analogue and digital supply. Anyway have done this mod to amps and cd players in the past to good effect.

 

[camrector]

I'll put it back together and see if it goes back to being a muddled sound, think they possibly bodged the transformer installation, the way the power cables crossed and dc cables were squashed in between the transformers bent back on each other is hardly having a totally separate analogue and digital supply. Anyway have done this mod to amps and cd players in the past to good effect.

This is a great mod. I’d love to see you take it all the way creating a separate box (ala Holo May)

 

[sbgk]

This is a great mod. I’d love to see you take it all the way creating a separate box (ala Holo May)

put it back together (it's a tight fit putting it back in) and lasted about half a track, impressive noise without the mod, but not coherent. With the mod in place I can hear every instrument etc

would like to take all the mains stuff to a separate box, but the iec socket is soldered in, so would have to cut it out, the voltage selector is quite close to the clock, the other side of the RF protection plate, presumably there's mains going though it.

the only issue is the side plate might be providing RF protection and with the mod I don't have it in.

 

[Kent10]

Hi,

I have a new Gustard R26 DAC. I am breaking it in and it seems to be working well except when I play a CD there are dropouts of the sound. Not a lot of them but they occur at the same place on the CD each time. For example, at 4 mins and 47 seconds on one CD. The CD is new and the dropouts do not occur when using my old DAC.

Any idea what is going on and how to fix this? I found one other person online with the same problem and he returned the DAC. He did not find a solution. I am hooked up via the optical digital output. When I get a new CD transport, I will hook up with HDMI I2S and will see if that solves anything.

Thanks, Kent

 

[sajunky]

Hi,

I have a new Gustard R26 DAC. I am breaking it in and it seems to be working well except when I play a CD there are dropouts of the sound. Not a lot of them but they occur at the same place on the CD each time. For example, at 4 mins and 47 seconds on one CD. The CD is new and the dropouts do not occur when using my old DAC.

Any idea what is going on and how to fix this? I found one other person online with the same problem and he returned the DAC. He did not find a solution. I am hooked up via the optical digital output. When I get a new CD transport, I will hook up with HDMI I2S and will see if that solves anything.

Thanks, Kent

Strange, it happens in the same place and on the optical connection. It means a connection is weak and DAC is sensitive to a specific pattern of a bit sequence. From my experience it would be also some random dropouts associated with the same cause.

Try different optical cable. Check whether a plug is inserted fully into a socket of a DAC. On a different equipment I had a case of dropouts and found a socket not alligned to a chassis properly. It caused that plug was stuck in the middle, not reaching a bottom. It was fixed with a screwdriver adjusting a socket assembly.

Can you use coax output for testing?

 

[NickyFlex]

not heard about twisting power cables before, think I'll keep that for signal cables

further mods

removed clock and bluetooth cables, wonder if clock cable was acting as an antenna as removal made a difference and those adding an external clock say the right cable is important

also removed the optical connection, something we did to the squeezebox touch as it just creates noise, just picked away at it with pliers until it was gone leaving 3 connections on the board, which I snipped

swapped the 2 white mains power connectors which means the wires for the transformers are no longer crossing and the transformers can be fully separate and further away from each other. Removed the metal screen plate to allow the dc cables to remain separate, think there might be some loss of shielding, but the transformers are further away now, might look at adding shielding back in or cutting holes for the dc wires in the original plate.

Shall look at boxing in or mounting the transformers so it's more robust, but sounds mighty fine.

turned out the screen was critical to the sound, drilled a hole to take the wires in the new location and filled in the old hole and reinstalled, sound without it was a bit thin

In which setup do you listen to all changes R26?

 

[Stellabagpuss]

put it back together (it's a tight fit putting it back in) and lasted about half a track, impressive noise without the mod, but not coherent. With the mod in place I can hear every instrument etc

would like to take all the mains stuff to a separate box, but the iec socket is soldered in, so would have to cut it out, the voltage selector is quite close to the clock, the other side of the RF protection plate, presumably there's mains going though it.

the only issue is the side plate might be providing RF protection and with the mod I don't have it in.

l guess you could bolt another enclosure to the side, something aluminium, drill holes in R26 side casing and new enclosure to transfer cables to new enclosure,you would be able to sheild, and route the cables properly, and they would further away, l guess you want a case that's the same side as the psu section, and in theory have a gap.
Any suggestions on a suitable case? l guess you even use mdf or plywood and use Copper tape internally for sheilding.

 

[sbgk]

Concerning twisting power cables, I have made many power cables up for my equipment over the years, twisting brings massive benefits in rejecting RF, helping to prevent noise from entering the power supply in the first place, it just seems like a good place to start. Using external earth around the hot and cold wires in a helix configuration also brings benefits.

Sbgk, I'd try twisting those cables whilst they are out and easily accessible, it would be great to get some feedback on the difference.

thought you were joking, but here is a lampizator with plenty twisting going on, terrible placement of transformers though, maybe he feels the RF rejection is more important than damping effect of transformer emf, but then external power supplies and batteries are a thing as well or maybe he just wants a one box solution

 

[Jake2]

Concerning twisting power cables, I have made many power cables up for my equipment over the years, twisting brings massive benefits in rejecting RF, helping to prevent noise from entering the power supply in the first place, it just seems like a good place to start. Using external earth around the hot and cold wires in a helix configuration also brings benefits.

Sbgk, I'd try twisting those cables whilst they are out and easily accessible, it would be great to get some feedback on the difference.

Something like this Rod? The cables are very pliable thanks to what seems to be soft silicon/Teflon (not sure which) sheaths and hold their form well.



Thanks @sbgk for the inspiration.

FYI the assembly instructions that came with my Hypex Nilai power amp instructed one to twist the power supply DC cables. A quick google reinforces this and the advice of Rod and others...

"Compared to a single conductor or an untwisted balanced pair, a twisted pair reduces electromagnetic radiation from the pair and crosstalk between neighbouring pairs and improves rejection of external electromagnetic interference..."

 

[Kent10]

Strange, it happens in the same place and on the optical connection. It means a connection is weak and DAC is sensitive to a specific pattern of a bit sequence. From my experience it would be also some random dropouts associated with the same cause.

Try different optical cable. Check whether a plug is inserted fully into a socket of a DAC. On a different equipment I had a case of dropouts and found a socket not alligned to a chassis properly. It caused that plug was stuck in the middle, not reaching a bottom. It was fixed with a screwdriver adjusting a socket assembly.

Can you use coax output for testing?

Thanks for the help. I checked all the connections and they are fine. The CD player doesn't have coax. One thing I noticed, however, is that even though the CD is new there are some missing spots looking in the light. I made a copy of the CD and it plays without the dropouts. It is still puzzling though, because other CDs have the same problem on the Gustard DAC but not on the old DAC. Something is extra sensitive with the Gustard. I will wait for the new transport at this point and see how it goes. The Jay's Audio is supposed to be particularly good with less than perfect CDs. Thanks again.

PS I am playing the CD now and it is dropping out again. So some areas solved but others not

 

[Jake2]

Thanks Jake
Just a thought you could cover the cube with some insulation tape,to avoid contact, if it does break free.
l going to give this try, l also plan to see if a similar thing can be done inside the cheap FMC, I know the damping can be done, but l doubt there is,enough space for tungsten in the case.

Damien

A quick update on this - heat and time have meant the sheets have bonded more to each other and to the cube so it is very firmly attached to the FPGA as one piece - not budging at all with modest lateral pressure from my fingers - will let sleeping dogs lie for now.

Re the K2, although my experiments to date found a cube sitting on top thinned the sound I may experiment more on this front, as Martin over the the clock thread used epoxy to bond a 2cm cube to the K2 in his X26 pro with good results. Pretty permanent solution though, it'd rather rip ones' shorts if the R26 sounded worse as a result. I have a less permanent alternative in mind but with hopefully equivalent or greater vibration damping coupling.