Hello, well done and battery power
Hello gentlemen
Having read through the last 15 pages, you are convincing me to get this DAC board and use it with output transformers (thinking of UTC A-20 or NTL1 which are easily available). Seems to me a nice easy mod (with disproportionate benefits) for someone who has soldered-up a few Velleman/nixie clock kits but does not really know how all the bits work together. I am hugely respectful of your efforts.
Has anyone got such a setup running on batteries? I have not seen the schematics of the board, but I am guessing the 12V supplies might not be needed if the analogue stage is not being used. Any advice on what is needed apart from batteries and where to connect them would be much appreciated.
Thanks
PS On the ignorance front, can anyone recommend to me a book/website/course to start learning about the electronics involved here. I appreciate it to be a very skilled blend of science + art, but I gotta start somewhere! If you can help, an email to oli AT hoverdonkey.com might be best to save the thread. Thanks.
Hello gentlemen
Having read through the last 15 pages, you are convincing me to get this DAC board and use it with output transformers (thinking of UTC A-20 or NTL1 which are easily available). Seems to me a nice easy mod (with disproportionate benefits) for someone who has soldered-up a few Velleman/nixie clock kits but does not really know how all the bits work together. I am hugely respectful of your efforts.
Has anyone got such a setup running on batteries? I have not seen the schematics of the board, but I am guessing the 12V supplies might not be needed if the analogue stage is not being used. Any advice on what is needed apart from batteries and where to connect them would be much appreciated.
Thanks
PS On the ignorance front, can anyone recommend to me a book/website/course to start learning about the electronics involved here. I appreciate it to be a very skilled blend of science + art, but I gotta start somewhere! If you can help, an email to oli AT hoverdonkey.com might be best to save the thread. Thanks.
This is the site that got me curious about DACs. Try the "Download Lampizator" link at the top. He's all over the place, wonderful chaos and lots of fun. I told him about the transformer outputs and I think he is investigating.
http://www.lampizator.eu/Updates.html
http://www.lampizator.eu/Updates.html
Stuart
I think the first DAC you have listed is more like the one I am used to. It has an input transformer for the coax source. I have read conflicting reports about the 9001 vs 8416 receiver. I have the 8416 and the unit has been great. I think a few folks in this thread have had good luck with it. As far as the power transformer is concerned. You should be able to pick up a 9vac for very little money locally so it may be a less expensive alternative. I went with the toroid from Hong Kong to save hassle. I have read in this thread that the EI has worked well, maybe better than the toroid.
Good luck and let us know how you progress.
I think the first DAC you have listed is more like the one I am used to. It has an input transformer for the coax source. I have read conflicting reports about the 9001 vs 8416 receiver. I have the 8416 and the unit has been great. I think a few folks in this thread have had good luck with it. As far as the power transformer is concerned. You should be able to pick up a 9vac for very little money locally so it may be a less expensive alternative. I went with the toroid from Hong Kong to save hassle. I have read in this thread that the EI has worked well, maybe better than the toroid.
Good luck and let us know how you progress.
In answer to surfstu, both of my DACs came from that seller ( snow48_6) and I had no problems. Delivery was within a week for the first one and around 2 weeks for the second one.
The first link shows a DIR9001 on a daughter board instead of the CS8416 in the photos however the description mentions the 8416. I have heard good things about the DIR9001 but in the comntext of this thread we have only got experience of the 8416. I guess the main board is the same so you could probably substiture one for the other.
Advantage of this board is that it has a transformer for the SPDIF cable input.
The lower of your two links is another subtly different board that has provision for a USB interface which is not populated. The SPDIF input does not have a transformer so this might be something you'd want to add. However, this board does have the advantage that the signals between 8416 and DAC are brought out to a header so reclocking circuits, etc. can easily be added. They have also done away with some of the unnecessary coupling electrolytics.
So, pros and cons to each. If you see yourself "just using it" I would personally go with the first one but there's not much in it.
As for a transformer you have to weigh up the cost versus shipping cost, I guess. It's relatively heavy compared to the rest of the kit. Having said that, It's not easy to come across a single transformer with windings to supply both rails in the Uk so that might make the kit with transformer worthwhile.
To hoverdonkey: Yes, it is correct that the +/-12v rails are just for the op amps. The other AC input is rectified and regulated down to provide a couple of 5v rails and a 3.3v rail. You could get away with connecting DC from a battery straight to the transformer terminals or remove the rectifier diodes and replace 2 of them with wire links. I'm guessing you could probably get away with an 8-12v DC input here. The regulators run pretty cool.
Kevin
The first link shows a DIR9001 on a daughter board instead of the CS8416 in the photos however the description mentions the 8416. I have heard good things about the DIR9001 but in the comntext of this thread we have only got experience of the 8416. I guess the main board is the same so you could probably substiture one for the other.
Advantage of this board is that it has a transformer for the SPDIF cable input.
The lower of your two links is another subtly different board that has provision for a USB interface which is not populated. The SPDIF input does not have a transformer so this might be something you'd want to add. However, this board does have the advantage that the signals between 8416 and DAC are brought out to a header so reclocking circuits, etc. can easily be added. They have also done away with some of the unnecessary coupling electrolytics.
So, pros and cons to each. If you see yourself "just using it" I would personally go with the first one but there's not much in it.
As for a transformer you have to weigh up the cost versus shipping cost, I guess. It's relatively heavy compared to the rest of the kit. Having said that, It's not easy to come across a single transformer with windings to supply both rails in the Uk so that might make the kit with transformer worthwhile.
To hoverdonkey: Yes, it is correct that the +/-12v rails are just for the op amps. The other AC input is rectified and regulated down to provide a couple of 5v rails and a 3.3v rail. You could get away with connecting DC from a battery straight to the transformer terminals or remove the rectifier diodes and replace 2 of them with wire links. I'm guessing you could probably get away with an 8-12v DC input here. The regulators run pretty cool.
Kevin
Thanks for the help/offers of help folks- in the end I took the easy route and e-mailed KingRex who got back in touch within half a day. Good service 
They said: "The kingrex preamp output impedance is 100ohm@1khz, input impedance is 100kohm@1khz."
So would I need to put loading resistors on the outputs of the Digitecs?
Many thanks,
- John
They said: "The kingrex preamp output impedance is 100ohm@1khz, input impedance is 100kohm@1khz."
So would I need to put loading resistors on the outputs of the Digitecs?
Many thanks,
- John
Thanks for the wisdom....
now i just have to decide between the dir9001 and the CS4398..
think i will ask snow to send me a transformer too, if the transformer is going to be hard to find
stuart
p.s. and just to throw a curve ball in.... anyone recomend a good device to send the digital signal wirelessly to the dac? or will this impede on quality?
now i just have to decide between the dir9001 and the CS4398..
think i will ask snow to send me a transformer too, if the transformer is going to be hard to find
stuart
p.s. and just to throw a curve ball in.... anyone recomend a good device to send the digital signal wirelessly to the dac? or will this impede on quality?
Choosing the board
Thank you for your advice, Kevin, battery power looks like a way forward.
I am now splitting hairs over which variation of the board to choose. Any experience from anyone on these two issues would be welcome;
1 - Is there anything between CS4397 and CS4398 sonically?
2 - To add an SPDIF input transformer, is it just an easy job of connecting one in series (in which case, having one built-in is not a deciding factor) or are there other components needed?
Thanks
Oli
Thank you for your advice, Kevin, battery power looks like a way forward.
I am now splitting hairs over which variation of the board to choose. Any experience from anyone on these two issues would be welcome;
1 - Is there anything between CS4397 and CS4398 sonically?
2 - To add an SPDIF input transformer, is it just an easy job of connecting one in series (in which case, having one built-in is not a deciding factor) or are there other components needed?
Thanks
Oli
thanks for the all the info people!
have just ordered myself one of these dacs:
http://cgi.ebay.co.uk/UPGRADED-24bi...hash=item230336590134&_trksid=p3286.m63.l1177
complete with transformer for £90, shame the pounds so weak but from what i read round here, it should be money well spent.
question: is it really noticable upgrading the op amps? I will be using valve pre and valve power so i'm thinking it is not necessary to add a valve output, but will changing the op amps be Really noticable?
stuart
have just ordered myself one of these dacs:
http://cgi.ebay.co.uk/UPGRADED-24bi...hash=item230336590134&_trksid=p3286.m63.l1177
complete with transformer for £90, shame the pounds so weak but from what i read round here, it should be money well spent.
question: is it really noticable upgrading the op amps? I will be using valve pre and valve power so i'm thinking it is not necessary to add a valve output, but will changing the op amps be Really noticable?
stuart
I'm still waiting on the cheap Edcor to arrive, ($32 for two). I will try these transformers in comparison to the UTC A-20. If they are good, I think we will have a cheapskates solution to the DAC mystery.
Honestly, I wouldn't bother with opamps, especially if you use tube equipment.
I have also ordered and waiting on the cheaper dual board CS4397 DAC, all smd. Let's see what it can do.
Ciao
Honestly, I wouldn't bother with opamps, especially if you use tube equipment.
I have also ordered and waiting on the cheaper dual board CS4397 DAC, all smd. Let's see what it can do.
Ciao
i'm happy to do away with the op amps, is this as easy as finding the first available output from the dac chip and irring in some transformers? do i need a lot of experience with a soldering iron?
I'll keep checking this post to see how those edcor transformers go for you,
cheers stuart
oh and is the squeezebox the only way for me to send data wirelessly to the dac? Seems like they have cornered the market if it is......
I'll keep checking this post to see how those edcor transformers go for you,
cheers stuart
oh and is the squeezebox the only way for me to send data wirelessly to the dac? Seems like they have cornered the market if it is......
Don't bother doing anything to the opamps. Stealing the signal directly from the DAC is very easy. As many on this thread have stated, you'll need a good soldering iron than can go to around 750 degrees.
There are 4 electrolytic caps immediately next to the DAC. Each pair provides the balanced analog output of the DAC. Heat the solder at the bottom of the leads for each cap and wiggle. Adding some quality solder to the existing stuff can help with melting. Clean each hole. Some quality solder can help with this.
Take some thin solid core wire, (I cheated and used stranded CAT5) and connect from the DAC side of where the electrolytics used to be directly to primary of the transformers. The secondary of the transformer goes directly to new RCA output jacks. The shield of each transformers is connected to the ground of stock RCA jacks. I soldered a 50k resistor across the secondary.
I hope this is clear. Anyway, what this thing can do blows away any DAC I've heard so far. It's really something special.
There are 4 electrolytic caps immediately next to the DAC. Each pair provides the balanced analog output of the DAC. Heat the solder at the bottom of the leads for each cap and wiggle. Adding some quality solder to the existing stuff can help with melting. Clean each hole. Some quality solder can help with this.
Take some thin solid core wire, (I cheated and used stranded CAT5) and connect from the DAC side of where the electrolytics used to be directly to primary of the transformers. The secondary of the transformer goes directly to new RCA output jacks. The shield of each transformers is connected to the ground of stock RCA jacks. I soldered a 50k resistor across the secondary.
I hope this is clear. Anyway, what this thing can do blows away any DAC I've heard so far. It's really something special.
mush:
thanks for the instructions, very clear for newbie.
Everyone:
thanks for all the discussion, you have inspired me to buy this dac, it's almost broke the bank, but I am determined to go down the input transformer route too....
would like to hear about the cheaper transformers, possibly ones that are available in the UK too,
stuart
thanks for the instructions, very clear for newbie.
Everyone:
thanks for all the discussion, you have inspired me to buy this dac, it's almost broke the bank, but I am determined to go down the input transformer route too....
would like to hear about the cheaper transformers, possibly ones that are available in the UK too,
stuart
Dc Cancelling
I have a question...
Is it correct to think the Dc offset of the DAC output is cancelled out in the primary of the transformer?
I'd like to play with some UTC A-20 or other transformers, but want to be sure the DC will cancel so I don't need a blocking capacitor anywhere in the signal chain.
Thanks
I have a question...
Is it correct to think the Dc offset of the DAC output is cancelled out in the primary of the transformer?
I'd like to play with some UTC A-20 or other transformers, but want to be sure the DC will cancel so I don't need a blocking capacitor anywhere in the signal chain.
Thanks
This is correct.
It is separated by galvanic separation from the primary to the secondary.
But no DC is allowed on the primary or secondary side of the transformer, as it would magnetize the core by very low voltages.
So you should measure the output of the DAC if there is any DC bias. For CS4398 there seems to be no DC.
Franz
surfstu said:
For cheaper transformers, you can buy this: As I have many dacs to modify, I like to try many transformer brands. These transformers are made by Tamura in Japan which has a great reputation in high end transformers. I didn't resist and bought a pair to try them. They are 1:1, 600:600 ohms transformers. As soon as I will receive them, I'll give you more news.
GA80080 on eBay
http://cgi.ebay.com/Yamaha-PM-1000-...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50