"No chance to search for the datasheet, which was never published before."
Oh that's a shame - nevermind!
Are you still using the Digitecs? Nobody seems to mention them here and I know you sent a few pairs out. Are you still happy with yours and still using the 10R resistors to each primary?
Definately still happy with mine, and I've finally ordered a chassis to put it all in from Modushop in Italy. I'm thinking of attaching some switches to the back panel to replace the 'mode' switches on the DAC circuit board. Then it will be easy for me to change to different sampling rates on the rear panel.
Surprisingly, I also prefer the optical input on my DAC (Despite many 'experts' saying optical is inferior). Sounds more natural to me.
Cheers,
- John
Oh that's a shame - nevermind!
Are you still using the Digitecs? Nobody seems to mention them here and I know you sent a few pairs out. Are you still happy with yours and still using the 10R resistors to each primary?
Definately still happy with mine, and I've finally ordered a chassis to put it all in from Modushop in Italy. I'm thinking of attaching some switches to the back panel to replace the 'mode' switches on the DAC circuit board. Then it will be easy for me to change to different sampling rates on the rear panel.
Surprisingly, I also prefer the optical input on my DAC (Despite many 'experts' saying optical is inferior). Sounds more natural to me.
Cheers,
- John
Atlplasma said:
I wouldn't mind trying a pair of UTC a-20s, but all the suppliers seem to be in China, which would mean 2-3 weeks for shipping. Know any sources in the US that have used or NOS UTC in stock (if you don't mind sharing).
Brianco listed a supplier in Cal. in post 878.
Good luck.
Atlplasma said:
I wouldn't mind trying a pair of UTC a-20s,........
Mine are now well used considering the time I have had them. I have followed the RCA / Jensen wire up at i:i. The sound I am now getting is absolutely amazing.
Gone is the rather congested 'row' which some orchestral or close miked very dynamic music could bring. Also the treble has taken on a very sweet and real quality.
But the biggest difference is that the 'solidity' or 'tonal substance' of each note from every instrument has increased beyond belief.
Another effect of the transformers is that in addition to a deeper, higher stereo sound-stage what I believe some are referring to is that - on decent recordings - you can now hear the hall-effect. The acoustics of the recording studio or concert hall are very clearly brought to life. I am sure that the extended to 50K bandwidth is mainly responsible for this factor.
Overall the effect in my 'resting' system (very elderly Perreaux 2150 based - I can now see why so many people preferred these amps to Krells back in the 1980s!)) is beyond belief for the money and time expended.....the whole set up rests under self-weight on a kitchen beech chopping board and is covered by a sheet of silicon paper with a Tyvex style graphite cloth over. I am intending to mount the DAC in a 9mm alloy box with copper lining - that should keep it isolated!
I am very happy with this set up
Mush said:
Taking a chance on upsetting, confusing, or ******* off some people, I'm going to try to explain again how transformers should be used with this DAC chip.
The chip has a differential output, meaning that it has a plus and minus output and has no ground, both are hot, just 180* out of phase.
Transformers are differential devices also, they have no ground, so they provide complete isolation from primary to secondary. Any time you connect a ground to a transformer you are defeating the design of the device you are using and introducing a possible problem with noise or ground loops.
If you connect the RCA shield pin to the ungrounded analog ground plane of the DAC you are adding an antenna to the input of your preamp which will pick up stray fields from the DAC unit.
If you also connect the DACs ground plane to earth you are also adding a nifty way for causing hum and hiss through a ground loop through the power wiring in your house.
The only ground connection you need is already taken care of in the input wiring inside your preamp, anything added is just added problems, not solutions.
Don't hesitate to ask questions if you don't get it, I don't mind at all. I hope I was helpful.
Best, Bill
brianco said:
Mine are now well used considering the time I have had them. I have followed the RCA / Jensen wire up at i:i. The sound I am now getting is absolutely amazing.
Gone is the rather congested 'row' which some orchestral or close miked very dynamic music could bring. Also the treble has taken on a very sweet and real quality.
But the biggest difference is that the 'solidity' or 'tonal substance' of each note from every instrument has increased beyond belief.
Another effect of the transformers is that in addition to a deeper, higher stereo sound-stage what I believe some are referring to is that - on decent recordings - you can now hear the hall-effect. The acoustics of the recording studio or concert hall are very clearly brought to life. I am sure that the extended to 50K bandwidth is mainly responsible for this factor.
Overall the effect in my 'resting' system (very elderly Perreaux 2150 based - I can now see why so many people preferred these amps to Krells back in the 1980s!)) is beyond belief for the money and time expended.....the whole set up rests under self-weight on a kitchen beech chopping board and is covered by a sheet of silicon paper with a Tyvex style graphite cloth over. I am intending to mount the DAC in a 9mm alloy box with copper lining - that should keep it isolated!
I am very happy with this set up
Thanks for sharing your impressions. I've ordered a pair of these and now just have to wait for the slow-boat to arrive. Would you mind sharing a photo or diagram showing how you have the transformers wired into the board?
Steve
1) utc a-20 and 2) spdif
1)Just to be sure for the connections...The markings are difficult to read on the transformer...For 500 Ohms: input at pin1(linked to pin6... 3,4 and ground joined); output at pin7(linked to pin12...9,10 and ground joined)?
2)If someone have an idea on this...Wanted to upgrade my clock and spdif of my cdp: bought an XO3 from Tentlabs (and the support is equal to none). Clock ok but SPDIF...Am I right to pick up that signal at the input of a 74hc00a?
Thanks
1)Just to be sure for the connections...The markings are difficult to read on the transformer...For 500 Ohms: input at pin1(linked to pin6... 3,4 and ground joined); output at pin7(linked to pin12...9,10 and ground joined)?
2)If someone have an idea on this...Wanted to upgrade my clock and spdif of my cdp: bought an XO3 from Tentlabs (and the support is equal to none). Clock ok but SPDIF...Am I right to pick up that signal at the input of a 74hc00a?
Thanks
Did I Buy the Right One?
Hi guys:
I purchased a pair of UTC transformers off ebay but am now wondering if they are the correct model. The seller has labeled the transformers as A-20 and LML-2500, but it only has three pinouts (for 500, 600, and CT). Since we're shooting for 500 to 600 ohms, this should be okay, correct?
If anyone has a moment, I've attached a screen capture of the units.
Hi guys:
I purchased a pair of UTC transformers off ebay but am now wondering if they are the correct model. The seller has labeled the transformers as A-20 and LML-2500, but it only has three pinouts (for 500, 600, and CT). Since we're shooting for 500 to 600 ohms, this should be okay, correct?
If anyone has a moment, I've attached a screen capture of the units.
Attachments
I own one these DACs and have been following this thread for some time - it's very interesting. I had originally done some simple modifications on it such as removing caps, adding resistors and changing opamps, (Bursons, etc), connectors and power transformers. While quite satisfied with the present sound I decided to take the plunge and order some more parts - a second board(which I will later pass on to a friend)a pair of UTCs, a pair of Edcors and various caps and resistors(values which have been used in this thread). I already suspect that my choice of Edcor PCW600/600(based on a recommendation on another forum) was probably a mistake.
I have very little DIY experience and sometimes get lost in the jargon and therefore would really appreciate it if someone who is satisfied with their setup could post some detailed pics along with a few "idiot proof" directives so that I can get this right from the start.
Thanks in advance
I have very little DIY experience and sometimes get lost in the jargon and therefore would really appreciate it if someone who is satisfied with their setup could post some detailed pics along with a few "idiot proof" directives so that I can get this right from the start.
Thanks in advance