Hi all,
Thanks for your thoughts.
I would think the power to isolator is not needed because the isolator is out of the way, maybe however it does have an effect, I can try this.
Doede,
When you say use a series resistor, should I use it on all three connections?
Btw. I also connected gnd to the shielding of the UFL cables so I asume this is connected to the board ground on the wave IO.
Ordered my 4 board set with transformer outputs for my christmas present this year!
Hope to have a great winter/spring getting it going, and comparing to my AudioNoteKits DAC4.1.
Tubed PSU and output stage vs. technically better I/O and DAC portion. We will see where the chips fall.
Thanks to Doede for putting such a great kit out for us.
Hope to have a great winter/spring getting it going, and comparing to my AudioNoteKits DAC4.1.
Tubed PSU and output stage vs. technically better I/O and DAC portion. We will see where the chips fall.
Thanks to Doede for putting such a great kit out for us.
Hi Doede,
congratulations to a very dedicated and fantastic development work.
I used much of the evening yesterday to read through your website, and were very impressed.
I already have 2 1794A DACs from Twisted Pear, but I just ordered your kit today
One of them has an LC Audio discreate BJT transistor stage with shunt regulator, and the other one a Lundahl transformer stage from K&K Audio - both sounds very good, but I havnt done any measurement on them.
I was tempted to buy your kit because of NOS and your dedicated work.
Because of limitid funds at the moment I will use some existing PSUs at startup.
All the best
Arthur
congratulations to a very dedicated and fantastic development work.
I used much of the evening yesterday to read through your website, and were very impressed.
I already have 2 1794A DACs from Twisted Pear, but I just ordered your kit today
One of them has an LC Audio discreate BJT transistor stage with shunt regulator, and the other one a Lundahl transformer stage from K&K Audio - both sounds very good, but I havnt done any measurement on them.
I was tempted to buy your kit because of NOS and your dedicated work.
Because of limitid funds at the moment I will use some existing PSUs at startup.
All the best
Arthur
Not that many solder slingers around anymore, thats a shame.
It seems to be a 1:1 unbalanced transformer.
I suppose this trafo will reflect the secondary 1:1, and maybe one will have to account for the resistance in the windings also. What did you put on the secondary as load ?
And the output is probably on the low side ?
It seems to be a 1:1 unbalanced transformer.
I suppose this trafo will reflect the secondary 1:1, and maybe one will have to account for the resistance in the windings also. What did you put on the secondary as load ?
And the output is probably on the low side ?
My experience with audio trafos show that some of them have a tendency to ringing if they dont work with the loads it wants to.
Sometimes it can be cured by a Zobel network (R-C) on the output, and sometimes it is not necessary. It probably also depends on the impedence of the following amp.
Sometimes it can be cured by a Zobel network (R-C) on the output, and sometimes it is not necessary. It probably also depends on the impedence of the following amp.
Maybe I am wrong, but I thought that a 1:1 trafo would reflect the impedance on the output back to the input. In your case with a 1:1 trafo that would be the 10K in parallel the input of the following preamp (maybe 50K). That would be around 8.3Kohm that is reflected back to the DAC.
And I have read many times that the DAC wants to see a very low impedance.
Anyone have comments on that ?
And I have read many times that the DAC wants to see a very low impedance.
Anyone have comments on that ?
danger here to mix up things. Did you downloaded my circuits on the website? that is helpfull understanding how it works. THE DAC is already loaded by the load resistors on the DDDAC1794 mainboard.... 34ohm for the 4deck version. therefore the load from the transformer must be as high as possible and to avoid ringing, the secondary load is recommended with 10k
Sowter 9545
I'm not suggesting anyone should rush out and buy a pair of these, only that I had them spare in the parts box, tried them in several configurations and this configuration proved one of the best sounding and something I put top of the list as being one to return to and have another play with, but as per usual I never seem to find the time to go back. (I can see most of you guys discussing transformers, are following the Doede doctrine of passive output, and seem to be looking at 10k:10k line driver parts, but anyway.....)
A pair of Sowter 9545's, primaries in series, (join brown and orange but don't ground, grey/blue to +/- on the DDAC mainboard), secondaries in parallel, so 2:5 == 1:2.5 step-up. 1R2 I/V resistors with a single deck, and a triode gain stage (x45) connected to the 9545 secondaries, for ~2V RMS single-ended output.
I'm not suggesting anyone should rush out and buy a pair of these, only that I had them spare in the parts box, tried them in several configurations and this configuration proved one of the best sounding and something I put top of the list as being one to return to and have another play with, but as per usual I never seem to find the time to go back. (I can see most of you guys discussing transformers, are following the Doede doctrine of passive output, and seem to be looking at 10k:10k line driver parts, but anyway.....)
A pair of Sowter 9545's, primaries in series, (join brown and orange but don't ground, grey/blue to +/- on the DDAC mainboard), secondaries in parallel, so 2:5 == 1:2.5 step-up. 1R2 I/V resistors with a single deck, and a triode gain stage (x45) connected to the 9545 secondaries, for ~2V RMS single-ended output.