Moreover, we can also try the Audionote's digital interface transformer
Magic Doughnut
For the IV trans, we can get the AN's Trans-450, but UK$70 each...expensive, but cheaper than the sowter one
An externally hosted image should be here but it was not working when we last tested it.
Magic Doughnut
For the IV trans, we can get the AN's Trans-450, but UK$70 each...expensive, but cheaper than the sowter one
I use a pair of Jensens but AN or Sowter should work as well or better. Make sure you take the input right off the i/v resistor off the dac chip.
I have a crazy idea I've been working instead of expensive transformers. Basically its the Zen I/V converter tuned down for low gain and super low distortion, then the 6n6p gain stage follows it. I can post the spice simulation if anyone is interested.
Here it is with a +-1ma Dac input it gives 150mvp-p, then this is feed to your 6n6pi tube stage gain of ~18 to give 2vrms. The advantage is the input impedance is only 7 ohms, think of it as an $800 AN transformer, doing the same steup but with less distortion and of course the benefit of the lower impedance load on the DAC.Letting the tube take the brunt of the gain duties allows the I/V to be biased for negligible distortion as shown here. Only disadvantage is the interstage coupling caps. I'm not proficient with PCB cad so was planning on breadboarding when I get time..
Dear Quanchao,
With the Dac End (The first version with 5687) what do you think is the max value of pot you can drive ? I have all the components as recommended in the instructions.
Thanks,
Davide
With the Dac End (The first version with 5687) what do you think is the max value of pot you can drive ? I have all the components as recommended in the instructions.
Thanks,
Davide
Which model of Scientific Conversion's transformer matched with the DAC-ASH?
How about SC961-04?
How about SC961-04?
You should have a pulse transformer on your transport, should not need one in the DAC. My posts are referring to a stepup transformer to lower the I/V resistor and voltage compliance on the DAC, a different subject.
I'm having a hard time finding some polypropolene caps for .1uF/25v x 12 listed in the BOM. The space is very tight.
What is everyone using there?
What is everyone using there?
Those are Metallize polyester. I was always told the polypropolene were better to use, no? The MKP are too big though for this.
Agreed, i just left them all out, except the ones across the cathode caps of the output stage tubes, where good small film caps made quite a difference.
But in powersupply, especially when using something like oscons with ultra low esr, they are not useful.
But in powersupply, especially when using something like oscons with ultra low esr, they are not useful.
ok, what about the .01uF x2 film caps on the input to the dac section ( C40/41). What is the best to use there? Or are you saying those are needed either?
No, of course they are needed to form the input circuit together with the 75R Resistor and the input transformer.
It is worthwhile to experiment a little with these caps, as they have big influence in sound quality. To me it has the same if not more significance than output caps of the output stage.
It is worthwhile to experiment a little with these caps, as they have big influence in sound quality. To me it has the same if not more significance than output caps of the output stage.
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