Yes, consumption from UltraBiB for digital supply is much higher then for analog +/- section, and I prepare larger heatsinks for that board, but after trials and first few weeks of longer use, I don’t see that is necessary.
Actual consumption of digital section (with dsp board) never go above 300ma, add about 100ma for shunt and that is all. Of course to avoid excessive unnecessary heat, input Vdc (across C1) must be not so much above 10V (in my case 10,3V), or about 5V higher then Vout.
Good oversized transformers (like Hammond 229C16) also help to keep temp on low side.
Output voltages from UltraBibs are very stable with very very low drift. But is really good to follow Salas advice to go with oversized power resistors with low temp coef and solder them few mm’s above board.
I put output pos-neg jumpers from above but posted picture is old one.
Actual consumption of digital section (with dsp board) never go above 300ma, add about 100ma for shunt and that is all. Of course to avoid excessive unnecessary heat, input Vdc (across C1) must be not so much above 10V (in my case 10,3V), or about 5V higher then Vout.
Good oversized transformers (like Hammond 229C16) also help to keep temp on low side.
Output voltages from UltraBibs are very stable with very very low drift. But is really good to follow Salas advice to go with oversized power resistors with low temp coef and solder them few mm’s above board.
I put output pos-neg jumpers from above but posted picture is old one.
Nice clean build. Was there a reason you didn’t simply do away with the heat sinks and bolt to the bottom of the chassis?
No, I haven’t any specific reason, and for sure bottom plate is nice solution. Except that I’m simply not big fan of insulators like kapton, silpads or thin and fragile mica with some questionable thermal conductivity.
Nice building!
Is it necessary to use this perfect regulated PSU for the digital part of the DAC? Or just use 7805? What do you think?
Jan
The Power Supply Board psu1951 the Søren sell as accessory uses two 7805 and a 7905. It's just that the Salas in the triplet kit seems a perfect match for the dam1941
You have to define what makes the digital part. The shift registers imho don't qualify as a "digital part" in this particular case.
So if I only use the 7805 to power the digital part, I won't lose the sound quality? I plan to use the superreg from Jan Didden only to power the analog part.
Thanks
Someone once said the marriage of DAM1941 and Salas PSU was made in heaven. After installation I think he was right.
People generally assume that digital is not affected by power supplies or parts choices because it’s “digital”. In my experience, there is no difference between digital and analog: power supply modification or component changes affect the sound quality equally for both.
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DAM1921 has 625 Ohm Zout and 1.3V when used single ended. Anything tube behind it is likely detrimental. It does not need gain like 99% of DACs and it has way lower output impedance than 99% of tube stages as well. So what would be the benefit of adding gain and upping output impedance? Exactly: nothing. It would add "tube magic" like higher noise and coloration (certainly with high gain circuits). One can tap oneself on the shoulder that one succeeded to add a tube again in this harsh digital world.
If one persists: with 1.3Veff one one could add a very low gain stage (or buffer). It all depends on the power amplifiers input impedance and gain. Since one can't deny the signal is already produced by "sand" one could consider an opamp stage as a buffer so practically no negative side effects and no added noise/coloration because of absurdly high gain stages. If one uses more than 1 digital or any other modern source (clearly except for old phono stages) and one uses a power/integrated amplifier with normal gain then one does not need gain in the form of a high gain preamp in the very most of cases.
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There are just sand switches, nothing to do with the wholesale damage an opamp is capable of.
Imho a single tubed stage is an essential musical ingredient for many systems. It can be in the shape of an active preamp but considering the excellent volume control of the DAM it makes sense to integrate it. Built as it should it will exceed the weight and cost of the DAM by at least a factor of 10 🙂
Jean-Paul, IMHO you generalize strongly. :-(
At least as much -poorly designed- SS device has "coloration", irritating tone as tube ones.
BTW where are -in this case- noise and "coloration"? 😛
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Yes I do but of course it was meant as built in many cases. I see more too high gain tube DIY stuff than I like (in situations where their specifications are not suitable...). Did you see the schematic?
Poor design is poor design whether it is with tubes or without but in the case of tubes many think adding a tube circuit in whatever form makes the DAC a better device. Adding something unnecessary while at the same time degrading technical specifications never has led to improvement. With 2Veff sources a high gain preamp is a thing of the past. With DACs focus should be more on low gain, low noise, low output impedance circuits that can drive any amplifier behind it.
In other words: circuits must be designed for the purpose so with predefined calculated gain and other relevant specifications.
Poor design is poor design whether it is with tubes or without but in the case of tubes many think adding a tube circuit in whatever form makes the DAC a better device. Adding something unnecessary while at the same time degrading technical specifications never has led to improvement. With 2Veff sources a high gain preamp is a thing of the past. With DACs focus should be more on low gain, low noise, low output impedance circuits that can drive any amplifier behind it.
In other words: circuits must be designed for the purpose so with predefined calculated gain and other relevant specifications.
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"Did you see the schematic?"
Several years ago I built this.
#26 tube, CCS load, capacitor coupled to S&B TVC.
Max. gain about 7.
Several years ago I built this.
#26 tube, CCS load, capacitor coupled to S&B TVC.
Max. gain about 7.
Yes that is the one but with other tubes, no CCS and no TVC behind it 😀
When the circuit as attached and discussed is used after the DAC with volume control after the output it there will be "tube magic" indeed.
When the circuit as attached and discussed is used after the DAC with volume control after the output it there will be "tube magic" indeed.
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