It's not a good idea to use the digital volume control above 0. Generally filters are made to be as close to the clipping boundary as possible. The same applies to music, the recording level is adjusted so that digital clipping does not occur. In DAM1021 and others, the digital volume control is between the first and second stages of filtering, so by increasing the volume above 0, we can feed the second stage with a deformed signal. The only reason to use the +10 correction are filters that lose a lot on the first stage, e.g. a filter with 1 coefficient which loses 18dB
Last year I bought a dam1021 rev7, I already had the rev1 fully modded.
The new rev7 in stock already sounded better than the old rev1 modded.
Looking at the rev7 board, there's not much to be modified, Soeren already updated the vrefs and the clock PS.
The only thing that I see was adding better caps to the shift registers decoupling,
searching in mouser/digikey I found the new Kemet KO-CAP T520 tantalum-polymer caps.
The 100uF 6.3v in a 1411 package with only 15mOhm is a good candidate,
they can be soldered next to the biggest existing ceramic caps, there are 12 of those.
Attention: those Kemet T520 are polarized, it is needed to check the polarity for each cap (no logic on the PCB)
The new rev7 in stock already sounded better than the old rev1 modded.
Looking at the rev7 board, there's not much to be modified, Soeren already updated the vrefs and the clock PS.
The only thing that I see was adding better caps to the shift registers decoupling,
searching in mouser/digikey I found the new Kemet KO-CAP T520 tantalum-polymer caps.
The 100uF 6.3v in a 1411 package with only 15mOhm is a good candidate,
they can be soldered next to the biggest existing ceramic caps, there are 12 of those.
Attention: those Kemet T520 are polarized, it is needed to check the polarity for each cap (no logic on the PCB)
Attachments
I have dam1021 ver 7, it work well.
Today, when dam1021 power off I used a multi metre and saw that at position j7: Pin 1,2,3,4 are connected. This is unusual, in fact, there are only 2 and 3 connected. The positions j6 and j8 are normal.
ver 7 uses +-9v dc, is it correct?
Thanks
Today, when dam1021 power off I used a multi metre and saw that at position j7: Pin 1,2,3,4 are connected. This is unusual, in fact, there are only 2 and 3 connected. The positions j6 and j8 are normal.
ver 7 uses +-9v dc, is it correct?
Thanks
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Hello, I am interested in one new board. Could you please PM me about HW version and requested price ? Thank you !
@soekris
A suggestion for your board line DAMs: offer them optional without the resistors of the ladder soldered on the board, but with the unmounted resistors - perhaps with some excess amount of resistors.
So one could match the resistors before soldering.
OK, I know, soldering 100 tiny SMD resistors, tightly spaced, is not fun
A suggestion for your board line DAMs: offer them optional without the resistors of the ladder soldered on the board, but with the unmounted resistors - perhaps with some excess amount of resistors.
So one could match the resistors before soldering.
OK, I know, soldering 100 tiny SMD resistors, tightly spaced, is not fun