Mostly the one embedded in the Kenwood unit in my car. 
But I do have plans to upgrade my excellent sounding dual ak4490 to a dual ak4493.. and then to a dual ak4497.. and then to a dual ak4499... and so on.. and so forth..
I still have the Soekris and it sounds great for certain "moods" but I am a bit addicted to the extra slam of the ΔΣ units.
But I do have plans to upgrade my excellent sounding dual ak4490 to a dual ak4493.. and then to a dual ak4497.. and then to a dual ak4499... and so on.. and so forth..
I still have the Soekris and it sounds great for certain "moods" but I am a bit addicted to the extra slam of the ΔΣ units.
Got back to differential mode - ohh - it's great what a difference in drive and dynamics. Cleaner also.
One 1121 directly coupled to Hypex NC400 with it's own SMPS600.
I'm running my speakers (side wall hanged) with 2,6 ohm (100W) in series with frequency compensation done in DAM using biquads (meas. below done in listening pos). I have never heard such a transparent EQ mechanisms as using DAM biquad filters. Kills the DLCP.
Total analogue path length per channel: 54cm.
Fantastic system performance!
I think I will change my HF caps to styroflex just for "fun" and be done with it :-D
//
what a difference in drive and dynamics. Cleaner also.One 1121 directly coupled to Hypex NC400 with it's own SMPS600.
I'm running my speakers (side wall hanged) with 2,6 ohm (100W) in series with frequency compensation done in DAM using biquads (meas. below done in listening pos). I have never heard such a transparent EQ mechanisms as using DAM biquad filters. Kills the DLCP.
Total analogue path length per channel: 54cm.
Fantastic system performance!
I think I will change my HF caps to styroflex just for "fun" and be done with it :-D
//
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Got back to differential mode - ohh - it's great
//
Totally agree. Recently substituted dual-mono 1021s for my dual-mono 1121s (similar power supplies for the 5V and using 9VDC linear supplies on the 1021s) and when I went back a week later to the 1121s there was a perceptible improvement in just what you mention above - dynamics and a sense of being cleaner and more resolving. Not night and day in any sense, but there. An ‘Ah...yes’ feeling that persisted days later.
Substituting a single-ended 1021 build with an 1121 build (again with similar supplies as above) the difference is harder to discern - although I prefer the 1121 (can’t wait to hear 4K filters on the 1121, Soren!
). A fully-realised differential implementation produces the best sound I’ve heard from either the 1021 or 1121. Amplification was Class D module(s) in all cases.Interested in the outcome of your 1121 tinkering..... please report progress. Or regress
Passive 3 Pole filter on NOS Dam1021
Hi
I was trying out trueNOS on my DAM a few weeks ago, since I never heard a NOS Dac before I was curious about it. I immediately liked it a lot, relaxed and a bit euphonic for my ears. But after a while I found that something is not quite right, just a tiny little bit and hard to pinpoint, maybe the frequency response or the supersonic mirrors.
So I thought, a proper NOS Dac needs an analogue filter, best with a little peak to flatten the HF response.
So I simulated a simple 3 Pole chebychev like lowpass, that would accomplish the task and built it.
Simulation translated pretty well, my implementation rolls of a little earlier, but that does not bother me.
My NOS DAM1021 is now pretty flat up to 15k and -3dB is 18k. My old ears go up to 14k with a sine wave, so that is OK with me.
Simulation says, response is down around 20dB at 40k, but I guess it is more in reality. Does not sound much, but the resulting voltage is only a tenth of the unfiltered voltage, that should take a lot of burden of the following equipment.
Since I use a 10k volume switching network with relays I have a defined impedance that the filter works into.
The capacitors are old Siemens Styroflex, very, very nice caps they are and the inductor is a TDK from a surplus store, I had to test a few to have a more or less matched pair, they where all over the map.
I am listening for a few days now and the sound is great, the compromise seems gone, pure joy. I can listen forever and without a hint of fatigue, which is something I am very sensitive for.
Of course highres files have a compromised frequency response, but 99,9 precent of my material is 44,1 k anyway and if I keep the filter I might make it switchable.
It is cheap and easy to built, I can just recommend to try that out and maybe modify it to your liking if you are a fan of no oversampling in DACs.
First Picture is NOS vs. NOS with the filter
Second one the schematics
Third is the response of both channels in higher resolution
Everything recorded into the analogue input of an old macbook and measured with fuzz measure.
Hi
I was trying out trueNOS on my DAM a few weeks ago, since I never heard a NOS Dac before I was curious about it. I immediately liked it a lot, relaxed and a bit euphonic for my ears. But after a while I found that something is not quite right, just a tiny little bit and hard to pinpoint, maybe the frequency response or the supersonic mirrors.
So I thought, a proper NOS Dac needs an analogue filter, best with a little peak to flatten the HF response.
So I simulated a simple 3 Pole chebychev like lowpass, that would accomplish the task and built it.
Simulation translated pretty well, my implementation rolls of a little earlier, but that does not bother me.
My NOS DAM1021 is now pretty flat up to 15k and -3dB is 18k. My old ears go up to 14k with a sine wave, so that is OK with me.
Simulation says, response is down around 20dB at 40k, but I guess it is more in reality. Does not sound much, but the resulting voltage is only a tenth of the unfiltered voltage, that should take a lot of burden of the following equipment.
Since I use a 10k volume switching network with relays I have a defined impedance that the filter works into.
The capacitors are old Siemens Styroflex, very, very nice caps they are and the inductor is a TDK from a surplus store, I had to test a few to have a more or less matched pair, they where all over the map.
I am listening for a few days now and the sound is great, the compromise seems gone, pure joy. I can listen forever and without a hint of fatigue, which is something I am very sensitive for.
Of course highres files have a compromised frequency response, but 99,9 precent of my material is 44,1 k anyway and if I keep the filter I might make it switchable.
It is cheap and easy to built, I can just recommend to try that out and maybe modify it to your liking if you are a fan of no oversampling in DACs.
First Picture is NOS vs. NOS with the filter
Second one the schematics
Third is the response of both channels in higher resolution
Everything recorded into the analogue input of an old macbook and measured with fuzz measure.
Attachments
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It became a revelation. Really. It's like a new system. Really.
But we also know how the mind play tricks on us. So I will come back in a few days and report if it sticks. But right now it is just appalling how there can be such a big positive change. Everything is better. It's crazy. It's so much more music. I hesitate to write this but it is my experience right now. The music message has changed - and it's lovely.
I'm I crazy? ....
//
PS. Did not try without..
But we also know how the mind play tricks on us. So I will come back in a few days and report if it sticks. But right now it is just appalling how there can be such a big positive change. Everything is better. It's crazy. It's so much more music. I hesitate to write this but it is my experience right now. The music message has changed - and it's lovely.
I'm I crazy? ....
//
PS. Did not try without..
Buy Polystyrene 2200pF 160V 1% axial at the right price @ Electrokit
Playing first tune this morning - phew, it's still there
//
Playing first tune this morning - phew, it's still there
//
Buy Polystyrene 2200pF 160V 1% axial at the right price @ Electrokit
Playing first tune this morning - phew, it's still there
//
It certainly is not just you. If I recall correctly many of the dam1021 mod’ers have experienced what you are now. So I’d say this is a must do mod and probably a thing to look in for the designer of the board if he wants to improve “old” products