I am considering the Soekris DAM1941 DAC. This version of Soekris's R2R DAC allows the user to pick their buffer. I am considering the following options but I am most interested in the transformer output:
B1 JFET Buffer - Since the DAM1941 only has balanced outputs I would need to use two to get balanced. Since the DAM1941 only has balanced out I guess I would need to mix with the Broskie BCF.
Broskie tube solution - There are three Vacuum tube solutions. The BCF Broskie Cathode Follower, Unbalancer and Unbalancer 2. However, all of these take a balanced output and turns them into single ended. For balanced maybe two Aikido Cathode Followers but I have never seen anyone do that.
Output transformer option - I find this to be the most intriguing and compact option. Bisesik finemet output transformers for DAC's. Although I don't understand them like I do regular output transformers for tube amps. Can someone explain output transformers for DAC's?
There seem to be many options. A transformer for current type DAC's. A transformer type for voltage type DAC's. Then there is 1:1, 1:1:1:1, 1:4, 600:600. Types with 2 to 6 coils.
Then there are these options as well.
80H:80H
20H+20H:80H
20H+20H:20H+20H
300H:300H
80H+80H:320H
80H+80H:80H+80H
B1 JFET Buffer - Since the DAM1941 only has balanced outputs I would need to use two to get balanced. Since the DAM1941 only has balanced out I guess I would need to mix with the Broskie BCF.
Broskie tube solution - There are three Vacuum tube solutions. The BCF Broskie Cathode Follower, Unbalancer and Unbalancer 2. However, all of these take a balanced output and turns them into single ended. For balanced maybe two Aikido Cathode Followers but I have never seen anyone do that.
Output transformer option - I find this to be the most intriguing and compact option. Bisesik finemet output transformers for DAC's. Although I don't understand them like I do regular output transformers for tube amps. Can someone explain output transformers for DAC's?
There seem to be many options. A transformer for current type DAC's. A transformer type for voltage type DAC's. Then there is 1:1, 1:1:1:1, 1:4, 600:600. Types with 2 to 6 coils.
Then there are these options as well.
80H:80H
20H+20H:80H
20H+20H:20H+20H
300H:300H
80H+80H:320H
80H+80H:80H+80H
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The first link in the above post is dead from here. No idea what you wanted people to read or to look at.
Regarding your question, it looks like Soekris DAM1941 has both balanced and single-ended outputs.
Soekris Audio ApS, Products dam1941 ...says:
Output Line -- Bal 2.6V RMS, Zout 1250 Ohm -- SE 1.3V RMS, Zout 625 Ohm
So then, what is it exactly that you want to do with transformers or output stages?
Regarding your question, it looks like Soekris DAM1941 has both balanced and single-ended outputs.
Soekris Audio ApS, Products dam1941 ...says:
Output Line -- Bal 2.6V RMS, Zout 1250 Ohm -- SE 1.3V RMS, Zout 625 Ohm
So then, what is it exactly that you want to do with transformers or output stages?
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I have the latest Soekris DAM 1021 with an Audiozen control board. On the Audiozen board there is the option to run the SE output as unbuffered (Zout 640R) or buffered. I definitely notice the difference when feeding my Luxman SQ-N100 tube amp with a buffered output, it's subtle but definitely noticeable to me.
The Soekris DAM 1941 balanced output line is Zout of 1250 Ohm. I can be used in SE with a stated Zout of 625 Ohm but that may be for the DAM 1921. The purpose of the DAM 1941 and DAM 1921 is to allow the user to pick their own power supply and buffers.
So instead of using SS or tube buffers I am considering output transformers. However, I don't understand what the specs mean. What I need and if it's a good match. Output transformers for DACs
The Soekris DAM 1941 balanced output line is Zout of 1250 Ohm. I can be used in SE with a stated Zout of 625 Ohm but that may be for the DAM 1921. The purpose of the DAM 1941 and DAM 1921 is to allow the user to pick their own power supply and buffers.
So instead of using SS or tube buffers I am considering output transformers. However, I don't understand what the specs mean. What I need and if it's a good match. Output transformers for DACs
IME output transformers often make dacs sound better in some ways and sound worse in other ways. Both effects are related to problems with distortion and noise.
However, while transformers can be easy to use, good ones tend to be costly. Also IME, transformers are never the best possible sounding solution. Their ease of use often seems to make up for giving less than the best sound, at least it looks sorta that way from here where I am. Should probably clarify when I say less than the best sound, many people who end up using transformers have never heard better, one reason for them feeling satisfied with the choice.
The preceding was the short version. We could get into what caused me to form such opinions, or maybe we should just talk about picking a transformer to try based on specs included in the OP and or based on other options.
In the case of transformers made by bisesik, if you PM him and if he has experience with the dac you want to use with his transformers, he can probably suggest which model he would recommend. That's sort of the brief answer about choosing one of his.
If you want to get into understanding transformers in enough detail that you could pick one yourself from specs, then I would say you might have some work ahead of you. Also, maybe some applied research to do. In any case, I would probably recommend to try try different transformers to see if they sound different to you and to see if there is one you prefer the sound of. Looking at specs, measuring, and modeling, etc., can all be informative but it the end they probably can't tell you exactly what it will sound like. For that you will just have to listen.
Regarding hearing a difference between different transformers, people seem to vary greatly in terms of what they hear/notice about sound. Also, other components in their reproduction system may mask or may be revealing of differences in transformer sounds. In general, if using cheap class-D power amps, or, say, maybe SET toob amps, those sorts of things, there is likely going to be some masking, possibly a considerable amount of it.
So, what do you want to do then?
However, while transformers can be easy to use, good ones tend to be costly. Also IME, transformers are never the best possible sounding solution. Their ease of use often seems to make up for giving less than the best sound, at least it looks sorta that way from here where I am. Should probably clarify when I say less than the best sound, many people who end up using transformers have never heard better, one reason for them feeling satisfied with the choice.
The preceding was the short version. We could get into what caused me to form such opinions, or maybe we should just talk about picking a transformer to try based on specs included in the OP and or based on other options.
In the case of transformers made by bisesik, if you PM him and if he has experience with the dac you want to use with his transformers, he can probably suggest which model he would recommend. That's sort of the brief answer about choosing one of his.
If you want to get into understanding transformers in enough detail that you could pick one yourself from specs, then I would say you might have some work ahead of you. Also, maybe some applied research to do. In any case, I would probably recommend to try try different transformers to see if they sound different to you and to see if there is one you prefer the sound of. Looking at specs, measuring, and modeling, etc., can all be informative but it the end they probably can't tell you exactly what it will sound like. For that you will just have to listen.
Regarding hearing a difference between different transformers, people seem to vary greatly in terms of what they hear/notice about sound. Also, other components in their reproduction system may mask or may be revealing of differences in transformer sounds. In general, if using cheap class-D power amps, or, say, maybe SET toob amps, those sorts of things, there is likely going to be some masking, possibly a considerable amount of it.
So, what do you want to do then?
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@analog_sa
I find your reply bordering on offensive. If you believe Nelson Pass's B1 buffer or TubeCad's tube buffers are a joke I'm fine with that. But please write it in a way that educates me. If you have something against transformers that's fine too. But once again write it in a way that educates me.
If a buffer is not needed then educate me how low does output impedance need to be. I'm a hobbyist and not an engineer.
Also, people use MC stepup transformers all the time for phono stages. If built to a high enough quality level people don't seem to mind. That was my thinking with the DAC output transformer for the buffer stage
I find your reply bordering on offensive. If you believe Nelson Pass's B1 buffer or TubeCad's tube buffers are a joke I'm fine with that. But please write it in a way that educates me. If you have something against transformers that's fine too. But once again write it in a way that educates me.
If a buffer is not needed then educate me how low does output impedance need to be. I'm a hobbyist and not an engineer.
Also, people use MC stepup transformers all the time for phono stages. If built to a high enough quality level people don't seem to mind. That was my thinking with the DAC output transformer for the buffer stage
MC-trafos are used because this situation requires 60 dB gain. The DAM dac is capable of playing into anything really.
But you haven't told us what is to be connected. Preamp? What impedance?
What you might achive is to add some coloration. Thats could be OK if thats your taste or your system needs a little bit of distorsion to sound it's best. Then a tube buffer could do the work. Trafo as well - adds a little different "taste"..
Good luck!
//
But you haven't told us what is to be connected. Preamp? What impedance?
What you might achive is to add some coloration. Thats could be OK if thats your taste or your system needs a little bit of distorsion to sound it's best. Then a tube buffer could do the work. Trafo as well - adds a little different "taste"..
Good luck!
//
Thanks. The Luxman SQ-N100 is a SS/Tube hybrid. It has a solid state preamp and the tube section is a PP Mullard UL EL84 with a 47k input impedance. Despite the tubes being probably over ten years old it sounds quite nice even with my Sennheiser HD650's. And the output is coming directly off the output transformers to headphones with what I think is a resistor to drop the wattage.
The McIntosh MC2155 sounded a tad more detailed with headphones and was barely noticeable. The McIntosh MX118 sounded the most clinical but I assume the most accurate of the three with headphones. Also, I did try a balanced XLR to headphone jack cable out of the Soekris DAM1021 which is possible due to the digital DAC volume control. Sounded the same as through the MX118 so I guess McIntosh does engineer good stuff.
I believe I am looking for perhaps a slightly colored sound but not an effects box. I think Markw4 has the best advice and I will just reach out to bisesik for guidance on what will work best for me. I want to try the transformers and compare to tubes.
Final question. Just how low does a preamp or DAC output impedance need to be for cables to not matter? My understanding is the lower the better and I find it odd that some prefer unbuffered
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Into 47k input impedance the 650 ohm output should be as transparent as possible with a short cable. If you like the buffered output of the dam better it might be a side effect of that output being louder. That seems to sound better without meticulous level matching, which is difficult without proper measurement devices. I did a comparison once with matched levels and found the unbuffered output into a 10k load sounding slightly better, but really only very slightly, but certainly not worse.
I would not use a transformer, because driven from that relatively high impedance it can only be 1:1 or step down. Since the low output of the dam needs some boost, if anything, a transformer seems to be without purpose, except breaking a ground loop.
I would not use a transformer, because driven from that relatively high impedance it can only be 1:1 or step down. Since the low output of the dam needs some boost, if anything, a transformer seems to be without purpose, except breaking a ground loop.
Thanks hop.sing. That bit of info is useful. The one thing I do notice with the DAM1021 is that output is very low even at 80% max output. So low that the Luxman SQ-N100 is at half volume in a small room with 98db horn speakers. When hooked up to the McIntosh MX118 & MC2155 the volume knob on the preamp was at 70% average.
Funny story I once hit the tuner button the the MX118 without re-adjusting the volume and the MC2155 power-guard was flashing continuously. The difference in output between the DAC and tuner section was that great. I had to run out of the room and re-enter with hearing protection and power-guard did save the amp and speakers.
So your post is quite helpful. I assume the output of the DAM1941 will be low as well and I don't want a transformer to reduce it further.
Funny story I once hit the tuner button the the MX118 without re-adjusting the volume and the MC2155 power-guard was flashing continuously. The difference in output between the DAC and tuner section was that great. I had to run out of the room and re-enter with hearing protection and power-guard did save the amp and speakers.
So your post is quite helpful. I assume the output of the DAM1941 will be low as well and I don't want a transformer to reduce it further.
Run the dam with 0dB output reduction (or 3 dB lower if you care about intersample clipping) and the difference won't be that extreme anymore
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