Hi Paul,
Have you tried the stock SE output of the DAM ?
Many report that the SE output sounds better than the buffered balanced output.
Regards,
Danny
I use a cathode follower with 6H6p tubes (cathode resistor 200 ohms). I recommend to try different values for the L-pad . The final sound depends a lot on this especially with the option to use different filters and 2 fixed volume settings in the case of the dam DAC. Normally one would use values like 30k in series/10k to ground or variations of the in series resistor’(cap is 1uF/400V). I got the best results with 10k in series and 4.3k to ground. I experienced exactly the same general effect with the Buffalo III DAC (really nice but nothing special) which I use together with the same output stage. I cannot tell if these L-pad values are the only reason for the extremely liquid, powerful, balanced, analog-like sound in the case of the R2R DAC as I use both DACs together with a miniSHARC for the volume control which allows me to bypass the DAC’s volume control. This sound character is less obvious if the DAC is set to 0dB instead of +15dB and the mini SHARC volume control is close to the max. So it is a combination of different factors as certain filters also sound quite different with 0dB and +15dB settings. I didn’t try how it sounds with the DAC volume control ON and without the miniSHARC.
This. There is no contest. Upon first trying the buffered outputs (always used unbuffered from the beginning) I ended up removing all the components for this section as they were just excess baggage I knew I would never use again.
I plan on placing a board directly above this now unused area for my relay shunt circuit I will be working on.
I have an aversion to SE.
Its fine for hooking up a TV, but that is about it imo.
Once Søren releases a firmware update that will allow dual mono I switch across but until then...
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But since the signal is originally SE and is "in a bad way" converted to balanced, you should at least try it - or put a transformer on something else like that on the output to convert to balanced.
Now why would I spend $300 on transformers as a stopgap measure?
How many have listened to the buffer after a decent burn in? I had the DAM running for about 220 hours on a burn in track while I was away on holidays. It's in no way scientific, but It seemed to be smoother sounding after that treatment. Someone actually recommended giving the DAC 400 hours on pink noise,.
The DAM has also been powered 24/7 for the last couple of months,
Perhaps it makes no difference but tbh I don't hear the buffered output as being particular bad. The op amps used are widely regarded as being some of the best available..
How many have listened to the buffer after a decent burn in? I had the DAM running for about 220 hours on a burn in track while I was away on holidays. It's in no way scientific, but It seemed to be smoother sounding after that treatment. Someone actually recommended giving the DAC 400 hours on pink noise,.
The DAM has also been powered 24/7 for the last couple of months,
Perhaps it makes no difference but tbh I don't hear the buffered output as being particular bad. The op amps used are widely regarded as being some of the best available..
With due respect that is just silly.
Balanced connections almost inevitably involve additional and often compromised circuitry. Their popularity is due in a large part to the marketing noise in some corners of the audiophile market. In a domestic audio system they add nothing and usually take a lot away.
That is your opinion, which your are entitled to. Based on my listening experiences I disagree, but that is my opinion. After all IMO = In MY Opinion and means exactly what it says.
FWIW This is what Nelson Pass wrote in one of the BOZ article.
My previous DAC was fully balanced with two pcm63p per channel, and it always performed far better running balanced than SE.
As I posted, I'm waiting on a dual mono update to the firmware at which point I'll run unbuffered balanced outputs. I've got little interest in applying special seasoning and sauces in the form of valve buffers, trafo, or whatever...
The only thing I've seriously considered doing and may still depending on how long we have to wait for the firmware, is that I'll possibly build up a THAT1646 unbalanced to balanced converter and see how that goes. I have a couple of chips sitting a box somewhere just a matter of rigging them up and building a power supply.
Spzzzzkt you have said that you don't want to start modifying the dac until you're done with the filter experiments. You think the filters are the most significant factor. I would agree. Yet many have stated that there is a significant improvement in quality of sound via the direct out connection, avoiding the inbuilt conversion to balanced. You have a cost free possibility there to better hear your filter experiments, and yet you refuse to try it. I'm sure I'm not the only one who doesn't understand that.
Looking at Douglas Self's list of advantages and disadvantages of balanced interconnects in his book on Small Signal Audio Desin
I see for the usual short wired and well controlled situation at home only the typically more noisy input as item of importance.
Moreover if you look at the output of the DAM of an single 1/(64*44100) second pulse you see that it looks different.
SE:
Balanced:
There will probably be no impact at the audio frequency range, but, as I interpret the images, there is some smoothing of (unwanted) very high frequencies at the balanced output. You might see that as an asset or an fault of the balanced output, your choice.
I see for the usual short wired and well controlled situation at home only the typically more noisy input as item of importance.
Moreover if you look at the output of the DAM of an single 1/(64*44100) second pulse you see that it looks different.
SE:
Balanced:
There will probably be no impact at the audio frequency range, but, as I interpret the images, there is some smoothing of (unwanted) very high frequencies at the balanced output. You might see that as an asset or an fault of the balanced output, your choice.
I don't need to understand; it's entirely for Spzzzzkt to make the decisions about he builds his kit.
Ray
I have send a mail, and the answer was it "No new production was planned, so minimum, so could take a couple of months, maybe more...
I don't know why.
If you were doing any component comparison how would you do it?
Basically,
a) Listen to filter "a" to establish a baseline.
b) Switch to filter "b" and listen to determine comparative differences and assess whether the change is positive, negative, or a combination of the two.
c) Switch back to filter "a" and listen again and verify you are actually here the difference you thought you were hearing.
d) Switch between "a" and "b" until you have a good feel for the differences then decide if "b" brings an overall gain in quality.
The important thing is to limit the variables, and focus on differences between filters. The differences between two variants are usually fairly apparent, especially when you are using a small selection of reference tracks.
I've done comparisons with three other DAC's at various points, but it's not especially useful. The DAM with stock filters was pretty close in tonal balance to a NAD M51 a friend owns, and the other two DAC's I own are a lot darker sounding, but they also sound very dark against the M51.
More recently I've also been doing reality checks vs Audirvana+'s Izotope SRC upsampling to 352.8kHz (which bypasses FIR1) to make sure things are not going too far astray. Given that the Izotope SRC is probably the best that is readily available and I can switch between the internal DAM filters and Izotope fairly rapidly it makes a good reference for direct comparison.
So the focus is on comparative changes in a specific setup. Providing the setup is constant and only a single element is altered at a time - the filters in this case - I believe the results are valid. It does mean that I can't use feedback that I can't verify on my system.
Even if the method was completely flawed, I upload any filters I think are of interest and anyone who is even remotely interested can download and listen for themselves. I trust that those who do so are sufficiently intelligent to be able to make up their own minds what works in their system and what doesn't.
There is enough information in the filter threads for anyone build their own filters. It is a Do It Yourself Audio forum after all.