Max. Vin for tent shunt
Hi Doede,
I am running the dddac with battery power and use as regulator a belleson super reg.
I use the belleson in other circuits as well and I am very impresed by them. The 10V regs on the decks are not so high grade and I think of removing them and feed the tent shunts direct with the 12V out of a belleson instead of the 10V ot of the 7810.... is this ok?
Thanks and greetings
Christian
Hi Doede,
I am running the dddac with battery power and use as regulator a belleson super reg.
I use the belleson in other circuits as well and I am very impresed by them. The 10V regs on the decks are not so high grade and I think of removing them and feed the tent shunts direct with the 12V out of a belleson instead of the 10V ot of the 7810.... is this ok?
Thanks and greetings
Christian
Hi Christian,
Doede answered this when I asked the same question:
http://www.diyaudio.com/forums/digi...pcm1794-waveio-usb-input-514.html#post4686132
Doede answered this when I asked the same question:
http://www.diyaudio.com/forums/digi...pcm1794-waveio-usb-input-514.html#post4686132
I hope this is OK to ask here, if not admin please delete.
I would like to try a set of cinemags but some say they sound good and others that the DAC sounds better with Cap outputs. I wondered if anyone has a set gathering dust that they would like to part with, or even loan me to try so that I could decide if the sound is better or not?
I would like to try a set of cinemags but some say they sound good and others that the DAC sounds better with Cap outputs. I wondered if anyone has a set gathering dust that they would like to part with, or even loan me to try so that I could decide if the sound is better or not?
Cinemag VS Capacitor
Today i got the small cinemags. I just have a 2 Deck so i ordered the small ones.
Compared to the capacitors (Mundorf silver oil) the cinemags have very detailed highs but lag a little bit in bass. also the depth of the stage seems to be better with the capacitor...
Anybody else who would say that capacitor is prefered against the caps?
Or do they need some time to perform?
Is there a big difference to a 4 deck dddac with better transformers?
Thanks and greetings
Cristian
Today i got the small cinemags. I just have a 2 Deck so i ordered the small ones.
Compared to the capacitors (Mundorf silver oil) the cinemags have very detailed highs but lag a little bit in bass. also the depth of the stage seems to be better with the capacitor...
Anybody else who would say that capacitor is prefered against the caps?
Or do they need some time to perform?
Is there a big difference to a 4 deck dddac with better transformers?
Thanks and greetings
Cristian
I have the Cinemags, and I prefer them compared to caps and the Sowter trafo’s. It all depends on personal taste and what kind of setup you have.
The Sowter’s was a bit to much for me. They had to much level in the bass heavy for my speakers. Caps soften the sound a bit to much, with less dynamics.
Cinemags sounds analog, have a lot of details and are a bit on the warm side.
But this is in my setup. A friend of mine prefer the Sowter’s.
Obs,,, I forgot to mention that I have choke input psu, and espesially the bass improve a lot with this kind of psu.
The Sowter’s was a bit to much for me. They had to much level in the bass heavy for my speakers. Caps soften the sound a bit to much, with less dynamics.
Cinemags sounds analog, have a lot of details and are a bit on the warm side.
But this is in my setup. A friend of mine prefer the Sowter’s.
Obs,,, I forgot to mention that I have choke input psu, and espesially the bass improve a lot with this kind of psu.
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Hi Alabama,
do you have some more information's regarding the buffers? I am using just 2 Decks, so maybe a buffer could help?!
Thank's and greetings
Christian
Hi,
By buffer I mean an active output stage. Tx is short for (output,) transformers.
As described I first used an SE valve output stage with and without txs, then tried the 'unbalancer' to take advantage of the balanced output and that was the best sound of all IMO
I have been wanting to try the transformers myself. I'm currently running single ended into an Aikido preamp. Looking at the cinemag specs a couple of things come to mind. The transformer is optimized for a 600ohm driving impedance. That means that a single board would need some resistance added in series in order to get to 600ohms. The stock output Z in balanced mode with 1 board would be about 270ohms. Another issue would be dc offset between the +and- dac outputs. On my dac one of the channels has 1mv and the other 6mv of offset. These small input transformers are not going to like any dc offset so it would be best to deal with it before going to transformer output. Even a small mismatch of the output resistors will result in a dc offset. With roughly 2.7 volts of dc on the +and- dac output even a small mismatch from 1% resistors will result in an offset. This could be adjusted out by paralleling a suitable resistor across the output resistor with the highest voltage.
Another issue is the termination impedance for the transformer output. If it isn't terminated properly then you will get frequency response issues. Since it is an input transformer, it really should reside in the preamp. If you put it in your dac and use long cables, the HF response will be effected and it will be easier to pick up noise due to the highish output impedance of the transformer. There are lots of things to optimize so that you get the best sound from the transformer. All this is before you take into account your personal preferences and goals for voicing your system.
Another issue is the termination impedance for the transformer output. If it isn't terminated properly then you will get frequency response issues. Since it is an input transformer, it really should reside in the preamp. If you put it in your dac and use long cables, the HF response will be effected and it will be easier to pick up noise due to the highish output impedance of the transformer. There are lots of things to optimize so that you get the best sound from the transformer. All this is before you take into account your personal preferences and goals for voicing your system.
Hi Bfpca
i am using the small cinemag... the CMLI-15/15B what has 18kOhm input impedance!
With this high impedance i don't think, that a small DC-offset is a big problem.
But: i think i have soldered a to high load resistor at the output of the transformer. What i have read is, that this could be the reason for the missing bass (or harsh highs)
Will try to change the resistor
Greetings
Christian
Hi Bfpca
i am using the small cinemag... the CMLI-15/15B what has 18kOhm input impedance!
With this high impedance i don't think, that a small DC-offset is a big problem.
But: i think i have soldered a to high load resistor at the output of the transformer. What i have read is, that this could be the reason for the missing bass (or harsh highs)
Will try to change the resistor
Greetings
Christian
Christian
The 18k figure is the reflected impedance with a load of 15k on the secondary. It includes the 15k + the series resistance which adds up to be 18k. That would be the load seen by the driving stage of the DDDac if the transformer is properly terminated with 15k on the output side.
The source impedance, which is usually referred to as Rs, is specified for the graphs in the data sheet as 600ohms. This can really become an issue when dealing with a capacitor coupled preamp that is driving an input transformer in an amplifier. A small output capacitor will have a large impedance at bass frequencies even though it may meet the spec at say 1khz. For the DDDac even a single board should have a low enough impedance to drive the cinemag CLMI15. The best plan is to use the recommended impedances, measure the frequency response and look at the square wave output on a scope to see if you are getting good results.
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I know that Doede did exactly this with the Sowter trannies (I'd guess the results are somewhere on the DDDAC1794 website). I would be surprised if he didn't do the same tests with the Cinemags, too. The Sowter transformer was designed to cope with a bit of DC imbalance without running into saturation. I think the Cinemags are quite tolerant with this, too.
I’m sure Doede did his homework on the recommended transformers. There are a lot of variations on how they will be implemented by the DIYer in terms of the termination impedances etc. It’s really no surprise that some people like them and others don’t. There are just so many variables in the overall sound signature of any system, as well as in the preferences of the listeners. I just wanted to mention possible issues that can impact the sound when you use transformers. They are definitely not plug and play for every system.
I have been having a lot of difficulty getting a consistent sound signature from my system lately. I have made so many changed recently, including adding the DDDac1794 to the mix, that I have not yet got the sound where I want it. I have found that many times a change will sound good initially but after listening to a range of music over a longer time problems show up. At that point I usually make some electrical and/or acoustic measurements to try to identify a technical reason for the changes. Quite often I find a frequency response issue is behind the problem. This can happen with a transformer that is not implemented correctly. I was running my DDDac with balanced outputs into an Aleph P clone but that preamp had some issues and I changed to single ended to try an Aikido preamp. Next I want to build a tubed balanced preamp or use the cinemag transformers to go balanced again. I am only running a single board at this point. I have tried the spdif input and it works pretty well but I prefer the USB with 44.1 cd files. I have had some inconsistent result with upsampling 44.1 to 176 and 352 using Pure Music 3.06. For my system it generally seems to add more HF energy as well as more resolution of ambience. I have however had some issues with the upsampler causing digital clipping on some tracks. I’m not sure why this would happen. it may be a bug in the upsampler. It caused me some concern until I figured out what was going on. It was clearly audible on some tracks. All part of the computer based audio adventure I guess.
I have been having a lot of difficulty getting a consistent sound signature from my system lately. I have made so many changed recently, including adding the DDDac1794 to the mix, that I have not yet got the sound where I want it. I have found that many times a change will sound good initially but after listening to a range of music over a longer time problems show up. At that point I usually make some electrical and/or acoustic measurements to try to identify a technical reason for the changes. Quite often I find a frequency response issue is behind the problem. This can happen with a transformer that is not implemented correctly. I was running my DDDac with balanced outputs into an Aleph P clone but that preamp had some issues and I changed to single ended to try an Aikido preamp. Next I want to build a tubed balanced preamp or use the cinemag transformers to go balanced again. I am only running a single board at this point. I have tried the spdif input and it works pretty well but I prefer the USB with 44.1 cd files. I have had some inconsistent result with upsampling 44.1 to 176 and 352 using Pure Music 3.06. For my system it generally seems to add more HF energy as well as more resolution of ambience. I have however had some issues with the upsampler causing digital clipping on some tracks. I’m not sure why this would happen. it may be a bug in the upsampler. It caused me some concern until I figured out what was going on. It was clearly audible on some tracks. All part of the computer based audio adventure I guess.