Do you by chance have THD and IMD measurements with the OPA140 in MyRef FE? I haven't seen them following your link.
I wasn't familiar with the Mod86 project, but looked it up after you mentioned it. It is clearly a similar amp to the MyRef, with balanced input and using a servo to control DC bias. Another alternative is the Twisted Pear Sympatico that is designed as a fully balanced, higher power amp of similar design. I haven't experienced either Mod86 or Sympatico. Both seem to be solid designs, however, I imagine that the MyRef and FE have gotten more development with a wider group of people building and experimenting with them. I think that the wider community represents more support for builders and, likely, better choices for better sound. Of course, in the end, it comes down to personal choice.
Jac
Finished the soldering part...
For all those with a trained eye, do you see any mistakes? Or bad solder joints, or...
And a comparison with mod86 would be really nice! Out of those 2 I choose the FE because of the hard work of Dario and his 'comrades' in those early threads. But if somebody could tell the differences in sound signature, I would be really curious
For all those with a trained eye, do you see any mistakes? Or bad solder joints, or...
And a comparison with mod86 would be really nice! Out of those 2 I choose the FE because of the hard work of Dario and his 'comrades' in those early threads. But if somebody could tell the differences in sound signature, I would be really curious
Attachments
Mod86 has been tweaked somewhat, but the general attitude of the designer and other posters on its two long threads is one of 'the measurements are already so close to perfect you'll never improve on them and even if you by some fluke manage to, it won't sound any better than it already does'.
OTOH MyRef seems to have been subject to many refinements based on listening and measurements appear to me to be somewhat secondary to enjoying its sound.
I am looking at the Mod86, the MyRef, and the Sympatico, each design seem to have its strengths and limitations. I really am interested in a technology combination. I have measured the MyRef in the original thread after some tweaks and found some qualities I like, and correspond with my listening experience, the full balanced design of the Sympatico is also interesting, I think there is also a version of the Mod that has that as well. The Mod86 has really low distortion which looks good on paper, but I still need to get it together to listen to it and measure as well.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Very nice build! I see You did not save on quality..
And I'm sure You will get warmly rewarded for your efforts!
I see only a little bit of difficulty in connecting speakers to it,
but I think You will be able to manage also that (Joking!!)
Thanks! Hope it does... Connecting speakers should be possible, I will try to solder the wires directly on the board. But there isn't that much space
Seems a pretty good job
But if somebody could tell the differences in sound signature, I would be really curious
Never heard the Mod86 but we can make some educated guesses from parts selection.
The first big difference in sound should be due to the opamp, the LM318 has a tubey signature and is slightly warmer than LME49710.
The LME49710 is more detailed than LM318 but part of this detail will be masked by the ordinary resistors and C0G ceramic capacitors of the Mod86's BOM.
I expect that the Mod86 will be a bit more neutral but less rich in harmonics, sound decay decay and reverbs than the Fremen Edition.
After that there will be other differences due to the different circuit topology and solutions but for those a listening session is necessary.
As you are probably aware, the Sympatico was designed by Russ White who was involved with the first generation of the MyRef pcb. He is a talented designer, for example the Buffalo III DAC was highly regarded. Many years ago, I bought an Opus DAC pcb from Twisted Pear. I asked a question about it on their forum but got no reply from either Twisted Pear guys or other forum members. In my opinion, there isn't much support from TP and the design is Mr. White's vision alone. That's not necessarily bad, but very different from the conversation we are having here. In the end, that's why I decided to go with the FE MyRef instead of Sympatico.
In the spirit of Dario's comments on the character of components, I have some experience with the LM4562 and OPA1632 which are used in the Sympatico. I would characterize the LM4562 as detailed and low noise, but cool (as in the opposite of warm). The OPA1632 seemed pretty neutral in the application that I tried it.
One other thought. If you are planning on comparing the Mod86 to the original MyRef, maybe you should add a recent version of the FE to the comparison. Although I haven't made a direct comparison, inmates that have said the FE was a nice improvement over the original.
Jac
Last edited:
What regards the sound of the other designs, in particular the LME497xx family, I know that this project of our member here, mzperx, had started out as a fully differential design with 3886-s and LME49720 in the control. After listening tests, they quickly changed to the OPA1632.
https://docs.google.com/file/d/0BzbIeQI27LjoV21seUw4MG5jQWs/edit
But it is not Tom's modul.
Then, I always wondered what effect the extra THAT input stage brings to the final sound? I have to see yet a stage with zero influence.
On the other hand, from my own little experience I start to understand that for loop stability it might be a better option to anchore down, define well the input / output conditions for the main controller element, especially if it is a bipolar amplifier like the 49710.
Then, in Tom's modul he had chosen a low total closed loop gain, that is, the amp is dead like a brick..
All this for having, reserve, more loop gain for better looking distortion tests.
Also, the low total gain gives less noise in output, which is not bad, because of the high input noise contribution of the THAT chip.
These are my observations, not my opinion on quality.
On the other hand, the myref has a simple gain structure with less input noise, especially with the new fet opamps. They also alleviate on the necessity on input signal conditioning. Also the loop gain is not driven to the extremes, with the consequential more relaxed stability conditions.
And the measurements, in my humble opinion, despite the much more relaxed gain structure, are not that far from the other design.
Would like to point out that at .0001% Thd, I'm at my tools measurement floor, who knows what are the real values, how low we are below, in the Myref / FE modules?
Ciao, George
https://docs.google.com/file/d/0BzbIeQI27LjoV21seUw4MG5jQWs/edit
But it is not Tom's modul.
Then, I always wondered what effect the extra THAT input stage brings to the final sound? I have to see yet a stage with zero influence.
On the other hand, from my own little experience I start to understand that for loop stability it might be a better option to anchore down, define well the input / output conditions for the main controller element, especially if it is a bipolar amplifier like the 49710.
Then, in Tom's modul he had chosen a low total closed loop gain, that is, the amp is dead like a brick..
All this for having, reserve, more loop gain for better looking distortion tests.
Also, the low total gain gives less noise in output, which is not bad, because of the high input noise contribution of the THAT chip.
These are my observations, not my opinion on quality.
On the other hand, the myref has a simple gain structure with less input noise, especially with the new fet opamps. They also alleviate on the necessity on input signal conditioning. Also the loop gain is not driven to the extremes, with the consequential more relaxed stability conditions.
And the measurements, in my humble opinion, despite the much more relaxed gain structure, are not that far from the other design.
Would like to point out that at .0001% Thd, I'm at my tools measurement floor, who knows what are the real values, how low we are below, in the Myref / FE modules?
Ciao, George
Last edited:
Off Topic, but fun anyway
That's a good one!
I did more or less the opposite. I built one of SY's valve phono preamps. I plugged it in and nothing happened, no lights. I quickly unplugged it and started looking for blown fuses. It took me a while to remember that valves need time to warm up.
Jac
Good luck!
When I started up mine inside the enclosure I saw a red light starting up! I thought that's it...I fried it.
I had forgotten that it has led's soldered on the board! Phew.
That's a good one!
I did more or less the opposite. I built one of SY's valve phono preamps. I plugged it in and nothing happened, no lights. I quickly unplugged it and started looking for blown fuses. It took me a while to remember that valves need time to warm up.
Jac