You can see the Rev Dac and about 10 supercaps on board.
The fallowing rails use SC. All clocks , all buffers (MCLK) and Avcc uses Murata with 45mR esr in parallel with another supercaps (2F) in total.
Furthermore the analog stage (opamps) have also supercaps that help decouple analog stage (especially the bass peaks) from the DC/DC convertor
DC/DC convertor has its own Gnd separated from main GND using common mode chokes..in series. We are using 4 CMC.
All switching elements are under shield .
Analog stage uses pre IV filter (not easy).
Final THD -125 !!!! (better than datasheet) THD+N at floor of our AP (-114.4)...on RCA output this is the best tested Dac
However Revolution is not about THD only . We took the time and listened.
We found the RFI on I2s lines is detrimental to sound quality and using a clever circuit we removed all RF on i2s. Almost no change on THD and yet better sound .
The fallowing rails use SC. All clocks , all buffers (MCLK) and Avcc uses Murata with 45mR esr in parallel with another supercaps (2F) in total.
Furthermore the analog stage (opamps) have also supercaps that help decouple analog stage (especially the bass peaks) from the DC/DC convertor
DC/DC convertor has its own Gnd separated from main GND using common mode chokes..in series. We are using 4 CMC.
All switching elements are under shield .
Analog stage uses pre IV filter (not easy).
Final THD -125 !!!! (better than datasheet) THD+N at floor of our AP (-114.4)...on RCA output this is the best tested Dac
However Revolution is not about THD only . We took the time and listened.
We found the RFI on I2s lines is detrimental to sound quality and using a clever circuit we removed all RF on i2s. Almost no change on THD and yet better sound .
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A few more words about sound of this Dac
It was our main focus to get the best sound out of ess9038q2m
The challenge was that ess9038 can sound "bright" . What I have found is thats false , the bright sounds comes from datasheet textbook implementation . You can see in the datasheet that RC filtering is far from ideal (hi cutoff frequency)
We corrected that and used a MFB filter (multiple feedback) on summing with filter before IV and filter after IV. We never had a real ess hump since we took the time and discarded the filter from datasheet
Rev was made for audiophiles and for my many friends here that pushed us to consider SQ . Still...SQ is not to be taken at the expense of THD. Both can be delivered .
To me, Rev sounds almost dark (not bright at all. read above about filtering) with the greatest musicality I heard from ess9038q2m ( RF reduction). Bass is controlled and strong (might be the SC and plenty of power on rails)
Reviews will come rather soon .
Make no mistake....this is an audiophile Dac (with many changes done to make it sound great) that happens to be also the best THD Dac (on RCA) in the world. Further , I have found a clear link between what audiophiles advocate (plenty of power /low impedance) and better THD especially at higher harmonics
It was our main focus to get the best sound out of ess9038q2m
The challenge was that ess9038 can sound "bright" . What I have found is thats false , the bright sounds comes from datasheet textbook implementation . You can see in the datasheet that RC filtering is far from ideal (hi cutoff frequency)
We corrected that and used a MFB filter (multiple feedback) on summing with filter before IV and filter after IV. We never had a real ess hump since we took the time and discarded the filter from datasheet
Rev was made for audiophiles and for my many friends here that pushed us to consider SQ . Still...SQ is not to be taken at the expense of THD. Both can be delivered .
To me, Rev sounds almost dark (not bright at all. read above about filtering) with the greatest musicality I heard from ess9038q2m ( RF reduction). Bass is controlled and strong (might be the SC and plenty of power on rails)
Reviews will come rather soon .
Make no mistake....this is an audiophile Dac (with many changes done to make it sound great) that happens to be also the best THD Dac (on RCA) in the world. Further , I have found a clear link between what audiophiles advocate (plenty of power /low impedance) and better THD especially at higher harmonics
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Path to our Nirvana
The Buddha said: "One who is willing to attain Nirvana, has to understand Four Noble Truths. These Noble Truths are the key to attain Nirvana, without proper understanding of Suffering, Cause of Suffering, Relief of Suffering and the way to end Suffering, These are the four Noble Truths.
1.Suffering
We found noise on 6Khz and all efforts for at least one year were to remove the noise
2. Cause of suffering
We took a long time to understand the noise root...finally we got it, spread spectrum from the TI chip , a technique that modulates the switching with +- 6Khz to reduce EMI
3.Relief of suffering
Our main engineer found a nice trick to disable the spread spectrum feature
4. End of suffering
Manufacturing .
Tomorrow I will post the first pics of Nirvana final version . Manufacturing is expected early next week for full 1500 units. Note that we foresee great demand...
Furthermore we already place order for 3k units but due to "situation" everything is delayed and next batch will take at least 2.5 months. We will be out of stock
Nirvana equals a very good LPS.(and is significantly better than most LPSes) However , in my opinion it is slightly less than Shanti (must be those supercaps and the fact that our LPS has plenty of power in reserve and output wire)
Still for the price and convenience , Nirvana is in a class by itself . Noise of 1uV or less over the entire 0-20Khz including mains frequency , earthed output , AC filter (with both CMC and L for common mode and differential noise). Over 4000uF on board! All this in real world situation . no readings were done with isolation transformers .
The Buddha said: "One who is willing to attain Nirvana, has to understand Four Noble Truths. These Noble Truths are the key to attain Nirvana, without proper understanding of Suffering, Cause of Suffering, Relief of Suffering and the way to end Suffering, These are the four Noble Truths.
1.Suffering
We found noise on 6Khz and all efforts for at least one year were to remove the noise
2. Cause of suffering
We took a long time to understand the noise root...finally we got it, spread spectrum from the TI chip , a technique that modulates the switching with +- 6Khz to reduce EMI
3.Relief of suffering
Our main engineer found a nice trick to disable the spread spectrum feature
4. End of suffering
Manufacturing .
Tomorrow I will post the first pics of Nirvana final version . Manufacturing is expected early next week for full 1500 units. Note that we foresee great demand...
Furthermore we already place order for 3k units but due to "situation" everything is delayed and next batch will take at least 2.5 months. We will be out of stock
Nirvana equals a very good LPS.(and is significantly better than most LPSes) However , in my opinion it is slightly less than Shanti (must be those supercaps and the fact that our LPS has plenty of power in reserve and output wire)
Still for the price and convenience , Nirvana is in a class by itself . Noise of 1uV or less over the entire 0-20Khz including mains frequency , earthed output , AC filter (with both CMC and L for common mode and differential noise). Over 4000uF on board! All this in real world situation . no readings were done with isolation transformers .
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Frankly I will think on it. The issue is that our DACs shine with good PSUs. The soundcheck challenge used a few times one PSU on Katana and tested vs DACs that were designed for one PSU... not ideal .
At last they did test with dual LPS (as we asked since day one) and ok it seems it sounded good...
So frankly I was not that happy.
Is there any voltage sag on Nirvana & Shanti, do you know? A lot of SMPS have some voltage sag at higher amperage.
Will you be taking preorders?...I expect shipping will be first half of June based on your description?