Hi, I am using Rossini apex amd planning to change Soulution 5 seris amp.
When connecting to rossini, would you recommend to use Soultion 525 pre and 511 stereo amp together or just rossini to 511 power is good enough?
By the way, the speaker is Marten mingus quintet2.
Simon, you affectively sked this 3 days ago, I wrote an answer which you read and correctly concluded:
Pete,
Thanks for the reminder. The 511 delivery is nextweek and the dealer suggest 525 is “ dramatically” improved the sound.
By the way, currently , 525 for home demo is almost impossible as the dealers have only one demo unit. I am buying 511 without testing at home….(from Next imports the price will go up 15%, so the dealers wants to keep a current shop demo unit not allowing home demo)
Simon, always be reasonably sceptical about dealer’s recommendations. They might be correct but ultimately they are trying to sell you something. An honourable objective but you don’t have to play along.
If you cannot arrange a trial then your choices are to buy the preamp and sell it if you do not like it or not buy it and spend your time wondering if you should have.
Most dealers will not arrange home trials unless you are a regular and a known customer with a good reputation. Even then you may need to buy the unit guaranteeing that the dealer is not risking leaving it with you but with an arrangement it can be returned within a limited period. Your local consumer law may help in this.
It depends where you are and the dealer
Pete,
Thanks for the comment.
The situation is that the different dealers carry differrent brands as a main ( full line up). My main dealers are 3 as they carry different brands as a main (eg. dCS/ Wilson, aurender/ Yg acoustics, Marten/Soulition, etc)
If you are familier with Soulution, last year they launched 3rd gen 3(entry) and 7 (top end) . I suspect In two years they will launch 3rd gen 5 series. So, the dealer offers me a good price for 525 preamp. I believe the dealer is in good intention when offering 525 preamp.
Once I used Pass X600.8 directly connecting to Rossini, then later I added xp32. The result was the highs are better (clearer) and with more airyness. I added aurender n20 for the same reason. With/without seperate streamer the sound is subtly diffrent and the effect was very dependent on associated gears and the space. I know this because hearing the target product at dealers with different gears and in different room size/ reflections from home is totally misleading the target gear evaluation.
After using 511, if satisfied i will get a used 525 as there will be 3rd gen 5 series in a few years time. or try a different brand.
By the way, my living room sytem of YG sonja 3.2 and Mastermind 845 monoblocks with dCS Bartok apex is so satysfing, I do not feel any need for upgrade. In a smaller study, room acoustics are worse for full high to low frequency, therefore I keep changing gears…
The use, or not, of a preamp usually comes down to personal preference (as Pete says) and of course how many sources are in use, and also perhaps the need to drive headphones. But I wonder at what point a lower than usual input impedance of the power amp - even within the limits specified by dCS for their dacs - becomes subtly audible. Soulution specify, I think, a 2 kOhm input impedance (balanced) for the 511, and dCS state a minimum requirement of 600 Ohms but with 10 kOhm or greater preferred. I think Stereophile have tested dCS dacs into 600 Ohms to confirm their performance, but tend to refer to that load as “punishing”.
Perhaps that brings us back to personal preference again.
Simon_C
I haven’t thought about impedance maching.
dCS clearly recommend over 10K ohm amp’s input impedance where Soulution 511’s imput impedance is only 2kohm.
My dealer did not inform me about this issue.
Natually, I will cancel 511 and look for other brand.
I sincerely appreciate your valuable advice !!
Although dCS recommends 10-100K Ohms, the minimum is specified as 600 Ohms. 2K Ohms lies within this range. This is not a subjective issue but relates to the efficient transfer of power in accordance with Ohm’s law and concerns the ratio of source to receiver impedance. I trust the guys at dCS to have calculated this correctly 
so 2K Ohms is acceptable if not ideal. if not then Soulution preamps should not be used with Soulution amps as their specified output impedance is 3 times that of the Bartok 
.
I think that you are in danger of over thinking this and may start to hear things even if they do not exist.
Note for @Phil or @James . Researching this I checked the latest Bartok manual ( Doc. DCS311659). This has acceptable input line input as maximum 600ohms and recommended 10-100K. That does not make sense ( at least to me) and maximum should read minimum, no?
Pete,
As you mentioned i am rhinking about this too much as the delivèry/payment is next week. Anyway I will cancel the order explaining the situation.
Thanks
The manual is correct. “Maximum” is the right term because it’s a difficult load the lower the impedance gets, hence the use of “maximum”. This was discussed not too long ago
That thread wanders around and spends time concerning supported sample rates.
Anyhow if AndrewS was puzzled and Phil says it is right but sounds wrong then it needs beater explanation as 600 ohms appears not to be the same thing as the rimpedance rage recommended for the source output.
And Simon does indeed need to cancel his order.
Just to clarify:
The lower the input impedance of a device, the higher the current drawn.
Maximum 600 Ohms means maximum current, which can be drawn from the outputting device.
Thanks Martin but the unit of current is ampere not ohms ( impedance). The specification is in ohms so it cannot be current. So even if your argument is correct it still requires rewording to avoid th econfusion which we all seem to have.
It does not need rewording Pete. The term is correct, and unfortunately its a term that requires some level of Electrical Engineering knowledge to make sense. It’s not intuitive otherwise.
Part of the Electrical Engineering knowledge @Anup mentions above is Ohm’s law (Voltage=Resistance*Current).
Ohm’s law: a law stating that electric current is proportional to voltage and inversely proportional to resistance.
This is a user manual, not a module in an IEE course. It has to be understood by the average reader even if it is correct otherwise and dCS needs to understand this. It is not to please engineering pedants but to tell people like me how to use the equipment.
Sorry Pete, I completely disagree.
There are many other aspects detailed in the Manual that mean very little to the average non-technical lay person and requires explanation (as we’ve seen numerous times here on dcs.community).
In the case of this particular specification, “Maximum Load” of 600 Ohms is absolutely the correct terminology. It’s a terminology that is commonly used in other technical reviews, as well as on Stereophile for decades.
Just because it seems unintuitive doesn’t mean a well understood and technically correct term should be dumbed down.
Completely? So you do not agree that a manual “Has to be understood by the average reader” ?
There is no need for the terminology to be technically incorrect. Rewording may just mean that the apparent contradiction between maximum 600 ohms and the minimum recommended load of 10Kohms in the specified range simply needs or further explanation.
We have ample evidence ( see thread and links) that it is casing confusion.
Being correct only may be good engineering but poor communication.
If every single technical term had to be written to suite the average non-technical reader the Manual would be 500 pages long 
Other than that one other thread raised by Andrew, and now this one, it hasn’t come up before. So, I hardly considered it as “ample evidence”.
There’s no poor communication in what’s in the manual. It’s concise and technical correct. Trying to add explanation beyond what’s in that specification is both unnecessary and unwarranted.
Thanks for all the opinions about dac→(preamp)→ amp connection from impedance matching point.
Before I judge with my ears, I wanted to satisfy maker’s recommendation.
Let me quote chat gpt’s reply.
“The dCS Rossini APEX is a high-end DAC with a sophisticated output stage. The relationship between the output impedance of the source (the DAC) and the input impedance of the amplifier is crucial for optimal performance.
According to dCS specifications and various reviews, here is the breakdown of the dCS Rossini APEX’s output impedance and the recommended input impedance for a connected amplifier.
Output Impedance of the dCS Rossini APEX:
Balanced (XLR) outputs: 3Ω (ohms)
Unbalanced (RCA) outputs: 52Ω (ohms)
Recommended Amplifier Input Impedance:
dCS recommends a maximum load of 600Ω for both balanced and unbalanced outputs.
More specifically, they recommend an amplifier with an input impedance in the range of 10kΩ to 100kΩ.
Why this matters:
A general rule of thumb in audio engineering is to have the input impedance of the amplifier be at least 10 times, and preferably much more, than the output impedance of the source component.
The dCS Rossini APEX’s balanced output impedance is extremely low at 3Ω, and its unbalanced output is 52Ω.
By recommending a minimum input impedance of 10kΩ for the amplifier, dCS ensures that the amplifier presents a very light load to the DAC. This allows the dCS Rossini APEX to operate in its ideal working conditions, preventing signal degradation and ensuring the best possible sound quality.
In summary, when pairing an amplifier with the dCS Rossini APEX, you should look for one with an input impedance of at least 10kΩ. The higher the input impedance (within the recommended 10kΩ - 100kΩ range), the better the DAC’s performance is likely to be.”
In summary, to fully extract Rossini’s potential, I need to connect dcs to (pre) amp with 10k ohm to 100k ohm where 100k ohm is the best. Therefore, dCS to Soulution 511 with 2.5k ohm will not extract full potential of Rossini apex. For dCS l, general rule of “ouptut impedance of source/ preamp × 10(or 20)= input impedance of amp” doesn’t appy.
For the premium product like dCS should clearly indicate best/recommended numbers only.
What ‘s the implication of stating maximum impedance of 600 ohm where recommended number is 10k to 100k ohm? It just confuse the customers. They do not buy dCS for compromised performance.
