The wording and specs for the input impedance requirements is correct in the manual, I do understand that it can be confusing but so can lots of different specs (as has been discussed) … RF SNR’s always stop me in my tracks while I try to work them out!
There should be absolutely no issues with @Simon2 connecting a dCS DAC to the input of a Soulution as it is well over the 600 ohm input impedance specified in the manuals. However, 2.5k ohms is quite a low impedance for an input - the norm for an audio input is 10k or above.
What do you mean by dCS →Soulution 511 (2.5k ohm) causes no issue while recommended amp’s inout impedance is over 10k ohm. Also what do yoi mean amp’s input maximim 600 ohm? I know 511’ 2.5k ohm inout impedance is unusually low compare to other amps. The point is I want ro set up the system where I can fully extract dCS’s potential, not just making sounds.
If not, why did I buy a premium/expensive product? I do not want make a compromised connection. Maybe I would keep an existing Pass xp32 preamp (input impedance of 42k ohm) and buy soulution 511 instead of trade-in the xp32.
I’m sorry if we’re being confusing … the analogue output from the DAC can drive into an input impedance of down to 600 ohms. This is the lowest impedance that will not affect performance however normally input impedance is 10k or higher so that is recommended.
If the dCS’s performance is in same level at 600 ohm and 100k ohm, the manual should say “Recommended” imput impedance of (pre) amp is over 600 ohm. This is simply and clear average customers.
After long list of replies, my final conclusion is that no one can surely say the range of best input impedance range of amps for dCS direct connecting.
Officially the recommended range is 10k~100k ohm from dCS.
AI programs answer input impedance which is 10 times more than output impedance of dcs will cause no problem whith is 30 ohm (3ohm ouyput of dcs ×10)
Phil’s final answer is 600ohm or above will not be a problem.
The two power amp I am interested in are both out of dcs’ recommended range.
One is 2.5k ohm of Soulution 511, and
The other is 1mega ohm of Dan Dagostino s250.
AI says two amps above will not have any impedance problems when directly connected to dCS.
To be safe, I decided to keep Pass xp32 (input impedance of 42k ohm) and get and connect Soulution 511 to Pass xp32.
Then I will try and compare;
Rossini→xp32→soulution 511. and
Rossini→soulution 511.
My gut feeling is both connections would not have any impedance problems. However due to xp32’s coloration, the connection with xp 32 will be slightly warmer and organic.
I arranged Soulution 511 to be delivered this week and exited to to hear the new gear!
Even though this is out of the dCS “recommended” 10K to 100K range, it is a good thing!
In the context of DAC-to-Amp direct connection, the impedance matching required - ie. low output impedance to high input impedance - is not about transfer of power, but transfer of signal integrity; the easier the load presented to the dCS (i.e the higher the Amp’s input impedance), the better the DAC will perform to its full specification.
Also, while the DD S250 has a specification of 1Mega Ohms, in actual measurement (Stereophile) it hoovers around the 150K Ohms range.
The DD Amp performs spectacularly well when coupled to dCS kit. As it does in dCS’s demo room.
I understand that this can be confusing. Let me try to unpack it for you.
600Ω is the specified minimum input impedance/maximum load. This means the limit at which the output stage will still perform to specification (in this case THD). The lower the input impedance the harder the output stage has to work to drive it, so the higher up its distortion curve it will be pushed. Therefore the recommended range is higher, 10k-100kΩ, but this is more indicative, those values are not critical limits.
Please ignore any information from AI engines that contradicts our specs. The ”10x rule of thumb” may apply to amplifiers in general, but definitely not to well designed amps with exceptionally low output impedances like ours. 30Ω is an extremely punishing load that will cause the output stage to run outside its specified performance envelope.
Both the amps you are considering are excellent amplifiers (albeit with very different sonic flavours) which your dCS DAC will be able to drive directly well within spec, with no need for a preamp.
You know what they say, with amplifiers you’re listening to the power supply for a large part. Different is what I would expect, didn’t know the Soulution where SMPS based. Enjoy!
Originally, Pass X600.8 monos were driving yg Sonja 3.2 in the living room with great sound. I switched Pass to Mastermind 845 monos (50w) and prefered tubes then Pass came to my study. In the space less then half the size, the heat from two x600.8 was unbearable. So, after disappointing cool runnimg class D, I settled with Soulution 511 stereo amp amd quite happy- sonically and less heat (one X600; 53C×2 vs stereo 511; 43C).
