Censorship over at the *Other Place"

[complin]

I know recently we have had discussions here regarding censorship on Head-FI particularly around criticism of sponsors products.

 

Well it seems any mention of this forum now results in instant removal of any reference!

 

I was involved in a conversation regarding the Metrum MK1 DAC and happened to mention the work Craig Sawyers had outlined on this forum to upgrade the output transformer. He also noted the need for correct cable matching etc.......... All very useful stuff.

 

Well within a hour or so of posting I received the following PM below telling me that the link had been removed.

They must be very touchy over there because people might find there are more informed and different opinions from the herd of sheep found elsewhere 

 

 

Post edited (with explanation) Conversation between jude, joe, and me

joe
Today at 3:19 pm

complin,

 

For myriad reasons (some of which you may or may not be familiar), we do not allow links or reference to Head-Case from Head-Fi. 
 
As a result, your post (the original unedited text of which can be found in the dialog below) was edited.
 
I hope you understand, even if you don't agree.
 
Best Regards,
Joe
 
(cc: Jude)

 

Quote:

Originally Posted by complin 

You can read about some investigations that have been carried out on the Metrum MK1 by an audio design engineer (Craig) over at the other place if you are interested 

 

In spite of these design compromises i've found it preferable to other DAC's costing 4 or 5 times the price.

I can perceive no roll off of high frequencies, its all there just not in your face presentation like much of todays digital reproduction.

Great dynamics and timbral accuracy, very very musical if you are into music rather that HI-FI .

 

Yes it has its limitations in terms of input capability and lack of native USB, handling very high rez files and DSD, but if you can live with this then its a real gem IMHO. 

 

Quote:

Originally Posted by Sapientiam 
 

 

Hard to answer this question without getting into fairly arcane technical details but I'll have a go.

 

The MDAC is using ESS9018 which is a sigma-delta based chip using noise-shaping to get the figures looking good. Noise shaping has various technical issues associated with it, many of which ESS have solved (compared to the other players in the field like ADI, TI/BB) but clearly not all. In particular the chip still exhibits shifts in the noise floor at particular output levels. Its also very hard to get enough subjective dynamics out due to the extremely high switching frequencies used in the on-chip DAC.

 

Metrum uses a ladder-type DAC and runs it at the lowest frequency (assuming you don't use your computer to oversample). Thus dynamics will tend to be better, also timbral accuracy. However the measurements relative to any ESS-based converter will suck - THD+N in particular and the FR will droop due to the NOS intrinsic roll-off.

 

Incidentally you're right there's something adrift with the Metrum's digital input - the digital ground beyond the isolation trafo goes into the ground fill.This induces HF noise currents into the sensitive analog ground and is a very common issue with commercial DACs, akin to the 'pin1 problem' with professional XLR connected kit. For anyone with the guts to mod, this can be quite simply fixed up. Just re-route the 0V side of the S/PDIF input with a dedicated ground wire back to the PSU input.

 

 

 

Reply

 

[tkam]

this is nothing new and has been policy over there for ages now.  going to lock this thread to avoid re-hasing this topic over and over again.