Well today's been both interesting while frustrating at the same time.
I try to avoid the darker side of HiFi – the tweaky side… enter the “darkside” and it’s a slippery slope that can only end in total madness!
Enter a simple resistor – one of the most basic Passive components... simple you would think, surly cannot have much effect upon sound quality so long as you use the same type (Metal film). Well, either Renata, Jiri & I have lost the plot or things are not a simple as one would like to assume.
The first 10 MDAC’s upgraded I used resistors I had in my personal stock – these maybe over 20 years old now (before the days of RoHS). Once these old stock parts had been depleted thinking nothing of it, I just ordered the “equivalent parts” from Farnell - Metal film, 1% 120R (MULTICOMP MF25 series made in Thailand). On final listening test I noticed that the L/R sound stage had collapsed, the sound was now lean and thin sounding – with hardness… at first I just presumed the MDAC was cold – but after warming the units up for 24 hours and listening again no improvement in sound quality!
I invited Jiri over last weekend, and during our listening tests we used Jem’s unit I had on test at the time that had the Multicomp resistors fitted… and then replaced them with the last of the original resistors I could find scattered on my lab bench – Bam! instantly the L-R sound stage and Bass was restored with no hint of hardness…! It was such a difference that from the very first opening second of the track as the Violin started playing on the very far right side you could hear the difference…! (Wailin Jennys - Glory Bound).
Now the problem was that I had no idea of the original manufacturer of the resistors I had used – they had been carefully sorted all those years back into individual component “trays” for each resistor value – but without relevant manufacture data etc.
So I ordered a what others had recommended as a “good sounding” resistor (the type you see fitted to expensive America Krell, Mark Levinson, Spectral etc) by Vishay Dale CMF55 series manufactured in Mexico / US.
The Dale resistors have a “Dark” full bodied sound – trading L/R sound stage for a narrower presentation but with more depth. Renata loves the sound in fact she “foot tapped” along so much that during the listening test Renata cracked the tea table we where sitting on:-
Renata One, Cheap Ikea tea table ZERO!
I cannot deny that with that Dale resistors fitted the L2MDAC has real foot tapping “rhythm” – still detailed, but I find myself yearning for the “missing” L/R sound stage and sligtly extra definition and “more open sound” of the L2MDAC upgrade using the original resistors.
In reality, I find most systems (Amplifiers and Speakers) tend to lean towards a Brighter and lighter presentation – so maybe a slightly “darker – full bodied” sounding DAC would be a better system match – think A08 software sound over V0.90
Not happy with this state of affairs I made a few more modifications to the MDAC with the Dale resistors which has now achieved simply the best overall sound quality I’ve yet heard from the MDAC – although the L/R sound stage is still not as open as the original L2 versions… but it has so much more “Body” Depth and detail… I’m happy to leave as is however….
I needed to try and findout the original brand and type of the resistors I had used, so going though about 100 plastic draws with different resistor values (not so easy as many of the plastic draws being over 20 years old just fractured as I tried to slide them open) I managed to find a tray of resistors which where sill in there original RS Component packets – with a valid part number
So the “original” resistors I used appear to be manufactured by TE Connectivity (Tyco) – however before the days of RoHS so there’s not guarantee that today’s RoHS complaint parts will still sound as good… so what to do?
The L2MDAC with Dale resistors has a massive full bodied sound, loads of detail and will have you foot tapping along sending the fear of God into Ikea tea tables – or L2MDAC with Tyco resistors that’s ever so slightly less foot tapping (maybe) but with extra wide L/R sound stage (a slightly less full bodied sound between the speakers as the image is spread much further / wider apart, past the speakers) with even greater detail… I’d be very happy with both – they are both a significant upgrade over the standard MDAC – but what’s preferable is dependent on system matching and personal preference.
I could sum up the sonic signature:-
Dale resistors akin to A08 software signature
Tyco Resistors akin to 0.90
I must stress that I still need to order and test “today’s” RoHS complaint Tyco resistors to see if they still sound as good as the original NOS 20 year parts I had used…
Jem, WAD62, SimonOM & JohanH your call? I can ship your units out on Monday with the Dale resistors fitted…
JohanH – for your system I’d suggest the slightly “darker sounding” L2Dale version as it would appear your system trends towards the brighter side…
Granted it’s a tough call… which ever you choose the SQ of the upgraded L2MDAC is impressive… Personally I’d go for the Tyco (assuming today’s modern versions are as good as the originals) – but my system is ultra smooth – never bright or hard sounding, but this is not common of most modern systems.
Renata would go for the Dale version!!... so it really comes down to personal preference! Ultra foot tapping or Ultra L/R sound stage with a tad extra detail and clarity!!!