Safe to remove those wirewound resistors / X-CAN V3

[PinkFloyd]

This applies to the X-CAN V3 and also the X-10 V3 line buffer.

There are 4 x 3 watt wirewound resistors fitted in the same position in the X-CAN V3 and the X-10 V3, here you can see them in the X-10 V3:



They are 4 x 40 ohm (3 watt) in parallel making a total of 10 ohms. There is no need to have four when all you need is ONE good quality "non inductive" / "non Magnetic" type. You simply remove all four of the wirewound resistors and fit one non inductive 12 watt / 10 ohm type between R8 and R6:



The non inductive resistor sounds SO much better, or should I say it sounds so much better with the 4 x wirewound resistors taken out of the circuit..... either way / it's a major improvement sonically.

My resistor of choice is the Mills MRA12 (12 watt / 10ohm) here is the spec sheet: www.partsconnexion.com/prod_pdf/mills_MRA.pdf

A few people have expressed concern that they may "overheat" but let me assure you that there is ZERO possibility of that. The MRA12 will survive for 250 hours when exposed to 350C temperatures and in the X-CAN V3 it runs at a stable 47C under load...... I tested it over a 3 hour period (with music playing on loop / volume level moderately high) and it never once went over 48C which is NOTHING for a resistor like the MRA12!

Put your fingers on the stock wirewound resistors and you'll most definitely go "ouch!" after a few seconds....... you can keep your fingers on the MRA12 until the cows come home, 47C is nothing.... some people actually sunbathe in those temperatures (well.... maybe not)

I just thought I would categorically state that using ONE 12 watt / 10 ohm / non inductive / non magnetic resistor is sonically far superior to employing 4 x cheap 40 ohm wirewound resistors in parallel and there is ZERO danger that they will "overheat"..... in fact, you will most definitely get scorch marks on the board (after a few years) from the wirewound resistors..... they run way too hot for comfort.

Here are a few photos of the MRA12 on test:







The two heatsinks are superfluous (not necessary) I just fitted them because I have them.... there is no need for them whatsoever.

Mike.

[PinkFloyd]

I am now using the Mundorf M-RESIST 10 watt / 10ohm resistor instead of the Mills MRA12. It has a bigger surface area, it's cheaper and according to the 7 people who have tried it already (I now ship them as standard with my X-CAN V3 and X10-V3 upgrade kits) it sounds damned good too!

Here is what Ryz Hajdul had to say (and he had ONLY fitted the one Mundorf resistor in his X10-V3 buffer at the time):

"Whoa Mike,
What the foofah!... and I've only swapped out the 4 resistors for the single one!
There I was, 3 rooms away in the kitchen making a cheese sarnie, waiting for the X-10 V3 to warm up and hells bells I could hear a difference from there!
At first I thought the music had dropped 1 semitone but then I realised that everything was still there but considerably richer.
The acoustic guitar and fiddles were now made of thicker wood and as for the double bass, well the bugger playing it was virtually squatting in my room.
As for those annoying ringy/gratey upper-mids that show up randomly in vocals - dear Joni, I always knew you were an angel.
I defy any deaf grandma not to hear the difference.
Just a newborn resistor for foofah's sake - how can that be?
Can't wait to put the rest of the gubbins in.

Ryz."

I always knew that those 4 x wirewound resistors were strangling the sonics and am absolutely chuffed to bits that my experimentations with other resistors have reaped sonic rewards. The X10-V3 and X-CAN V3 upgrade kits now ship with the Mundorf M-RESIST as standard and there is no price increase.

[PinkFloyd]

How to do it:

Remove the 4 x wirewound resistors R6 / R7 / R8 and R9.

Fit the 10ohm Mills MRA12 or 10ohM Mundorf M-RESIST between R6 and R8 as shown below:



Turn on, tune in and wonder why you didn't do this a long time ago

[stevejbatt]

Are you selling these resistors stand alone? I have already upgraded my X-can v3 with your kit.

[stevejbatt]

OK, found them on your site, will order soon.

[d0lph1n]

I did replace the resistors on my tube buffer with a Mundorf and to be honest..It sounds too low, maybe compressed and too far for my taste. It messes with the highs and it it's not as aery as before. So I couldn't tolerate it and I put the original resistors back.
I'm listening in this config:
iphone 8(dac) => X-10V3 => Creek OBH-21SE => Beyer Dynamics DT1350
I've been listening to the same Chesky Records tracks before and after.

What's your testing gear?

[xcanfan]

I installed my kit, but I noticed some issues with the sound. I don't know why but I guessed that it was the ohmite 10ohm resistor placed across R6 & R8. I bought and installed the Mills 10ohm resistor instead and it immediately cleaned up the harshness I was hearing. It's so much cleaner and smooth sounding. The Ohmite was sounding so harsh, especially with the volume turned up. Anyway, it looks like this one resistor can have a huge impact on the sound quality! It's almost like changing the tubes. I will try other resistors to see how they sound as well.