Optimal resistor choice for transparency / sound quality

[PassionForSound]

I'm likely needing to include some resistors in a signal path (between DAC and multiple amps) and want to ensure that whatever I do has zero impact on the sound so I'm wondering what my resistor choice should be (brand / series / wattage rating).

My setup looks like this:

DAC RCA out --> 3-way split --> S.E.X., Mainline & Quickie (all 100k loads)

Of course, I could just switch RCAs over, but it's a PITA! If I'm correct, this setup currently presents 33k to the DAC output so if that's too low, I was planning on adding an additional 100k resistor to each channel. Does that make sense and what brand / series / wattage resistor should I choose to have zero impact on SQ?

I've asked the manufacturer for the minimum load on the RCA outs to see if any of this is necessary, but also using this as a learning opportunity too.

 

[Grainger49]

I had written 3 sentences and stopped.  What are you going to do with the resistors?  What purpose will they serve?

The three 100k Ohm devices in parallel present a 33.33k Ohm load to your DAC.  That is probably safe.

 

[PassionForSound]

Thanks Grainger. I was going to use them to increase the load seen by the DAC (by essentially doubling the impedance of each amp).

Out of interest, if I were to do this (very happy not to if it's not needed)

A) Is there a better way than adding a resistor to each channel on each amp?
B) What resistors would you recommend to prevent any loss of SQ?

 

[Grainger49]

I would think the 33k isn't bad for the DAC, but the manufacturer will know for sure.  My solution would be a selector switch to feed the different amps.

If needed I would put the resistor inside the individual kits, between the input RCA jack and the volume control.  There will be better isolation for them there.

Many Bottleheads are using good Dale/Vishay metal film RN series (military spec I think) in their stepped attenuators.  A 1/8W rating will be fine.  Any voltage rating will be fine, the output will be under 10V.

 

[mcandmar]

I might be mistaken, but as far i know most solid state amps present as low as a 10-20k load to the DAC so i don't see that being an issue.

As for resistor choice, i've all ways used the Dales as i find them transparent, certainly whenever i replaced generic brands with them there has always been an improvement.  Doesn't seem to matter the wattage rating, i.e. RN55, 60, 65, of if they are mil spec or industrial range CMF vs RN as they all perform just as well.

Only other boutique brand i have tried are PRP (the bright red ones), and i didn't like them as much. I got the impression they were smoothing over the sound a little, or maybe the Dales have just become my norm.

 

[PassionForSound]

Thanks Grainger and Mark. Very helpful as always.