Do I need "high quality" loading resistor?

I saw a quite expensive (US$1000+) phono amp is only using Philips carbon film resistor as loading resistor. I am curious to know if changing it to, e.g. Caddock, will improve the sound quality?

I did read on one Forum or another, a long time ago, that the quality of loading resistors is important - even though it's hard to see why - in a shunt position - they should have an affect on the sound (apart from "taming" the cartridge response).

I've never done such experimentation myself (I just use Beyschlag metal films that I get from my amp designer) but you might like to experiment. Whether Caddocks would really be good, though ... is something you would have to try out. ;) Other good candidates, I would suggest, are Holco/PRP and Vishay S102.

BTW, some people swear by carbon film resistors! ;)


Regards,

Andy
 

jcx

Member
2003-02-17 7:38 pm
..
the value of loading R and C tune the bump from cartridge LCR - effects mostly seen top octave

the values really should be selected for each cartridge, though 47k is a common standard

there is no DC bias so excess noise isn't an issue

MM carts "high" output still doesn't heat a naked eye visible 47k R enough to worry about tempco distortion

as far as "resistor sound" - someone can be found that say they like just about any type over another
 
andyr said:
even though it's hard to see why - in a shunt position - they should have an affect on the sound
Shunt and series have the same effect on signal, which may be negligibly small or significant depending on the situation.

Some people have a concept called 'signal path', which seems to relate mainly to series components. It is based on a misconception so best ignored.
 
Some people have a concept called 'signal path', which seems to relate mainly to series components. It is based on a misconception so best ignored.

I think very good enginiers don't share your opinion about "signal path". About shunt and series differences depend a lot of quality resistors because shunt it's only one noise resistor & series you are summing each step another noise resistor.
 
I'd expect a $1000 phono preamp to be aimed at MC carts. Otherwise agree with what you said.

BTW, Top tip for MM cart users:
The orange stripe on the 47K resistors can add warmth to the sound, but you lose that with 1% or other "precision" resistors that use the 5 band color code. Best to stick to 5% or 10%, depending on whether you prefer the silver or gold.
 
Yes, I am referring to MC phono amp.

After google for more, what I found is the quality of resistor do have influence on the tone but not necessary more expensive resistors would out-perform cheap resistors. It is the combination of L,R,....Therefore, hearing is believing - back to square one - I don't have a pair of golden ears.

Yet, a correct loading is something that I can hear. I purchased a new MC cartridge that come in a wooden box and crafted the optimum loading resistor as 100R to 200R (Loading range is 100R to 47K). However, after a month of run-in, I still don't like the tone, its too high. I gradually increase the resistor and found 520R is the best in my system. When I was wondering why the margin is so great between my system and the factory's recommendation, I discovered the correct loading resistor from the factory's website shows 500R! Obviously, the wooden box is an old version.
 
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merlin el mago said:
I think very good enginiers don't share your opinion about "signal path". About shunt and series differences depend a lot of quality resistors because shunt it's only one noise resistor & series you are summing each step another noise resistor.
You would have to define what you mean by "very good engineers". Most of what is said about 'signal path' is wrong e.g. that series components affect it more than shunt components.

As Sunsun22 has discovered, the correct component value is far far more important than anything else.
 
You would have to define what you mean by "very good engineers". Most of what is said about 'signal path' is wrong e.g. that series components affect it more than shunt components.

As Sunsun22 has discovered, the correct component value is far far more important than anything else.

I don't want to discuss with you, for you affect the same one output cap than one shunt cap, no need engineers to know that affect more an output cap or a cap on the signal way, the way to name it isn't impoortant, the important fact is that don't affect the same.

I agree right component value is important, what that's is other history.
 
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jjrenman

Member
2013-03-01 6:23 pm
I recently experimented with loading resistors after switching to a LO MC as I was curious. When I switched from the standard carbon composite to a mid level metal film Caddock the music was more detailed especially low level detail. I then switched the Caddock with a more expensive Vishay "nude" metal film and, at least in my system, it did not improve the sound any further.
 
Yet, a correct loading is something that I can hear. I purchased a new MC cartridge that come in a wooden box and crafted the optimum loading resistor as 100R to 200R (Loading range is 100R to 47K). However, after a month of run-in, I still don't like the tone, its too high. I gradually increase the resistor and found 520R is the best in my system. When I was wondering why the margin is so great between my system and the factory's recommendation, I discovered the correct loading resistor from the factory's website shows 500R! Obviously, the wooden box is an old version.

Very well done, SS22! :) You obviously have:
a) a revealing system, and
b) good ears. ;)

But have you gone above 520R? Why I ask is that the spec sheet provided with my Benz LP says "470-47K" for the load. In fact, the Benz/Lucaschek phono stage provides 47K ... but, to me, the bass was too "woolly" with a 47K load. So I use 1K5.


Regards,

Andy
 
I tried to solder quite a few resistors; in parallel and in series to the phono board but eventually ended up using dip switches and combinations of resistors to discover a preliminary optimum loading resistor for my system. After which, I used a numer of resistors available in my stock from 470R to 550R and eventually settled at 510R carbon film (520R was a typo in my previous thread).

I would like to try out Caddock but it seems it does not have 510R. I will try 499R instead.
 

jjrenman

Member
2013-03-01 6:23 pm
In my system I've experimented with both using two resistors of the same make and type in parallel versus a single of the same make and type. The single was marginally better but it was a smaller difference than switching to metal film. Both differences paled in comparison to getting the load correct for my Dyna 20 x2 Low.