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Group order of switched ladder attenuator? Anyone interested?

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#221
Re: Re: Re: Re: Re: How to build this thing?

Peter Daniel said:

Hey Brian,

I was asking because I've heard of one guy who "just reversed the fuse's polarity and it sounded different."😉
Click to expand...

Almost an interesting observation. I installed the resistors in my series attenuator so that the colors lined up:
An externally hosted image should be here but it was not working when we last tested it.


This is my recommended way to assemble the series unit. I choose a 22k series ladder with Riken 0.5w resistors (available from Parts Connexion)
I can post the value of the resistors in my ladder if anyone is interested. I am finishing it now, and haven't tested it yet. The first channel does have logrithmic tracking like the 25k Noble pot that I have here.

Important Note: The Elma series unit is actually a 25 position switch, unlike the Goldpoint unit. This means that if you follow the Goldpoint series component listing, you will be short a resistor for the series. I didn't realize this myself, so I just put a short on the 24 position. This means that the second from the last click is the same as the last click for the volume, which isn't too much of an issue for me. I would have changed it, but I already ordered the resistors to make a perfect 22k series combination.

--
Brian
 
#224
Variac said:
I wouldn't mind seeing your series values....😎
Click to expand...

16, 33, 47, 68, 82, 91, 100, 120, 150, 180, 220, 270, 330, 470, 620, 820, 910, 1.1k, 1.3k, 1.5k, 2.2k, 4.7, 6.8k.

Of course, you could slightly modify it to add an additional value to have 24 resistors instead of 23. I plotted the curve and modified it until it was fairly close to logrithmic. This is the best I could get and keep the 22k, also considering the limited values these resistors are offered in.

The resistors are $2 each from Angela.
http://www.angela.com/catalog/resistors/Resistors.html

--
Brian
 
#227
Brian I was thinking of useing Holco resister's from Micheal Percy I've not ordered them but like you I thought these were 24 position switch's my question is if you could be so Kind as to figure 22k useing all 25 postion's then I would like to order resisters based on this thank's in advance
 
#228
jhead said:
Brian I was thinking of useing Holco resister's from Micheal Percy I've not ordered them but like you I thought these were 24 position switch's my question is if you could be so Kind as to figure 22k useing all 25 postion's then I would like to order resisters based on this thank's in advance
Click to expand...

The Holco resistors come in a lot more values then the Riken ones, which seem to follow old 5% values. I would check into the Holcos, as I heard they aren't non-magnetic any more for the new ones.

As for the ladder, I would probably just stick a 10 ohm resistor in the bottom part of the ladder to fill the 24 resistor positions, as the taper seems to be fine. I tried to follow the Goldpoint taper with the limited Riken values.

I would recommend plugging the values into Excel to calculate the attenuation, the choose values that give you the taper that you need. (put the plot on a logrithmic scale) This is what I did for the Riken values.

--
Brian

--
Brian
 
#230
Here is a picture of the the taper of the 22k series pot I made with the available Riken Ohm resistors. I compared it to the Goldpoint Taper on the same chart:
An externally hosted image should be here but it was not working when we last tested it.

The curves mostly overlap.

I also attached the xls sheet if you wanted to modify it for your setup. It is kind of messy, since I just made it a few minutes ago, as I couldn't find my original sheet.

Again, I would just add a 10ohm resistor to the bottom, since it won't change the taper much, except add another high attenuation step.

--
Brian
 

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#232
I finished assembling the amp with the attenuator the the other day. As for the resistors, you will want to still use 23 resistors, and put the short circuit jumper in the 1st position. With my current attenuator, in the lowest position, there is still low volume audio coming out, and if the short jumper was in the lowest resistor position, then the volume would be fully muted.

As it is now, I will just short the bottom resistor out, and it will be muted. I don't think that I will need the lowest position anyway.

So, if you are following the Goldpoint schematic (thanks Arn for posting this stuff!) , then for the Elma switch:
elma switch position = goldpoint schematic
R1 = short jumper
R2 = R1
....
R24 = R23

Following the above should work out perfectly.

As for my current amp, I will be using a selection switch, with 3 sources, and 4 positions, making one position the off position, effectively muting the amplifier.

--
Brian
 
#234
O.K.
So I nead one help...I nead some resistor for serial attenuator...I still don't know what value ( I nead it for xbosoz which will drive alephx ) ...
So I was wondering what tipe of resistors to buy...maybe I will go crazy on this and buy some exotic like caddock,vishay...etc...
so my question is , which of those you prefer ;
caddock MK132
vishay s102k
AN tantal 0.5W
Riken
Dale

Price for caddock,vishay,AN is sime...
since I will be buying this once in my life time,I hope, I think that I can go crazy, but I don't won't to make mistake.
so any opinion on all those resistors ???
 
#236
yoke said:
So I was wondering what tipe of resistors to buy...maybe I will go crazy on this and buy some exotic like caddock,vishay...etc...
so my question is , which of those you prefer ;
caddock MK132
vishay s102k
AN tantal 0.5W
Riken
Dale
Click to expand...

Each of those will sound different, and depending on your equipment/preferrence there is no simple answer.

Caddock: sounds good, but lacks a bit of smoothness and may seem a bit "rough"
Vishay: very smooth sounding, but seems like some highs are missing, may seem too "polite" sometimes
AN tantalum: very good midrange and bass, but obvious lack of highs, so called "air" isn't there.
Riken: good overall sound, maybe highs a bit exagerated, to the point that it may seem bright.
Dale: not bad overall, but comparing to other a bit "dirty" sounding.

My personal choice would probably be a Vishay, but again it still depends on the rest of the circuit.
 
#240
Hi,

Elso,

While I'm in agreement regarding gold-plating versus hard silver soundwise and durabilitywise I never had either reliability problems nor disturbling interposition clicking with my Elma switches.

However, it should be noted that my stuff is usually only used in my system so the switch only ever gets set to position 10 or 11.
Other than that I just use the mute switch which is totally independent in operation from the Elma rotary.

Sure, the Shallco and Blore Edwards switches are better on all counts but at those prices one could just as well opt to go the full hog and build with mercury wetted reed switches which AFAIK don't sound like anything at all.

Cheers,😉
 
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