Welwyn RC55Y low value where?

Hello guys,

i was searching for low value metal film (possibily no magnetic) resistors.
I came across this brand: Welwyn.
I have tried to search for them on the differenc common diYer's dialers as Newark, Farnell.... but they don't have low value 1/4W 1% ...like for instance 0.22 0.33 0.8 ..
Actually the lowest value they carry is 70ohm (RC55Y serie).

Does anybody have a clue on where to find these resistors and/or other good as well that are no magnetic metal - relialble - precise?

I have been searching a lot but couldn't find anything.....hope somebody can help me here.


Thanks a lot.

Best,
Stefano.
 
yep...checked.
The RC55Y serie starts from 1ohm and there're actually other series that start from lower values.
Onfarnell i could find something but not the rc55Y that seems to be better (it's a 0.5% tollerance)
Eather way any other suggestion on different brand with that characteristic is welcome.
I need to finish the the output potentiometer.
 
thanks for the idea.....but one resistor is like $9 and with that price i almoust buy two naked vishay :) ....which are a lliiitttlee bit better...

unfortunately i need 24 resistors for 4 decks.....it make a total of 96resistors....times $6.....makes toooooo much....

and this is basically the reason of why i'm searching for a good metal no magnetc part....but nothing exotic...like naked vishay
 
You are unlikely to get values below 1 ohm at anything better than 5%.

The last time I used something that size and value, I ordered from www.conrad.de. 0R22 5% is e.g. #417130-36. They were from Philips, now sold to Thomsen.

The easiest way round is to use any decent 1R 0.6W 1% metall film and parallel them. 5x gives you 0R2 0.2%, 3x 0R33 0.3%, 2x 0R5 0.5%, ...... Of course you can start combining 1Rs & 2Rs to give other values. And you get much reduced inductance as a bonus. Only penalty is just a bit more space.

This is what I do nowadays.


Patrick
 
I correct myself.

You CAN get values below 1R at 1% from RS. Brand unknown.

0R1 is e.g. #135-487
0R22 # 135-500
etc.

They cost around 5 Euros for ONE pack of 10. So still affordable.
I doubt you will find any non-magnetic resistors below 1 Euro and below 1R. If you would find them, please let us know.

Welwyn RC55Y is magnetic (steel endcaps).
You can also try Beyschlag (also magnetic) as recommended by Mr. Curl some time ago.


Patrick
 
is there any way where i can get PRP resistor for low value...i would drop the 0.22 0.33 0.85 ohm resistors

At this point for the sake of the clarity it is usefull to post the value that i need and the relative attenuation


Atten Res
--------------------------
53 0,224374426
46 0,503711773
41 0,899265652
37 1,432776044
34 2,035883532
32 2,576607896
30 3,265543203
28 4,146132201
26 5,276314482
24 6,734491107
22 8,628683001
20 11,11111111
18 14,40241013
16 18,83390465
14 24,92601748
12 33,54498311
10 46,24752956
8 66,1425342
6 100,4760238
4 170,9713864
2 386,2116094
0,2 4293,136699


I could even thnk on not using the first 3 steps since the attenuation is so high...and start from the 1.4ohm res...

is there any way where i can fit 1oh PRP res? as far as i know have a good sound and i would be glad to use them on the output potentiometer?
 
Sometimes we just have to use what we can get. Or pay for them even if expensive.

At the lowest attenuation levels, you would not have the sound level to hear the finest difference. It is thus so important ? If yes, then just bite the bullet & use naked film throughout. If not, then just use them at critical listening levels, which is probably 3 or 4 positions on your selector (say between 20 to 30dB).

I would try them with ordinary resistors first, see what are the mostly used levels, and then try some fancy resistors and see whether I could hear much difference, before making the decision.


Patrick
 
yes that makes sense to me.
I don't like to have different resistors, it gives me the idea of something not propertly done....but i get the point...and flexibility of the solution.
I actually think that on a shunt attenuator the serie resistor MUST be fancy like naked vishay s102.....but...actually what is on the potentiometer is shunted from output to ground and therefore is ...technically.....less important, but i could be wrong.

Of course, i can't take a low grade resistor, place it there and pretend it sounds like a good one.
For this reason, i was thinking of using a good...PRECISE...resistor on the output...but not as fancy as a naked vishay.

I have downloaded the datasheet of the audio resistor serie...and it says that it starts from 1ohm...which is pleny fine to me.
i will probabily leave for now an empty spot on the fist 3 steps (shorted to ground)
I will rarely use that position anyways so....

An interesting thing is that on the data sheet i have download it said "available on a small quantity"...and therefore i have inquired a request.

What do you think of what i have just said?
Do you share my thoughts?
 
The only people I can think of interesed in selling say 10 resistors to an end user is Texas Components, which is a small operation.

For any decent-sized company, just the paper work alone costs more than the value of goods. You might be able to convice them to send you samples if you were in America and has an Audio company, like Nelson Pass, e.g.

But by all means ask them. Costs nothing to ask.
I would bet in the end you end up using all naked bulk films.


Patrick
 
well the parts will go to the US and not here in Europe...in case it would make difference.
I understand what you are saying....but if you look up to the datasheet you will notice that on the description there is that voice saying "small quantity available".
ehehe....i understand that small is all a relative concept and couold be 1000units...ehehe.....but as youo outlined ....ask doesn't cost anything.

I would love to use the bulk vishay s102......the only problem is the high price that doesn't allow me to use them on a "large scale".
 
This is the reason I keep spools of good resistance wire around. I just finished an attenuator for an instrument where the low value 1 ohm resistor was simply 5" of Manganin wire, folded over and wound to cancel inductance. By running a fixed current through the resistor and measuring the voltage drop, one can get as much accuracy as they want. My attenuator was better than .05% with no special fussing other than selecting the rest of the higher value resistors with a DVM. Lacking that, I'd probably go with the parallel solution as the cheapest and easiest alternative. (Stefano- just noticed it was you! Email me and I'll be happy to post a length of suitable wire to you.)