Vitreous Wirewound resistors ?

[Rileyman]

I've just run out of a couple of values -- where (apart from Farnell !) should I be looking for small quantities ?

Laurie.

[robinshack]

Try a wanted on here?
In new stock, I have just a few values of the dark green enamel in I think 3W, maybe 10 to 50 each value? Most likely below 100R, though may be some oddball values as well ?
Rob

[lesmw0sec]

Cricklewood electronics.

[electroanorak]

I have hundreds of 3R9.

Dan.

[Ken G3XSJ]

ESR Electronics offer matt white wirewounds if stuck for vitreous green types.

[GrimJosef]

Originally Posted by electroanorak

I have hundreds of 3R9.

Handy for making up speaker dummy loads when testing audio power amps.

Cheers,

GJ

[factory]

What values & wattage are you after? I have a good selection of these (currently in storage).

David

[trh01uk]

Originally Posted by GrimJosef

Handy for making up speaker dummy loads when testing audio power amps.

Cheers,

GJ

Just curious........are wirewound resistors not too inductive if testing an amp at the high frequency end of its range?


Richard

[bigfathairyvika]

Originally Posted by trh01uk

Just curious........are wirewound resistors not too inductive if testing an amp at the high frequency end of its range?


Richard

I would have thought no more inductive than a wirewound speaker coil.

[robinshack]

Seems OP is not replying. My offer now withdrawn. Have other things to do.

Rob

[The Philpott]

There's over 150 UK listings on ebay, but only for individual values, not assortments.
Frank sent me all sorts of misc resistors, there should be a few of these in there..random values.

[trh01uk]

Originally Posted by bigfathairyvika

I would have thought no more inductive than a wirewound speaker coil.

Probably not. But in the context of running tests, I don't think its usual to run a test with the inductive load of a speaker coil in place. The point of the resistors is to provide a load that is resistive, as I understand it.


Richard

[GrimJosef]

Electronics folk commonly run tests into purely resistive loads. Audio folks say they don't tell you everything you need to know, although they might well tell you if the equipment is faulty. Over the years various more realistic load circuits, using passive components, have been developed better to mimic a 'typical' speaker.

I was thinking more of the sort of soak testing where you want to run an amp at reasonable power for a while to see if anything changes with temperature, say. Then you need a load with a plausible impedance that can dissipate at least a few watts for an afternoon.

I also often use a wirewound as the temporary load on one channel of a stereo amp when I'm testing the other channel into a more well-defined load.

Cheers,

GJ

[Rileyman]

My thanks to you all for your replies -- I'm just back from some unexpected (and unrelated) problem-solving . Rob is not the only one having "other things to do" -- especially those not of one's own making ! My request was not an urgent one , otherwise I'd have said so . I'd given up on e-bay , but struck lucky at Cricklewood (thanks/diolch , Les !).
David , it's the green Welwyn/ERG/Painton types I'm looking for (in either 4.5W. or 6W.) and now only need a couple each of 18K. and 39K.

Regards ,

Laurie .

[factory]

Looking at my pictures I have some 18k W22 6W (W22 is now listed as 7W, which is the power rating at 25°C, rather than de-rating of 6W at 70°C), nothing higher than that, the Welwyn datasheet explains why, the 6W/7W range is from 0.1ohm to 22k, W23 9W/10.5W goes to 60k, don't have any in the correct values.

Unfortunately I can't access the resistors until Friday afternoon at the earliest, the storage access times are a bit limited, mostly working hours.

David

[Rileyman]

Thanks , David .
Don't go to a lot of trouble , it's not that urgent ! But if you do come across a couple of 18K please P.M. me .
Thanks again ,

Laurie .