I am trying to find a 360 Ohm / 50W non inductive resistor for thisKT88 SE amp
Wich one would you choose from this list? (Vishai Components)
I think that maybe the RTO50 type would be ok, but there is also the RCH and RTOP that maybe could be fine.
What brand of resistors do you use for this purpose?
Cheers
Wich one would you choose from this list? (Vishai Components)
I think that maybe the RTO50 type would be ok, but there is also the RCH and RTOP that maybe could be fine.
What brand of resistors do you use for this purpose?
Cheers
Hi,
Jean Hiraga recommends Dale or Sfernice NI WW.
I think to Sfernice should be available in Spain and it wouldn't surpise me if they're part of the Vishay group of companis as well since Vishays' been gobbling up quite a lot of companies the past ten years.
The ones shown in the Vishay datasheet are thick film types, I never tried those but I hear WW is to be preferred.
Cheers,😉
Jean Hiraga recommends Dale or Sfernice NI WW.
I think to Sfernice should be available in Spain and it wouldn't surpise me if they're part of the Vishay group of companis as well since Vishays' been gobbling up quite a lot of companies the past ten years.
The ones shown in the Vishay datasheet are thick film types, I never tried those but I hear WW is to be preferred.
Cheers,😉
pingfloid said:
Hello ,
Why non-inductive , I would have thought a 50watt aluminium clad wirewound bolted to the chassis do the trick ? I believe the 'non inductive' metal film power resistors can be noisy but will inductance be an issue with a 360 ohm resistor ?
316a
Hi,
Just like the HF correction cap across the primary of the OPT, the use of a non-inductive WW is part of the target here, namely to build a SE amp with as linear as possible response upto 100K Hz.
In his designs Jean Hiraga always recommends the use of non-inductive WWs.
Noise shouldn't be a big issue here as a NI WW should have no more than twice the noise of a regular WW resistor; 360 Ohm or 720 Ohm...
Cheers,😉
Just like the HF correction cap across the primary of the OPT, the use of a non-inductive WW is part of the target here, namely to build a SE amp with as linear as possible response upto 100K Hz.
In his designs Jean Hiraga always recommends the use of non-inductive WWs.
Noise shouldn't be a big issue here as a NI WW should have no more than twice the noise of a regular WW resistor; 360 Ohm or 720 Ohm...
Cheers,😉
Ah !
...but yes 100kHz with SRPP ECC83 input stage ? More than marginal to say the least especially if the amp is preceeded by a passive line stage .
316a
fdegrove said:
...but yes 100kHz with SRPP ECC83 input stage ? More than marginal to say the least especially if the amp is preceeded by a passive line stage .
316a
You're right Frank, both Dale and Sfernice are part of the Vishai group.
Does WW means WireWound? In that case they maybe inductive. Isn't it? 🙄
Sorry, my link to the Vishay was not the intended one. This is the correct one:
http://www.vishay.com/resistors-discrete/power-more-five/res10-10K/
Sch3mat1c said:
Hmm. 37.5 x 37.5 /360 = 3.9W. I would make sure that a 5W resistor is VERY well heatsinked running that close to spec since heating leads to derating 🙂
Brian.
Hi,
WW means WireWound, the suffix NI stands for non-inductive.
That NI types are usually more than twice as expensive as the regular ones.
The way they arrive at cancelling out inductance is by coiling the ni-chrome wire twice, once going the other coming.
This is known as the Ayrton-Perry technique after its inventor.
Global NFB is applied and the amp does meet the target spec.
That plus the fact that you need to consider fault conditions as well.
Cheers,😉
WW means WireWound, the suffix NI stands for non-inductive.
That NI types are usually more than twice as expensive as the regular ones.
The way they arrive at cancelling out inductance is by coiling the ni-chrome wire twice, once going the other coming.
This is known as the Ayrton-Perry technique after its inventor.
Global NFB is applied and the amp does meet the target spec.
That plus the fact that you need to consider fault conditions as well.
Cheers,😉
i`d prefer to use a couple of 2 watt carbon resistors in parallel. this way, you got no induction and you should be able to dissipate enough.
try maby 4 in parallel to be safe. value should be about 1.5k 2watts.
try maby 4 in parallel to be safe. value should be about 1.5k 2watts.
fdegrove said:
1. Resistors are rated for typical conditions at a typical temperature (usually 25øC). A heatsinked type may be rated for case at 25øC (like a transistor) whereas a sand resistor may be rated for ambient instead.
2. 5W is about 70% of the actual load. On a *really* hot day (or a typical one in India, hehe) in a stuffy chassis, it might have trouble.
3. Ah, I see you believe in burning a $30 tube to save a $.10 resistor...
Tim
Going back to the catalogue, I guess that the correct one may be this one:
RW 19X64 NI AN 360 5%
http://www.vishay.com/docs/50016/rw.pdf
Now I just have to find a delaer (it is not the one they use to have in stock at the corner's e-shop)
Cheers
RW 19X64 NI AN 360 5%
http://www.vishay.com/docs/50016/rw.pdf
Now I just have to find a delaer (it is not the one they use to have in stock at the corner's e-shop)
Cheers
yup. thats the normal problem. and unless you are ready to order a 1000pcs of a single value, i don`t think you will be able to get any of these quality resistors.
and the delivery time about 5 or 6 weeks. He he he he... 
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