IWAKI power resistors - need info

[reaction]

Just bought a lot of NOS Japanese made IWAKI resistors and I am looking for more info about them - are they wirewound or film ones, are they inductive or non inductive ones etc. I have found the IWAKI site but unfortunately it is only in Japanese and there is no email address for inquiries.

This is the link of the product line (in Japan).

The marking of the resistors is:

CS5P (5W)
RM IWAKI

Appreciate your help - thanks.

 

[cpu_bach]

Hello. I checked the Web site per your questions.

These are the answers:
1. They are wire-wound resistors.
2. Five Watt resistors are
inductive for 0.02 Ohm to 30kOhms
and non-inductive for 18 Ohm to 15k Ohms.
3. Non-inductive resistors have suffixes of K, H or F
per their accuarcy. I could not find at the Web site
if the suffixes are shown on the resistor bodies.

Hope this helps.

 

[greyhorse]

They mention that the bobbin (nearest translation) is made of a material with very good heat transfer characteristics, so they are probably wire-wound. With the markings on your resistor, they are the inductive type. The non-inductive ones are labeled NCS5P.

 

[reaction]

cpu_bach and greyhorse - thank you very much for your speedy help!

An offtopic question - what is your personal opinion regarding the audio signal quality about using inductive wirewound resistors as power line resistors in tube amp PSUs? Personally, I don't find any audible difference when using inductive and non inductive ones in my tube circuits.

 

[cpu_bach]

I don't care if the resistors are inductive or not in view of the sound. However, I care the inductiveness when I apply the resistors for wide-band amplifiers. You may get an oscillator instead of an amplifier, if you use inductive resistors.
I usually make tube amplifiers and avoid using inductive resistors for plate loads which has high circuit impedance and cause high frequency unstability.
Regards.