UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Mullard 3-3 voltages query

Diabolical Artificer · 17th Apr 2021, 7:53 am

There are quite a few references to using non inductive dummy loads in various tomes like in Morgan Jones Valve Amps and on Utoob. It makes sense on one level, IE you want your test load to be purely resistive and have no reactive element lest it skew your test results. I too was spent ages looking for non inductive resistors a few years ago, until learned more and had a think.

As mentioned any inductance is small and will only effect RF frequencies possibly, that and there are reactive capacitances and inductances in your test leads and as Andy says a speaker is reactive anyway so does it really matter. For someone just wanting to do some home testing I'd say the answer is no.

BTW David, you could just use a few 1/2w resistors in a cup of water as your load, something like two 10r's in parallel with a 3r3 in series with the them.

Andy.

17th Apr 2021, 7:53 am	#37
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,669	Re: Mullard 3-3 voltages query There are quite a few references to using non inductive dummy loads in various tomes like in Morgan Jones Valve Amps and on Utoob. It makes sense on one level, IE you want your test load to be purely resistive and have no reactive element lest it skew your test results. I too was spent ages looking for non inductive resistors a few years ago, until learned more and had a think. As mentioned any inductance is small and will only effect RF frequencies possibly, that and there are reactive capacitances and inductances in your test leads and as Andy says a speaker is reactive anyway so does it really matter. For someone just wanting to do some home testing I'd say the answer is no. BTW David, you could just use a few 1/2w resistors in a cup of water as your load, something like two 10r's in parallel with a 3r3 in series with the them. Andy. __________________ Curiosity hasn't killed this cat...so far. Last edited by Diabolical Artificer; 17th Apr 2021 at 7:59 am.