LCR meter to measure inductance

[SimontY]

Hi,

I've been playing with my speakers' x-over, and sort of accidentally unwound some inductors. I rewound them from scratch to a random value that seems to work. I have good sound, but I want to match L + R speakers properly, I'd also like to know what x-over points I've created. I also want to upgrade the coils in my 'pc' speakers - Tangent Monitor 6....

So, I obviously need an LCR meter. The cheapest thing I've seen is such a meter selling at www.cpc.co.uk -for £32 ex. tax.

The spec for L reads:
2mH to 20H inductance range. 1µH resolution. ±5% + 5 digit accuracy.

Obviously typical x-over inductors might be 0.3, 0.7mH etc. So will this meter do it? I don't know if 2mH means on that setting it goes *upto* 2mH, or that it can't actually measure anything less than 2mH. I don't have money to waste, so if anyone can reassure me that would be great!

http://custom1.farnell.com/cpc/produ...ct%5Fid=267510

[PCC88]

While I can't vouch for that particular product, I can vouch for the AVO LCR meters.

Measuring inductors, you need to be certain of accuracy.

I would suggest to look on ebay for an AVO B183 or AVO B184, or an AVO B131, which is the one I use.

All of these meters are digital 'point and shoot' types.

If you shop carefully; you could find a better quality secondhand product for the same sort of money.

HTH

[janneman]

The 2mH range is full range. Normally these things have at least 4 digits, so the meter would indicates 0-2.000 on the 2mH scale. For .2mH, it should show 0.200 (nominally). The accuracy could be stated in % full scale, here 5% which is 5% of 2mH is .1mH uncertainty. That means a nominal 0.2mH can show as anything between .1 mH or .3mH. Then there is the 5 digit accuracy which means your indication can be between 0.095 and 0.305, all for a nominal 0.2mH coil. Doesn't look good.

Now, if the 5% is not full scale accuracy but of the indication, things look much better: It means that the nominal .2mH will show anything between .185mH or .215mH, and that is OK I would think.

So, review the specs carefully!

Jan Didden

[SimontY]

Thankyou both very much!

I will leave the CPC meter alone for now, as it does seem a little risky, possibly being useless in the useful range, aheh.

Ebay is great isn't it? I'm looking now, none of the ones you mention there right now valve, but there are a couple of LCR meters...

Wavetec LCR 55 Component Tester going soon for just over £20. They claim it's worth £150 new, but there are no specs and Google reveals very little Picture is too blurred to make anything out either.

Might it be worth going for it, max. £25 or so? Or would I just be risking the same 5% accuracy problem?

Cheers!

[PCC88]

The Wavetek might be worth a look.

Wavetek (before they were bought by Fluke, when Fluke went on a 'meter manufacturer buying spree') produced some very decent DMMs and LCR meters.

The AVO B131 I have is also marketed as a Wavetek in the States.

You may also want to try a search for user comments on
rec.audio.tubes using Google usenet.

Go to usent and do a search LCR on rec.audio.tubes

Go to this link below, this guy has an AVO B183 for sale.

I have used him before, he's ok.

homepages.tcp.co.uk/~diverse/teste.htm

[SimontY]

Aaaah, the Ebayer had spelt Wavetek as Wavetec, so that's why my search turned up so little!

I found some specs:
http://www.testequip.com/sale/used/c.../WAV_LCR55.pdf

It looks really good, currently just over £20. I think I will buy it, if the price doesn't shoot right up!

Unless of course, you think the AVO B183 LCR meter would be much better or more suitable for my purposes. What sort of price might that be going for?

Thanks!

[janneman]

Originally posted by SimontY
Aaaah, the Ebayer had spelt Wavetek as Wavetec, so that's why my search turned up so little!

I found some specs:
http://www.testequip.com/sale/used/c.../WAV_LCR55.pdf

It looks really good, currently just over £20. I think I will buy it, if the price doesn't shoot right up!

Unless of course, you think the AVO B183 LCR meter would be much better or more suitable for my purposes. What sort of price might that be going for?

Thanks!

If you want to buy it, hold your bid until the very last moment. No use letting others up YOUR bid. This may come to seconds! Do you have a fast connection?

Jan Didden

[SimontY]

Originally posted by janneman

This may come to seconds! Do you have a fast connection?

I know, I've bought a few things off Ebay lately, capacitors mainly

I have a fast connection here and at home, but the bugga is, the auction ends at 5.30pm, and I'll be in the gym pumping iron then

[PCC88]

Originally posted by SimontY

I know, I've bought a few things off Ebay lately, capacitors mainly

I have a fast connection here and at home, but the bugga is, the auction ends at 5.30pm, and I'll be in the gym pumping iron then

Surely your audio should come before your machismo


The Wavetek LCR meter doesn't look too bad, but personally I would still go for an AVO.

[SimontY]

Hehe, life is full of tough decisions!!

I'll probably just think of the absolute most I want to pay for it and leave my bid just before leaving work. (yes, I am at work, not working much...<whistles>)

If I don't win it, I'll look into ones like you've suggested, but do consider that my needs are only fairly basic, and the Wavetek seems to have sufficient resolution to get two inductors nicely made up, the same as each other.