Urei 809 Crossover inductor values

[eso]

Does anyone have any information on the Inductor values for the Urei 809 crossovers?

Like the 811-815 C series these incorporate the tapped inductors and I have not been able to find any information that specifies these. I know Rob built some 811C crossovers and can come up with those specs, but I'm sure the 809 is different.

I'm putting together a pair for a friend's recording setup using some JBL coax drivers I found on ebay and I have an NOS set of 809 horns. I might try fitting up a pair of my wooden Urei horns as well.

Any help would be appreciated.

eso

[stephane RAME]

http://www.jblproservice.com/pdf/URE...s/809A-L,R.pdf
http://www.jblproservice.com/navigat...%20Series.html

Stéphane

http://audioheritage.org/vbulletin/s...t-Plains-audio

[Earl K]

Stephane,

FYI, the schematics that you posted are missing the inductor values ( for L1 & L2 ) .

Are you aware of this omission ?

As a consequence , eso is still no further ahead in his search for their values .

[stephane RAME]

Hi
Inductors has 3 points ?
They are variable ?
Stéphane

[Earl K]

Hi
Inductors has 3 points ?
They are variable ?
Stéphane

- I'll take your answer as a 'no" to my question .

-"L1" & "L2" have three connection points because they are a tapped inductor ( coil ) .

- The inductance isn't variable although depending on where the "tap" is taken from the coil / there's variable amount of attenuation available .

- Read this thread on "Tapped Autoformers" for some backgrounding on the subject .

[eso]

Thanks Stephane, but I already have those sheets, And Yes Earl, the tapped configuration is the issue.

I had a discussion about this with Rob 3606 last year in the Urei 813B thread:
http://www.audioheritage.org/vbullet...i-813b-project

The 809 crossover is similar to the "C" series crossovers in that is uses the tapped inductors. Rob has built an 811C crossover and had obtained the values for that one.

Is it possible to measure inductance from the input to the tap, and then from the tap to the output and then add those figures to determine the total value of the coil? Also if measuring in that manner were valid, would using two coils with the the same values as the measurements of either side of the taps achieve the same result?

If taking those measurements would provide the info I need, I might have to spring for a meter that will measure inductance and just determine the values from the pair of 809s I already have. I'm a wood butcher, not an electronics tech so I'm not all that quick on the uptake with these items.

eso

[Earl K]

snip,,,,,,
Is it possible to measure inductance from the input to the tap, and then from the tap to the output and then add those figures to determine the total value of the coil? Also if measuring in that manner were valid, would using two coils with the the same values as the measurements of either side of the taps achieve the same result?

If taking those measurements would provide the info I need, I might have to spring for a meter that will measure inductance and just determine the values from the pair of 809s I already have. I'm a wood butcher, not an electronics tech so I'm not all that quick on the uptake with these items.

eso

- I'd measure L1 & L2 out of circuit .
- I don't believe you can get an accurate measurement of those coils while they are in the circuit.

- Once out of circuit, you can easily find each coils total "L" value, as well as the inductance for each of the 2 portions .


- Yes, buy yourself an LCR meter that measures inductance & capacitance ( as well as R).
- They're less than $100. / delivered /from eBay sellers .




RE; using 2 regular coils in series with a centre tapped wire / to equal one tapped coil ?

- Years back , Giskard ( 4313B ) explored this question and offered up a solution .
- This same question became the genesis behind the posted link which I offered above ( for "Tapped Autotransformers" by David Smith ).

- Honestly, I didn't understand the ( precursor ) solution offered at the time because I couldn't see how the resulting loss of mutual coupling ( K ) between the 2 inductances ( of 2 coils vs a single coil ) would equate ( to a single tapped coil ) when the 2 new coils might be separated by some critical distance .

- There's likely a formula available to off-set the loss of mutual coupling ( of separated coils ) / but I don't happen to know it .

<> cheers

[4343]

...

- Yes, buy yourself an LCR meter that measures inductance & capacitance ( as well as R).
- They're less than $100. / delivered /from eBay sellers ....

<> cheers

On this point, a simple LC meter is around $50 delivered at Parts Express, Sku 390-570.
I'm not sure if it's the same one I've been using, but make sure any meter you buy has the ranges you think you will need...

[eso]

On this point, a simple LC meter is around $50 delivered at Parts Express, Sku 390-570.
I'm not sure if it's the same one I've been using, but make sure any meter you buy has the ranges you think you will need...

Most inductors I see spec'd in crossovers are no more than .1mH, so a resolution of 1µH should be plenty, shouldn't it (.001mH)?

Like this:

http://cgi.ebay.com/3-1-2-bridge-LCR...item334b3e809a

I may still be able to come up with the specs from JBL Pro, but just in case I need a backup plan.

eso

[grumpy]

it's the accuracy spec (2-5%) that will be the limit, not the resolution...
but for matching like-pairs for L/R use (probably more important than
beating 2% in an absolute sense), something like that should be ok.

IIRC, WT2 can do this as well:
RLC and Cable Measurement
in 100pF-1000uF, 10nH-10H,
and .01-100K ohm Ranges

a bit more bang for your buck as well (ok, an extra $100 or so) ...

[eso]

it's the accuracy spec (2-5%) that will be the limit, not the resolution...
but for matching like-pairs for L/R use (probably more important than
beating 2% in an absolute sense), something like that should be ok.

IIRC, WT2 can do this as well:
RLC and Cable Measurement
in 100pF-1000uF, 10nH-10H,
and .01-100K ohm Ranges

a bit more bang for your buck as well (ok, an extra $100 or so) ...

Sounds worth the extra.
Do you have a link for that one?

eso

[grumpy]

http://woofertester.com
(Smith and Larson Audio)

[eso]

http://woofertester.com
(Smith and Larson Audio)

^&*&*!!!

I have only Macs...

Thanks anyway. Any other suggestions?


eso

[grumpy]

I can suggest you -skip- trying to install "Parallels" ... r/t i/o was somewhat lacking
(works as a Win7 virtual machine... but WT2 moaned and complained, ... no fault of
its own).

Meters will do. Fuzzmeasure is a nice Mac-centric package, but isn't as focused
(or at least not to the same place) as WT2 + hardware on a winXP+
system. Cheap/giveaway laptop works quite well