Alpair 12P

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pre65
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#16 Re: Alpair 12P

Post by pre65 »

I'm trying Squeezebox and Bushmaster 11 now, started with Siri.

Well, never heard her sound so good. :D :D

This is the best my system has ever sounded, well pleased.
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#17 Re: Alpair 12P

Post by pre65 »

On Siri's "the song of love" I noticed an edge on her voice.

Never noticed it before.

Is that on the recording ?
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#18 Re: Alpair 12P

Post by pre65 »

I came across Simons blog on the 'net today, and reading about his James D parallel crossover for the Alpair 12P.

Very interesting Simon. :)
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#19 Re: Alpair 12P

Post by pre65 »

Simon, the inductors pictured in your blog look large (and expensive ?), can you remember who supplied them ?

http://simonsnewadventuresinhifi.blogsp ... chive.html
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#20 Re: Alpair 12P

Post by Scottmoose »

Mundorf VL200 air cores? You can get them from Hificollective.
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#21 Re: Alpair 12P

Post by pre65 »

Scottmoose wrote:Mundorf VL200 air cores? You can get them from Hificollective.
Thanks Scott, I should have read the article properly. :oops:

They seem quite expensive, would I really need the 2mm wire version ?

http://www.hificollective.co.uk/catalog ... ors-0.html
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#22 Re: Alpair 12P

Post by Scottmoose »

Assuming you don't want to change the Q of the bass driver, the lower the coil resistance the better, although the effects will also vary depending on the output impedance of the amplifier so YMMV.
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#23 Re: Alpair 12P

Post by pre65 »

Still trying to find some "cost effective" air core inductors, I could be tempted by the AC125 Sup from Falcon.

http://www.falconacoustics.co.uk/audio- ... uctor.html

Got to be better than the el-cheapo ferrite core ones I'm using on the series crossover.

I've now got two 100uf MKP capacitors coming, just ordered them.
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#24 Re: Alpair 12P

Post by Toppsy »

pre65 wrote:
Scottmoose wrote:Mundorf VL200 air cores? You can get them from Hificollective.
Thanks Scott, I should have read the article properly. :oops:

They seem quite expensive, would I really need the 2mm wire version ?

http://www.hificollective.co.uk/catalog ... ors-0.html
Phil,
Why ask the above question when Scott answers
"Assuming you don't want to change the Q of the bass driver, the lower the coil resistance the better, although the effects will also vary depending on the output impedance of the amplifier so YMMV."
and you then proceed to ignore this advice (not untypical) and go searching for a cheaper option inductor with a smaller gauge wire and a higher DCR? What did you not understand with Scott's answer? As always it seems you prefer to penny pinch to make savings. Those Falcon inductors are not heat bonded so the whole windings are loose on the bobbin and it is only the tape wrapped around the windings that is holding it all together. After a while the glue on the tape will breakdown and the coil will become loose. This has happened to me in the past. Try Jantzen air cores if you think the Mundorf's are too expensive. Believe me you get what you pay for with inductors.
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#25 Re: Alpair 12P

Post by IslandPink »

You might try the 'feron' core ones from Mundorf Phil, if this is an interim project. They should be lower distortion.
I'm surprised you don't need to drop the efficiency of the bass driver now, since the Alpair is a fair bit less efficient than the FE167E in the midrange (?)
Which circuit do you have at the moment and where did you put the 2R ?
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#26 Re: Alpair 12P

Post by pre65 »

Thanks for the advice Colin.

Sometimes my "penny pinching" enables a project to get completed, and that is an important consideration for me. :wink:

It may be that I have to add series resistance to the bass helper circuit, so the difference in resistance may ,or not, be so worthy of concern, but I won't know till it's all connected up and tested.

I always consider the advice I'm given, whoever it's from, but I don't feel constrained to follow it to the letter. I hope those who give advice so willingly will forgive me ? :lol:

Anyway, I'm still looking at my options inductor wise.
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#27 Re: Alpair 12P

Post by pre65 »

IslandPink wrote:You might try the 'feron' core ones from Mundorf Phil, if this is an interim project. They should be lower distortion.
I'm surprised you don't need to drop the efficiency of the bass driver now, since the Alpair is a fair bit less efficient than the FE167E in the midrange (?)
Which circuit do you have at the moment and where did you put the 2R ?
The crossover is the same as Nick G uses on his baffles, and I use an 80uf Solen and 9mH cored inductor.

The 2R (now 1R) is to the 12P pos terminal.

As the circuit in Simons blog is pertinent to the 12P, and James D was involved, I think it's worth giving it a go. As in the previous post, the 18" Fane may (or not) need some resistance to even things out.

Thanks for the info on the Mundorf "feron" cored inductors. :D

Image
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#28 Re: Alpair 12P

Post by IslandPink »

So is it a bit like this but with the values changed - 80uF, 9mH & 2R in place of the 3.3R ?
quasar_filter_474.gif
quasar_filter_474.gif (4.63 KiB) Viewed 5226 times
I could swear you just added a picture while I was writing !
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#29 Re: Alpair 12P

Post by pre65 »

[quote="IslandPink"

I could swear you just added a picture while I was writing ![/quote]

I did ! :lol: I was having a bit of trouble with Photobucket at the time.
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#30 Re: Alpair 12P

Post by Greg »

Toppsy wrote:Those Falcon inductors are not heat bonded so the whole windings are loose on the bobbin and it is only the tape wrapped around the windings that is holding it all together. After a while the glue on the tape will breakdown and the coil will become loose. This has happened to me in the past.
How long is 'after a while'?

My original KLS3's are over 22 years old and they use Falcon air cored inductors all of which show no observable deterioration in the security of the tape or the windings. Maybe your own experience should not be expressed as an irrebuttable statement of fact?
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