B&W 801 Series 2 Van Alstine x-over mods

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misterbobman

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Joined 2004
#1
B&W 801 MkII Van Alstine x-over mods

Trying to attain a copy of the Audio Basics publication (by Frank Van Alstine) December 1989 on the subject of B&W 801 MkII x-over upgrades (primarily to eliminate inductor field interferences). Many Audio Basic's are on the web but not 1989/12 issue.
 
#2
Re: B&W 801 MkII Van Alstine x-over mods

misterbobman said:
Trying to attain a copy of the Audio Basics publication (by Frank Van Alstine) December 1989 on the subject of B&W 801 MkII x-over upgrades (primarily to eliminate inductor field interferences). Many Audio Basic's are on the web but not 1989/12 issue.
Click to expand...


Hi,

Did you ever get any information on upgrading this speaker. I'm looking for information too. Perhaps we can share.

Thanks, Nick
 
#3
B&W 801 MkII Van Alstine x-over mods

Below is all that I've found at: http://www.avahifi.com/root/audio_basics/ab_pdf/ab1990-10.pdf and at http://www.avahifi.com/root/audio_basics/ab_pdf/ab1992-01.pdf
1989/12 • B&W 801 Crossover Design Goof • four
pages
We write to Stereophile documenting a design blunder
in the B&W 801 Matrix crossover board layout. Two
large inductors are positioned so that they interact magnetically
and thus bass is dumped into the midrange
speaker and midrange into the bass speaker. A minor
do-it-yourself change to the crossover board greatly
improves the sound quality of the speaker.
1990/01 • B&W 801 Matrix Crossover modifications. •
2 pages
We go into more engineering detail on the 801 crossover
design and suggested upgrades, including graphs of the
frequency response before and after the changes.
 
#4
Re: B&W 801 MkII Van Alstine x-over mods

misterbobman said:
Below is all that I've found at: http://www.avahifi.com/root/audio_basics/ab_pdf/ab1990-10.pdf and at http://www.avahifi.com/root/audio_basics/ab_pdf/ab1992-01.pdf
1989/12 • B&W 801 Crossover Design Goof • four
pages
We write to Stereophile documenting a design blunder
in the B&W 801 Matrix crossover board layout. Two
large inductors are positioned so that they interact magnetically
and thus bass is dumped into the midrange
speaker and midrange into the bass speaker. A minor
do-it-yourself change to the crossover board greatly
improves the sound quality of the speaker.
1990/01 • B&W 801 Matrix Crossover modifications. •
2 pages
We go into more engineering detail on the 801 crossover
design and suggested upgrades, including graphs of the
frequency response before and after the changes.
Click to expand...

Hi,

Thanks for sharing that info. If I come across any info, I'll share it with you too.

Thanks again, Nick
 
#6
Re: Re: B&W 801 MkII Van Alstine x-over mods

Netlist said:

Euh...this perhaps? page 30 http://www.avahifi.com/root/audio_basics/ab_pdf/ab1989.pdf

Root: http://www.avahifi.com/root/audio_basics/

/Hugo 🙂
Click to expand...


Hi Hugo,

Thank you so much!! I haven't been on this website long, but I was beginning to think that most of the people were unhelpful... or that no one was interested in what I was interested in. Anyway, Thank you again.. I will try to do the same for someone else in the future.

Take care, Nick
 
#7
Re: Re: Re: B&W 801 MkII Van Alstine x-over mods

kensetsu said:
I will try to do the same for someone else in the future.
Click to expand...
People…unhelpful…here?
You must be kidding. 🙂
Regarding any influence I might have:
I try to be generous where I can and I consider your appreciation as one of the most important factors for the well being of this forum. 😎

/Hugo
 
#8
Re: Re: Re: Re: B&W 801 MkII Van Alstine x-over mods

misterbobman said:
Trying to attain a copy of the Audio Basics publication (by Frank Van Alstine) December 1989 on the subject of B&W 801 MkII x-over upgrades (primarily to eliminate inductor field interferences). Many Audio Basic's are on the web but not 1989/12 issue.
Click to expand...


Netlist said:

Euh...this perhaps? page 30 http://www.avahifi.com/root/audio_basics/ab_pdf/ab1989.pdf

Root: http://www.avahifi.com/root/audio_basics/

/Hugo 🙂
Click to expand...


Netlist said:

People…unhelpful…here?
You must be kidding. 🙂
Regarding any influence I might have:
I try to be generous where I can and I consider your appreciation as one of the most important factors for the well being of this forum. 😎

/Hugo
Click to expand...


Hi,

I spoke with Frank Van Alstine himself the other day. Great guy!! He e-mailed me a schematic of the crossover and step by step directions on how to fix it. Anyway, anyone that would like me to forward the e-mail to them, please let me know. Actually, I'm beginning to think that the $1600.00 external crossover that's offered by Northwest or whatever they're called is nothing more than the Vanalenstein mod.

Later, Nick

P.S. I won't post the information that I received from Mr. Van Alstine, because I didn't get his permission and that would be disrespectful.
 
#9
B&W 801 Matrix series 2 crossover modification

Hi, I am new to this sight,and have read of the Van Alstine crossover mod on this sight.I have found some limited information elswhere,but would like the detailed plan with pictorals,etc. I have completed everything but the resisor in series with L1 as I am unsure of its installation location.I have the Jan 1988 year model and believe the track on the pc needs cut and two holes drilled in pc for resistor. What I really need is a pictoral of this location. Any help would be greatly appreciated. Thanks, Jeff
 
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