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patric deimon
 
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Default Bose 901 series II-questions

I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?

Question 2...Anyone know someone or somewhere that works on the active
eq's for these systems?

Thanks for any help and info

Patric
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Geoff@work
 
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"patric deimon" wrote in message
news
I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in)


MacDonalds ?

;-)

geoff


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Kalman Rubinson
 
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On Thu, 29 Sep 2005 16:50:45 -0700, patric deimon
wrote:

I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?


Should be easy to figure out and emulate unless it is
level-dependant.

Question 2...Anyone know someone or somewhere that works on the active
eq's for these systems?


Nope.

Kal
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Phil Allison
 
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"patric deimon"
I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?




** The published curve for the Bose 802E equaliser is as follows.


20 Hz = -5 dB
30 Hz = -1 dB
40 Hz = +3 dB
60 Hz = +14 dB
100 Hz = +5 dB
200 Hz = +1 dB
600 Hz = 0 dB
800 Hz = 0 dB
1 kHz = + 1dB
2 kHz = + 4 dB
3 kHz = + 5 dB
4 kHz = + 8 dB
6 kHz = + 11 dB
10 kHz = + 15dB
15 kHz = + 17 dB


It might be smart to subtract say 8 dB from all the figures before setting
them on the sliders of a graphic to keep the plus and minus dBs even.



.......... Phil































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Phil Allison
 
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"Phil Allison"


** The published curve for the Bose 802E equaliser is as follows.



** Arrrgh - the OP has 901s - the home hi fi speakers.

The eq curve is similar but not the same as the 802 one.




............. Phil





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Phil Allison
 
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"patric deimon"
"Phil Allison"


** The published curve for the Bose 802E equaliser is as follows.


20 Hz = -5 dB
30 Hz = -1 dB
40 Hz = +3 dB
60 Hz = +14 dB
100 Hz = +5 dB
200 Hz = +1 dB
600 Hz = 0 dB
800 Hz = 0 dB
1 kHz = + 1dB
2 kHz = + 4 dB
3 kHz = + 5 dB
4 kHz = + 8 dB
6 kHz = + 11 dB
10 kHz = + 15dB
15 kHz = + 17 dB


It might be smart to subtract say 8 dB from all the figures before
setting
them on the sliders of a graphic to keep the plus and minus dBs even.



Thanks Phil. Where did you find this info?




** Graph in the Bose 802 service manual.



........... Phil



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Scott Dorsey
 
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Kalman Rubinson wrote:
On Thu, 29 Sep 2005 16:50:45 -0700, patric deimon
wrote:

I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?


Should be easy to figure out and emulate unless it is
level-dependant.


The EQ curve is in the manual that came with the things, and as I recall
it is such a huge boost that I don't think you'll be able to do it with
a single graphic EQ. Maybe two chained together.

Question 2...Anyone know someone or somewhere that works on the active
eq's for these systems?


Nope.


There is nothing much in there that your local TV repair shop can't handle.
They are very easy to fix.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Don Nafe
 
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"patric deimon" wrote in message
news
I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?

Question 2...Anyone know someone or somewhere that works on the active
eq's for these systems?

Thanks for any help and info

Patric



Why don't you try Ebay for a replacement



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William Sommerwerck
 
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I have an old set of 90 IIs. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have
a restaurant I think they would be good in) I would just like to see
them working.


If one channel is good, and the other bad, you have a working reference. It
should be a straightforward job to troubleshoot the bad side and repair it.

A competent service tech should be able to do this for a lot less than it
would cost to put together a new equalizer. Indeed, if the problem isn't
something simple -- like a broken jack or disconnected wire -- wholesale
parts replacement would probably fix the channel quickly and at a relatively
low cost.

If you can't find anyone locally to do it, let me know and I can probably do
it for you.

If you need to know the actual response, it can be measured with an audio
generator and meter.

This is not a complicated problem to fix. Don't turn it into one.




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William Sommerwerck
 
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I'm sure Phil's numbers are correct, but they represent the final, net
curve. Simply setting an equalizer to these settings will not necessarily
produce the same curve.

In practice, you would probably start by setting the 60Hz and 15kHz values,
then seeing how close the other frequencies are, and trimming accordingly.

Again, it would probably be less trouble to simply fix the equalizer.

20 Hz = -5 dB
30 Hz = -1 dB
40 Hz = +3 dB
60 Hz = +14 dB
100 Hz = +5 dB
200 Hz = +1 dB
600 Hz = 0 dB
800 Hz = 0 dB
1 kHz = + 1dB
2 kHz = + 4 dB
3 kHz = + 5 dB
4 kHz = + 8 dB
6 kHz = + 11 dB
10 kHz = + 15dB
15 kHz = + 17 dB



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patric deimon
 
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In article ,
"William Sommerwerck" wrote:

I have an old set of 90 IIs. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have
a restaurant I think they would be good in) I would just like to see
them working.


If one channel is good, and the other bad, you have a working reference. It
should be a straightforward job to troubleshoot the bad side and repair it.

A competent service tech should be able to do this for a lot less than it
would cost to put together a new equalizer. Indeed, if the problem isn't
something simple -- like a broken jack or disconnected wire -- wholesale
parts replacement would probably fix the channel quickly and at a relatively
low cost.

If you can't find anyone locally to do it, let me know and I can probably do
it for you.

If you need to know the actual response, it can be measured with an audio
generator and meter.

This is not a complicated problem to fix. Don't turn it into one.


Thanks William (and all who chimed in) for the advice. You are right.
It should be easy.

I did go in with a multimeter and check the voltages looking for
anomalies between the two sides. Strange, I didn't find any.

Power supply is putting out about 15 volts. Couldn't get anything to
reveal by wiggling or tapping and no visible signs.

I was just checking voltages, not signal, and there seemed to be
voltages as far as I checked. I ran out of time. It has been awhile
since I used my techie brain and it felt like it it had been replaced
with oatmeal.

Man, I was forever taking apart, fixing, modding my Otaris, Ataris,
synths, drum machines.

I did call around town here (Anchorage, Alaska) and got the same kinds
of responses that made me go back to school for a couple years to be an
electronics tech.

Back in the 70's/80's I'd need work on my Otaris and Ramsa Boards and no
one had a clue. Happy to look at it for 60-100 bucks but no clue.

Bose has gone so far down the car audio/office radio path the hi-fi
stores here had no clue about the legacy stuff.

Thanks for the offer to look at it yourself. Your opinions and tech
talk on this group are always good stuff. First I'll find more time to
go back in and see what I see. Crap....It's just an EQ! Ha!

Patric
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Phil Allison
 
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"patric deimon"


I did go in with a multimeter and check the voltages looking for
anomalies between the two sides. Strange, I didn't find any.

Power supply is putting out about 15 volts. Couldn't get anything to
reveal by wiggling or tapping and no visible signs.

I was just checking voltages, not signal, and there seemed to be
voltages as far as I checked. I ran out of time. It has been awhile
since I used my techie brain and it felt like it it had been replaced
with oatmeal.



** Check all the op-amp pins 1 and 7 for large DC voltages - should be only
millivolts.

Any with more than 1 volt DC on those pins are dud.




.......... Phil





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William Sommerwerck
 
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Thanks for the offer to look at it yourself. Your opinions and tech
talk on this group are always good stuff. First I'll find more time to
go back in and see what I see. Crap....It's just an EQ! Ha!


Thanks for the compliment, but I _am_ wrong sometimes. My strength is that I
try to look at things in terms of basic principles, something I don't see
many other people here doing.

Regardless...

If the voltages are OK, the next step is to put a 'scope on it and track the
signal. You could do this with an AC voltmeter, of course, but it's easier
if you can "see" the signal.

When you finally fix the problem, you'll feel very pleased with yourself.

Good luck!


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Dr. Dolittle
 
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What are you going off about?

SSJVCmag wrote:

Actually that's BOSE' -preference-... One thing Dr B knows is cold-hearted
marketting to the elite scale coupled with product IT protetction and that
means "don;t ask... You can;t fix it... Leave it to us" as both relief to
the Mecedes consumer who wants HELP ("Daddy's here, go take a nap and when
you awake, all will be well) as well as the more realistic brutal Keeper Of
Secrets (Technicisn, you are not on a need-to-know basis... It's more than
you can handle anyway... Send it home where we can care for it PROPERLY).
Every attempt at a call to BOSE tech support and questions about a problem
containing specific thoughts as to what an unmarked componet is and does was
met with respone akin to asking the Secret Service where the President's
limo would be stopping for gas that day. It's not unlike software today.

  #17   Report Post  
SSJVCmag
 
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On 10/1/05 11:27 AM, in article
, "Dr. Dolittle"
wrote:

What are you going off about?

SSJVCmag wrote:

Actually that's BOSE' -preference-... One thing Dr B knows is cold-hearted
marketting to the elite scale coupled with product IT protetction and that
means "don;t ask... You can;t fix it... Leave it to us" as both relief to
the Mecedes consumer who wants HELP ("Daddy's here, go take a nap and when
you awake, all will be well) as well as the more realistic brutal Keeper Of
Secrets (Technicisn, you are not on a need-to-know basis... It's more than
you can handle anyway... Send it home where we can care for it PROPERLY).
Every attempt at a call to BOSE tech support and questions about a problem
containing specific thoughts as to what an unmarked componet is and does was
met with respone akin to asking the Secret Service where the President's
limo would be stopping for gas that day. It's not unlike software today.



Mainly the few lines preceding my answer (which you snipped):
On 9/30/05 11:59 PM, in article
, "patric deimon"
wrote:

Bose has gone so far down the car audio/office radio path the hi-fi
stores here had no clue about the legacy stuff.


Thus my answer that Not only is it that maybe the store folks HAVE no
answers, but even if they DID, the Bose Way is not to SUPPLY such answers.

Pay attention.

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GregS
 
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In article , "Don Nafe" wrote:

"patric deimon" wrote in message
news
I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?

Question 2...Anyone know someone or somewhere that works on the active
eq's for these systems?

Thanks for any help and info

Patric



Why don't you try Ebay for a replacement


Get sombody to fix it or yes, buy another one.

I think there was some shoddy eq's out there from the start
I tested one thatseemed like the treble was totally out of control.
I forget if the op-amps are in sockets. The bass of the 901
gets 18 dB boost at 30 Hz. Both 901 and 801 get a very sharp dropback just below
the bass boost as shown on the chart, something a normal eq has difficulty
with. As shown, you dont need the lowest bass de[ending on the suituation.
The 901n goes to 29 Hz cutoff, where the 801 goes to 50 Hz.

greg
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GregS
 
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In article , (GregS) wrote:
In article , "Don Nafe"
wrote:

"patric deimon" wrote in message
news
I have an old set of 901 -II's. The active EQ only works on one side.
Before anyone posts that them not working is a blessing (I have a
restaurant I think they would be good in) I would just like to see them
working.

Question 1... Has anyone figured out the eq curve for these for those of
us with graphic eq's lying around doing nothing?

Question 2...Anyone know someone or somewhere that works on the active
eq's for these systems?

Thanks for any help and info

Patric



Why don't you try Ebay for a replacement


Get sombody to fix it or yes, buy another one.

I think there was some shoddy eq's out there from the start
I tested one thatseemed like the treble was totally out of control.
I forget if the op-amps are in sockets. The bass of the 901
gets 18 dB boost at 30 Hz. Both 901 and 801 get a very sharp dropback just
below
the bass boost as shown on the chart, something a normal eq has difficulty
with. As shown, you dont need the lowest bass de[ending on the suituation.
The 901n goes to 29 Hz cutoff, where the 801 goes to 50 Hz.

greg


Sorry, I didn't notice the Series II in the subject field. It used descrete transistors.
Any of the models equalizers could be used though, should I say, depending on
sound quality! That series II equalizer is a bit tough to take apart. Should I say, I actually
used this system in the 70's, and one side seemed began to dissapear, but it
was only the failing of the output coupling caps. I don't have the speakers anymore but still have
that equalizer!

greg
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