I've been playing with this active crossover

http://sound.westhost.com/project09.htm

and have used TL072 which I have lots of. But wondered what would be
better - without paying a fortune?

--
*Be more or less specific *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:

I've been playing with this active crossover

http://sound.westhost.com/project09.htm

No workee it seems ...

and have used TL072 which I have lots of. But wondered what would be
better - without paying a fortune?

whatever 5532, OPA 275, BB 2134 come to mind, OPA 275 or 176, if applicable,
are very well behaved turn-on and -off wise, nice if you have a power
outage. Remember a 100 Ohm series resistor on the output.

Do not run your power amps flat out, attenuating 15 dB makes a lot of sense
and greatly reduces the risk of mishaps.

5532's surprised me in a listening test I was a part of but are perhaps "too
forward". OPA275 are perhaps a wee bit laid back. My favourites are OPA176
or the also "up front" 2134.

Most circuits I can imagine have two amplification stages, using different
opamps may sound better than twice the same.

Using a digital controller has interesting properties: steeper x-over
possible, adjustable eq for troublesome midrange-units and DA conversion
after x-over.

Feel free to disagree, those who think there is no difference should buy the
cheapest that sounds no different from the best to them. There are vastly
costlier alternatives out there.

Kind regards

Peter Larsen

In article ,
Peter Larsen wrote:
Dave Plowman (News) wrote:

I've been playing with this active crossover

http://sound.westhost.com/project09.htm

No workee it seems ...

Ah - it's not, is it? Was working earlier on today.

and have used TL072 which I have lots of. But wondered what would be
better - without paying a fortune?

whatever 5532, OPA 275, BB 2134 come to mind, OPA 275 or 176, if
applicable, are very well behaved turn-on and -off wise, nice if you
have a power outage. Remember a 100 Ohm series resistor on the output.

Right. For a direct replacement in the PCB they'd have to be 5533 or
another dual op-amp. I've incorporated a mute relay before the power amps.
100 ohm resistor present

Do not run your power amps flat out, attenuating 15 dB makes a lot of
sense and greatly reduces the risk of mishaps.

Right.

5532's surprised me in a listening test I was a part of but are perhaps
"too forward". OPA275 are perhaps a wee bit laid back. My favourites
are OPA176 or the also "up front" 2134.

Right again. I'll get some prices.

Most circuits I can imagine have two amplification stages, using
different opamps may sound better than twice the same.

Pity the site is down. There is an input stage, two stages each for high
and low pass, four for mid, and an output driver for each. But non doing
anything terribly taxing for any op-amp. The input has the choice of
balanced - and I'd guess could be improved upon.

Using a digital controller has interesting properties: steeper x-over
possible, adjustable eq for troublesome midrange-units and DA conversion
after x-over.

I've enough problems with analogue. ;-)

Feel free to disagree, those who think there is no difference should buy
the cheapest that sounds no different from the best to them. There are
vastly costlier alternatives out there.

Kind regards

Peter Larsen

--
*If one synchronized swimmer drowns, do the rest have to drown too?

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Peter Larsen
scribeth thus
Dave Plowman (News) wrote:

I've been playing with this active crossover

http://sound.westhost.com/project09.htm

No workee it seems ...

and have used TL072 which I have lots of. But wondered what would be
better - without paying a fortune?

whatever 5532, OPA 275, BB 2134 come to mind, OPA 275 or 176, if applicable,
are very well behaved turn-on and -off wise, nice if you have a power
outage. Remember a 100 Ohm series resistor on the output.

Do not run your power amps flat out, attenuating 15 dB makes a lot of sense
and greatly reduces the risk of mishaps.

5532's surprised me in a listening test I was a part of but are perhaps "too
forward". OPA275 are perhaps a wee bit laid back. My favourites are OPA176
or the also "up front" 2134.


You did use those in appropriate settings for the amps concerned with
respect to biasing and compensation and checked that they weren't
oscillating at several MHz etc?..

Its that I have heard some comments like that on some forums and people
seem to think that can just swap op-amps around willy nilly.. And then
wonder why they do sound rather different;!...

Most circuits I can imagine have two amplification stages, using different
opamps may sound better than twice the same.

Using a digital controller has interesting properties: steeper x-over
possible, adjustable eq for troublesome midrange-units and DA conversion
after x-over.

Feel free to disagree, those who think there is no difference should buy the
cheapest that sounds no different from the best to them. There are vastly
costlier alternatives out there.

Kind regards

Peter Larsen






--
Tony Sayer

"Dave Plowman (News)" wrote in message
...
I've been playing with this active crossover

http://sound.westhost.com/project09.htm

and have used TL072 which I have lots of. But wondered what
would be
better - without paying a fortune?



Take care with the circuit design particularly biasing resistors.
The TL072 is a bi-fet op-amp and thus relatively high input
impdenece which some designer may have tried to use.


--
Woody

harrogate three at ntlworld dot com

"Woody" wrote:
"Dave Plowman (News)" wrote in message
...
I've been playing with this active crossover

http://sound.westhost.com/project09.htm

and have used TL072 which I have lots of. But wondered what
would be
better - without paying a fortune?



Take care with the circuit design particularly biasing resistors.
The TL072 is a bi-fet op-amp and thus relatively high input
impdenece which some designer may have tried to use.


There was a time I was trying to replace 4136 with TLO75 . None to be had.
I was going to then use special boards and use more exotic. I still have
the parts !
I would try to stay with the same input type. Faster opamps may oscillate,
depending on board layout. Transistor input may load things down. Unless
you need more output drive, the 07's should be just fine.

Greg

In article
,
gregz wrote:
"Woody" wrote:
"Dave Plowman (News)" wrote in message
...
I've been playing with this active crossover

http://sound.westhost.com/project09.htm

and have used TL072 which I have lots of. But wondered what
would be
better - without paying a fortune?



Take care with the circuit design particularly biasing resistors.
The TL072 is a bi-fet op-amp and thus relatively high input
impdenece which some designer may have tried to use.


There was a time I was trying to replace 4136 with TLO75 . None to be
had. I was going to then use special boards and use more exotic. I still
have the parts ! I would try to stay with the same input type. Faster
opamps may oscillate, depending on board layout. Transistor input may
load things down. Unless you need more output drive, the 07's should be
just fine.

Output is normal domestic line level. Input is balanced line level.

--
*Why are they called apartments, when they're all stuck together? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 6/11/2013 12:37 AM, Dave Plowman (News) wrote:
I've been playing with this active crossover

http://sound.westhost.com/project09.htm

and have used TL072 which I have lots of. But wondered what would be
better - without paying a fortune?


**I'm rather partial to the AD825. Modestly priced and very high
performance. You'll need to consider surface mount techniques though.
Not available in DIP. Brown Dog have suitable adapters.

--
Trevor Wilson www.rageaudio.com.au

Re-read the OP. You're talking about active crossovers so
probably running at relatively high levels. IME you would be
probably spending money unneccessarily - the TL072 is quite good
at higher levels.

I once built a set of line amps for my Quad33 using TL074s taking
the tone controls out in the process. I ended up with amps that
were frequency flat within +/-0.1dB from 14Hz to 240KHz and had a
worst case phase error of about 15degrees at around 12Hz back to
0 degrees before 30Hz. They were noticably 'cleaner' than the
original discrete amps.

Later I built the pre-amp board with the same ICs and it too
sounded good. I later replaced the TL074's with LM837sand could
not tell any difference.

The source was either CD or LP with AT90E(?) m/c cartridge
feeding the Quad, thence a home built dual mono power Mosfet amp
using amp boards from Ambit (remember them?) and a regulated
supply designed by the great JLH, into a pair of transmission
line speakers to the Dr Bailey design from WW 1972 (oh how I
loved those speakers.) In an 18x12ft lounge I could rattle the
windows with the pedal reeds from the organ of Limburg
Cathedral - pity that disc went walkies.

Them were't days................


--
Woody

harrogate three at ntlworld dot com

On 05/11/2013 20:09, Woody wrote:
snip

The source was either CD or LP with AT90E(?) m/c cartridge
feeding the Quad, thence a home built dual mono power Mosfet amp
using amp boards from Ambit (remember them?) and a regulated
supply designed by the great JLH, into a pair of transmission
line speakers to the Dr Bailey design from WW 1972 (oh how I
loved those speakers.) In an 18x12ft lounge I could rattle the
windows with the pedal reeds from the organ of Limburg
Cathedral - pity that disc went walkies.

Them were't days................


Do you happen to have the speaker design?
--
Cheers, Rob