Hi!

I'm looking for a straightforward HiFi circuit for a line level
amplifier. This is to give up to +10dB from the output of my
NAD ST402 tuner, down the line to an M-Audio Audiophile
A/D converter, thence into the PC for digital recording.

A rough spec would be
Input overload - better than 2V.; distortion better than 0.1% total.
Line in - line out 0 to + 10dB variable
Z in 10k ; Z out 600R
Preferred power supply = +/-10 ~ +/-20V.


I haven't been able to find this on the web, and would very
much appreciate any links/references etc.

TIA

NickW

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You can probably use any audio-intended op-amp for a circuit like
this. The 5532 (2channel) or 5534 (1 channel) and any of their modern
successors, like the OPA2604 or OP-275, would seem adequate. A simple
non-inverting 10dB configuration should be on the spec sheets. You
can use a variable FB resistor to vary gain or simply precede the 10dB
stage with a VC.

Kal



On Fri, 06 Oct 2006 15:55:10 +0100, equills wrote:

Hi!

I'm looking for a straightforward HiFi circuit for a line level
amplifier. This is to give up to +10dB from the output of my
NAD ST402 tuner, down the line to an M-Audio Audiophile
A/D converter, thence into the PC for digital recording.

A rough spec would be
Input overload - better than 2V.; distortion better than 0.1% total.
Line in - line out 0 to + 10dB variable
Z in 10k ; Z out 600R
Preferred power supply = +/-10 ~ +/-20V.


I haven't been able to find this on the web, and would very
much appreciate any links/references etc.

TIA

NickW

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In article ,
equills wrote:
I'm looking for a straightforward HiFi circuit for a line level
amplifier. This is to give up to +10dB from the output of my
NAD ST402 tuner, down the line to an M-Audio Audiophile
A/D converter, thence into the PC for digital recording.

A rough spec would be
Input overload - better than 2V.; distortion better than 0.1% total.
Line in - line out 0 to + 10dB variable
Z in 10k ; Z out 600R
Preferred power supply = +/-10 ~ +/-20V.


I haven't been able to find this on the web, and would very
much appreciate any links/references etc.

NE5532 was my choice for a very similar app. It's a DIL 8 dual op-amp.
Costs pennies. You could arrange the feedback loop so the minimum gain is
1 and the maximum what you want. +/-15 volts will allow it to feed any amp.

If you Google on op-amp you should get plenty of generic circuits to do
what you want, and explain how to set the gain, etc. But they're pretty
simple.

--
*'ome is where you 'ang your @ *

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

On Fri, 06 Oct 2006 17:45:57 +0100, "Dave Plowman (News)"
wrote:
etc.

NE5532 was my choice

Thanks for your kind reply
Dave

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On Fri, 06 Oct 2006 12:07:39 -0400, Kalman Rubinson
wrote:

You can probably use any audio-intended op-amp

Thanks for your kind reply, Kalman

NickW

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"equills" wrote in message
...
Hi!

I'm looking for a straightforward HiFi circuit for a line level
amplifier. This is to give up to +10dB from the output of my
NAD ST402 tuner, down the line to an M-Audio Audiophile
A/D converter, thence into the PC for digital recording.

Are you absolutely sure that's a good idea? Surely the tuner should be
giving you full line-level output and the A/D converter should be fine with
that. Are you sure it's not the recording level on your PC that's causing
the problem?

Are you absolutely sure that's a good idea? Surely the tuner should be
giving you full line-level output and the A/D converter should be fine with
that. Are you sure it's not the recording level on your PC that's causing
the problem?


It's a fairly old NAD ST402 (sounds great) into a Linn Intek.
Intek output to the PC line is very variable, from +5dB from CD to
-10dB or so from FM Radio 3.
The solution until the next upgrade is to patch in my EAR headphone
amp as a variable gain control [-inf to +15db] Naughty, but nice.

Thanks for your e-mail

equills

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"equills" wrote in message
...


Are you absolutely sure that's a good idea? Surely the tuner should be
giving you full line-level output and the A/D converter should be fine
with
that. Are you sure it's not the recording level on your PC that's causing
the problem?


It's a fairly old NAD ST402 (sounds great) into a Linn Intek.
Intek output to the PC line is very variable, from +5dB from CD to
-10dB or so from FM Radio 3.
The solution until the next upgrade is to patch in my EAR headphone
amp as a variable gain control [-inf to +15db] Naughty, but nice.

Thanks for your e-mail

Do you get the same problem if you take the Intek out of the circuit
altogether? And do you have to turn the volume right up when listening to
the radio normally?

"equills" wrote in message

Hi!

I'm looking for a straightforward HiFi circuit for a line
level
amplifier. This is to give up to +10dB from the output
of my
NAD ST402 tuner, down the line to an M-Audio Audiophile
A/D converter, thence into the PC for digital recording.

A rough spec would be
Input overload - better than 2V.; distortion better than
0.1% total.
Line in - line out 0 to + 10dB variable
Z in 10k ; Z out 600R
Preferred power supply = +/-10 ~ +/-20V.

I don't think that a preamp should be required. The recorded levels may be
a tad low, but you can fix that with any good audio editor including
Audacity.