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Line signal to Mic

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October 23, 2004 11:21:39 PM

Archived from groups: rec.audio.tech (More info?)

Hi,

I'm trying to find out if there is a way to connect the REC/Phones output of
my Roland Micro Cube amplifier to a Microphone input on a laptop. Assuming
the Mic-In is low impedance, is there a way to convert the high voltage
line signal of the amp to the microphone input? All I found so far is to do
the opposite: connecting a mic to a line input. Where can I buy such a
impedance matcher?

Also, I would like to know if it is ok to connect a 600 Ohm mic to a 10kOhm
mic input.

best,
Jeroen

More about : line signal mic

Anonymous
October 23, 2004 11:21:40 PM

Archived from groups: rec.audio.tech (More info?)

"JW" <wijnhout@science.uva.nl> wrote ...
> I'm trying to find out if there is a way to connect the REC/Phones
> output of my Roland Micro Cube amplifier to a Microphone input
> on a laptop. Assuming the Mic-In is low impedance, is there a way
> to convert the high voltage line signal of the amp to the microphone
> input?

You need a simple attenuator to knock the line~level from your
amplifier down to mic-level for your laptop. Note that most
laptop mic inputs are mono. Hope you weren't expecting to
listen/record stereo. Impedance is really not the issue here.

> All I found so far is to do the opposite: connecting a mic to
> a line input.

That would be a mic preamp.

> Where can I buy such a impedance matcher?

Last time I checked, you could buy a cable at Radio Shack
here in the US that had an attenuator built-in for connecting
line-level sources to mic-level inputs. Dunno if you have
an equivalent electronics mass-marketer in .nl? Likely
available someplace online also.

Or if you are a friend are handy with a soldering iron, it is
easily made with a couple of resistors that cost only a few
pennies. Information (more than you will ever need!) is
availble at www.epanorama.net

> Also, I would like to know if it is ok to connect a 600 Ohm
> mic to a 10kOhm mic input.

Yes. Impedance isn't really the issue here either.
Anonymous
October 24, 2004 12:21:41 AM

Archived from groups: rec.audio.tech (More info?)

"Laurence Payne" <l@laurenceDELETEpayne.freeserve.co.uk> wrote in message
news:28lln01v46snj950a3dsaoao1raua1ofr9@4ax.com...
> On Sat, 23 Oct 2004 19:21:39 +0200, JW <wijnhout@science.uva.nl>
> wrote:
>
>>I'm trying to find out if there is a way to connect the REC/Phones output
>>of
>>my Roland Micro Cube amplifier to a Microphone input on a laptop. Assuming
>>the Mic-In is low impedance, is there a way to convert the high voltage
>>line signal of the amp to the microphone input? All I found so far is to
>>do
>>the opposite: connecting a mic to a line input. Where can I buy such a
>>impedance matcher?
>>
>>Also, I would like to know if it is ok to connect a 600 Ohm mic to a
>>10kOhm
>>mic input.
>
> A quick Google found this. Still true for non-specialist computer
> sound systems I think.

http://www.epanorama.net/links/pc_sound.html
Related resources
Anonymous
October 24, 2004 2:05:11 PM

Archived from groups: rec.audio.tech (More info?)

On Sat, 23 Oct 2004 20:21:41 -0700, "Richard Crowley"
<rcrowley7@xprt.net> wrote:

>http://www.epanorama.net/links/pc_sound.html

Which of the many links there do you recommend? I rather liked:

"a mic input jack (with a 1/8" stereo minijack). Here's what you
should do with this: nothing. It's not meant for music mics at all.
It's designed specifically for computer mics. The fact that it has 3
connections should give you a hint that there's something weird about
this jack. Pretend it's not there and don't plug a thing into it,
especially a microphone! One guy who wrote to me was tearing his hair
out in frustration because his recorded sound was so distorted; it
turned out he was recording through his computer mic that he forgot
was plugged in there..."
from:
http://www.homerecording.com/sound_card_basics.html
Anonymous
October 24, 2004 2:05:12 PM

Archived from groups: rec.audio.tech (More info?)

"Laurence Payne" wrote ...
> On Sat, 23 Oct 2004 20:21:41 -0700, "Richard Crowley"
> <rcrowley7@xprt.net> wrote:
>
>>http://www.epanorama.net/links/pc_sound.html
>
> Which of the many links there do you recommend?

Hard to recommend a specific one as the original question was
somewhat incoherent.

> I rather liked:
>
> "a mic input jack (with a 1/8" stereo minijack). Here's what you
> should do with this: nothing. It's not meant for music mics at all.

Sounds good to me.
October 26, 2004 1:29:38 PM

Archived from groups: rec.audio.tech (More info?)

Richard Crowley wrote:

> "JW" <wijnhout@science.uva.nl> wrote ...
>> I'm trying to find out if there is a way to connect the REC/Phones
>> output of my Roland Micro Cube amplifier to a Microphone input
>> on a laptop. Assuming the Mic-In is low impedance, is there a way
>> to convert the high voltage line signal of the amp to the microphone
>> input?
>
> You need a simple attenuator to knock the line~level from your
> amplifier down to mic-level for your laptop. Note that most
> laptop mic inputs are mono. Hope you weren't expecting to
> listen/record stereo. Impedance is really not the issue here.

Mono is ok.

>> All I found so far is to do the opposite: connecting a mic to
>> a line input.
>
> That would be a mic preamp.

Yes, precisely the opposite from what I want.

>> Where can I buy such a impedance matcher?
>
> Last time I checked, you could buy a cable at Radio Shack
> here in the US that had an attenuator built-in for connecting
> line-level sources to mic-level inputs. Dunno if you have
> an equivalent electronics mass-marketer in .nl? Likely
> available someplace online also.

Sure we do! The only problem is to find the right word/component to ask for.
I will ask for an attenuator, as you suggested.

thanks for your answer,
Jeroen
Anonymous
October 26, 2004 1:29:39 PM

Archived from groups: rec.audio.tech (More info?)

"JW" wrote ...
> Richard Crowley wrote:
>> Last time I checked, you could buy a cable at Radio Shack
>> here in the US that had an attenuator built-in for connecting
>> line-level sources to mic-level inputs. Dunno if you have
>> an equivalent electronics mass-marketer in .nl? Likely
>> available someplace online also.
>
> Sure we do! The only problem is to find the right word/component
> to ask for. I will ask for an attenuator, as you suggested.

I hope the people in your shops are better than in ours. Likely not
1 in 10 of them would even know how to pronounce "attenuator"
much less know what it is.

See RadioShack # 42-2152 "6.5' Attenuating Dubbing Cord"
On our side of the pond, it pays to do your homework and
walk into the shop with a model number.
October 26, 2004 1:32:39 PM

Archived from groups: rec.audio.tech (More info?)

Laurence Payne wrote:

> On Sat, 23 Oct 2004 19:21:39 +0200, JW <wijnhout@science.uva.nl>
> wrote:
>
>>I'm trying to find out if there is a way to connect the REC/Phones output
>>of my Roland Micro Cube amplifier to a Microphone input on a laptop.
>>Assuming the Mic-In is low impedance, is there a way to convert the high
>>voltage line signal of the amp to the microphone input? All I found so far
>>is to do the opposite: connecting a mic to a line input. Where can I buy
>>such a impedance matcher?
>>
>>Also, I would like to know if it is ok to connect a 600 Ohm mic to a
>>10kOhm mic input.
>
> A quick Google found this. Still true for non-specialist computer
> sound systems I think.

I have found this answer myself too, this is not the problem. All my
connectors are mono anyway.

> The main points are that the mic input is mono. Ring doesn't expect
> one of the stereo channels, it outputs a voltage. This is current
> limited, you'll do no harm to computer or source by connecting to it.
> But you won't get one channel of your music.
>
> So you need a cable that connects both stereo outputs to tip of a
> 3.5mm jack plug.
>
> You'll need to adjust the output level of your source way down. The
> computer's software mixer almost certainly acts on the signal after it
> has been digitised. It can't compensate for overload at the input.
> And you have the potential for MASSIVE overload here. Nothing will
> blow up, but it will sound terrible :-)

This is the description of my problem/question, not an answer! ;-)

> ...............................................................................................................
> Soundblaster soundcard series (SB16, SB32, AWE32 and AWE64) have all a
> microphone input designed to be used with the electret microphones
> which come with the soundcard package (some packages) or with separate
> microphone designed to be used with SoundBlaster soundcards (there are
> separate microphones and some monitors have built-in microphones like
> this).
>
>
> Typical characteristics of Sound Blaster microphone input:
> Input Type: Unbalanced Low Impedance
> Input Sensitivity: Approx. -20dBV (100mV or 0.1Volt)
> Input Impedance: 600 to 1500. (Ohms)
> Input Connector: 3.5mm Miniplug (Stereo Jack)
> Input Wiring: Audio on Tip, Ground on Sleeve, 5Volts DC Bias on
> Ring

Now, this is useful info. I couldn't find info like this on the Creatives
website...

> Because the microphone input needs very high input levels it is not
> suitable to be used with any other micophone

best,
Jeroen
Anonymous
October 27, 2004 1:25:47 AM

Archived from groups: rec.audio.tech (More info?)

"JW" <wijnhout@science.uva.nl> wrote in message
news:cle3v3$nog$1@reader13.wxs.nl...
> Hi,
>
> I'm trying to find out if there is a way to connect the REC/Phones output
> of
> my Roland Micro Cube amplifier to a Microphone input on a laptop. Assuming
> the Mic-In is low impedance, is there a way to convert the high voltage
> line signal of the amp to the microphone input? All I found so far is to
> do
> the opposite: connecting a mic to a line input. Where can I buy such a
> impedance matcher?
>
> Also, I would like to know if it is ok to connect a 600 Ohm mic to a
> 10kOhm
> mic input.

Does your laptop have a Mic Input but no Line Input ?!!!

geoff
Anonymous
October 27, 2004 1:25:48 AM

Archived from groups: rec.audio.tech (More info?)

"Geoff Wood" wrote ...
> Does your laptop have a Mic Input but no Line Input ?!!!

Virtually all laptops have mic inputs.
A small minority of them have line inputs.
Anonymous
October 27, 2004 12:00:21 PM

Archived from groups: rec.audio.tech (More info?)

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10nsh9fqvvsjr1b@corp.supernews.com...
> "Geoff Wood" wrote ...
>> Does your laptop have a Mic Input but no Line Input ?!!!
>
> Virtually all laptops have mic inputs.
> A small minority of them have line inputs.


100% of the laptops that I have experience have a Line In. But that is only
one !

geoff
Anonymous
October 27, 2004 1:11:40 PM

Archived from groups: rec.audio.tech (More info?)

"Jeroen" <wijnhout@science.uva.nl> wrote in message
news:clnuej$p8q$2@info.science.uva.nl

> I've spotted this one too. However the "McGriffin IMic" is 50%
> cheaper, because it doesn't offer the digital and optical inputs I
> don't need.

The Griffen iMic is IME a highly asymmetrical device. The playback side
sounds (and measures) great for the price while the record side sounds (and
measures) pretty bad.
!