Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.pro
[email protected] tshepard@rcsreg.com is offline
external usenet poster
 
Posts: 7
Default Mic preamp build?

What are your thoughts on this?

They want $22 for the circuit board. Not sure what the components
cost.
  #2   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

wrote:
What are your thoughts on this?


On what?

They want $22 for the circuit board. Not sure what the components
cost.


Who does? What is the front end? Is there a transformer? If so,
expect that to be the majority of the cost.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #3   Report Post  
Posted to rec.audio.pro
Tobiah[_5_] Tobiah[_5_] is offline
external usenet poster
 
Posts: 1
Default Mic preamp build?

Oh, you want the link I suppose!

http://sound.whsites.net/project66.htm

On Saturday, November 5, 2016 at 3:37:23 PM UTC-7, Scott Dorsey wrote:
wrote:
What are your thoughts on this?


On what?

They want $22 for the circuit board. Not sure what the components
cost.


Who does? What is the front end? Is there a transformer? If so,
expect that to be the majority of the cost.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."


  #4   Report Post  
Posted to rec.audio.pro
Don Pearce[_3_] Don Pearce[_3_] is offline
external usenet poster
 
Posts: 2,417
Default Mic preamp build?

On Sat, 5 Nov 2016 15:43:48 -0700 (PDT), Tobiah
wrote:

Oh, you want the link I suppose!

http://sound.whsites.net/project66.htm

On Saturday, November 5, 2016 at 3:37:23 PM UTC-7, Scott Dorsey wrote:
wrote:
What are your thoughts on this?


On what?

They want $22 for the circuit board. Not sure what the components
cost.


Who does? What is the front end? Is there a transformer? If so,
expect that to be the majority of the cost.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."


There's no +48V phantom.

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

  #5   Report Post  
Posted to rec.audio.pro
Mike Rivers[_2_] Mike Rivers[_2_] is offline
external usenet poster
 
Posts: 2,190
Default Mic preamp build?

On 11/5/2016 6:26 PM, wrote:
What are your thoughts on this?
http://sound.whsites.net/project66.h.../project66.htm
They want $22 for the circuit board. Not sure what the components
cost.


Since Phil is around here, you might ask him about whether it's even
available currently. I notice that the date on the linked web page is 2008

The circuit is pretty common, very much like a Mackie, maybe even
exactly like a Mackie. I didn't compare the schematic for component values.


--

For a good time, call http://mikeriversaudio.wordpress.com


  #6   Report Post  
Posted to rec.audio.pro
Mike Rivers[_2_] Mike Rivers[_2_] is offline
external usenet poster
 
Posts: 2,190
Default Mic preamp build?

On 11/5/2016 6:52 PM, Don Pearce wrote:
There's no +48V phantom.


That's part of what makes it a DIY project. There's no power supply or
box either.

--

For a good time, call http://mikeriversaudio.wordpress.com
  #7   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

Tobiah wrote:


Oh, you want the link I suppose!

http://sound.whsites.net/project66.htm


They want $22 for the circuit board. Not sure what the components
cost.



** The PCB allows two low noise per-amps to be built.

By the time you have purchased all the small components, a pair of 10kohm reverse log pots and XLR sockets the total cost will be over $40.

The NE5532 can be swapped for a TL072 with some saving and less current draw, but stick with the recommended 2N4403 input transistors or you will not get anywhere near the specified low noise.

The idea is that it would be incorporated inside equipment that lacked such pre-amps.

..... Phil

  #8   Report Post  
Posted to rec.audio.pro
gareth magennis gareth magennis is offline
external usenet poster
 
Posts: 73
Default Mic preamp build?



"Mike Rivers" wrote in message ...

On 11/5/2016 6:26 PM, wrote:
What are your thoughts on this?
http://sound.whsites.net/project66.h.../project66.htm
They want $22 for the circuit board. Not sure what the components
cost.


Since Phil is around here, you might ask him about whether it's even
available currently. I notice that the date on the linked web page is 2008

The circuit is pretty common, very much like a Mackie, maybe even
exactly like a Mackie. I didn't compare the schematic for component values.


--

For a good time, call http://mikeriversaudio.wordpress.com





Allen&Heath use this circuit also.

Gareth.

  #9   Report Post  
Posted to rec.audio.pro
gareth magennis gareth magennis is offline
external usenet poster
 
Posts: 73
Default Mic preamp build?



wrote in message
...

What are your thoughts on this?

They want $22 for the circuit board. Not sure what the components
cost.




FWIW, Reverse Log pots are now commonly available, they didn't used to be.

http://www.ebay.co.uk/itm/Reverse-Au... 6uMPFGoCyCZ-A



Gareth.

  #10   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

gareth magennis wrote:



FWIW, Reverse Log pots are now commonly available, they didn't used to be.

http://www.ebay.co.uk/itm/Reverse-Au... 6uMPFGoCyCZ-A



** Nothing stops you using a regular log pot operating in the reverse sense, with gain increasing in the CCW direction.

A very satisfactory solution is to use a 12 position rotary switch and a chain of 11 resistors wired across adjacent contacts.

For 4 dB steps, the values a

15, 27, 39, 68, 100, 180, 270, 470, 1k, 1.5k & 3.9k



...... Phil





  #11   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

In article , Mike Rivers wrote:
On 11/5/2016 6:26 PM, wrote:
What are your thoughts on this?
http://sound.whsites.net/project66.h.../project66.htm
They want $22 for the circuit board. Not sure what the components
cost.


Since Phil is around here, you might ask him about whether it's even
available currently. I notice that the date on the linked web page is 2008

The circuit is pretty common, very much like a Mackie, maybe even
exactly like a Mackie. I didn't compare the schematic for component values.


This circuit is pretty much what you will find in any transformerless mike
preamp with a couple exceptions.. everything from Millennia to Mackie. It is
as good as the front end is allowed to be.

The 2N4403 is not exactly a low noise transistor but if you're careful about
where you get them and cull out the occasional outlier, they can work pretty
well in this circuit. The thing about the 2N4403 is that it's sold as a
swithing transistor with very relaxed specifications on the datasheet, and it
only has to meet the specifications. Most of the time it does much better,
but not always. This is the difference between spending three cents for a
transistor and three dollars.

Now... this said... if you build this, you're still in for building a
power supply and the power supply is going to be more expensive than the
circuit itself. Add a nice machined case and the cost goes up even more.
But, if you build it well with good parts it will outlast any of the consumer
stuff you'll find at that price range.

I disagree strongly about there being no problem with DC bias on modern
electrolytics, but there ought to be a couple volts across C2 and C3 if
I read this right. If there aren't, mylars might be a good plan. I might
also dramatically increase the values of C2 and C3 well beyond the values
needed to get good response.

You're going to need to add some input capacitors on this as well if you add
a phantom supply, so put that into your price equation.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #12   Report Post  
Posted to rec.audio.pro
[email protected] makolber@yahoo.com is offline
external usenet poster
 
Posts: 614
Default Mic preamp build?



I disagree strongly about there being no problem with DC bias on modern
electrolytics, but there ought to be a couple volts across C2 and C3 if
I read this right.


C1 is the more interesting case.

m
  #17   Report Post  
Posted to rec.audio.pro
Don Pearce[_3_] Don Pearce[_3_] is offline
external usenet poster
 
Posts: 2,417
Default Mic preamp build?

On Mon, 7 Nov 2016 08:52:40 -0800 (PST), wrote:

On Monday, November 7, 2016 at 9:06:17 AM UTC-5, Scott Dorsey wrote:
Don Pearce wrote:
On Mon, 7 Nov 2016 05:36:04 -0800 (PST),
wrote:

I disagree strongly about there being no problem with DC bias on modern
electrolytics, but there ought to be a couple volts across C2 and C3 if
I read this right.

C1 is the more interesting case.

m

It is. It has to be big to keep a low impedance relative to 22 ohms in
the high gain situation.

But looking at the topology it is clear that both C2 and C3 could have
been eliminated by returning the overall feedback (R12) to Q1. That
would have set the DC bias in the front end, and C1 could have been
dispensed with too. A matched pair for Q1/3 - preferably in a single
can - would make that more than feasible.


The bad news is that a matched pair like the THAT array dramatically
increases the parts cost but then again you're saving the cost of some caps
too.
--scott



without C1 (with C1 shorted) there is a high DC gain and any offset voltage will be amplified. Matched parts will reduce that offset but that is still a lot of DC gain.


Yup, that's why I stressed the matched pair of input transistors. In
practice it would probably be a good idea to leave C1 in place.

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

  #18   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,481
Default Mic preamp build?

On 7/11/2016 5:00 p.m., Phil Allison wrote:

** Nothing stops you using a regular log pot operating in the reverse sense, with gain increasing in the CCW direction.

A very satisfactory solution is to use a 12 position rotary switch and a chain of 11 resistors wired across adjacent contacts.

For 4 dB steps, the values a

15, 27, 39, 68, 100, 180, 270, 470, 1k, 1.5k & 3.9k



..... Phil



Makes for more accurately repeatable settings too, if that's a benefit
to one's particular way of working.


geoff

  #20   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

Scott Dorsey wrote:

What are your thoughts on this?
http://sound.whsites.net/project66.htm




This circuit is pretty much what you will find in any transformerless mike
preamp with a couple exceptions.. everything from Millennia to Mackie. It is
as good as the front end is allowed to be.

The 2N4403 is not exactly a low noise transistor but if you're careful about
where you get them and cull out the occasional outlier, they can work pretty
well in this circuit.


** The 2n4403 is still one of the best available devices for low noise at microphone impedances. The measured noise figure of 1dB speaks for itself.


I disagree strongly about there being no problem with DC bias on modern
electrolytics,


** Disagree all you like, but there is no issue.


I might
also dramatically increase the values of C2 and C3 well beyond the values
needed to get good response.



** Using 10uF caps as shown gives a -3dB point under 1Hz.


..... Phil



  #21   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

Phil Allison wrote:

I disagree strongly about there being no problem with DC bias on modern
electrolytics,


** Disagree all you like, but there is no issue.


Run some numbers, it's very interesting to watch. You still get a dramatic
increase in distortion near the zero crossing. It's enough distortion you
can use that old HP 334 and see it with a test jig. It's not anywhere near
as bad as it was with the capacitors of the seventies though.

I might
also dramatically increase the values of C2 and C3 well beyond the values
needed to get good response.


** Using 10uF caps as shown gives a -3dB point under 1Hz.


Check out Doug Self's book on power amplifier design. Again, the issue
isn't the frequency response, it's distortion from the ripple across the
capacitor. You want the lowest possible ESR and one way to get that is
to use a capacitor with already low ESR and then oversize it considerably.

Some people bypass electrolytics with film caps to achieve the same results
and this can work if you actually measure it and make sure you're doing what
you think you are.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #22   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

Gareth magennis:


Allen&Heath use this circuit also.



** The A&H GS3000 desk has a mic-pre that is fairly similar, other models use a simplified topology and one has dual gang control that varies the gain of the op-amp as well as the diff pair.

A variety of pnp input transistors are used too, one of them being the 2N4403.

The basis topology dates from the late 1970s and is used in countless desks - for low noise and flat response at all gain settings it is very hard to beat.

Ane alternative is to use an input transformer stepping the mic impedance up to about 10kohms and then an op-amp like the NE5534 as in early Soundcraft and Peavey desks. If the transformer has a CT, this make supplying 48V phantom a cinch.



..... Phil

  #23   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

Scott Dorsey wrote:


I disagree strongly about there being no problem with DC bias on modern
electrolytics,



** Disagree all you like, but there is no issue.



Run some numbers, it's very interesting to watch. You still get a dramatic
increase in distortion near the zero crossing. It's enough distortion you
can use that old HP 334 and see it with a test jig.


** There is NO distortion in the arrangement AS SHOWN !!

Polarised electros operate perfectly in bi-polar mode long as the AC voltage across them does not exceed a few hundred millivolts.


** Using 10uF caps as shown gives a -3dB point under 1Hz.


Check out Doug Self's book on power amplifier design. Again, the issue
isn't the frequency response, it's distortion from the ripple across the
capacitor.


** Which does not exist in the circuit shown as the 10uF caps are DC biased.


You want the lowest possible ESR ...



** Massive irrelevance.



...... Phil

  #24   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,481
Default Mic preamp build?

On 8/11/2016 2:40 p.m., Scott Dorsey wrote:

Some people bypass electrolytics with film caps to achieve the same results
and this can work if you actually measure it and make sure you're doing what
you think you are.
--scott



....and the even then the 'purists' will only use polyprop caps.
(primary cap or as a bypass)

geoff

  #25   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

Phil Allison wrote:
Scott Dorsey wrote:

Run some numbers, it's very interesting to watch. You still get a dramatic
increase in distortion near the zero crossing. It's enough distortion you
can use that old HP 334 and see it with a test jig.


** There is NO distortion in the arrangement AS SHOWN !!


Everything has distortion. Nothing is completely linear. It's how physics
works.

Check out Doug Self's book on power amplifier design. Again, the issue
isn't the frequency response, it's distortion from the ripple across the
capacitor.


** Which does not exist in the circuit shown as the 10uF caps are DC biased.


DIfferent issue, not related to DC bias. Again, check out Self's book.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."


  #26   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

geoff wrote:
On 8/11/2016 2:40 p.m., Scott Dorsey wrote:

Some people bypass electrolytics with film caps to achieve the same results
and this can work if you actually measure it and make sure you're doing what
you think you are.


...and the even then the 'purists' will only use polyprop caps.
(primary cap or as a bypass)


May or may not be a smart idea. You have to measure it and see. Once you
see the distortion spectrum on the analyzer you'll know if the bypass is
making things better or worse or whether it's totally unnecessary.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #27   Report Post  
Posted to rec.audio.pro
JackA JackA is offline
external usenet poster
 
Posts: 2,052
Default Mic preamp build?

On Saturday, November 5, 2016 at 6:26:52 PM UTC-4, wrote:
What are your thoughts on this?

They want $22 for the circuit board. Not sure what the components
cost.


Did I ever tell you the story, I worked in R&D and boss gave me a book on Operational Amplifiers. Inside was a instructions and parts list for a Phono Cartridge preamplifier. I designed and etched the PC Boards, boss helped me select only but the best components for low noise, even had the Grade A DIP Op Amps I needed (4). I built it and it worked like a champ!! Was even featured in a High Fidelity magazine. Decades passed, and I found the author, Walter Jung, online, so I thanked him for his great design!! Oh, and HE said he liked my MP3 snippets (on site) I enhanced!!

Jack

p.s. Electronic Parts continue to be tough to find!!
  #28   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

Scott Dorsey wrote:


Run some numbers, it's very interesting to watch. You still get a dramatic
increase in distortion near the zero crossing. It's enough distortion you
can use that old HP 334 and see it with a test jig.


** There is NO distortion in the arrangement AS SHOWN !!


Everything has distortion.


** Really?

Even your barking mad opinions.



Check out Doug Self's book on power amplifier design. Again, the issue
isn't the frequency response, it's distortion from the ripple across the
capacitor.


** Which does not exist in the circuit shown as the 10uF caps are DC biased.


DIfferent issue, not related to DC bias.


** ********.

Again, check out Self's book.



** I know what Doug S wrote.

You are wildly miss-interpreting.


..... Phil


  #29   Report Post  
Posted to rec.audio.pro
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default Mic preamp build?

On 07-11-2016 13:35, Scott Dorsey wrote:

[Allison mic pre]

You're going to need to add some input capacitors on this as well if you add
a phantom supply, so put that into your price equation.


I would expect that to always be a must, minimum 52 volts ...

--scott


Kind regards

Peter Larsen




  #30   Report Post  
Posted to rec.audio.pro
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default Mic preamp build?

On 08-11-2016 03:44, geoff wrote:

On 8/11/2016 2:40 p.m., Scott Dorsey wrote:


Some people bypass electrolytics with film caps to achieve the same
results
and this can work if you actually measure it and make sure you're
doing what
you think you are.
--scott


...and the even then the 'purists' will only use polyprop caps.
(primary cap or as a bypass)


A few more dollars on caps when making recordings with a high quality
mic pair does not appear extreme. Before the manufacturing 100 times
cost multiplier on a many channel contraption ... a much different issue.

Listening for single component distortion is a good pastime but requires
good source material and good playback equipment.

geoff



Kind regards

Peter Larsen




  #31   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

Peter Larsen wrote:

Listening for single component distortion is a good pastime but requires
good source material and good playback equipment.


I used to spend a lot of time doing that. Today instead I use test
equipment. These differences are readily measurable today.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #32   Report Post  
Posted to rec.audio.pro
gareth magennis gareth magennis is offline
external usenet poster
 
Posts: 73
Default Mic preamp build?



"Phil Allison" wrote in message
...

Scott Dorsey wrote:

What are your thoughts on this?
http://sound.whsites.net/project66.htm




This circuit is pretty much what you will find in any transformerless mike
preamp with a couple exceptions.. everything from Millennia to Mackie. It
is
as good as the front end is allowed to be.

The 2N4403 is not exactly a low noise transistor but if you're careful
about
where you get them and cull out the occasional outlier, they can work
pretty
well in this circuit.


** The 2n4403 is still one of the best available devices for low noise at
microphone impedances. The measured noise figure of 1dB speaks for itself.


I disagree strongly about there being no problem with DC bias on modern
electrolytics,


** Disagree all you like, but there is no issue.


I might
also dramatically increase the values of C2 and C3 well beyond the values
needed to get good response.



** Using 10uF caps as shown gives a -3dB point under 1Hz.


..... Phil








The Allen & Heath MixWiz3 has a very similar circuit but omits (shorts) C2
and C3, the op-amp having a somewhat different front end.

Gareth.

  #33   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Mic preamp build?

gareth magennis wrote:



The Allen & Heath MixWiz3 has a very similar circuit but omits (shorts) C2
and C3, the op-amp having a somewhat different front end.



** Got a link to the schem ?

Earlier Mix Wizes used a bare bones version of the topology with a dodgy looking phantom arrangement.


.... Phil
  #34   Report Post  
Posted to rec.audio.pro
gareth magennis gareth magennis is offline
external usenet poster
 
Posts: 73
Default Mic preamp build?

On Thursday, November 10, 2016 at 6:19:44 AM UTC, Phil Allison wrote:
gareth magennis wrote:



The Allen & Heath MixWiz3 has a very similar circuit but omits (shorts) C2
and C3, the op-amp having a somewhat different front end.



** Got a link to the schem ?

Earlier Mix Wizes used a bare bones version of the topology with a dodgy looking phantom arrangement.


... Phil






No link, but I took a photo.
Not quite as similar as I thought.

http://tinypic.com/r/200wvfl/9



Gareth.
  #35   Report Post  
Posted to rec.audio.pro
[email protected] makolber@yahoo.com is offline
external usenet poster
 
Posts: 614
Default Mic preamp build?



Listening for single component distortion is a good pastime but requires
good source material and good playback equipment.


I used to spend a lot of time doing that. Today instead I use test
equipment. These differences are readily measurable today.
--scott


I was hoping someone was going to say that.
m



  #36   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

In article ,
wrote:

Listening for single component distortion is a good pastime but requires
good source material and good playback equipment.


I used to spend a lot of time doing that. Today instead I use test
equipment. These differences are readily measurable today.


I was hoping someone was going to say that.


Well, the bad part is that now we can measure all sorts of things that we
can't hear, so figuring out what measurements are important is difficult.

But with things like distortion products caused by capacitor linearity it's
easy to see what is going on with a modern test set.

And it's also very easy to make a lot of those decisions. If component X
gives a very low distortion spectrum but component Y gives an even lower one
and costs no more, then by all means I'll pick component Y even if the actual
sonic effect may be zero. On the other hand, if component X has a spectrum
with even harmonics dominating and component Y has a spectrum with odd
harmonics dominating and both have distortion down near zero, I might have
to think about how these harmonics might add to all the other ones in the
device to make a competent decision, even if the end result is very close to
zero.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #37   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,481
Default Mic preamp build?

On 11/11/2016 8:20 a.m., Scott Dorsey wrote:
In article ,
wrote:
Listening for single component distortion is a good pastime but requires
good source material and good playback equipment.
I used to spend a lot of time doing that. Today instead I use test
equipment. These differences are readily measurable today.

I was hoping someone was going to say that.

Well, the bad part is that now we can measure all sorts of things that we
can't hear, so figuring out what measurements are important is difficult.

But with things like distortion products caused by capacitor linearity it's
easy to see what is going on with a modern test set.

And it's also very easy to make a lot of those decisions. If component X
gives a very low distortion spectrum but component Y gives an even lower one
and costs no more, then by all means I'll pick component Y even if the actual
sonic effect may be zero. On the other hand, if component X has a spectrum
with even harmonics dominating and component Y has a spectrum with odd
harmonics dominating and both have distortion down near zero, I might have
to think about how these harmonics might add to all the other ones in the
device to make a competent decision, even if the end result is very close to
zero.
--scott


However if said signal is passing thru 20 components the that minor
distortion is multiplied, so it may well be worth the extra cost unless
ginormous for esoterica and/or snake-oil components.

It's all totally swamped by the distortion from any transducer anyway ...

geoff

  #38   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Mic preamp build?

geoff wrote:
On 11/11/2016 8:20 a.m., Scott Dorsey wrote:

And it's also very easy to make a lot of those decisions. If component X
gives a very low distortion spectrum but component Y gives an even lower one
and costs no more, then by all means I'll pick component Y even if the actual
sonic effect may be zero. On the other hand, if component X has a spectrum
with even harmonics dominating and component Y has a spectrum with odd
harmonics dominating and both have distortion down near zero, I might have
to think about how these harmonics might add to all the other ones in the
device to make a competent decision, even if the end result is very close to
zero.


However if said signal is passing thru 20 components the that minor
distortion is multiplied, so it may well be worth the extra cost unless
ginormous for esoterica and/or snake-oil components.


Right. On the other hand, if the signal is passing through 20 components of
a different sort, the distortion produced might be completely masked by that
of the other parts. Which is why watching that FFT analyzer and listening
are important.

It's all totally swamped by the distortion from any transducer anyway ...


Depends... transducer distortion is very high indeed, but usually worst at
lower frequencies and usually has lower odd harmonics dominant. So it will
tend to hide other lower odd harmonic distortion but it won't do anything
much to hide 6th harmonic in many cases. God only knows how this plays out
for intermodulation effects.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Build, baby, build! [email protected] Audio Opinions 0 January 12th 09 06:53 AM
Perhaps Mr. Krueger should build one of these: RapidRonnie Audio Opinions 1 May 29th 08 02:12 AM
System build [email protected] Car Audio 1 November 9th 07 08:17 AM
Would you build this DIY project? Paul Stamler Pro Audio 0 November 12th 04 09:48 PM
Help me build my first DAW Billy Bee Pro Audio 1 October 16th 03 07:03 AM


All times are GMT +1. The time now is 11:07 AM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"