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$5 mic preamp beats $1500 pre Single-Channel Preamps
Old 15th August 2008
  #31
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Quote:
Originally Posted by Corran View Post
I think that a small, $50 or so DIY kit of this preamp would be awesome. I really want to start doing DIY preamps but I don't want to spend $150-$200 on something and then SCREW IT UP! So spending around $50 would be a lot easier to stomach, at least as a first-time thing.

I would be extremely interested in hearing this against the Earthworks 1024, Audiop. I would love to have like 24 channels of Earthworks pres but that ain't happening anytime soon
http://www.fivefish.net/

Not 50$ but 100$ Per channel.
Old 15th August 2008
  #32
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dickiefunk's Avatar
Isn't the M Audio DMP3 and Burr Brown INA 163 based pre?

Wouldn't this be on par with the $5 amp in this thread?
Old 15th August 2008
  #33
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Corran's Avatar
 

Yes I've seen that one, but still it's twice as much! I want really cheap for my first DIY.

That being said when I finally get an extra $100 I will probably get one to build. But then you have to include the PSU, Rack, etc...I think this preamp could be $50 with everything, so including the PSU and a smaller, very basic inclosure. Or maybe just $100 with all that, still a lot cheaper.
Old 15th August 2008
  #34
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Heartfelt's Avatar
Quote:
Originally Posted by Corran View Post
I think that a small, $50 or so DIY kit of this preamp would be awesome.
The Schematics are here. I am hoping one of you knowledgeable guys will translate that to a plan for us.
Old 15th August 2008
  #35
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corran.
some of the op amp manufacturers like linear technology n maxim semiconductor
have reference designs for mic pre's.
they even will send you samples of ultra low noise op amps that can cost 5 buks or more if you ask em nice.
a op37 type op amp is nice but needs juice to run it.
meaning a powerfull supply. but if you dont know bout this stuff, best to take a course
at a adult lectronics college.

frankly jim williams on his site who i respect highly has a nice loking mic pre card
for a little over 100 buks , so most of the work seems already done.
audioupgrades.com if i remember.

if u wanna start with something simple, you could always go to canakit i think it is n order a 14 buk simple mic pre to learn from with transistors/op amps if i remember .
i think they even got one for 7 buks.
a good starting point is buy a few transistors. 10 for a buk, n start experimenting.
its a great learning experience...learning how to bias a transistor and things like common base n common emittor etc. plus you can experiment with a 9 volt battery so its safe..cos no mains current.
there are lots of schematics for transistor pre's on the net.
the much revered /sought after old school op amps years ago were just transistor circuits,
if i remember correctly , put in an enclosure n potted to hide the circuits.


heres canakit...one of many.
Electronic Kits : Microphone Amplifiers
a cheap way to start learning.

google for on line electronics lessons n mic pre schematics.
Old 15th August 2008
  #36
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Corran's Avatar
 

Hey manning, thanks for the link!!! That's just what I was looking for, I had not heard of canakit.
Old 15th August 2008
  #37
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corran.
one thing you can do once you get the canakit.
if it comes with an op amp.
look at the model no of the op amp.
then knowing the model of op amp go on line to analog.com for example.
and sub a better op amp that meets the same parameters.
as i said you can even get free samples if you ask nice.
people like adi n linear n others n TI sell better spec lower noise op amps.
sometimes subbing a better op amp works, other times not.
note..those canakits will only work with dynamics.

you can upgrade the canakit in other ways too.
for example if it comes with noisy resistors like carbon comp,
useing a multimeter ( you WILL need a multimeter cheap ones are a few buks at radio shak.)
measure the resistance of the resistors , then try replaceing with low noise metal film
resistors from say vishay or other sources. (get yourself a free digikey.com catalog.
its very usefull for diy n keeping up on new parts introduced.) .
but as to whether the kit will sound better/lower noise you wont know till you experiment with
subbing parts.

i urge you if your serious bout this to also scour various guru sites like "prodigy"..
with lots of gurus there.
Prodigy Professional :: Index

another trik if your serious is you could build your own line mixer very low noise useing
low noise op amps. once again lots of schematics on the net. google.

the beauty of building a line mixer also is , if your happy with the canakit but gain isnt enough,
just take output of canakit pre into the diy line mixer.

heres some circuit schematics to get you started on the "madness"...lol.
ESP Projects Pages - DIY Audio and Electronics - Audio test equipment
ESP Projects Pages - DIY Audio and Electronics - Mixers, meters etc.

heres a ton of various schematics..lol..
UaShem.com | Audio

use google for tons more schematics.
just enter in google search.."mic pre schematic" or
"guitar amp schematic" or "audio mixer schematic".
sometimes includeing the word "diy" helps.

have fun !!

ps...you might also want to go to your local library n look for electronics books covering
useage of transistors n op amps in audio circuits.
PS..DONT MUCK AROUND WITH MAINS POWER IF YOUR NOT TRAINED.
FOR YOUR SAFETY !
Old 15th August 2008
  #38
Gear Guru
 
AllAboutTone's Avatar
 

I did not think that # 2 was so great at all, a little harsh for my taste.
#1 was thin, #3 was rich.
Old 15th August 2008
  #39
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Coyoteous's Avatar
 

Quote:
Originally Posted by dickiefunk View Post
Isn't the M Audio DMP3 and Burr Brown INA 163 based pre?

Wouldn't this be on par with the $5 amp in this thread?
Yes sir, and the Meek 3Q, IIRC... I have one of each and they sound pretty darn good. You can take the insert out on the ThreeQ, if you want to bypass the comp. and EQ. But remember, caps, PS, opamps and other components matter too.
Old 16th August 2008
  #40
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just a point to remember.
yes the INA are mebe nice chips , but my concern is they arent available from lots of manufacturers.
for example a op37 op amp or op 27 is made by quite a few manufacturers.
the problem with many op amps is also for battery applications one can go thru lots of
batteries. cos of the current draw. eg op37 is a nice op amp but draws a lot of current.
so no good for example in battery mic pre's.

a question ..has anyone found an op amp yet that draws very low current that can be used
in mic pre battery driven applications ?
closest i found wes a motorola mc33078 if i remember. and a linear LT1012.

folks might be interested to know ...linear tech if i remember have a chip that will take a positive voltage n create the -ve.

one other point. the hassle with op amp based circuits is the bipolar supply need.
i suspect one will go thru lots of batteries in that 5 buk mic pre.

corran...
you might want to check this out for a mic pre where lots of work is done for you.
-127 noise claimed.
the transformer is integrated. not many components needed .
been around a long time...50 buks..
but i dont know how good it is...
anyone know ??
http://www.opamplabs.com/360bm.htm


wow i just found a reference on the 360bm , looks like this is high quality stuff.
RECORDING Op Amp Labs mixer? - Hello, I'm new here. I just bought an OpAmp Labs mixer at a garage sale for $50. It's the 8 channel version of the 1204-tv. I'm not sure of the model #, but the preamps and eq sections are the same as the 1204. I saw on

ive been meaning to get one myself for a long time to try out.
anyone got more feedback on these ?
the comment seems to suggest high end level .
Old 16th August 2008
  #41
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Corran's Avatar
 

Thanks for all the suggestions manning. When I get some free time I will definitely be buying some of those kits and messing around with stuff. I have a multi-meter already and I know the very basics, so I've got a good start...
Old 16th August 2008
  #42
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Corran.
just be aware , getting into serious diy can be expensive.
ive seen guys spend lots on test gear for example.
scopes etc etc.
yes...its lotsa fun n learning. n if yer a nut for it like me.
just be aware you might spend months n not end up with anything better than a
low cost mic pre you can buy at any store.
Old 29th August 2008
  #43
Gear Head
 

Quote:
DONT DO IT

I have spent well well over $5 dollars and it is still sounding like crap. It is also really vulnerable to EMI.
Not worth it.
Old 1st September 2008
  #44
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Iggy Poop's Avatar
 

Quote:
Originally Posted by virtualsamana View Post
Come on slutz take this challenge and see if you can honestly tell the difference.

Microphone preamplifiers - can *YOU* hear the difference? (with audio)

You should really start manufacturing these. I'd buy it for $200.
Old 1st September 2008
  #45
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Quote:
Originally Posted by gizm770o View Post
DONT DO IT

I have spent well well over $5 dollars and it is still sounding like crap. It is also really vulnerable to EMI.
Not worth it.
Took a Ferrari for a drive the other day.. ended up in a cornfield upside-down. Crappy cars those Ferraris..

;-)


/Peter
Old 1st September 2008
  #46
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Iggy Poop's Avatar
 

Quote:
Originally Posted by Audiop View Post
Took a Ferrari for a drive the other day.. ended up in a cornfield upside-down. Crappy cars those Ferraris..

;-)


/Peter
****, my ferrari did the same freakin thing. I'm writing a letter to the company.
Old 2nd September 2008
  #47
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dannygold's Avatar
 

Same site has an article about how awesome the built in mic on an iMac is... the title is something about how you should throw out your studio mic because you have a better one built in your iMac. This makes me think that these people just want cheap stuff to be great.
Old 2nd September 2008
  #48
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Well.. what if the iMac mic IS good then?

After all, a small electet capsule bought in bulk is cheap and can have a very natural sound compared to resonant-prone large capsule studio mics.

I have everything from very costly to cheap components in my recording and playback set up and judge things by performance instead of price.

/Peter
Old 2nd September 2008
  #49
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macgee's Avatar
the LA610 didn't have the best definition but it did sound the best quality. A & B had an irritating 2-4k crackle that would just drive me up the wall.

B has potential but needs a bit of work
Old 3rd September 2008
  #50
Gear Nut
 

Number 3 was easily the best sounding pre and I'm listening on a laptop. You really have to listen due the 'spoken word' sound byte, but still pretty fun. I own a 610, so maybe I had a slight advantage
Old 24th September 2008
  #51
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John Suitcase's Avatar
 

I liked the third preamp on both samples, though on the first mic, preamp 1 sounded second best. On both I thought #2 sounded a little distorted or something, just a little grungy in a bad way. On the second mic, the first preamp sounded particularly bad, and on the first mic it sounded a little 'plastic' which is the sound I used to hear on most new low-end IC based mixers, like soundcraft and Yamaha, behringer, mackie, etc. The 3rd pre sounded a little more beefy, more mixable to my ear.

I've done a bit of research on different opamp based preamps, but it seems the ones I like the best have input transformers, and some have output transformers, as well. I think that part of the circuit has as much, if not more, effect on the final sound coming from the preamps.
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