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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: sunjan on March 24, 2009, 12:26:18 PM

Title: $40 budget stealth noname pre: for noobs?!
Post by: sunjan on March 24, 2009, 12:26:18 PM
This surfaced on ebay recently:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370171960171

I don't expect the quality to be anything to write home about, but the price is hard to beat for noobs on a tight budget.

Since they offer shipping from several countries, you can avoid customs and long distance postage costs no matter where you live.
I don't think there are any other offerings where a noob in EU can get a stereo preamp incl. shipping for less than $50.

I've mailed a few question regarding gain (fixed or steppable?), plug-in power etc, which weren't covered in the FAQ.

One drawback is the odd powering option: one G27A 12V non-rechargeable battery. It remains to be seen how long the runtime is in a taper setting.

Technical data:
    * WIDE COMMON-MODE
    * LOW INPUT BIAS AND OFFSET CURRENT
    * LOW NOISE en = 15nV//Hz (typ)
    * OUTPUT SHORT-CIRCUIT PROTECTION
    * HIGH INPUT IMPEDANCE J–FET INPUT STAGE
    * LOW HARMONIC DISTORTION : 0.01% (typ)
    * INTERNAL FREQUENCY COMPENSATION
    * LATCH UP FREE OPERATION
    * HIGH SLEW RATE : 13V/ms (typ)

The line-in preamp is built with high speed J–FET input quad operational amplifiers incorporating well matched, high voltage J–FET and bipolar transistors in a monolithic integrated circuit. The devices feature high slew rates, low input bias and offset currents, and low offset voltage temperature coefficient.


(http://gaurshop.com/ebay/pho/linestereo/onpalm.jpg)
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: rsimms3 on March 24, 2009, 08:37:38 PM
sunjan you find some of the coolest stuff!

+t
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: sunjan on March 25, 2009, 03:43:03 AM
sunjan you find some of the coolest stuff!

Too much time to kill at work, drooling at ebay stuff   ;D

Now we need a noob on a tight budget, that can take the plunge and test this POS. ;-)
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: stevetoney on March 25, 2009, 10:16:52 AM
But _IF_ any noobs happen check out this thread and give some thought to buying this ebay preamp, you should also consider going to Chris Church AKA Church Audio and give some thought to buying one of his recycled 9000 or 9100 preamps for about the same price!!!  See link below.

http://taperssection.com/index.php/topic,110146.0.html
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: sunjan on March 25, 2009, 06:21:42 PM
But _IF_ any noobs happen check out this thread and give some thought to buying this ebay preamp, you should also consider going to Chris Church AKA Church Audio and give some thought to buying one of his recycled 9000 or 9100 preamps for about the same price!!!  See link below.

http://taperssection.com/index.php/topic,110146.0.html

Neat! I didn't really see the used CA preamps being advertised anywhere, but if they're available it's a lot better value for money.
Although buyers in EU would still need to calculate customs on top of that, which might add another $40 or so on a bad day :-P

Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: digifish_music on March 28, 2009, 04:59:54 AM
Ha, the first demo track at ebay matches your sig-pic...

http://www.gaurshop.com/ebay/mp3/linemic/1.mp3

:)
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: nameloc01 on March 28, 2009, 01:34:43 PM
"
Now we need a noob on a tight budget, that can take the plunge and test this POS. ;-) "


LOL
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: Nixoo on March 28, 2009, 06:41:09 PM
If the this actually has gain steps, you'd be able to add zero gain and use it as a batterybox to power your mics? That's pretty interesting. Size of an CA-ugly, price of the ol' battbox. Good lookin' too!
Sunjan, have the gotten back to you about the adjustable gain?

Please, someone buy this and convince me I need one too *grin*.
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: Scooter123 on March 29, 2009, 11:39:20 AM
Spy Shop and its internet retail shop make all sorts of microphones, croakie mounts, and other stuff suitable for stealth.  I haven't tried any of them, but based on their price, they are either an incredible bargain or low end stuff. 

Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: Church-Audio on March 29, 2009, 11:57:50 AM
My reaction is why does he need a quad opamp for a stereo preamp, especially with limited gain control?  But anyway, 15nV/rtHz is not particularly low noise, ~ -113dBA maybe.  Could be quieter than some inputs, maybe not all though.

I also expect Chris could build this fairly easily using his existing circuit, it's just a matter of the battery and battery access in the case.  These little 12V A27s have a mere 22mAh life, vs. 625mAh for a 9V.  At least I would think about using an A23 instead, that's 55mAh.

My favorite one is this "LOW HARMONIC DISTORTION : 0.01% (typ) " um yeah at what input voltage :) lol..
Title: Re: $40 budget stealth noname pre: for noobs?!
Post by: sunjan on April 01, 2009, 06:32:01 PM
If the this actually has gain steps, you'd be able to add zero gain and use it as a batterybox to power your mics? That's pretty interesting. Size of an CA-ugly, price of the ol' battbox. Good lookin' too!
Sunjan, have the gotten back to you about the adjustable gain?

Finally got an answer from the seller. Seems that he has a very foggy notion about the specs.
Mic plugin power? 6-12V! ::)
Gain? Yes, freely adjustable.
Range? Umm, maybe +60dB or so? No kidding?!  ::)

Given these answers, you can't really trust any of the other specs mentioned. He's probably just making them up along the road...

For usage as a bbox, you'd probably still would have to figure out another battery type to power it like mshilarious mentioned, because of the weak runtime of that 12V batt.