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Reviews Categories | Receive Pre-amps | Pioneer 621 or 99 Electronics lil pre amp Help

Reviews Summary for Pioneer 621 or 99 Electronics lil pre amp
Reviews: 1 Average rating: 5.0/5 MSRP: $Less than $10!!!
Description: Simple, easy to install receiver preamp
Product is in production.
More info: http://
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You can write your own review of the Pioneer 621 or 99 Electronics lil pre amp.

N4UE Rating: 5/5 Aug 6, 2009 15:53 Send this review to a friend
NOT just for CB!!  Time owned: 3 to 6 months
OK, the first review of these little jewels got lost in cyberspace, so here we go again.....

I have a large colection of boatanchor receivers. Although I have recapped, and aligned them all, there are just some that are a wee bit on the 'deaf' side.
One day, one of my 'favorite searches' (for 'preamp') on good 'ole ePay, turned up one of the above preamps. I honestly can't remember which one, but they are VERY similar!
For < $10 and FREE shipping, I thought: "if nothing else, I could use it on some of my HF counters that require a BIG signal to register".

Wow!! Was I pleasently surprised!!! The first one I built into a small project box with BNC connectors to evaluate it on both a radio and a counter.
The results were so good, I have ordered a LOT more of these little guys. Yea, I could probably throw together a preamp and enclose it in heat-shrink, like these. However, I don't think I could beat the price.

Here's an example. I have just finished a complete restoration of a Nice Allied A-2516 receiver.
Although the radio has excellent reviews (both on eHam and ER Magazine), it's claimed sensitivity of 2 uv left me wanting for more. I put one of these little preamps in the radio. The 'noise floor' with the antenna disconnected, rose about the width of the s-meter needle! However, when tuning in a SSB signal on 20M, it nade > 2 s-units of improvement!
I have had the same results with a bunch of other 'older' radios. They just flat work excellent from 160M through 10M.

Now for the downside. If your radio has 12VAC or DC available (12V tube filiments, for example), you are in tall cotton. If however, your radio has all 6.3VAC filiments (like some of mine), you are going to have to either:
1. run the preamp from a 9V battery or
2. build a small 12 VDC ps for it.

I tried using the 6.3VAC filiment supply, but was met with hum, melting wires, etc. This was using my standard practice of a ss 'bridge rectifier and cap'. I use this to power a 12 VDC fan which I put in EVERY radio I own.

The problem come from the preamp using 'ground' for both the VCC and RF ground.
By the way, the preamp works FB on any voltage from 6-18 VDC!!!

What I did, is crack open a small 'wall'wart', and ensuring it has a good rectifier and cap design, wire it to the 115VAC supply, then the preamp.
Bingo! works perfect. I had several working with an external 9V battery, but I would forget to disconnect it etc.
It would be easy to wire a 'preamp' switch and LED, but I'd rather just have the preamp come on with the radio.

I have NO connection with the mfg of these preamps and I DO NOT have a CB radio!! ha ha
They just work wonderful on these old girls!!!


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