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Reviews Categories | Filters, Audio: (DSP and others) | NEScaf Audio Filter Help

Reviews Summary for NEScaf Audio Filter
NEScaf Audio Filter Reviews: 34 Average rating: 4.8/5 MSRP: $29.00
Description: The NEScaf is a switched capacitive audio filter based on the MF10 chip. It is
designed to be simple to build and use.

It is more flexible than previous filters for QRP rigs. It has two panel-mounted
controls -- a single center-detent potentiometer that sets the center
frequency of the filter's bandpass (default value settable between ~415Hz and
~1kHz), and a dual-ganged potentiometer that provides a continuously
variable bandwidth control (from ~60Hz to ~1500Hz). This ability to smoothly
vary the bandwidth is very useful.

The NEScaf is designed to be driven with a phones or speaker level signal.
Product is in production.
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K2TL Rating: 4/5 Jul 17, 2014 17:30 Send this review to a friend
Great bargain!  Time owned: 0 to 3 months
First of all, it cost $31.00, so how can you complain?
60hz bandwidth? I doubt it. It seems more like 400hz, but I have no way to accurately measure it. Still, it works very well.
There is a terrible thumping in the headphones or speaker if you are going to use it with a transceiver. At first I thought it was RFI. To make a long story short, it has something to do with the power supply you use. I tried 4 different supplies, they all thump. Use a 9 volt battery and it is 100% clean. I'm going to get a small 12 volt AGM battery for it, even though it seems to work fine on 9 volts.
The circuit board is not of the highest quality ($31.00 kit!). The traces can easily lift off the board even with low heat if you are not careful.
Having a good audio filter such as the NESCAF really is practical regardless of all the high tech DSP you may have in your rig. It just has a more pleasant tone. If you are being clobbered by close by mega signals, you are going to need IF filters. Otherwise, this little kit is a real joy for casual operating. I'm glad I bought it.
KD8BBK Rating: 5/5 Apr 11, 2014 19:48 Send this review to a friend
Great little filter  Time owned: 0 to 3 months
I purchased my first NEScaf audio filter about 4 weeks ago and was so impressed with it I purchased a second one. The filter was easy to build and the instructions are well written. If you have Icom 718 you need to try this filter out. I run one on my Icom 746 and the Icom 718. The work excellent for receiver overload, noise and QRM. So I highly recomend trying one of these filters. You can't go wrong for the money.
KE1L Rating: 5/5 Dec 12, 2013 11:10 Send this review to a friend
A nice addition to most stations  Time owned: more than 12 months
The NESCAF delivers a lot of bang for 31 bucks ($35 with the connector kit, add $8 outside the US and Canada). It's mainly for CW and digital operators, though the widest bandwidths do a little bit of good on phone. The center frequency and bandwidth are both adjustable with pots. The added filtering makes it a lot easier to dig out weak signals and makes listening more pleasant.

Buying the connector kit is highly recommended if you plan to build the NESCAF as a standalone unit rather than building it into a radio. You'll have trouble coming up with those parts for $4.

Current production uses the LTC1060 switched capacitor chip. Testing has shown its performance to be equal to the LMF100 (which is no longer available in DIPs); both are quieter than the MF10 used in early kits. Owners of an early NESCAF might want to add an LTC1060 (about $7.50 for one) to their next Digikey order; the new chip is a drop-in replacement.

Disclosure: I have helped kit the NESCAF and was the person who found the LTC1060 when the LMF100 in DIP packages went out of production. But I'm also a satisfied customer.
KU3V Rating: 5/5 Nov 20, 2013 18:03 Send this review to a friend
Great Adjustable Audio Filter  Time owned: 0 to 3 months
I already own a Hi-Per-Mite audio filter. That filter is great but only gives you a 200Hz fixed band width. The NEScaf has an adjustable bandwidth from ~60Hz to ~1500Hz. Thus I can find the signal I want and also zero beat by reducing the bandwidth while adjusting the frequency of the transceiver. Goes very fast. The center-detent potentiometer that sets the center frequency of the filter's bandpass (default value settable between ~415Hz and ~1kHz), is great also to get the tone you like to hear for receiving CW. Instructions were fantastic, board and parts went together easy over three nights for a total of about 5 hours. I also drilled and prepared a hobby box made of Aluminum from Radio Shack. I rate this a 5 out of 5.
N4LQ Rating: 4/5 Jul 21, 2013 17:50 Send this review to a friend
Good after some mods  Time owned: 0 to 3 months
I went through 6 power supplies and picked out one with the lowest amount of hum. I then added 12,000 mfd of capacitance from pin 6 of the LM-386 to gnd. Finally the hum was eliminated. A very well regulated and filtered supply is needed or run it on batteries but that would be expensive.
The other issue is hiss. All LM-386 amps have lots of residual white noise. With headphones, it was very annoying. I eliminated most of it by connecting a 22k resistor and .01 uf capacitor in series between the speaker output and pin 1 of the LM-386.
The nescaf now sounds fairly clean in the headphones. I'm thinking about designing a better amplifer for it. For the price it's a good deal but it just needs some refinement.
BTW I'm using it with my K3. QSK is much more pleasant now. Sure the K3 has wonderful filtering but you are left with band noise. The SCAF cleans that up.
N4LQ Rating: 0/5 Jul 19, 2013 07:27 Send this review to a friend
Unusable with transmitter  Time owned: 0 to 3 months
I recently built the kit. The filter works great however voltage regulation is causing annoying thumps when I key the rig. I've tried several power supplies. Many of the "wall warts" had hum problems. Using the rig's Astron there is no hum but thumping when the rig is keyed. I have enclosed the nescaf in a metal box and installed bypass capacitors on every lead. I believe the problem is more related to an extreme need for voltage regulation than RFI. I have managed to make it work with my highly regulated B&K bench supply but it's huge and should not be necessary
There seems to be no means of support from the NEQRP Club. There website has no links that work for non members, no phone numbers, no email addresses and no forums unless you are a member and I don't even see a way to join nor do I want to.
So the thing is useful only for receive. Possibly a battery supply would help but I don't want to supply power via battery.
Hopefully someone will have an answer to this. If I can solve it, I will be glad to give it a 5+.
W4UTI Rating: 5/5 Jun 19, 2013 10:13 Send this review to a friend
Oh! MY!  Time owned: 0 to 3 months
WOW! Okay, it's a kit, and it's VERY inexpensive. The kit: I'm almost 84 and my eyes aren't as good as 60 yrs. ago, and my hands aren't as steady, BUT this kit went together so easily. Directions clear, and many checks as you go. But then when I hooked it up, it worked FAR better than I expected. It does such a great job it's hard to remember it cost $31 shipped, plus a cabinet and a few extra Radio Shack parts. When easily adjusted, you must tune the receiver slowly or you will miss stations, it's so sharp. I soon learned to tune by widening the bandwidth a little. Then back it goes for VERY narrow bandpass. I ordered this to use with my "standby" KNWD TS520S, but it works so well on my Omni V I plan to order another one. I keep the Omni filter set on .250 and "Narrow." The NESCAF is even sharper than that. I'm surprised I haven't heard about this little jewel before.
KA8SYX Rating: 5/5 Aug 18, 2012 17:18 Send this review to a friend
Wish it came with an enclosure  Time owned: 0 to 3 months
I've had my NEScaf kit bumping around for a while and last spring built the board up during a business trip last year. Time owned reflects the period since I completed it and have used it. I wasn't able to finish it until recently when I decided it needed to go in a box. It works as I understand it should and it impressively can torque right down onto a single CW signal and that's really cool. Toggling the filter in and out after setting it right, and hearing the stark difference between the desired signal and the desired signal buried in adjacent QRM/QRN is amazing. But I would have gladly paid more for a drilled enclosure and cut-to-length interconnecting wires and cables. As it is, the kit is a bargain for what the buyer gets, but for the little bit of time I have available to play radio (on the air, messing with antennas or building stuff) I would have liked to be able to finish my SCAF to a completed product from start to finish. This isn't a bust on the designers or kitters in NEQRP, only a suggestion to maybe offer a supplemental enclosure kit along with a connector kit.
KB8LZG Rating: 5/5 Jul 5, 2012 07:08 Send this review to a friend
Great Kit, Great price...  Time owned: 0 to 3 months
Built and tested mine in about 3 hours scattered over about 2 weeks. Parts are correct and directions are fine.
I would recommend this for anyone who likes to build and needs an audio filter for their rig.
Two thumbs up to the New England QRP club and those who made this kit possible!!
Thanks guy's
W1JKA Rating: 5/5 Dec 27, 2011 08:32 Send this review to a friend
It works  Time owned: 0 to 3 months
Just finished mine,a few hours a day for three days(yes I'm old,shakey and half blind).After a few wiring glitches and figuring out what R9 was all about it's now working FB on my MFJ cubs,MFJ 90 series qrp rigs and really shines on my old FRG 7700 rcvr.A very nice fun and useful project.
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