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Reviews For: Idiom Press/Ham Supply SCAF-1

Category: Filters, Audio: (DSP and others)

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Review Summary For : Idiom Press/Ham Supply SCAF-1
Reviews: 93MSRP: 108.95 kit 148.95 assembled
The new SCAF-1 filter from Ham Supply/Idiom Press makes your radio listener friendly, whether you are an SSB or CW operator. Using a modern but little known technology called SCAF filtering, the SCAF-1 is an active audio low pass filter offering user control of the filter cut-off frequency, yielding a stunning 96dB per octave roll-off of signals above the cut off frequency, and no white noise. It is the perfect partner for your crystal or mechanical filters. And, unlike most audio filters, there is absolutely NO ringing.
Product is in production
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# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
N3VY Rating: 2005-11-22
Well worth the price. Time Owned: 0 to 3 months.
Nov. 1, 2005 I ordered the SCAF-1 assembled, and received it in record time. Had several contacts with factory, all questions answered. Upon receipt, immediately removed the cover and made adjustments for external speaker per instructions. Used RadioShack cables. No help for my cheapy earphones. Haven't tried on SSB, since I operate cw only. White noise and static greatly reduced, and desired signal isolated. I use it in conjuntion with wide or narrow cw filter, or none; with dsp filter, or not. Results are entirely satisfactory. Makes my listening and signal perception much easier than without it. It works for me! I have not used any other external filters.
W4GAL Rating: 2005-11-09
Excellent product!! Time Owned: 0 to 3 months.
This little jewel works better than I had hoped! I use it cw mobile and it is amazing for eliminating unwanted crud. The stations pop out and are easy to copy. A pleasant surprise was the elimination of the low end and the cw just sounds good as a result. I wouldn't want to operate without it.
KC0SOG Rating: 2005-11-07
Does the Job Time Owned: 0 to 3 months.
I finished assembling and my SCAF-1 filter. I give it a 4. The filtering capability is as it should be. On CW it really helps with my high AC line noise levels and really eases fatigue on my ears. The filter seems to excel when using a CW offset of 500 or 600. Often I used my 500hz CW filter to reduce line noise, but I find the SCAF to be more effective. When the band is packed with CW signals my 500hz filter is still needed. I gave it a good workout by tuning around the bands during the Nov ARRL CW contest.

On SSB it makes speech more legible in noisy conditions at the expense of dynamic range.

Mechanically the filter has issues. The headphone jack does is not switched so you have to unplug the speaker jack. Or just let the headphones run all the time even when using the speaker then just unplug the speaker.

The headphone output has pots in the circuit that allow adjustment of the drive and volume so that the filter in the ON/OFF positions can have the same output levels. The speaker jack does not have this adjustment. So when I'm using the speaker output with the filter OFF then switch it ON the volume jumps rather loudly.

My filter has artifacts. When switched OFF, the bypass circuit has audible hiss. When the filter is ON and set at a higher frequecy, I get a couple of minor electronic artifacts. This is likely due to imperfections of my less than perfect soldering skills and is not bothersome. I can tweak the adjustment ever-so-slightly to remove the artifact.

I'd like to see a switched headphone jack mounted in the front. I would be nice to have a pot that can adjust the volume level of the output when the filter is in the OFF position and a balancing adjustment for the speaker jack when the filter is in the ON position.

Overall the SCAF-1 does what it needs to do and that is to help me manage my AC line noise problems on 30 and 40 meters.

73, Doug, KC0SOG
K5UNY Rating: 2005-06-17
Works as said on Idiom Web Site Time Owned: 0 to 3 months.
I have had my SCAF-1 for 2 weeks. I bought it used(looks new) from a Ham near Austin Texas for $75. I got the SCAF to use with my Icom 735 primarily on CW.
First couple of things I did was to move the speaker output from the 1/4 inch jack to the 1/8 inch jack and the headphones over to the 1/4 incher. Then I cut a couple of jumpers to use Mono plugs instead of stereo.
Operationally, I am absolutely tickled pink with the way the SCAF functions on CW It does everything exactly the way Idiom Press says it should, reduces QRM/QRN and makes that CW note Pop out of the speaker. It is Not IF-DSP on SSB so don't expect a miracle if you use it on SSB. By the way, if yours is really loud on a speaker there is an adjustment internally to cure that issue. In my mind the SCAF-1 was worth the purchase and I wouldn't hesitate to buy a new one if I had to.
THC1 Rating: 2005-06-10
Lot of hype,does not live up to it Time Owned: 3 to 6 months.
Bought the factory assembled version,tried it on four different transceivers. A slight improvement
but not vs. the expense.
KC0W Rating: 2005-06-09
Way overrated Time Owned: 0 to 3 months.
I don't understand all these glowing reviews of the SCAF-1. By reading then you would think that this is a must have item & will do everything but wash your dishes.

I'm not impressed.

I bought a factory assembled one and used it for a month or so.......Then it went straight to eBay.

Get a few 2nd party filters & forget the SCAF. I felt that it was marginal at best for my CW needs. I also don't like toying around adjusting the knob on the SCAF to reduce QRM. The volume of the SCAF while playing with it on almost blew out my ears a few times.

This box is way, way overrated!!!!

Tom kcØw
N1UH Rating: 2005-06-09
Buyer Beware! Junk Product and Non-Existent Service - Rip Off! Time Owned: 0 to 3 months.
After having read the reviews of this unit I decided to purchase one. I tried for several weeks to contact the company; multiple calls and emails but got no reponse. I finally decided to order it off the web site. The unit arrived several weeks later and did not perform as advertised - very poor performance. Basically a waste of time and money for a useless gadget. I returned the unit for a full refund. 3 months later I got the refund but it was minus a mysterious $20. Later I was informed that it was for a "re-stocking fee", which was never mentioned during the ordering process, web site or order form. I guess that this is how they make their living ...from fees that they do not tell you about ahead of time. Overall, a terrible experience with the company, lack of timely communication and information, and feels like a one person, basement operation for a device that is a piece of junk!
M0MRR Rating: 2005-04-19
Excellent product Time Owned: 0 to 3 months.
I live in a typically small and overcrowded English town and suffer lots of noise. I am using a Yaesu FT-897 and have recently been learning CW - a mode that interests me a lot. As a result of the noise I played with the DSP settings on the FT-897 - over-rated is the best way to describe it. I do like the rig as it is multi mode and can do most things - just the DSP is not very good. To combat noise I bought a BHI dsp speaker - excellent product - you can read the separate review I have already written. When I was researching filter products I read the eham reviews about the SCAF filter - that seem to fairly regularly updated. All reviews were positive and eventually I took the plunge and ordered a kit.

The kit took over 2 weeks to arrive - I notice the post date was 28th March, yet I only received it 13th April. Must have been something with Royal Mail slowing down due to the Royal wedding. Hi Hi. Whilst waiting for delivery I sent several emails to Idiom Press which were all promptly answered by Cynthia assuring me that the product had been sent. I like prompt replies to queries and consider this to be good customer service.

Upon arrival I commenced construction of the kit. In checking all the parts against the parts list I noticed that the components appeared to be of good quality and the PCB was double sided with plated thru holes. The metal work for the case had been screen printed and the nuts and bolts were stainless steel.

The instruction manual appeared a little daunting - zillions of step-by-step instructions - but no pictures just text. Mounting all the passive components was straightforward. The kit only came with two DIP sockets - yet there are 6 IC's. Murphy’s law prevailed and I managed to solder the LM386 back to front. On a double-sided board this is somewhat of a disaster! I ended up cutting the IC out and making new pins for it using cut resistor legs. These chips are very resilient. If the kit had 6 DIP sockets this wouldn’t have been the problem it was - it may have also helped having pictures on the instruction sheets. It also would have helped if I had checked more carefully!! I noticed that the instruction sheet referred to making a jumper link - but the PCB did not account for the link. After careful scrutiny it appeared that PCB was a newer board and the instruction sheets hadn't been updated. The wiring loom and final assembly of the product was straight forward and 6 hours after starting I plugged the SCAF filter in.

It worked immediately (thank goodness re the LM386). I tuned around the bands for CW signals then also for SSB. The bands by this time were limited to 80m & 40m. Over the next few days I used the product over all bands - well 80m, 40m, 30m, 20m, & 15m.

This product works really really well. The attenuation of adjacent qrm is excellent. In CW mode you can 'tune' signals that first appear on top of each other - quite remarkable. In SSB mode, I found I could attenuate the strong adjacent stations that were splattering over other stations. The audio is all 'real' time - no delay at all. There is no 'speaking thru a bucket' effect. All in all a very impressive product and one that I would recommend. I rate this product 5/5 based on its performance and 1st class customer service.
IV3EPO Rating: 2005-03-27
Money well spent !! Time Owned: 0 to 3 months.
I received SCAF-1 one week ago in kit version.
Very easy to build and to set up.
In owner's manual they write is't very useful for old rigs; I use it with IC-775 and I can say it's the best filter I've added in my shack.
You can't have same result with any dsp on market so I've decided do not buy any extra cw's filter for IC-775.
Thanks to anybody has written a review about it on this site before I bought it.
I'm sure money well spent.
73' de Giorgio IV3EPO
KX0R Rating: 2005-02-27
Joy for your ears! Time Owned: 6 to 12 months.
The SCAF-1 audio filter does what it claims. It is a lowpass filter with adjustable cutoff frequency and very steep attenuation above the cutoff. The filter also strongly attenuates low frequencies. Most of the low-frequency hum and bass frequencies are removed from your audio, along with as much of the high-frequency end as you choose to roll off.

Many fine receivers produce an unacceptable level of wideband audio hiss noise. Depending on the design of the receiver, this hiss may originate in the audio chain itself, or may come from the IF upstream. The problem is especially noticeable in receivers with narrow IF selectivity, because considerable noise may be generated after the primary IF filter. Unless there’s a post-IF filter, this broadband IF noise is processed through the product detector and delivered to the audio chain. The narrower the IF filter, the more apparent this post-filter noise is. Modern headphones make the noise more audible. The SCAF-1 eliminates high-frequency hiss, as well as low-frequency hum and thumps, from your audio. The remaining signals are much easier to listen to. You’ll like your receiver better!

The SCAF-1 is especially appropriate for CW operators, who generally listen to a narrow band of frequencies. The SCAF-1 is easily adjusted to roll off right above the desired beat-note frequency. Most of the receiver’s hiss noise, plus much of the QRN and line noise are eliminated. If you like a low beat tone of 300-500 Hz, you’ll really like the SCAF-1, because you can get maximum noise reduction with a low frequency audio note. When used this way the SCAF-1 becomes a narrow bandpass filter, since the lows are also reduced – yet there’s no ringing as with a conventional sharp filter.

Another really big benefit of this filter is that your rig’s sidetone will have a purer sound, since the harmonics and noise are rolled off. You’ll enjoy sending more.

I originally bought the SCAF-1 to use with my TS-520S. This classic rig has considerable audio hum and high-frequency hiss, particularly with phones. I originally improved my transceiver by putting a resistor in line with the headphone jack, so that I could advance the audio gain somewhat and improve the overall S/N ratio. My TS-520S has a nice CW filter, but it does little to reduce the broadband hiss. With the SCAF-1 the TS-520 is a different radio! CW sounds clean and pure. The effective passband of the receiver is reduced when the cutoff of the SCAF-1 is moved downward. Key clicks are rolled off along with noise, so bad transmitters seem better. DX signals sound cool. The transmitter’s sidetone is firm and sweet.

Once you have a SCAF-1, you’ll wonder how you listened to so much dirty audio all those years! Of course, your brain did the filtering…but the price was fatigue. Many receivers contain terrible compromises.

Recently I bought a Yaesu FT-817ND. This radio needs a narrow filter to be useful for CW. I ordered a 300 HZ mechanical filter for the FT-817 from IR, and wow, what a beautiful, sharp, filter! It’s worth every buck if you plan to operate your FT-817 on CW. However, with the narrow filter in use, a significant fraction of the audio output is broadband hiss noise. This hiss goes up and down with the RF/IF gain setting, so it appears to come from the IF amp after the CW filter. With the SCAF-1 connected, the CW from the FT-817 sounds pure. The previously nasty sidetone of the FT-817 is sweeter, and the quality of the radio experience is enhanced. By adjusting the FT-817’s CW pitch, the selectivity effect of the SCAF-1 can be maximized by choosing a low-frequency note. It’s a personal compromise, but you can match these two devices to each other. The FT-817’s ability to switch BFO injection to either side of the signal is another plus – the SCAF-1 just makes it work better. Low-frequency thumps and many other sounds not desired on CW signals also are gone.

On SSB the SCAF-1 is very effective, but less obvious if your rig already has a good IF filter. You set the rolloff frequency of the SCAF-1 near maximum to avoid reducing the essential speech frequencies. High-frequency noise, heterodynes, and low-frequency hum are cut. The audio is crisp, and intelligibility is often improved. I operated my FT-817 during the 2004 Field Day, and I left the SCAF-1 on most of the time I operated SSB. This device reduces fatigue when conditions are rough.

The only problem with the SCAF-1 and the FT-817 is that you’ll want to use it most of the time, so you’ll have to add it to your collection of little gizmos you use with your radio! While small, the SCAF-1 is almost half as big as an FT-817.

The specs say the SCAF-1 requires 300mA at 12V, but it actually uses 50 mA driving headphones. It will drive a speaker, so you might use it to add speaker power for a QRP rig with minimal audio output.

If you like “Hi-Fi” SSB with lots of bass, the SCAF-1 is not what you want. It’s not DSP, and it won’t reduce heterodyne signals in the desired passband.

The SCAF-1 will improve the audio from older tube-type receivers, many of which have excessive hum and noise, particularly with phones and on CW. Many old sets have sharp IF crystal filters, followed by several noisy high-gain IF and audio amplifier stages. The SCAF-1 may do miracles for your vintage gear.

I built the kit version of the SCAF-1, and it was easy. The instructions were clear, and all the parts were there. The unit worked fine – if there was any puzzle, it was with the initial adjustments, where you do have to make some judgments based on what you hear. These adjustments let you match the SCAF-1 to your particular radio, but those settings may not be just right for each of your rigs. I guess the solution is to order more SCAF-1’s!

The worse your radio is, the more you need this filter. This product is a real jewel. Bottom line: more bang for your buck than most accessories