Buy High Pass Filter or KAB RF1?

The KAB RF1 will do what you want.  The high pass filter won't  I own the KAB, it got rid of every bit of the feedback without altering the bass.  It uses all audiophile graded parts inside.

Thank you very much. It either buy the KAB or buy a preamp with rumble filter I guess. I was thinking of possibly the pro-ject tube box S2 if I don’t go the KAB route. 

I'm pretty new to the forum and have read a thread about rumble filters and how some folks think they degrade the sound.  

I have a second system that I use a MoFi Studio phono pre that has a rumble filter which I use and it works quite nicely.  I haven't noticed any sonic degradation but maybe my system or ears are not quite as resolving as others.  

Why do you need it ? 

I need it because the cones on my two speakers as well as the woofer on my sub are modulating very badly when playing phono. 

@craigert...……………………………...

Everyone here will tell you to relocate the turntable, put it on a maple, slate or granite platform, or tennis balls, mount  turntable to a shelf on wall, change cartridge, etc.  I tried all that, blowing money on 3 different platforms, new cartridge and I STILL had to buy the KAB Rumble Filter.  Save yourself the grief and expense that I did and get the filter.  I can't hear  a difference with and without it and I am feeding it expensive cables to boot.

Thanks Stereo5. Yes, it’s quite frustrating the number of people who say to relocate the table when they know a TT has about two feet worth of phono cable length to work with. There are only so many relocation options. 
On other threads I have asked questions like...what does everybody like better A or B....and everybody seems to want to give C as the answer. Lol 

I have already determined I am getting some sort of rumble filter to try no matter what anybody says, because the problem can come at an instant when I am showing my system like last time I had guests and I want to be prepared. 
I will probably get the KAB and then buy an Atoll phono preamp because they are my favorite sounding audio company. 
I just hope having the KAB and the Atoll feeding into a line input in my Marantz isn’t going to be too many connections.

Do you think it will? 

Also, how do most people have the KAB hooked up?

I biamp my speakers so it would have to be between the TT cables and the Marantz Preamp Processor for my system.
The problem is that this means that I will need rca cables for between the other side of the KAB to the Marantz phono inputs right?  Maybe they sell 6” pigtails.

My preamp has both a tape loop and processor loop.  I run it through the processor loop.

Another option!
https://store.acousticsounds.com/d/60042/DB_Systems-DB_Systems_Subsonic_Filter-Turntable_Accessories

Give them a call!
https://www.dbsystemsaudio.com/

@yogiboy...……………………………..

Good call, had forgotten about those.  It's cheap enough, I would give it a try.

So I called the company and the guy said the $22 passive version is pretty much just a high pass filter and would technically make an audible difference. He said they have an active product around the same price as the KAB now where you can’t hear the difference when using it. 

I just ordered the KAB. I can’t take this anymore. lol 

Rega thinks it’s a cartridge mismatch but my cartridge only weighs 2 grams more than the one that comes with it and the compliance is spot on I think. 
I think the needle is picking up feedback from the speakers.

being new to this stuff I found that people have an argument that doesn’t make sense. They ask why a filter is necessary and act like it’s a band aid. Yet, these same people will tell you that even rumble that you can’t hear is bad for your system. So that means their systems may be rumbling and they don’t even know it. Why not have this in the system to protect it if nothing else. I haven’t heard one person say it degrades sound. 

Craigert,  Based on one of your posts here, do you seriously plan to put the filter between the phono cables and the phono input of your preamplifier?  If so, that's a no-no, if you care at all about SQ.  If you're bi-amplifying the speakers, do you use an electronic crossover?  And do you have separate amps for bass and treble?  If so, put the filter at the output of the crossover that feeds the bass amplifier. Whatever your set-up, I suggest you avoid putting the active rumble filter directly across the very low voltage output of the cartridge.

Lew,

Thanks for the tip. The ultimate goal is to buy the Atoll phono preamp and put the KAB on the back side of it before it goes into a line level input of the Marantz.

i have a 5 channel amp that feeds my front two speakers and my sub has its own built in amp. 
The crossovers in the front two speakers are built into the speakers and the crossover that controls the sub is in the Marantz. 
There is only one line feeding the sub so I’m not sure how I would connect this just to the sub.

Do I need to wait until I receive the outboard preamp or is there a way to Connect in the meantime? 

There is only one line feeding the sub so I’m not sure how I would connect this just to the sub.

Does the problem still occur when the sub is not operating? If so connecting the filter just to the sub won’t help very much, of course.

If the problem only occurs when the sub is operating, though, you could connect the filter between the Marantz and the sub, with a y-cable connecting the bass signal provided by the Marantz to both inputs of the filter, and with just one of the outputs of the filter connected to the sub.

The reason for the y-cable is that I see in the instructions for the filter, which I found online, that there is an "important note" saying that it should never be used with only one of its two channels connected, and "if you must do that" a y-cable should be used to connect the input signal to both inputs. I’m guessing the reason for that might have to do with the possibility that noise occurring in an unused channel as a consequence of having its input unterminated may couple into the channel that is being used. If so, a shorting plug on the unused input could be used as an alternative to a y-cable.

In any event, I agree with Lew that the filter should absolutely not be connected to the output of the cartridge. There are several reasons for that. Just to cite a couple: The hum & noise produced by the filter is specified as "> -85 db ref 1 volt." Since the 5 mv rated output of the cartridge is 46 db less than 1 volt it would mean that hum and noise produced by the filter could be as little as 85 minus 46 = 39 db below the rated output of the cartridge, which would be unlistenable. Also the unspecified and unknown input impedance of the filter stands a good chance of being too low to provide reasonable results when used with a moving magnet cartridge.

Regards,
-- Al

Guys,
I may have figured it out and I would like to get your opinion. The P3 mass is 11 g. My Nagoaka MP-110 cartridge is 6.5 g with only a 6 for dynamic compliance. Using an online calculator this puts the resonant frequency at a 15-16 Hz!I believe it’s supposed to be around 10 Hz correct?
Do you agree this is most likely my problem?

Great insight on the y connector Al!

Also, I cancelled the order for the KAB because I now think it’s a cartridge incompatibility issue with my light tonearm since the dynamic compliance of the cartridge is a mere 6 causing the cartridge resonance to be 15-16 Hz.

It looks like I will be on the hunt for a new cartridge first. 

I posted the following in one of your other threads:

It appears that the Rega P3 is normally fitted with a Rega RB300 tonearm, which according to the listing at Vinylengine.com has an effective mass of 11.5 grams. Also, since the cartridge is made in Japan its dynamic compliance is probably specified on the basis of 100 Hz, rather than on the 10 Hz basis that is usually used by the calculators, such as this one. I would expect that its compliance at 10 Hz is **probably** in the rough vicinity of 10 or so.

Plugging a compliance of 10 into that calculator in combination with a tonearm effective mass + cartridge weight of 11.5 + 6.5 = 18 grams results in a calculated resonant frequency of 11.86 Hz, which is within the 8 to 12 Hz range that is often considered to be ideal.

But note the word "probably" in my statement. It’s hard to say for sure.

Good luck. Regards,
-- Al

Your calculation is wrong. Your nagaoka has 6cu dynamic compliance only when it’s measured at 100Hz just like all japanese cartridges.

For your calculation you must use dynamic compliance measured at 10Hz (not at 100Hz), this is a problem if you don’t know.

Convert 6cu @100Hz to 10Hz

6 x 1.7 = 10.2 cu

this is a compliance of your nagaoka at 10Hz , now you can use this data for calculation of tonearm/cartridge resonance. Actually it can be from 10 to 12cu compliance. The range of RF is 8 - 15hz 

@craigert I am having the exact same problem and dilemma about what to buy as you are! Wow...was about to post myself. I ordered some Harrison Labs "FMODs" (20 Hz high pass)..I plan to put one on one channel to start and see if I can hear a difference in sound. I hope they solve my woofer pumping.

My Focal Aria 906's are getting "woofer pumping" when I use my turntable as well.  I've tried EVERYTHING, it's not an isolation problem (verified by moving it all over and trying different experiments...and making a digitial recording from my 'pre-out' into a digital recorder and playing it back, the problem STILL persists!)
@stereo5 any idea what's actually causing the problem? I have the same issue as you can see above in this message :/

Ok thank you so I am in compliance. Plus Rega told me people use this cart with my P3 all the time. 
Will a KAB fix a feedback problem? Just curious. 
I thought rumble could be caused by feedback but I have somebody telling me a filter wont fix feedback.

@craigert I'm sure it will...I had someone come over today with a preamp that has a subsonic filter built in and the issue went away. I can't speak for the KAB, but I may have to buy one someday as well so I hope you let us know how it works out if you do buy one :)

Just build your own and experiment.  $25 filter is just probably a resister and a capacitor.

Thanks Brandon I’ll stay in touch! I just saw your first post. This is crazy isn’t it?

im now thinking about buying the out board pre amp first so I can get the table away from the speakers and see if it’s a feedback issue. 
I have also heard that you can buy a test record that will help to identify the problem but it’s like $50.

i also saw in another similar thread that if you turn on the turntable but don’t play the record and then crank the volume way up that if the speakers pump it’s a feedback problem. 
Finally somebody told me if it’s a feedback problem that a filter won’t work but I thought that “rumble” = “feedback” problem.

i am convinced a simple passive filter will hurt sound since the designer of one mentioned in this thread told me it technically does. He said whether you hear it or not is another story. I have also read that while an active filter may not degrade sound it may throw the bass out of phase. 
I thought I was simply just going to buy a record player and spin records a couple months ago. Lol 

Do the woofers flop with the sound turned down?

What program material? I have some classical recordings where the HVAC is blowing on an unscreened mic. The sub worked so hard it shut down.

If you can see your woofer’s flopping, it is likely below ≈10Hz which is very low for feedback.

It’s over 30 years since I had a turntable, the last ones had disc clamps which do wonders. The TT, HA & Pre were in a separate room... ZERO feedback at any playback level.

’Rumble’ filters on consoles and pre-amps are often quite high ≈40Hz.

The db systems HP is just a ≈140nF cap. Actual frequency will vary if phono impedance is not 45k. It will only ½ the excursion @ 12Hz. An adjustable multipole filter [4th order L-R HP] to the sub and bass driver amp is preferred.

The KAB RF1 is mono below 140Hz. Not all LPs are mono below that frequency.

@craigert No problem!  In my case I don't think it's a feedback problem, as I recorded (without the speakers on at all) to a digital recorder and played it back and the woofers still pumped. 

I feel you on the passive filter...but for $25 I think it's worth a shot. I ordered them on Friday so got 15% off, which offset the exchange rate a bit.  Still cost me $20 in shipping though. Insanity.

My woofers DON’T flop with the volume turned down. 
It started out of nowhere on my AJA album Black Cow. Something wasn’t right so I switched to Led Zeppelin II and it was rumbling on that too!

The weird thing is why are my front speaker drivers rumbling too when signals below 80 Hz are being sent to my sub?

Craigert, Re this last post, define "rumbling".  Are you hearing a noise or are you watching the drivers do a dance, in and out?

The weird thing is why are my front speaker drivers rumbling too when signals below 80 Hz are being sent to my sub?

Looking at the manual for the AV7704, I see that depending on some menu settings frequencies below 80 Hz may or may not be sent to the main speakers, in addition to being sent to the sub.

Also, I don't think an answer has been provided to a question I stated earlier, namely "does the problem still occur when the sub is not operating? "

Regards,
-- Al
  

Oops sorry I forgot to check your question Al. When I get home tonight I will play a record without the sub and will report back!

Thanks for reading my manual!

There was only one time there was audible noise that came from one of my front speakers, but it’s pretty much just noiseless extra flapping of the cones and woofer. 

Ok Al I moved the fronts forward of the turntable and it appears only the subwoofer sitting next to the TT is rumbling now.

When I turned the Sub off there was no rumble present.

Is it safe to assume that the rumble in the Sub is feedback?

I am giving my boy a bath right now but I can try to relocate the sub to see if it all disappears. 
One thing is for sure, I need to buy an outboard preamp so I can get rid of that phono cable extender. It’s horrible. I’m surprised so many people have recommended to just extend it. The hum is so bad it’s not even listenable. Rega seemed adamant that it’s a certain length for a reason. I’m a total believer now.

Update: I also moved the sub farther away and now I have no rumble whatsoever. 
I kept being told to move the table but being limited with existing ICs the way to go for me was to move all of the speakers. 
I’m happy that I won’t need a rumble filter now. 
The question now is whether buying an outboard phono preamp like the Atoll P200SE will make an audible difference because my Marantz AV7704 sounds pretty damn good and I can’t imagine it getting much better. Thoughts? Will the difference really be audible?

Glad to hear you figured out the rumble problem. Having the sub too close will definitely create issues for your turntable.  

I have never tried the phono output in my AV7704, it's possible that it's better than I think it is, but when comparing the phono out in previous pre-pros I've used to a decent outboard phono stage, there is no comparison.  

An outboard phono stage should give you an improvement in sound quality and many of them will give you different loading and gain settings so that you can customize the settings to work best with the cartridge you're using.

Update: I also moved the sub farther away and now I have no rumble whatsoever.

I’m happy that I won’t need a rumble filter now

Exactly, i don’t understand why anyone need those filters.
You can properly isolate your turntable from vibration, AT’s pneumatic insulators are very effective. Here is how it works.

Thanks guys!
I can’t wait now to try the Atoll. I feel that the Marantz AV7704 is the best bang for the buck for new audiophiles who aren’t rich. Coupled with the right amp it sounds great. It sounds industrial and horrible with my Anthem A5 but beautiful and detailed with my Atoll. I’m sure the ribbon tweeters on my speakers help too.
I am a musician and a drummer, so I definitely have an ear for sound and can tell the difference quite easily.

Chakster, On a purist basis, I would question the use of those AT pneumatic isolators under a loudspeaker, because it seems to me that depending upon weight of speaker and stiffness of the AT feet, the speakers might be free to rock back and forth when driven hard. That results in waste of amplifier energy, as some is lost in order to move the speaker, and distortion, because the signal to the speakers is partially diverted.  I suppose it would be on a case by case basis whether it does anything audibly bad.  Normally, you want the speakers to be anchored rock solid, so all the amplifier energy goes to moving the drivers.

I need to buy an outboard preamp so I can get rid of that phono cable extender. It’s horrible. I’m surprised so many people have recommended to just extend it. The hum is so bad it’s not even listenable. Rega seemed adamant that it’s a certain length for a reason.

The reason people recommended trying an extension cable is that in most situations it would not cause anything like the hum problem you experienced. I think someone mentioned early in one of your other threads that the Rega’s grounding configuration is unusual, which presumably has contributed to or caused the problem in this case.

In any event, congratulations on finding a solution to the rumble issue. I can’t comment on phono stage possibilities in the price range you are considering, or how they might compare to the one that is built into the AV7704. I note, though, that the Atoll phono stage provides a choice of two load capacitance settings, differing by 100 pf, which is nice although not quite as flexible as the four or so settings some much more expensive phono stages provide.

FYI, BTW, whenever any phono stage provides a load capacitance setting designated as "0," the actual capacitance presented by that setting is not really zero (which would be impossible). My guess is that it may be a few tens of pf’s, and the 100 pf setting is 100 pf higher than whatever it is in the 0 setting.

Continued good luck. Regards,
-- Al

Gotcha thank you Al. I ordered the Atoll today from Canada. I figured it was worth a try because I have never heard magic before like what comes from my Atoll amp. I figured they must know what they are doing to some degree. You would know better than I, but my experience so far is that more expensive may have a better chance of being better, but more expensive doesn’t always mean better. I think I have said it before but my $4500 Anthem A5 sucks! Lol 

...  my experience so far is that more expensive may have a better chance of being better, but more expensive doesn’t always mean better.

Very well said.  I concur 1000%.

Best regards,
-- Al
 

my $4500 Anthem A5 sucks

in your opinion in your system. Could be the cat’s meow in another's

Indeed ieales, indeed. I’m going to try the Anthem as driving my Atmos and surrounds in the theater room I am building in the basement, and use an Atoll for the fronts down there.

I also have an Atoll upstairs for my record player driving my two Monitor Audio Golds. Soon I will have the Atoll phono preamp.

I have two Marantz AV7704s, one for each room.

As Al rightly said, the majority who suggested an extension of the phono cables as a test did NOT suffer the hum you describe, or obviously the suggestion would not have been made!

And I do believe the majority suggested as a test not an ultimate end of game fix.

But I will admit I have never owned a Rega so unsure as to how that would have reacted in my system under the same circumstances.
Neither of my two JVC DD tables had any issues with phono cable extensions for testing.

Crap the rumble is back just on the subwoofer, and only when it’s turned up past 10 o’clock. 
I’m assuming if I put a single passive high pass filter on the sub it’s my best option for hurting sound the least other than buying the KAB and getting a Y connector.