Buy High Pass Filter or KAB RF1?

...  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
 

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

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
  

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

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