[felixscerri]

G'day all, I don't think I've raised this subject here before, but in recent times I've completed successful construction of two more DIY ESP P99 sub bass filters that have gone on all of my already built ESP P06 phono preamps. 

I now think that sub bass filters are practically mandatory on phono stages, especially with 'ported' loudspeakers.  I think they make a big difference (improvement).  Any comments?  Regards, Felix.

[BaMorin]

G'day all, I don't think I've raised this subject here before, but in recent times I've completed successful construction of two more DIY ESP P99 sub bass filters that have gone on all of my already built ESP P06 phono preamps. 

I now think that sub bass filters are practically mandatory on phono stages, especially with 'ported' loudspeakers.  I think they make a big difference (improvement).  Any comments?  Regards, Felix.

Yes, and for more reasons than you state. As with any amplification, there are only so many watts to go around. Why run a preamp into compression using up the wattage to produce worthless sound? My preamp has two filter settings, 18 and 36hz. Mine stays on 18. Running panels, (maggies) I don't have to worry about woofer pumping. It does sound better with it on than off. I credit that due to having extra headroom.

[felixscerri]

G'day mate, yes you're absolutely right.  My little amp in here is only 15 watts per channel and there is no power available to waste in amplifying unwanted sub bass energy!  Regards, Felix.

[BaMorin]

G'day mate, yes you're absolutely right.  My little amp in here is only 15 watts per channel and there is no power available to waste in amplifying unwanted sub bass energy!  Regards, Felix.

Hi Felix, yes the amplifier gets a rest as well.........but, I was refering also to the amplification circuit of the preamp too. It has a limited amount of wattage as well. Sending a "clipped" or "compressed" signal to the power amp only amplifies that already clipped signal. There is really not much of anything recorded below 20hz (pipe organ at 16hz) Open E on a 4 string bass is 40hz.

[orthobiz]

I use it and threw in a poll for good measure!

Paul

[TheChairGuy]

It's amazing that it's not part of many phono circuits today...as it is often helpful.

Some that have it make it optional on-off...which helps as you actually hear the difference with it on and off. Others design it into the circuit so it's there but you don't know it.

Some, however, don't build it in to the circuitry at all.  I suspect there may be reasons for this (I seem to remember a long topic on this subject years ago at Vinyl Engine), but it seems to be better to have it rather than not.

John

[BPoletti]

Subsonic filters are not necessary in a system that is properly set up.  Furthermore, there is a LOT of subsonic information in many recordings, particularly classical, that is part of the performance or characteristic of the venue.  Filtering the low frequency / subsonic information that is part of the recording subtracts from the performance or space in which it was recorded. 

[neobop]

Subsonic filters are not necessary in a system that is properly set up.  Furthermore, there is a LOT of subsonic information in many recordings, particularly classical, that is part of the performance or characteristic of the venue.  Filtering the low frequency / subsonic information that is part of the recording subtracts from the performance or space in which it was recorded.

+1
Your entire signal goes through that filter. In no way will it improve the quality of the signal, unless you have a problem. In that case, you probably can't live without it. I use vented woofers and TLs with no problems. One preamp has a switchable subsonic filter. I don't use it. If I switch it in, you can hear the effect, like switching in tone controls.

There was a thread here, a few months ago on this subject. Same thing.
neo

[Quiet Earth]

I tend to agree with not using a filter.

filters are not necessary in a system that is properly set up

It might not seem like you have a tracking problem with filter always on. Better to not have one and adjust the tracking the best that you can.

Maybe op amp users appreciate the benefit of a filter more than tube users. The filter might make life easier for a fussy op amp. Just a thought.

[Quiet Earth]

Some that have it make it optional on-off...which helps as you actually hear the difference with it on and off. Others design it into the circuit so it's there but you don't know it.

Sure enough, I just checked mine and there it is. I've been using the "always in circuit" filter without giving it a second thought.

Disregard my last post as I open my mouth to insert my foot.