Subsonic filter help
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Just out of curiosity, what sort of sub-sonic issues are you having with your system? This may help you select the filter. 
tnsilver
Stereo Puppy
Why? It's another, mostly undesired, link in the signal chain and I've never heard a sub-sonic filter that did not alter the sonic in some way. Sub-sonic filters remove the symptoms of a disease - they don't cure it. It's like aspirin for a hangover. You're still intoxicated, you're just not in pain. Deal with the source of the problem. It's always one of two things other than the odd warped record, and it boils down to either insufficient isolation or a cartridge/tonearm mismatch. There's a plethora of commercial, as well as DIY solutions to the first and you know what to do with the later.
You need a steep filter to be sufficiently effective below the cut-off frequency. A passive would have far too much insertion loss in the passband, so active is really the only way to go.
Whether or not there's any benefit to a subsonic filter is a matter of debate, as evidenced by the comments above. I'd agree that it makes sense to address any physical/ mechanical issues first. Subsonic filters seem to have fallen out of fashion but if the kit doesn't cost too much money you'll soon be able to judge for yourself whether there's any trade-off for the potential benefits of using one.
Coolhandjjl
Embiggened Pompatus
I'd recommend 25Hz.
Lavane
Lunatic Member
The issue is woofer huffing at higher volumes. It starts around 12:00 on the volume control. My system has a tube preamp and amplifiers. I'm very happy with the setup other than the woofer pumping using the turntable. I've tried various things like positioning, dampening under the TT feet, etc. I dont listen to records as much as other sources, so I don't really want to shell out for another turntable. I'm using an AT LP-1240 with a Nagaoka MP110 cartridge. I also have one of those $11 cartridges with both the stock conical and elliptical stylus mounted on a head shell. If I listened mainly to vinyl records I would probably start with a better TT. So my thinking was to try a filter.
Lavane
Lunatic Member
Yes. I had this problem with another turntable I owned in the early 80's. No matter what I did other than use a filter, I had a problem with subsonics.
Lavane
Lunatic Member
All of the speakers I own except for one pair I use in the garage are ported or have passive radiators.
I would go with the 15 - but the others should improve your sound.
FWIW both Holman and Advent 300 phono circuits have integral 3rd order 16 Hz filters, and I don't see ant complaints about those. Typical ow filter on receivers and integrated amps are more like 50 HZ and first order and do affect sound... My 2 cents
FWIW both Holman and Advent 300 phono circuits have integral 3rd order 16 Hz filters, and I don't see ant complaints about those. Typical ow filter on receivers and integrated amps are more like 50 HZ and first order and do affect sound... My 2 cents
doctor fuse
Super Member
How about making a DIY fluid damper for your tonearm? All you need is some wire and scrap plastic, and some thick oil (ideally silicone) to try it out and see if it reduces the woofer pumping.
I use a white plastic tofu container for the paddles, champagne cork stopper for the wire and any old junk plastic container that fits, for the trough (this is the most difficult part to scavenge).
Good luck!
Here is a good DIY guide:
http://www.enjoythemusic.com/magazine/bas/0809/
I use a white plastic tofu container for the paddles, champagne cork stopper for the wire and any old junk plastic container that fits, for the trough (this is the most difficult part to scavenge).
Good luck!
Here is a good DIY guide:
http://www.enjoythemusic.com/magazine/bas/0809/
Lavane
Lunatic Member
The Marantz model 33 preamp I owned had a 50hz and 100hz switch. It did effect the sound. I'll look at the schematic and see if I can make the filter selectable. Maybe it just takes a resistor swap. The dual 15v power supply will cost more than the filter board kit.
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I have sand-filled platforms for each of my turntables. Seems to absorb sub-sonic vibrations --- as neither table has issues with run-in or run-out woofer movement.
And I'm running 2 X 15-inch subs and 2 main speakers with 15-inch woofers.
https://www.tnt-audio.com/clinica/sandblaster_e.html
And I'm running 2 X 15-inch subs and 2 main speakers with 15-inch woofers.
https://www.tnt-audio.com/clinica/sandblaster_e.html
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I have the boards and parts to build myself a subsonic filter. For my purposes its to keep the sub from violently bottoming out if I bump the turntable. I don't have turntable rumble or feedback problems. Plan is to put it in the tape loop, but if I don't like how it sounds maybe I'll move it between the preamp and the sub amp. If I hate it, at least I'll have learned something without spending a fortune.
AudioFeline
Super Member
At least with a kit you will know how to modify it to experiment with different frequencies.
Hope you get some benefits from it.
Hope you get some benefits from it.
Lavane
Lunatic Member
The filter board I'm going to try arrived today. I'm still looking over several dual power supplies. The filter board is only about 2"×3". Depending on the power supply, it loooks like I'll be able to keep the housing small. It has the resistor values that can be swapped for 3 different frequency responses printed on the back.
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