TT when played loud hums and distorts speakers?

Dabutcher

I have tried four different phono preamps and the current one is parasound z unit. What am I doing wrong? There do not seem to be any sonics coming to TT or phono pre from SDA's my CDs sound awesome loud. I wish I could safely jam louder w TT? As always thanks for any help. Darryl

treitz3

Unless his sig has changed, a Sanyo DC Servo player TP 727 turntable Keiko.

Dabutcher, how close are the speakers to the TT or TT stand? What kind of isolation is provided for the TT itself and what kind of stand/mount does the TT sit on? Is the TT situated on a suspended wood substrate?

Tom

SCompRacer

Sounds like what Mike and Tom are asking about, acoustic feedback. Do you have the problem with the stylus cued up and off the record? That is turn the volume up with the table on, without the needle in the groove, phono selected. Got a pic of your setup?

Dabutcher

Turntable is on a glass Bello TV stand .TT has rubber type feet . I have never aligned or set up cartridge? I am kinda pressed for room here. Maybe mount it on a wall shelf above speakers? TT sits on left side top shelf ,right above GFA 555. Thanks. DarrylAttachment not found.

hochpt21

I see the problem right there. Just take that Bears rug and throw it out...that should solve all of your issues.

I kid...I kid.

You can get four sorbothane balls or four vibrapods for about $25. Don't know if that would solve it, but it should help. My guess is that the sda's rattle that glass when you get loud.

When I was researching isolation for my TT, most feedback told me wall mounting was the only way to go for isolation. If you can make it work, that seems like a solution, but it looks kinda tight above the speakers.

mhardy6647

I'm thinking acoustic feedback (too). Common problem - and a "tight quarters" system like that is begging for trouble.
This is also a good time to check how well matched are the arm mass and cartridge compliance - the resonant frequency of the arm/cartridge/stylus suspension resonant system may be outside of the (nominally) optimal 8 to 10 Hz neighborhood.

mhardy6647

(missed the edit deadline, d'oh...)

What cartridge are you using?

Distortion at high levels suggests (???) that the phono preamp might be overloaded by the cartridge output - this is extremely unlikely. It is (slightly) more likely that, if you're using an outboard phono preamp, its output might be a tad too high for the line-level inputs of your amp or preamp (but this is not likely and would manifest itself at any volume... although it might be more obvious at higher system volume levels).

Good one-stop shopping for tt/cartridge resources (in case you didn't know of it): www.vinylengine.com (free registration required to download from their extensive document library)

The tt is a complete unknown to me; Sanyo - although certainly having built some very good hardware (e.g., their "Plus Series" of components) - generally sold pretty mediocre stuff at the lower-end of the mass market. That said, chances are the tt was an OEM from one of the "big names" in Japan turntable manufacture; very possibly CMC was the OEM, but, again, I'm speculatin'.

Speedskater

Try moving the TT a few feet from anything that might have a power transformer or fan motor in it.

George Grand

Get that tt away from the speakers.

erniejade

George Grand wrote: »

Get that tt away from the speakers.

+1 I dont think no matter what you do to try to isolate it, its going to pick up vibrations from the speaker. About the only other thing besides the feet that might help is if your pre had a subsonic filter. The needel or arm will pick up vibrations from the speakers and cause a hum.

Like others say make sure the cart is alligned properly. THis will cut down on distortion but not the hum.

Mike Reeter

I don't guess there is any chance you have the Output leads from your Phono Preamp hooked up to the Phono Input on your AVR, is there? If so, that would be wrong. Have you tried hooking the TT directly to the AVR (assuming it has a Phono Input) and not using the Dedicated Phono Pre, to see what that sounds like? Just a thought.

SCompRacer

Try moving your turntable is the best solution although you are limited by length of IC's. More than two meters of turntable IC to phono pre is not advisable due to low mV of cartridge. Maybe try moving your table in front of audio rack, although you are still in that 'zone'. Isolation alone won't cure room acoustic issues as the table still absorbs the frequencies.

A turntable between speakers boxed by corners is more likely to have problems. I can create the same feedback issue here by putting my turntable between the speakers with my south wall setup (even with speakers 3 feet from side walls and the use of acoustic treatments/stacked corner bass traps). By 75dB, feedback starts. Table/gear on sidewall with speakers on south wall, no issues. With my west wall setup, the right speaker is open to dining area and the table can be between the speakers at any volume setting with no problems.

mhardy6647

SCompRacer wrote: »

Try moving your turntable is the best solution although you are limited by length of IC's. More than two meters of turntable IC to phono pre is not advisable due to low mV of cartridge. Maybe try moving your table in front of audio rack, although you are still in that 'zone'. Isolation alone won't cure room acoustic issues as the table still absorbs the frequencies...

True and good advice - but I don't think it's the low output of the cartridge per se but rather the impact of inteconnect capacitance on HF rolloff (doubtless exacerbated by the miniscule signal level). That said, there's a pretty easy - if not necessarily inexpensive - workaround :-) The OP may want to try a separate phono EQ/preamp with a nice low impedance output. A vaccum tube cathode follower, e.g., is said to allow a 50 ft cable run with no audible loss of signal quality. No doubt that the line level output signal from a separate preamp is more robust than the signal from the phono cartridge itself.

Just a serving suggestion :-)

TSWisla

hochpt21 wrote: »

I see the problem right there. Just take that Bears rug and throw it out...that should solve all of your issues.

I kid...I kid.

You can get four sorbothane balls or four vibrapods for about $25. Don't know if that would solve it, but it should help. My guess is that the sda's rattle that glass when you get loud.

When I was researching isolation for my TT, most feedback told me wall mounting was the only way to go for isolation. If you can make it work, that seems like a solution, but it looks kinda tight above the speakers.

I was born in Chicago and live in the suburbs now and I have absolutely no problem saying it, THE BEARS SUCK.