# Tivo2 upgrade - Hum on audio now



## grahamg (Aug 18, 2006)

I am pleased to say that I have added a 2nd 250gb drive to my 40gb Tivo. It was very easy to do and works great. Thanks to the guidlines on this Forum.

However I now notice that there is a small, but irritating 60hz main hum on my surround sound system bass speaker which was not there before I added the 2nd drive.

I suspect that the extra hard drive is taxing the power supply and causing the supply to rails have more AC ripple on them than before and that is getting into the Tivo's audio channels.

Is this a known problem, can I add more smoothing capacity somewhere in the Tivo to kill the 60hz hum?

Thanks.


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## Seattle (Dec 13, 2001)

Sounds like a ground loop problem. Are all to connections secure? Is the TiVo plugged in to a different outlet?


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## litzdog911 (Oct 18, 2002)

How are the Tivo's audio outputs connected to your TV and/or AV Receiver? 

Also, try temporarily disconnecting Tivo's cable/antenna input cable and playing back a recording. Is the hum gone?


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## grahamg (Aug 18, 2006)

Thanks for the replies, you are both on the right track. The TIVO,Surround sound amp,50" Plasma share the same AC distribution strip but all use 2 pin connectors. So the inter component ground is via the connecting cables. I did try adding short grounding straps between the components but the reduction in AC hum was marginal.

But when I disconnecting the TIVO antenna coax I found that the hum went completely away. I then realised that about 10' away where the coax came into the Condo there is a 2 way RF splitter and an AC wall outlet a few inches away from it. I found that by installing a short grounding strap between the RF splitter case and the AC outlet ground reduced the AC hum by 80%. At normal listening levels the remaining hum disappears in the sound, so I have a fix.

To completely elimate the ground loop causing the hum I need something to pass the coax center pin through and to seperate the outer shield with capacitors, to form an isolator. I dont know I can buy such a thing, I could make one though.

I then remembered that I have changed something major. I turned in my HD cable box from Charter Communications a few weeks ago. I was tired of paying $100 p/m for view on demand that contained old movies and HD TV channels that pixelated often. We found that TIVOing the normal resolution channels was the most reliable. Also the HD box went through the TIVO's S-video cables so we lost the full HD anyway.

To replace this we signed up for the Blockbuster online DVD rental, best thing we ever did and we save $75 p/m over the Charter HD.

Anyway, originally we were using the cable box to do the decoding and fed the TIVO with S-video and audio. But now we feed the TIVO with RF so there is the big change - and what caused the problem.

Thanks for the suggestions. Off subject I am curious if there is a way to see how much storage capacity the TIVO has left at any time. I know it can store 320hrs now of low resolution. But I can't find anyway of seeing how much space my recordings are taking and how much space is left.

Thanks again.


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## IminMs (Sep 10, 2006)

grahamg said:


> Thanks for the suggestions. Off subject I am curious if there is a way to see how much storage capacity the TIVO has left at any time. I know it can store 320hrs now of low resolution. But I can't find anyway of seeing how much space my recordings are taking and how much space is left.


There is no menuselection to see how much disk space is left. You can estimate the amount used by looking at how many movie/shows you have saved. Also add in the amount of the shows in the "ToDo" list. As you schedule a recording, it reserves that much space for it.


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## grahamg (Aug 18, 2006)

Thanks, I can understand that, I am using best quality for everything right now, I can check with Tivo Desktop to see how much each 1/2 hour takes and estimate the space. It just seems a bit basic though. I was hoping for some hidden remote control function or something. Anyway thanks.


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## luder (Sep 7, 2006)

I experience something like that but, it's not really noticeable .. I don't know how i can explain what i'm hearing so i will try to record it upload it here soon.. I hear it when i have my ear right up to the front speakers of my surround sound.. i'l post soon the sound


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