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Phono cable/grounding/loading questions

Hi, I am finally settling with my analog set up which I run in balanced(RCA @ TT end with ground wire and balanced at phono pre-amp, balanced from phono to preamp..)configuration. I do have some questions that I need answered to convince me what is right. I have looked in to archives but have not found clear cut answers. So here goes:

1. Is the purpose fully designed phono cable always better than the regular ics used as phono cables?
2. If there is no hum present without ground wire connected at TT end, technically is it correct to do so? (When I connect the gorund wire, the presentation a little more articulate but on brighter side)
3. Could I use phono cable with RCA/RCA and use RCA/balanced adapter at phono preamp end? Would I be getting full benefit of balanced configuration this way?
4. My helikon cartridge loading with all new burn-in cables sits at 40 ohms currently and there is still peak (4-5 db) at 10 K hz. Rest of the spectrum very good but this peak is annoying at times. Why is this happening?
5. Bi-wire question: Is it okay to use biwire speaker cables with Jumpers or is it defeating the purpose? More importantly is this dangerous?

Sorry to load you with too many questions but I wanted have only one thread to put my mind to rest.

Thanks in advance!!
nilthepill
dgarretson
2,598 posts
 
Raul,

The BAT phono stage has both RCA & XLR inputs but ONLY balanced outputs. The RCA input is inverted within the phono stage and passed through differentially balanced amplifiers for true balanced output to the preamp. As I mentioned above, a cartridge is not a true balanced source. There is no third ground pin, no inversion of +/- with reference to a ground, no common mode noise rejection. So the matter comes down to whether to use the XLR connector or the RCA connector into the balanced phono stage. The XLR input will divide the output current of the coil between the differential amps and produce a lower SNR than an RCA. A low-mass RCA plug (Nextgen, Eichmann, etc.) may also sound better than XLR due to the XLR's heavy metal barrel.

This issue has been covered in several threads elsewhere. Here is a good one for background:

http://db.audioasylum.com/cgi/m.mpl?forum=vinyl&n=111640&highlight=phono+balanced+connection&r=&session=

Regards,

Dave
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rauliruegas
13,064 posts
 
Dear Dave: I agree that the cartridge is not a balanced item but it is not single ended either, the cartridge is a signal generator: that's all.

The point on the subject reside on the phono cable to take advantage of the balanced input in a true balanced phonolinepreamp.

Any one can tell me how I can post a picture/diagram here for explain about?

Regards and enjoy the music.
Raul.
fcrowder
191 posts
 
Several years ago I switched from a Helicon to a Titan on my Rockport and at least in the Rockport arm, the Titan is significantly better. Cleaner at the top and definitely more bass but in my system the greatest improvements were in dynamics and presence. Perhaps the Titan is just a better match for the Rockport arm but in my system significantly better.
nilthepill OP
842 posts
 
Larryi, You are so right! Finally I gathered all the courage to fiddle with VTA. Ofcourse after reading very precise instructions written in my manual. It does say that don't assume 'factory set' VTA is always right, since the cartridge heights are different and is not industry goverened, and that the cutters angles are different depending upont record labels, slight change in VTA is necessary depending upon the cartridge. 5.3 turns of the micrometer changes the angle by 1.25 degs and it recommends to try this setting. Lucky for me I can adjust the VTA while record is playing. Try I did and sure enough slight sibilance I had left over when I disconnected the ground cable was gone and sound changed dramatically (I could now bear 47k loading sound v/s absolutely earshattering sound before).

It tunrned out that at current 40 ohm loading though, these many turns actually 'blunted'the sound so I found a good balance at about two turns , cartridge tail down. When I get 100 ohm resistors I will play again with VTA adjustment. Thx for thr tip!!
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