Long IC runs and TVCs

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mingles

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Long IC runs and TVCs
« on: 26 Feb 2008, 06:55 am »
Hi John, I recently picked up a Bent TVC with S&B trannies. I'm pretty excited about that. I've been looking for six months! It has RCA in and out, but no balanced. I need to run 3 meter ICs from my phono stage to the TVC. Can you recommend some ICs that will do the least damage? I understand that capacitance is the big issue here. The last thing I want to do is soften the bass or roll off the highs.

In general, what has been your experience with longer IC runs and TVCs? Does balanced handle it better? If so, is it possible to rewire the unit I have?

Best regards,
Mark

John Chapman

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Re: Long IC runs and TVCs
« Reply #1 on: 27 Feb 2008, 03:32 am »
Hello!

Glad you found one. The cable before the pre-amp (ie from the phono stage to the TVC) will be driven by the phono stage so I'd need to get the specs of the phono stage to take a stab at how well  it'd drive the 3M cable. If you have the model or can point me to a link I'd be happy to scope it out for you. If you've been using the stage with that cable length in the past with good results it should not be a problem when you make the pre-amp change.

Thansk!

John

mingles

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Re: Long IC runs and TVCs
« Reply #2 on: 27 Feb 2008, 06:08 am »
I have an EAR 834P. I'm using the internal SUT at the moment, but I have some CineMag transformers on the way.

Stereophile's measurements:

http://www.stereophile.com/phonopreamps/797ear/index3.html

Set to MM, the 834P's input impedance was 49.7k ohms in the left channel, 51k ohms in the right. The input impedances for the MC setting were 515 ohms and 516 ohms (L&R). The output impedance measured 524 ohms in the left channel, 538 ohms in the right.



John Chapman

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Re: Long IC runs and TVCs
« Reply #3 on: 27 Feb 2008, 04:45 pm »
Hello!

Thanks for the specs. When it comes to the cable from the phono stage to the pre-amp the spec that matters is the 'Output Impedance' of the phono stage - in this case about 500 ohms. The input side of the phono pre-amp (ie what the cartridge 'sees') is entirely isolated from the output side by the circuits in the phono stage - they matter to the cartridge but have nothing to do with the connection downstream to the pre-amp. The type of step-up, etc is not in any way connected to the output side of the phono stage.

With the 500 ohm output impedance I'd look for low capacitance cables. It's not scary high for an output impedance but it is a bit on the highish side and so could be affected by the cable type. None of this has anything in particular to the TVC or type of pre-amp so if it was working for you with your previous pre-amp it should continue to work fine.

Thansk!

John