Tea1 series 2

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bear
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Tea1 series 2

Post by bear » Tue Feb 27, 2018 1:41 am

Some questions about this phono stage. What is the lowest output MC cartridge that can be used on the 54 dB input? Is the SUT used on the high gain input a 12 dB gain Jensen JT-346-AXT with a 6.8Kohm resistor on the secondary? Can the 54 dB input be used with a 5mv output moving magnet cartridge without causing any overload?

ronenash
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Re: Tea1 series 2

Post by ronenash » Wed Feb 28, 2018 2:37 pm

A 5mv cartridge will not overload the phone stage but you will have way too much gain. 2.5mv will work fine.
ronenash
----
Power:CJ LP125m SE, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura

bear
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Re: TEA1 series 2

Post by bear » Wed Feb 28, 2018 8:57 pm

Thanks for your reply, ronenash. I don't see why there should be a problem since 5mv into the 54dB gain gives an output of 2.5 volts. There are many CD players or tuners which output this or even more voltage. Should be in range of any conrad-johnson linestage. But the owner's manual for the 55dB TEA2 says: "It is not recommended for use with higher output cartridges (>1mv), as they may overload the circuits resulting in excessive distortion". I do agree that this is way too much gain for a MM cartridge but I think it should work. Any owner's have tried this on either the TEA1 or TEA2?

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Re: Tea1 series 2

Post by ronenash » Thu Mar 01, 2018 11:06 pm

You are correct of course but do remember that cj preamps are zero feedback and thus have 20db or more gain on their own. Most preamps top at 10db.

I have the Premier 15 plugged into an ACT2 can can tell you that I cannot go much beyond a volume of 20 with a 5mv cartridge. Even with the volume at 1 it's loud enough to disturb other house members late at night.
ronenash
----
Power:CJ LP125m SE, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura

bear
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Re: Tea1 series 2

Post by bear » Fri Mar 02, 2018 10:27 am

ronenash, just to clarify your experience with a moving magnet into your 53 dB gain Premier 15: The line stage volume is kept very low but the sound works without any distortion or overload? I know there is no problem on my cj linestage when I use high output CD players or FM tuners at volumes of 20-30 as well.
Switching to moving coils, how low an output cartridge can you use with your Pr 15? And what number are you at on the volume control of your ACT2?

ronenash
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Re: Tea1 series 2

Post by ronenash » Sun Mar 04, 2018 1:12 am

Yes it works with no overload but you volume will be high.
As for moving coils you cannot go much below 1mv on the Premier 15 without losing dynamic range and raised noise levels. With my Benz Ruby H (0.7mv) i am using a 1:10 step up. With this setup i am getting some of the best vinyl playback i ever heard. Absolutely gorgeous.
ronenash
----
Power:CJ LP125m SE, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura

bear
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Re: Tea1 series 2

Post by bear » Sun Mar 04, 2018 6:34 pm

With your 10:1 step up you have added 20 dB to the Pr15's 53 dB giving a huge total of 73 dB. Your Pr15 is seeing 7 mv input. What volume number are you at on the ACT2?
Thanks so much for sharing your experience in saying that the Pr15 doesn't work well with low output MC cartridges. I think conrad-johnson would disagree with you, the owner's manual says to use cartridges of less than 1 mv but it does not state how low.

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Re: Tea1 series 2

Post by ronenash » Tue Mar 06, 2018 1:46 am

I know CJ would disagree but that's my experience. Normal listening levels are between 30 and 45.
ronenash
----
Power:CJ LP125m SE, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura

bear
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Re: Tea1 series 2

Post by bear » Sat Apr 07, 2018 8:06 pm

What step up transformer are you using that doesn't compromise the beautiful tone of the Premier 15?

ronenash
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Re: Tea1 series 2

Post by ronenash » Sat Apr 07, 2018 11:11 pm

I am using CineMag 1130 which I think are fantastic.
ronenash
----
Power:CJ LP125m SE, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura

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