5693 as a phono preamp?

Original Burnedfingers · 17th August 2006, 11:32 AM

Just wondering if someone has had experience using a 5693/6SJ7 as a phono preamp. If so do you have any schematics to share?

Thanks

SY · 17th August 2006, 01:14 PM

Triode connected?

Original Burnedfingers · 17th August 2006, 11:43 PM

Well, it only has an amplification factor of 19 when it is triode connected. I cannot find the amplification factor in pentode. Maybe its not a good choice after all.

SY · 18th August 2006, 01:10 AM

Pentodes in general aren't good phono stage tubes because of partition noise, the excess noise inherent in pentodes because of the statistical nature of electron flow when given a choice between screen and plate. In this service, you'd do better with a triode. The 5691 could be a good choice if you can live with the input capacitance (a few hundred pF).

17th August 2006, 11:32 AM	#1
Original Burnedfingers diyAudio Member Join Date: Nov 2002	5693 as a phono preamp? Just wondering if someone has had experience using a 5693/6SJ7 as a phono preamp. If so do you have any schematics to share? Thanks

17th August 2006, 01:14 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Triode connected? __________________ If there's a sucker born every minute, where do the rest of them come from?

18th August 2006, 01:10 AM	#4
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Pentodes in general aren't good phono stage tubes because of partition noise, the excess noise inherent in pentodes because of the statistical nature of electron flow when given a choice between screen and plate. In this service, you'd do better with a triode. The 5691 could be a good choice if you can live with the input capacitance (a few hundred pF). __________________ If there's a sucker born every minute, where do the rest of them come from?

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17th August 2006, 11:43 PM	#3
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Well, it only has an amplification factor of 19 when it is triode connected. I cannot find the amplification factor in pentode. Maybe its not a good choice after all.

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