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pete millet low mu preamp
pete millet low mu preamp
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Old 8th January 2012, 08:00 AM   #1
tubo is offline tubo  Philippines
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Default pete millet low mu preamp

hi,

has anyone built or heard this low mu preamp? does the circuit invert phase? i don't need to much gain in my amps that's why im interested in building this.any input please.thanks

Low-mu preamp
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Old 8th January 2012, 08:53 AM   #2
dsavitsk is offline dsavitsk  United States
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Quote:
Originally Posted by tubo View Post
hi, has anyone built or heard this low mu preamp?
Yes to both.

Quote:
Originally Posted by tubo View Post
does the circuit invert phase?
Yes

Quote:
Originally Posted by tubo View Post
i don't need to much gain in my amps that's why im interested in building this.any input please.
The 6AS7 can be a very noisy tube. Look around for the 12B4 threads -- you can build much the same design with that tube, but it is quieter and more linear.

http://www.diyaudio.com/forums/tubes...nded-grid.html

12B4 Line Stage Amp
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Old 8th January 2012, 08:54 AM   #3
TonyTecson is offline TonyTecson  Philippines
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pete millet low mu preamp
the 6AS7 has a mu of about 2, it is an inverting type line amp.....
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Old 8th January 2012, 08:55 AM   #4
TonyTecson is offline TonyTecson  Philippines
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pete millet low mu preamp
and the 12b4 can be microphonic...be warned....
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Old 8th January 2012, 09:54 AM   #5
radiostar is offline radiostar  Yugoslavia
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My friend made it with 6AS7, works fine for my ears ...


Good luck!
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Old 8th January 2012, 10:14 PM   #6
tubo is offline tubo  Philippines
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thanks guys,

i think ill just convert the 6v6line amp to cathode follower and see what happens.
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Old 9th January 2012, 05:53 AM   #7
Jeffrey Davison is offline Jeffrey Davison  United States
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Built one about a year and a half ago. Went with a single transfomer but dual power supplies, one for each channel. Went with a grid choke instead of a grid leak resistor. Geartz hybrid with the rectifiers. Need a touch of gain so went with a 421a. Just a little hum, but not intrusive enough to distract from the music. Just last week I went with DC on the 421a filament with a vccs rectifier/regulator. Also upgraded to Clarity Cap MR on the 10uf output caps, not that the Obligatos were bad, just want a bit more out of this piece. The pics were taken after I finished building it. Rectifier tubes are now a pair of EML 274B mesh plates and went with Shuguang Treasure series 6Ca7 as the old KT77's I had were a tad noisy as a CCS. Treasures were much quiter. VERY happy with the sonics.

JD
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Last edited by Jeffrey Davison; 9th January 2012 at 06:05 AM.
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Old 9th January 2012, 02:15 PM   #8
radiostar is offline radiostar  Yugoslavia
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Tidy job!

Congratulations!!!
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