Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rzenc on December 03, 2012, 10:35:36 am
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Bass player asked if it is possible to build B15S preamp only. His idea is to use it to drive mixing consoles and also a SS poweramp + Ampeg 810 :help:
Schems for REV C and REV D:
http://www.el34world.com/charts/Schematics/files/ampeg/Ampeg_B15S_RevC.pdf (http://www.el34world.com/charts/Schematics/files/ampeg/Ampeg_B15S_RevC.pdf)
http://www.el34world.com/charts/Schematics/files/ampeg/Ampeg_B15S_RevD.pdf (http://www.el34world.com/charts/Schematics/files/ampeg/Ampeg_B15S_RevD.pdf)
This guy already owns Alembic F-1X.
Have you tried such a thing?
What would be your considerations regarding such project?
My idea so far is to use complete schem from input jack to P.I. output and insert a A.C.C.F. to provide lo Z outs.
Many thanks in advance for insights!
Best Regards
R.
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Isn't this what the EXT AMP jack is for?
Hmmmm.... if driving a different power amp you may want another gain stage.
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Thanks PRR!
I thought about ext jack as a mean to provide him an output jack for his rackmount korg tuner. So that it may be hooked fulltime without adding load to bass signal.
If I need to implement another gain stage to drive power amp, then Could I keep P.I. as is and adopt your suggestion as low Z outs? I know a picture is worth thousands of words but my pc decided to crash and I can't use/access schema Until it is good again...
I plan to use xformer balanced out for mixing board and leave AC C.F. for stage amps.
Thanks for your attention!
Best Regards
R.
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I added a gain stage.
Stock, the design level at EXT AMP was like 0.4V. A standard PA rack-amp needs 1.4V-2V to get all the power you paid for. So I figured it had to be done.