From benjamin.kuris@hp.com Wed Nov 17 14:41:31 2004
Subject:Re: DIY tube preamp? + vacuum tube birthday


I have a speakeasy-- it sounds great. But I also built my own preamp
along the same lines but w/an EL84 output tube running into an 8 ohm
dummy load. It has a very different sound due to feedback (tightens
low end) and obviously a different power tube that you can really
saturate for lots of grind (even did some bass-reamping on a session
w/it).

Anyway there are 2 approaches:
1) start w/a very small monophonic hi-fi amp (pay no more then $50 on
ebay). You want 1 preamp tube, 1 powertube. You may need to add a
standby switch. Replace caps (will save space). Wire front end-- I
used a tweed fender deluxe 5E3 as a starting pt.
(www.schematicheaven.com) and added a gain switch to chose 1 or 2
stages of gain. (www.schematicheaven.com). . Add proper output jack
(I prefer to have an 8 ohm switchable load so you can use as a preamp
or power amp).

2) scratchbuild the whole thing or look into for a fender champ kit
(www.tubegarden.com has one) or start w/an alembic F2-B:
http://www.ofgb.org/reference/Music/Alembic/ and then tack on the
right output stage. Allied electronics, under the filament
transformer heading has the best low-cost preamp power transformers
but weber-vst is now making all sorts of transformers too.

Don't neglect output transformer size / freq. response if you want to
run bass through the amp. It is also pretty straightforward to add
a leslie 147 hookup.

Online groups to look at are www.ampage.com and www.ax84.com (the P1
is a good design to start w/too but most of the gain tweaking is for
guitarists not keys players).

--- In CloneWheel@yahoogroups.com, hudakjm@m... wrote:
> Hello group: