has any one made this Fender Blackface preamp?

Started by doug0147, April 22, 2009, 12:01:45 PM

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hawk900

 The one from red circuit is fine except non-tube it's fet.. To put in into front of a guitar amp is insane.  No wonder it's bland . You are shooting into a guatir amp which already contains  a tone stack(aka pre amp) another preamp. Plus even the best Fender amps from the tweeds and blackfaces in the late50's and 60's even the heads have a tone stack. Even the best Marshalls and above mentioned Fenders use class A/B amplification. . You are contradicting the hole purpose.
If anything and dont want to tap your amp to bypass the the tone stackeg(cut the traces to the amp sector and tap this baby in there).  If you wanna sound kick ass and super  clean and natural. You can add reverb and distortion later. Send this signal into an amp just amp               Look for a list of class A amps especially for home stereo's. Preferrably ones that have mono option. If not branch the two left and rights  together with an adapter two rca's for home stereo that bond too 1  1/4 inch mono guitar jack. If not swap out the rca jacks for for 1/4.inch mono jacks. Just make sure your amp doesn't match or is biggerer wattage then your speaker combo  The battery option sucks.so if you can wire a dual spliced 9v dc adapter(max3500ma) properly to the parallel battery ps you'll be totally impressed.
Seriously check house stereo amps(classAonly)  eg. THX stereo or what I do is use a McIntosh 2100 which I branch the left and rights(double ohms higher n watts) to feed my fx to 2 JBL e-120 8ohm wired in series. The Mc spits out 240watts mono but stereo branched spits out 280 watts into the two 300 watt jbl's.
You'd be shocked at the quality amplification of a Class A home stereo amp does. No 5.1 or surround just find a Class A stereo amp. Google a list if you can't afford a McIntosh.
Just remember the cleaner the sound from your guitar preamp and amp the better the the FX will sound.  The JBL series I use has the largest sensitivity range and longest voice coil ever. You can literally hear crystal clear sound even your pick plastic flicking. This is so clean it I literally shatter class.
Hawk.ps  check this:
http://www.wald-electronics.com/preampmods.html

Ben N

1) I never built an amp (Tiny Giant is on queue, though), so take anything I say with a grain of salt.

2) @hawk900, did you even look at the schematics that the OP posted? Seriously...

3) I see no reason why your idea shouldn't work. However, as RG Keen often points out when people with only stompbox experience take on amp projects, the real challenge is not so much the preamp (which is very much like a stompbox) or the power amp (which by itself is almost trivial), but the power supply (which is typically a good bit larger and more expensive than the power amp itself) and heat dissipation. Don't go further until you have thought those issues through.

4) If you want to have the option of generating more midrange and distortion in the preamp, put a switch between P3 and ground. Breaking that connection will give a hefty boost and largely cancel the effect of the tonestack.

5) To learn how the preamp design works and how to tweak it to taste, read up on mu-amps and SRPPs at amz and geofex. But that big lossy tonestack in between the stages is very likely to prevent any kind of serious crunch. For that, see #4, above.

6) I second the idea posted above of adding another muamp stage after the preamp. After all, in classic blackface amps, the first thing to distort as you crank it up is (AFAIK) typically the phase inverter. Actually, come to think of it, that amp you have there is stereo. Do you plan to use it in a push-pull configuration? If so, you will need a phase inverter, which you can implement with a single transistor (as found in any diff-amp design).

7) Look around for a discrete MOSFET based power amp as an alternative to the Aaroncake one. MOSFETs may overload more nicely than the TDA1554, and give you some gain options that the clean doncha-dare-exceed-the-headroom power amp do not, more like a real tube amp.

Edit: BTW, have you looked at this? http://www.diystompboxes.com/smfforum/index.php?topic=96465.0
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