Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Leevi on February 09, 2011, 01:54:17 pm
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I should build a small SE bass amp for home/studio use.
Any ideas for schematic?
/Leevi
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I would just take a good sounding bass preamp and but a power tube after it.
A while ago there was a similar discussion:
http://www.el34world.com/Forum/index.php?topic=9760.0 (http://www.el34world.com/Forum/index.php?topic=9760.0)
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The funny thing is the older alembic F2B preamp is nothing more then a Fender 2 stage typical guitar amp.
There's plenty of lows in that design you just have to know how to get them.
Make a BFChamp amp with a bigger OT and a 6L6GC power tube w SS rec. Tweak it a bit, maybe adjustable NFB and variable cathode bypass cap/resistors. Then run it through a good quality 10"-12" bass speaker, not one of those low SPL speakers that handle 1000 watts, just a descent one, even the Eminence BP102 might be good. As long as the SPL is high and the XmaX is long. Then take one of those car sub woofer boxes which are simple/cheap and have a shelve for the lows. That would probably make a GREAT amp to use and louder then you think because of the efficiency of the lows from the speaker and cab. Modern 2x10 cabs are not efficient and are a power soak. You'd be better off with an old SUNN 115 cab and a D140 JBL.
Maybe use a beefier PT like the Allen Champ/Princeton one and use a KT88 or 6550 w/ss rectifier.
There's a lot of low wattage guitar amp designs out there that can be modified to become some very interesting low power bass amps. You can add a direct out for recording or a PA and use it live as a monitor too. The thing about them is their TONE, great tone, a mini B15 for instance using a 6SL7 preamp tube and a 7591A power tube. The tone will be superior to anything you have with wattages in the hundreds, even tube amps. Simple tube circuits tweaked properly will deliver great tone and great tone happens at lower wattages. Once you get up there it's raw power over tone, that's the way humans hear.
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+1 BP102, GO look over on Bill Fitzmaurice's site do a "DR" style box if you have the woodworking chops, and an Omni/Jack box if you dont.
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Make a BFChamp amp with a bigger OT and a 6L6GC power tube w SS rec.
This sounds an interesting idea. Maybe 6550 could be an alternative power tube?
In order to keep the sound as clean as possible big filter caps could be used together with SS rectifier.
A good thing in this is that there is 2-knob tone stack.
/Leevi
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I would absolutely love to build a small SE for playing with Bass.
I do not think however i could survive without parametric eq - i play a few different basses and like to dial them in using mid scoop more than often.
In theory the 6550 should be good but i have always preferred my bass coming out of el34's (then again i have played no bass through SE amps so maybe that could change :) )
solid state rectification would be good too.
If anyone does come up with something for a SE Bass amp keep us posted!