Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on November 20, 2011, 08:22:31 am

Title: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: kagliostro on November 20, 2011, 08:22:31 am

Which is your preferred ?

Thanks

Kagliostro

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: stratman_el84 on November 20, 2011, 09:11:46 am

What kind of power are we talking about?

Would a Sunn 200S type amp with a pair of KT88s work for you? Here's a Weber 6S100 kit schematic & layout.

https://taweber.powweb.com/store/kits_60a.htm#6s100

The circuit works well for bass as-is, but is even better if you tweak the tone stack cap values a bit. A lot of people have built that amp for both guitar and bass and rave about it. Ted Weber while still alive stated it was his personal favorite amp out of all his kits for it's sound.

If you want to walk on the wild side (meaning the amp takes some serious skills and tweaking after completion) you might want to take a look at the AB200 circuit/layout. This thing can stand toe-to-toe with an SVT. This monster uses a freaking *EL34*(!) as a driver! What that EL34 pushes is plenty scary enough...SIX KT88s! You can get a side-job crushing rocks when not gigging.

If you click the link below there's even a guitar head version, the ML200. That's gotta be a "doomer"'s fantasy-amp!

https://taweber.powweb.com/store/kits_weber.htm#ml200

Hope that helps!

Strat

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: kagliostro on November 20, 2011, 09:30:13 am

Thanks

I was thinking to something from, at least 50W, till 100W not more

Kagliostro

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: stratman_el84 on November 20, 2011, 09:54:48 am

Quote from: kagliostro on November 20, 2011, 09:30:13 am

Thanks

I was thinking to something from 50W till 100W not more

Kagliostro

Well, that 6S100 is a 100-watt circuit. IMHO it's probably a good idea to err on the side of having more power than needed rather than risking not having enough clean volume when it comes to bass. That circuit and layout is also very stable and forgiving, despite the power. Not much, if any, "chop-sticking" or tweaking needed if built in a similar-size chassis and the layout followed. It's been recommended often to people as a good choice for a first higher-powered amp build. If built in a chassis comparable in size to the kit chassis, there's tons of room in there to keep things well-separated and make the amp easy to build and quiet.

Strat

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: ernie_jr on November 20, 2011, 10:32:04 am

You may want to try a Sunn 200s with an Ampeg B25 preamp.  Ampegs tone controls give a bit more control than Sunns.
Ernie

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: kagliostro on November 21, 2011, 12:58:54 pm

Quote

You may want to try a Sunn 200s with an Ampeg B25 preamp.  Ampegs tone controls give a bit more control than Sunns

May be that is a good idea, but I don't want to mess with layout design

so my request is to find an amp that people like but which the layout is readily available

(like for Fender amps, but strangely no one told me a Fender model, up to now)

Thanks

Kagliostro

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: sluckey on November 21, 2011, 01:57:14 pm

In 1976 I built an AB763 Twin Reverb but replaced the normal channel with the Bassman AA864 bass preamp. Worked very well for guitar or Fender Jazz bass back in the day. Don't know if it would hold up for a modern 5 or 6 string bass though. Here's the schematic and layout, but it's pcb design and probably ain't what you're looking for...

http://home.comcast.net/~seluckey/amps/misc/76_Amp_Project.pdf (http://home.comcast.net/~seluckey/amps/misc/76_Amp_Project.pdf)

See the attached for Fender's original schematic/layout for the AA864 Bassman. (I don't know why this isn't in Doug's library.)

Title: Re: Looking for a Bass amp schem. with available layout - which is your preferred ?
Post by: kagliostro on November 21, 2011, 04:25:36 pm

Quote

Here's the schematic and layout

Many thanks for sharing your experience

Kagliostro