has any one made a bass amp out of this circuit?

[kmenard]

Just wondering

My brother has switched over to Bass and is looking for a cool but relatively simple amp to build.

[krx]

There was a thread about this within the past month. Check the archives for a pretty good discussion.

[kmenard]

dangit...I did a search first for bass amp and came up blank

[krx]

Here you go:

http://www.18watt.com/modules.php?name= ... ic&t=23198

[kmenard]

ahh...I was thinking the 36watt more than the 18...just because it would have more oomph.

[krx]

ahh...I was thinking the 36watt more than the 18...just because it would have more oomph.

Either way it's not going to be loud enough for anything but acoustic jams or low volume practice, so you might as well build the cheaper one. No reason you couldn't do a 36 if you wanted to though.

[zaphod_phil]

Just wondering My brother has switched over to Bass and is looking for a cool but relatively simple amp to build.

One of our members here, veets, has built at least one bass amp around the Lite IIb design, using 6L6GC power tubes with bigger transformers and higher voltages to suit. For that kind of a build you would use solid state rectifiers, plus big filter caps, and either cathode-biased with a 2200uF cathode cap or else fixed biased. To drive the 6L6s the PI would need a 15k tail resistor and 470 ohm cathode resistor, instead of the 18W's stock 47k/820R combination. Should be good for around 50 to 60W out.

[SpentMusic]

By the time you get done changing the circuit to suit the requirements of a bass guitar frequency, there would be very little left of the 18 watt circuit. Not the least is EL84's just don't have what it takes to make a bass amp. They overload to quickly and unless you are just building a practice amp and a reason to discover more about amp building/design easier to start from a different circuit.

Go for a HiWatt DR504 if you want a low power bass amp with a good sound. Still not loud for bass but you could do small gig's with it.

[darkbluemurder]

The bass player in one of my earlier bands got the best bass sound using a Fender Precision Bass through a Fender Silverface Twin Reverb through a Marshall 4x12" cab loaded with 4 JBL speakers. That cab was dang heavy for sure. We were playing Southern and Country Rock in small clubs and the amp was loud enough.

Later he switched to a modern bi-amped bass rig and volume and tone was all gone. Too sad.

I would imagine that a Fender Twin or Showman circuit would work well as a bass amp.

Cheers Stephan

[zaphod_phil]

Unfortunately, not quite what the original question was asking for....

By the time you get done changing the circuit to suit the requirements of a bass guitar frequency, there would be very little left of the 18 watt circuit. Not the least is EL84's just don't have what it takes to make a bass amp. They overload to quickly and unless you are just building a practice amp and a reason to discover more about amp building/design easier to start from a different circuit.

Actually Jeff, those who've tried it have found very few change are needed to the regular 18W Lite II design to make a fine bass amp, using 6L6 tubes, with about the same power output as an Ampeg B15N or Hiwatt DR504. It might not be powerful enough for a stage rig (depending on size of venue, drummer etc), unless you also take a line output into the PA desk.

[krx]

Well, I think for a guitar player who dabbles, it'd be okay, but I don't think most bass players would be happy with the sound.

I'd certainly think about increasing the size of the coupling caps to get the corner frequency lower. And fixed bias, negative feedback, and a proper speaker cab would be a must to get any kind of remotely modern sound. Maybe put in a James/Bax stack, too.

[zaphod_phil]

FYI I used to gig regularly as a bass player. AFAIK veets is also a bass player more than a guitarist. Just check out the Ampeg B15N. It's also cathode biased with 6L6s, and even uses a tube rectifier. People rave about the tone of that amp. Now some people (me included) think it's a little low-powered for serious gigging use, yet there are plenty of others who say it's perfectly fine for small clubs or studio work. So I think the same would apply for a Lite IIb with 6L6s.

[krx]

FYI I used to gig regularly as a bass player. AFAIK veets is also a bass player more than a guitarist. Just check out the Ampeg B15N. It's also cathode biased with 6L6s, and even uses a tube rectifier. People rave about the tone of that amp. Now some people (me included) think it's a little low-powered for serious gigging use, yet there are plenty of others who say it's perfectly fine for small clubs or studio work. So I think the same would apply for a Lite IIb with 6L6s.

Yeah, the B15 is cool but it isn't the tone most bass players want these days, certainly not in a rock context, at least. It also has a James stack and negative feedback. Anyways, I'm not saying an 18-derived bass amp is a terrible idea, but it will be of limited use to most players.