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Bass amp ponderings

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6/15/2004 9:48 AM

Bass amp ponderings

Hi all.

I am having a hard time convincing bass players in this city that great rock bass tone doesn't live in a mosfet 400W amp and a 4x10+1x15 stack. can anyone help me? i'm not a bass player so i'm not really sure what the legendary amps are.

i'm NOT building an SVT.

although the 12BH7 driving the power tubes is a cool idea.

the bass tone i'm sold on is the kind of earthy stuff John Paul Jones and John Entwhistle used to get. with a bit of breakup. I have a donor amp lined up, a 50W silver face Jansen Bassman that i've already gutted leaving me with PT (puts out 550VDC when SS rectified cap-input, 12V heater, -40V bias tap) and OT (5k, will handle 75W)... any ideas on a design starting point?

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Darren

6/15/2004 7:33 PM

I've read that JPJ used an Acoustic 370 amp through much of the Zep years. Whether he used it for recording in addition to live playing, I don't know. If he did however, then that was a transistor bass sound. I'm not sure what Entwhistle used. I'm a major fan of tube bass amps and their tone, but there is something to be said for the sound of transistor amps too. You may consider some of the Sunn or Ampeg portaflex circuits. The Sunn was UL, so it almost needs different transformers than what you have, but you could probably get close by copying the circuit. I'm rebuilding and modifying a Sunn 200S right now. The Portaflex amps are probably closer to what you have now and also sound very good. Keep in mind that the cabinet choice and speaker choice make a huge difference for bass.

Greg

6/15/2004 9:59 PM

hrm...

furthur research has convinced me to either build a plexi and scale the caps for bass, or a vox ac-50 and do likewise.

i wonder! i think the ac-50 will be more up my alley. time to cruise to the local music store and plug in a bass pod

thanks heaps for your input! man what is it with ampeg, they seem to want to use a zillion gain stages in their amps. the portaflexs have ~eight preamp stages!!!!! i was thinking more like two or three hehehe

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Darren

6/16/2004 3:31 AM
Justin Thomas	Entwhistle had HiWatts at Live At Leeds-one of MY all time favorite bass sounds. Tons of pictures of the stage around. And whatever Geddy Lee used up through Moving Pictures is another favourite...V4B, right? Then there's the venerable B-15...Justin

6/16/2004 6:09 AM
Darren	true man, live at leeds has great everything tone! i have no idea what a B-15 is, i'm in the dark ages as far as bass amps go but yeah that particular portaflex seems a bit more clone-able than the others... anyone know what kind of B+ the B-15-N has?

6/16/2004 6:51 AM
Darren	heh, furthur investigation finds the answer is 430V B+. ha! my favourite ever bass amp was a Matchless one - which now that i look into the B-15, was a copy of the B-15, fliptop lid and all! definately building that one.

6/16/2004 6:51 PM

B 15 is the same things as the Portaflex, and you're right, there were many different models of them. A lot of people seem to like the B 15 N, so I think thats a good choice. I've used one for recording in the past and was very happy with it's sound.

From what I've seen about Geddy Lee's sound up to Moving Pictures, he used a Rickenbacker bass, with the stereo jack, the neck pickup going to an Ampeg SVT or V4B and the bridge pickup going to a Sunn 2000S. The SVT was setup for clean, deep bass, and the Sunn was setup for a bit of gain. I've never played a Hiwatt for bass, but I do know others have and that they sound good.
Greg

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