Musicman 100b

Nino · #1 06-01-2010, 08:48 AM

Hi i've been looking for a tube bass amp head for a while. I was originally interested in the fender bassman, but it was too expensive. Now I am looking at a musicman 100b because it seems more affordable. However, I can't find very much information on this amp such as how it sounds, how much its worth, its ohms rating, etc.

The current one I am looking at is being sold at $380, but may be able to be talked down to lower. It is in decent cosmetic condition. It is said to work functionally. However, the power chord is melted in several spots. How much would it cost to replace the wire or get this amp checked out?

Because I live far away from the seller, I was wondering if any of you have any soundclips or helpful information on this amp.

Thanks

Rickett Customs · #2 06-01-2010, 08:58 AM

IIRC, it's a SS pre, with a tube power section.

JTE · #3 06-01-2010, 09:05 AM

The melting on the power cord isn't really a big deal if you know how to solder and know how to work on high-voltage tube amps safely. The cord's melted because it was put into the amp before the tubes cooled down. Hard to tell from the photos, but while it doesn't look like any of the inner conductors are exposed, it's not really safe that way. But if you're handy, and have some experience it's an easy fix. If you're not experienced, let someone who knows fix that.

As for the amp itself, they didn't make many. It was one of the last things Music Man developed before going under in bankruptcy, and it was the attempt to modernize. The previous series (the 65 and HD-130) were two-channel amps cosmetically similar to Fender's bass amps- Volume, treble, middle, bass, a deep switch on one channel and a bright switch on the other one, and a master volume. However, the 65 and HD-130 were solid state pre-amps, and used big beefy output transformers with 6CA7/EL34 tubes (instead of Fender's 6L6 power amp and all-tube pre-amp).

I've never seen a 100b in the real world other than at one NAMM show back in the days when I had hair... Can't comment on their sound. According to the schematic for it, it's got two 6L6 power tubes and the rest is SS. It looks to have a bass and treble control, and five bands of active EQ. I can't tell much more from what I see, and frankly don't recall the details from the catalog at the time.

John

Here's a website devoted to original MM amps... http://www.pacair.com/mmamps/

danomite64 · #4 06-01-2010, 09:12 AM

I had one a few years back; I sold it because I had just got a Mesa/Boogie 400, but I wish I had kept it.

brett7276 · #5 06-01-2010, 09:24 AM

I had one- it became a money sewer...as I understand from my tech some of the preamp components (ie solid state transistors?) tend to go out= as they did on mine- and it became nearly impossilbe to fix. I amp tech who is VERY good advised me to dump mine- I had a bassman 50 at the time which was;'t good for much but practicing- got the mesa 400 to replace it= and have been pretty much in sonic narvana since. I like old musicman amps- but I think you'd be better off based on exp with the 100B to find a bassman.

Nino · #6 06-01-2010, 12:52 PM

So the pre-amp that controls the tone is Solid State? What effect does the tubes have on the output? And would this amp be considered a "hybrid" then?

Thanks for the help so far!
If anyone else has any more information on this amp, experiences with it or suggestions feel free to post em.

brett7276 · #7 06-01-2010, 03:07 PM

yes this amp is a hybrid- oppoiste of how hybrids are done now
most on the market today are tube preamps w/ solid state power amp

this is exaclty the opposite solid state pre - and tube power.

JTE · #8 06-01-2010, 04:07 PM

When the Music Man amps were designed in the early to mid '70s, SS power amps were still heavy and expensive. So, Leo designed them with a SS pre-amp going for low noise and reliability, but a tube power amp because it was proven technology. Now 30 years later doing the reverse is more common because SS power amp design has come so far.

The original Music Man amps (the 65 and HD-130) with the 6CA7/EL34 power amps are generally very reliable and stable. The 100b may have had some issues, as Leo had already checked out (may have still officially been at MM, but his mind wasn't there any more) and they probably did spec ICs or transistors that now are difficult to source.

John

danomite64 · #9 06-01-2010, 04:12 PM

Quote:

Originally Posted by JTE

The original Music Man amps (the 65 and HD-130) with the 6CA7/EL34 power amps are generally very reliable and stable. The 100b may have had some issues, as Leo had already checked out (may have still officially been at MM, but his mind wasn't there any more) and they probably did spec ICs or transistors that now are difficult to source.

John

Leo was long gone by the time MM made the 100B, but even if he was still working for MM then, it's irrelevant as he wasn't involved with amplifier production.

RickenBoogie · #10 06-01-2010, 04:16 PM

Also, with only two 6L6 power tubes, you won't get much more than 50 watts from that head. Good price and all, but I'd hold out for something a little more modern, (and reliable).

johnk_10 · #11 06-01-2010, 04:22 PM

IMO, if you're going for that type of amp, i'd look for a vintage Fender Bassman 100 instead. they're basically a point-to-point 100% tube amp and can be repaired, restored or serviced forever, with no problems finding original spec'd replacement parts. IMO, they sound better too.