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Increase headroom in bassman 50W

#41
elwuss said:
you are funny.

actually, I heard an insider info on the fridge - Ampeg is cutting the cost of production so they put 1 10" driver in it, the others are just plain, black paper.

hence the inefficiency!:atoz:
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Funny, but, the last time Bill Fitzmaurice was asked about the fridge, he claimed that, if you cut it in half ( longways ), it would be actually more efficient and just as loud. I never could tell if he was being sarcastic or not. :D
 
#42
jnewmark said:
Funny, but, the last time Bill Fitzmaurice was asked about the fridge, he claimed that, if you cut it in half ( longways ), it would be actually more efficient and just as loud. I never could tell if he was being sarcastic or not. :D
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It is what it is, which is a 40-odd year old design. It still works just fine for many. No, it's not terribly efficient but it's not bad, really. Gets pretty darned loud with 300 watts behind it. It of course does this by being tuned rather high, so it doesn't do super low bass. But if it works it works. I can tell you from first-hand experience that it gets loud enough for band work with a fifty watt tube head, provided the band isn't really loud.
 
#44
PetrusLarsson said:
Just bought a silverface bassman 50W 1968 with the 2x12 cab. It must be one of the earliest silverfaces, possibly blackface circuit?
I'm very happy with the sound, it's just what i'm looking for. This is also my first tube amp and first "real" amp.

My only concern is the volume! Yes, I have realistic expectations on a 50W amp, and yes, I know that the old fender cabs are not considered great. With that said, can someone give me any tips for getting the most out of this setup volume-wise? I have no problems with a little grit/overdrive, but now it's farting out all over the E-string with volume at 3,5! Guessing that the speakers are responsible for this fart sound?

First step is to change the drivers to eminence beta 12. Thoughts on this? What can I expect?

I guess that a tune-up of the amp only makes marginal difference. The tubes are svetlanas, don't know about the capacitor condition. Maybe I shouldn't expect miracles from a capacitor change and bias adjustment?

What about jumping the channels together? I use the normal channel, it seems more focused. Any inputs on tone settings or channel jumping on a bassman? Or other ideas or tips?

Thanks!
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This was the exact same experience I had with my first amp - a '65 Bassman 50 with a 212 cab of the same vintage. I hated that amp because you could not turn it up past 3 without it farting out. You can change out anything you want in that amp and what you end up with will be a 50-watt amp that isn't loud enough for anything but playing in your bedroom.

Conclusion - the Bassman 50 is a pretty good guitar amp. Bass amp? No. Not at all. Recommendation - sell it to a guitarist and buy a bass amp.
 
#46
I don't imagine that all 50W amps are born equal.
e.g. comparing the NZ made Jansen Bassman 50s & 75s to a Fender Bassman:
'...JANSEN uses an extra tube in the driver stage ECC82 so that the output tube drive signal is much cleaner and has enough voltage to fully drive the output tubes...'
Invalid Link Removed

And my recently serviced 1970's Selmer 50 T'n'B and TL 1x15" w/3015HO stood up well in a gig with two guitarists, one with an AC30 just breaking up. No farting, but I doubt I could have turned up much more and stayed fairly clean.
I'm going to build a 2nd TL cab and fit a 3015HO so I can use my 50 & 75W amps for some gigs.

Anyway - back to the original poster's question.
It seems that a Fender Bassman 50 may well struggle.
More drivers could help. Fender made 2x15s with silverface grillecloth.
Efficient drivers can help - personally I like the Eminence 3015HO.

If you like the Bassman vibe, perhaps you can keep an eye out for a Bassman 100 or a later 135.
 
#47
Stumbo said:
Check TBr fdeck's HPF v.3 high pass filter. It will eliminate all the power sucking frequencies below 35hz, give you a cleaner, tighter low end (thus more loudness) and also protect your speakers. There's a big thread on it.

Also, sfx makes The Thumpinator and then there's the Fishman Platinum Pro DI.

Here's a thread with more discussion: http://www.talkbass.com/forum/f15/how-common-rumble-filters-543371/
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I'd be surprised if anything below 35Hz made it through the output transformer of a tube amp.
 
#49
webmonster said:
I don't imagine that all 50W amps are born equal.
e.g. comparing the NZ made Jansen Bassman 50s & 75s to a Fender Bassman:
'...JANSEN uses an extra tube in the driver stage ECC82 so that the output tube drive signal is much cleaner and has enough voltage to fully drive the output tubes...'
Invalid Link Removed

And my recently serviced 1970's Selmer 50 T'n'B and TL 1x15" w/3015HO stood up well in a gig with two guitarists, one with an AC30 just breaking up. No farting, but I doubt I could have turned up much more and stayed fairly clean.
I'm going to build a 2nd TL cab and fit a 3015HO so I can use my 50 & 75W amps for some gigs.

Anyway - back to the original poster's question.
It seems that a Fender Bassman 50 may well struggle.
More drivers could help. Fender made 2x15s with silverface grillecloth.
Efficient drivers can help - personally I like the Eminence 3015HO.

If you like the Bassman vibe, perhaps you can keep an eye out for a Bassman 100 or a later 135.
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You are on to something here. They may not all be created equal. The Sunn 200s would walk all over a Bassman or 85w Dual Showman of the era. It was called 60w. We shouldn't be able to hear that 10w difference. While the Showman & the Sunn 200s both had JBL D140s the Sunn cab was state of the art at the time while the Showman cab was....some speakers in a box. This lends credence to the quality of the cab design argument.
 
#50
No big mystery, guitar amps and a lot of bass amps to varying degrees don't have OT's that have full low end frequency response, many roll off in the 60-100 Hz range; there will certainly be a noticeable difference in clean output between a guitar amp and an amp the has an OT with more HiFi response specs, not to mention more robust supply filtering and PT VA to help with transients and limit sag, and of course a preamp actually voiced for bass guitar. Driving a pair of tubes cleanly to full output doesn't take any additional circuitry, just proper design.

All that said, if you think a 60 watt amp is loud for bass, your definition of volume is way different than mine. ;)
 
#51
JGR said:
No big mystery, guitar amps and a lot of bass amps to varying degrees don't have OT's that have full low end frequency response, many roll off in the 60-100 Hz range; there will certainly be a noticeable difference in clean output between a guitar amp and an amp the has an OT with more HiFi response specs, not to mention more robust supply filtering and PT VA to help with transients and limit sag, and of course a preamp actually voiced for bass guitar. Driving a pair of tubes cleanly to full output doesn't take any additional circuitry, just proper design.

All that said, if you think a 60 watt amp is loud for bass, your definition of volume is way different than mine. ;)
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Yes the Bassman was a guitar amp design. The Sunns were hifi designs so capable of much wider frequency output. The pre was bass specific. The transformers were quite a bit larger than the Fender Bassman.

Fender had the same opportunities as anyone else to get this right. They kept going anemic with some notable exceptions.

The low wattage Ampeg B-15 had more cajones then the Fender bass amp offerings of the day.

Yes loud may be in the ears of the behearer. ;)

When I gig with the 160w BBII its with singer songwriter duos. I need watts and efficient cabs to deliver full fidelity. 500-1000w is my regular gigging choice if a drummer is involved. Not to be loud per se but to deliver full clear tone at any volume level. I never want to return to those days where we were seen and not heard.
 
#52
Yup, and it brings up a good point that lower wattage tube amps may be more useable in a lot of instances than one would initially think if they take into account the aforementioned considerations. I'm putting together something in the 60-70 watt range, with a full-bandwidth power section, so we'll see how it fairs.
 
#55
Mr. Foxen said:
Well, many people define volume by db rather than w for starters.
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Gee, no kidding. Even with efficient speakers, 50W will only produce so much SPL. If it works for you, great. Just accept that your volume/headroom needs may be different than the majority of folks.
 
#57
Mr. Foxen said:
Well, many people define volume by db rather than w for starters.
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Please pass the Cranberry sauce. It may tone down some of the snark. :)

Seems like a our conversation is embracing your theory or experience that 50w is enough in your situations because of the use of efficient speakers. Right here a dedicated designer just said he's working on this to use 50w & 75w designs.

Ultimately using db one amp is louder than another.

It's just that if I say 50w works for me that's unarguable. If I say a 50w amp can operate at the top of the SPL spectrum even fully distorted that is arguable.
 
#60
Hmm..My first amp was a Bassman 50 with a 2x15 cab.I bought it new in 1974 and that thing cranked. I played with the high school jazz band and quite a few garages and it was plenty adequate.I wish I had it today as I play in a big band.Now I have a Mesa M Pulse with two cabs that weigh a ton.I would trade it for a mint Bassman in a heart beat.;)
 

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