Keep in mind bands became progressively louder over the years. Combos from the mid 60s would, for the most part, not perform well by today's standards.
The ACB 50 has a vintage look but uses a modern ported cab design. I don't believe it's a particularly Fendery sounding amp. Also, 50W is 50W. This is not an amp to push a loud band in a big arena.
1959 Tweed Bassman
Notice the open back design. This causes low frequencies to cancel and does not provide any loading to control driver excursion. Mediocre as a bass amp...highly coveted as a guitar amp.
AFAIK, many of the 60's era Fender Bassman models were coveted more as guitar amps than bass amps. My understanding is the Dual Showman (85W) was preferred for bass over the Bassman of the era. The Showman 215 cab was larger than the Bassman 215.
Towards the late 60s you start to get bass amps that are significantly differentiated from guitar amps. Also this is when bass amps with more than 100W started to become more common. Examples include Acoustic 360/361 and Ampeg SVT.
That 1959 410 Bassman amp was a crap bass amp specifically because of its open back design. Of course the Thiele-Small parameters hadn't been determined yet so it was mostly trial and error. That 410 Bassman was a big mistake as it blew speakers all over the place when you tried to play bass through it. Don't EVER try to play bass through an open back cab. Without any back pressure the speakers will exceed their extension limits and tear the speakers apart.
HOWEVER, it turned out to be a great amp for guitarist and they kept selling it as a guitar amp. In fact Fender is selling it again as part of their Blues Breaker series of amps. Back in the mid-60's when I had my Bassman 50-watt 212 amp, the Bassman was already popular with guitarist and as recently as 2010 I saw guitarist using Bassman tube amps.They had a great sound and 20% more power than the corresponding Fender Bandmaster amp that was designed for guitar.
You can get a decent sound out of heads designed for guitar. In fact back in 1997 I had a GK guitar amp that I got from my brother-in-law that had stopped working. A $50 repair fee later, it worked great. I ran it through a couple of JBL 112 PA cabs with that wide horn on top and the sound was great. The problem for speakers comes with the bass frequencies which can require the speakers to move - A LOT - to reproduce those low frequencies well without tearing the speaker apart. It also takes a LOT more power to get the same SPL out of bass speakers than it does out of a guitar amp that doesn't have to deal with those low frequencies. Typically takes about 8 times more power to get to the same level that a 100-watt guitar amp can do for a guitar. So guitars can sound great through a bass amp, but a bass played through a guitar amp at gig levels will tear it apart. Quite bedroom practice should be OK, but not at any level that you'd play along with a drummer at.
The Blackface 50-watt all-tube Bassman amp with 212 cabinet was more popular than the Dual Showman because it was less expensive than the Dual Showman and was still plenty loud enough to play just about anywhere. I was the envy of all the bass players in town when I bought mine in 1966. However, touring nightclub groups usually did choose the Dual Showman for its added power, larger speakers, and better reliability.
In 1966, I bought a brand new Fender Bassman amp for $449 (
equivalent to $4,328.30 in today's money). It was still the blackface head but had the bigger cabinet although it still had the 12" Jensen speakers in it. Folks had been turning the 65 and earlier Bassman cabs on end (speakers vertical) and putting the amp on top which gave them a weird "T" profile. So Fender made a bigger cab that the head would not hang over the edges and turned the logo so it was right side up when turned for that vertical alignment. It looked impressive and sounded great. However, the Jensen speakers it came with did not like playing loud in that cab. I blew 3 of those Jensen speakers out of it before I traded it in towards a Standel.
I was touring with a nightclub group throughout the Pacific, Western, and Mid-West US in the early 70's playing 5-nights a week, 50-weeks a year, for three years. I started with my Fender Bassman and everything went swimmingly well until the guitarist and keyboards guys bought Vox Super Beatle amps a few months after I joined them. Then I couldn't be heard. We were playing in Lincoln, Nebraska at a venue that had 900+ occupancy rating and everyone was telling me to turn up when there was nothing more that poor Bassman amp could do.
So the next day I went to the music store in town (Hospe's Music) looking for a Fender Dual Showman. They'd sold their last one two days ago and their store in Omaha, NE was also sold out of them. So I tried everything in the store and came out with a Standel MCIIb/SAM30b piggy-back amp. It was crazy loud and I could bury those 120-watt 412 Super Beatle amps easily. Had to keep it on #3 on the dial indoors or it would push people out the door.
The cab on that Standell was a powered bass reflex cab with 4 round ports placed vertically next to its two vertical CTS 15" speakers. I could actually turn it all the way up and hit my low E without distorting the speakers at all - and yes, I did that in the music store before I bought it. Scared everyone in their downstairs "Bass-ment"! You can buy a guitar amp to use for a bass in a pinch and although the EQ will be optimized for guitar frequencies, it will work OK for Bass, but you CAN'T run a bass at any level you would use in a group through guitar speakers without damaging them or tearing them apart. Just don't do it...
