60's Solid State Bassman

[b/o 402]

Relevant 1969 catalog pages

 

[TomB]

Love the photos & text. The gear? ...that’s been discussed.

 

[Steve Dallman]

In my long career of gear spotting, I’ve only ever seen one of those on stage. The Beatles had one set up for their rooftop show, which you can sometimes glimpse in the footage. It is seen in side view at about 1:03, to the left of Billy Preston. I find it hard to believe it’s in the signal path for the mics, but who knows? Probably just for live PA/monitors (you can see they had the matching columns in other photos from that time period.)

It could be a PA head...either used as a PA or keyboard mixer/amp.

I said mine hissed...I did have the matching 4x10 Fender PA columns. I had added two tweeters to each cabinet so maybe the hiss wouldn’t have been an issue if they were stock. I replaced the head with a 5 channel Peavey 130 watt head. That didn’t hiss.

I also had a Fender oil can delay I used with it. Not a long delay but useful on vocals and quite bubbly sounding.

 

[byacey]

Transistor amps in the 60s were still in the infancy era. Designers still were working on trying to design transistor power amps using tube design mentality with interstage and output transforers.

Also, silicon power transistors were just being developed with a lot of designs still based around germanium transistors, with their inherent leakage and low power ratings. At that time, a 50 w transistor amp was considered high power. Temperature tracking bias circuits were still just over the horizon, and thermal runaway was an ongoing problem for amp designers.

 

[b/o 402]

It could be a PA head...either used as a PA or keyboard mixer/amp.

You are correct, it’s the PA head. I should have made that clear in my first post.

 

[TomB]

Transistor amps in the 60s were still in the infancy era. Designers still were working on trying to design transistor power amps using tube design mentality with interstage and output transforers.

Also, silicon power transistors were just being developed with a lot of designs still based around germanium transistors, with their inherent leakage and low power ratings. At that time, a 50 w transistor amp was considered high power. Temperature tracking bias circuits were still just over the horizon, and thermal runaway was an ongoing problem for amp designers.

Indeed. My next SS amp after the Fender SP3100 was a Standell (1970), a solid state head & 115 with a 115 extension cabinet, rated at 125 watts, I think. It blew the Fender away in every respect and was a very gig-worthy combo. Fender was just one small step ahead of their time with that product line.