Oliver Powerflex 500

I bought the amplifier new in the summer of 1969 in Washington, DC. The list price was $645, I paid $350 for it as it was on clearance.

The Oliver company was founded by Jess Oliver (formerly with Ampeg). The Amp head, a vacuum tube design, was rated at 60 watts RMS. I doubt it was a class A design. It had two channels, the second channel having tremolo and spring reverb. In addition to bass, middle and high tone controls, the second channel also had an ultra high tone control. The back of the unit had a hum filament balancing control. There was also an auxiliary speaker jack on the back. The front of the amp, where all the control knobs but the aforementioned rear mounted one were, had a black, edge-lit glass face with green labeling somewhat like a McIntosh Stereo Preamp. For protection, the amp would disappear into the speaker cabinet by means of an electric motor. A hand crank was supplied in the event the motor failed or blew its separate fuse. The speaker cabinet was a bass reflex design with two 12 inch Eminence speakers (Altec Lansing speakers were an option) mounted one above the other with 5 port holes at the top. Fifteen inch speakers were also an option. A dolly with large casters that screwed to the bottom of the speaker cabinet was also provided. The Powerflex 500 was a guitar amplifier, not a bass amp though it employed a bass reflex cabinet design. Oliver also made bass amplifiers but I don?t remember what they were called. I do remember that Oliver made two piece bass amps using stagger tuned speakers speaker cabinets.

The Eminence speakers were the weak point. I never knew the model of speaker but they were standard on many amplifiers such as Sunn. They had silver dust caps with a hole in the center and stamped metal baskets instead of the more expensive cast aluminum. Unlike JBLs, Altecs or EVs,their voice coils weren't vented to the rear. They seemed to be very inefficient as the amplifier didn't sound much louder than lower power Silver Tone Twin Twelve .

The name Powerflex referred to the electric motor powered amplifier (again the amplifier receded into the speaker cabinet at the flick of a toggle switch) and the reflex speaker cabinet design, Though it appeared to be a two piece unit, it really was a combo type as the amp was not intended to be removed from the speaker cabinet. It was an elegant design that impressed non musicians whenever I played in public.

The tone was clean, clear and bright. The amp was quiet. I sold the amp over seas in 1971 for $645. I always thought it would have been a good amp with better speakers and if I could find one I would probably buy it if not for old time sake, then just to hear it with a pair of good speakers. I never tried over driving it to see how it sounded when clipping. I don?t think the speakers would have survived that as there was no way to cause the amplifier to clip at low volume.

To put my comments in to perspective, two recent, well known amps that I like are the Fender Twin Reverb '65 Reissue and the Fender Blues Deluxe. When I bought the Powerflex 500 I was hopping it would sound like a 65 Twin Reverb with D120 JBLs. I never liked the silver face Twin Reverbs.

The amp never failed and appeared to be a reliable, stable design.

Jess Oliver, the president of the company personally answered my letter containing technical questions.

I've been playing for 30 years.

I own two Fender amps, One Silvterone Twin Twelve, one Carvin DC200, a 1966 4 pick-up Silver Tone guitar, 6 Taylor guitars, one Breedlove, and a Kirk Sand. I also have a Carvin mixer and DC1500 poweramp, Electo-Voice speakers and microphones and a Music Man reflex speaker cabinet in which I replaced the original Celestions with two JBL E120s. I use a G4 for recording.

This bass amp was made back in the 70s(?) and has more power and better tone than any other bass amp that I've ever played. With 300watts of TUBED playing power through two Jensen 15" speakers, I'm surprised I haven't broken anything. It's most attractive feature though, is how the green back-lit powerhead raises up from inside the top of the cabinet by a small AC motor. The amp was designed by 'so-and-so Oliver who also did Ampeg's units and some of Kustom's as well.

The sound put out by this bass amp is incredible, my cabinet is so old though, it rattles when I get after it. I'm not sure if this is a factory flaw or if it is just old age, but besides that, it's great.

So far, it's been pretty reliable. The only thing I've done is get the speakers re-papered, and that was only because the guy who owned it prior to me didn't take care of it. I am also in search of the AC motor because it was gone when I got the amp.
*if anybody knows where to find one please contact me

Overall, I like the amp and prefer it over all the other amps I have played, but I have heard better (but not for the money!!!). If any body out there has any other information on the unit, please contact me as soon as you can. My e-mails are riffG0D@aol.com or riff-man@juno.com