Oliver PA150XR Masteramp

From what I gather It was made in the Early 70s. It's mentioned in this article: http://www.vguitar.com/brands/details.asp?ID=100
It's basically a 10 tube PA system that works great for guitar. 4 channels, each with gain, bass and treble knobs a reverb switch and two 1/4" inputs. That makes 8 inputs! A master gain and reverb depth knob as well. Standby, power and ground switches. Of course I replaced the 2 prong power cord with a 3, and removed the 'grounding' capacitor. It has a 4 spring foot switch-able reverb, and a preamp out. 2 8 ohm outputs, and 2 16 ohm. I don't know if they all work at once or not. This is the same as the PA100XR, except with a different preamp section, and I think extra channels or inputs. I don't know how many watts it is, but it gets quite loud. It doesn't blow my 120 watt 4x12, so I doubt it's 150 watts like the name might imply. Probably 50 or 100. But it more than keeps up with my bass players 400 watt amp. I never turn it all the way up. That would be crazy! The channel and main I usually have up about half each. 2x7027 power tubes (which are no longer made, but I hear these can easily be converted to accept 6L6s) 1x5AR4 rectifier, 1x6DR7, 5x6EU7, 1x6AN8A preamp tubes. Can't think of anything it can't do that I would want it to.

I'm using an Ibanez RG320DX with 2 split coil humbuckers and a 5 way switch. Also have used it with a drum machine and keyboard. Use it for vocals too until I have a dedicated PA. Sounds incredible with them all! Playing it through a Marshall 120 Watt slant top 4x12. Very clean and sparkling high end, very detailed mids, and great lows too after some cap replacements. I play a few different styles, Punk, Jazz, Noise, and I think it's good for them all. It's basically a PA amp, so it's made to accurately reproduce sound. So it sounds like what you feed it. And creamy smooth! It's doesn't really distort, but with a good tube distortion pedal it screams and punches. Very articulate. Low hum. The reverb is really great with vocals, but if you want to use it only on one channel, it will probably bleed into the other. I guess that's to be expected though when it's all going out one channel in the end anyway. But all in all it's really breathtaking.

It's lasted for about 30 years, so I'd say it's pretty reliable. When I first got it I turned it on without plugging it into a cab(big mistake). Blew the rectifier, and a filter cap. Replaced them, and got a 4x12, and sounded great. It popped some though after taking out of standby, and with high input transients. Replaced the other filter cap, and that was almost all gone. Worked/sounded great. Replaced some other caps and kablooie! It was ok in standby, then when I took it out, burning blue 350V sprague, and sparkling rectifier tube. Replaced the 5AR4 and put back the original 350V cap pair. Started up great this time. I don't know what I did wrong! Sounded better than ever! Tried turning it on again a week later, and bam! Blown fuse, and sparking sounds from the problem caps. Can't figure it out. All my fault. I must have done something wrong. But I'll have the schematics soon!

Jess Oliver still has a repair shop in Long Island NY. I called him up for schematics, and he gave me some advice, and is mailing them over now.

Been playing over 7 years. Got a Dunlop Crybaby 535Q wah, an EH Memoryman Deluxe analog delay and a Dean Markley Overlord tube distortion. I love it! 8 inputs in a guitar amp! Very great deal. Super value. Got it cheap on E-Bay, I guess since no one ever heard of it! It was designed by one of Ampegs early designers though, so I went for it.