The Barney Oliver from Hewlett Packard

[Wavebourn]

Process is 13.6V max.

What does it mean: breakdown voltages?

 

[scott wurcer]

What does it mean: breakdown voltages?

Yes.

 

[Wavebourn]

Yes.

In such case I am going to try them on higher voltages, some may survive.

 

[john curl]

You be crazy, Wavebourn!

 

[Wavebourn]

I know, John Curl!

Crazy end results mean crazy ways to obtain them.

 

[john curl]

Try if you want, but I suspect their QC is better than what we were used to in the past, and the limit will still be reached. But I agree with you, that I cannot prove this.

 

[BrianL]

First 'super op-amp' as power amp? The first I encountered was the HK Citation 12, but it was largely cribbed from an RCA ap-note of the period, so obviously not new. I don't recall what the JBL amp with Locanthi's "T" output stage looked like on the front end. Don't remember the exact chronology of Dan Meyer and SWTPC, but I think it was a couple years later. Didn't the Marantz tube amps use a "long tail pair" for input and phase splitter. That would almost qualify, though not DC coupled due to the output transformer.

 

[pooge]

I don't recall what the JBL amp with Locanthi's "T" output stage looked like on the front end.

http://users.ece.gatech.edu/mleach/papers/tcir/tcir.pdf

 

[john curl]

The input circuit was pretty good, being differential. Still, it had a single ended driver that ruined the symmetry.
Dan Meyer's complementary differential input stage came out years later, maybe 5 years.
Earlier Meyer amps were more conventional.

 

[jackinnj]

Well Allen, that is what it was. G job. I was doing comp diff. bipolar at Ampex in 1968-1969 with essentially the same parts.

...and all i was doing was having fun, listening to Janis Joplin, and regretting not making it to Woodstock.

 

[john curl]

I worked with Janis Joplin one night, she looked pretty bad, back stage, but on stage, she was DYNAMITE! This was in 1970.

 

[Zero Cool]

We just dug out a Barney Oliver from the back room at work! I managed to get it half running. there was a shorted cap in the power supply and i need one MJ4502 to get it back to 100% unfortunately the wood sides and metal top seem to be MIA. but wow what a cool amp!

 

[wayne]

I just acquired two of these and a manual. A little work and they should be up and running. Typical HP build quality of 1972.

 

[wayne]

Another view.

 

[Zero Cool]

Awesome Wayne! I would love to have one of these for my shop amp. But alas they are a rare find and even if you do find one, rarely affordable!

 

[wayne]

I was very lucky in getting this pair of amps. I met the owner stepping out of my plane and he gave me someflying tips. It turns out he was the father of the HP calculator line and we started talking about electronics and he said he wanted me to have them. Just a super guy with a ton of great stories.

 

[Zero Cool]

Have you read the story of these online? how they came to be?

 

[Zero Cool]

Here is the story


http://www.hpmemory.org/news/barney_ampl/barney_page_00.htm
http://www.hpmemory.org/news/barney_ampl/barney_page_00.htm

 

[jackinnj]

The front-cover is reminiscent of the Audio Research SP1 preamp -- introduced in 1970.

 

[jan.didden]

I think the volume controls are worth a ton by themselves.

jan