Talk:Earth Sound Research

I recently bought an Earth Sound Research amplifier and I have tried finding information on them, though it is very hard. I've found this page, http://earth.ampage.org/ which is devoted to this brand, and on different guitar and bassrelated sites I've found topics regarding the brand. But that is it. The information on this brand is very limited and often something someone heard from somewhere, nothing definitive, though I think it is important with this article, so people at least know that it is a real brand and not just some copycat firm (even though they apparently did copy the design of known brands.)194.239.215.55 (talk) 12:23, 24 January 2008 (UTC)

I worked at Qualtrol, which made some of the ESR guitar amps and mike mixer consoles.

ESR literally stole its designs from Peavey. They copied the printed circuit boards and circuitry but used output transistors from Sensitron and later Solitron instead of a major semiconductor manufacturer.

So try to look at the amplifier tubes, etc., and see if you can find the equivalent Peavey unit.

No, I don't have any of the schematics. ~2026-17884-76 (talk) 22:18, 22 March 2026 (UTC)

don't we think? —Preceding unsigned comment added by 93.97.101.136 (talk) 14:48, 2 June 2009 (UTC)

I put this in the article twice but they keep removing it.

My name is Joseph Reinckens. I worked as an electronic tech at Qualtrol, testing and repairing guitar amps and mixing consoles coming off the assembly line. For awhile I also did the sound test of units ready to ship to Earth Sound Research.

I can confirm that Qualtrol and ESR literally stole Peavey's designs. When Peavey would come out with a new unit Qualtrol would buy one, strip it down, and create a new ESR cabinet for advertising photos. The advertising units had ESR cabinets with electronics removed from the Peavey unit. Qualtrol would then duplicate Peavey's printed circuit board and circuitry.

The main reason ESR failed was that to save on production costs Qualtrol used low-quality output transistors from a local Long Island semiconductor manufacturer. Those could short out, burning out $200 of speakers ... in 1970's dollars. So ESR got a bad reputation. At one point Qualtrol told ESR to add a fuseholder in the speaker output line but ESR refused because it would cost 38 cents more! ~2026-17884-76 (talk) 22:14, 22 March 2026 (UTC)