I would like to build a replica of the original Olson-Morgan 6F6 triode amplifier described in the Nov.1950 Issue of Radio & TV News. ("A High Quality Sound System for the Home", p.59 ). Apart from the above-mentioned article in R&TV News and a Japanese redrawn schematic there are very few informations available on the web. (There's a short mention of the Olson amp in J.Hiraga's book, which I also have). I would be interested by any more informations or references regarding this amplifier, additional pictures of the original amplifier,historical facts,data's about the recommended RCA 214T1 output transformer,etc...
Please note that my intention is to build a replica as close as possible to the original for historical purposes, thus I am NOT interested about advices and comments telling me that it's an old-fashioned poorly designed circuit and how it can be "improved". (it should not sound too bad as shown,with the recommended RCA LC1A loudspeaker)
But if you have build one I would be interested hearing from you and seeing a few pictures of your amp.
Please note that my intention is to build a replica as close as possible to the original for historical purposes, thus I am NOT interested about advices and comments telling me that it's an old-fashioned poorly designed circuit and how it can be "improved". (it should not sound too bad as shown,with the recommended RCA LC1A loudspeaker)
But if you have build one I would be interested hearing from you and seeing a few pictures of your amp.
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HI , I built two monofonic Olson-Morgan with the original electric diagram in 1999
I found all information on a special Italian Magazine " CHF" Costruire HI FI
THE original project is si ce 1938 and not 1950.
A company in Milano built the transoformer and I found the original 6F6 Rca with iron bulb norm Mil in Rome . I also test the two amplifier with 6F6 with glass bulb , but I prefeer the first one.
If you need Somethings , write me.
Igino Pedemonte
Livorno Italy
I found all information on a special Italian Magazine " CHF" Costruire HI FI
THE original project is si ce 1938 and not 1950.
A company in Milano built the transoformer and I found the original 6F6 Rca with iron bulb norm Mil in Rome . I also test the two amplifier with 6F6 with glass bulb , but I prefeer the first one.
If you need Somethings , write me.
Igino Pedemonte
Livorno Italy
The original amplifier is very good indeed and if you make it identical to the original more likely it will measure better, in particular at the bottom and top ends of frequency range, because it's easy to find better transformers today without spending a fortune. So you will remain within the spirit of the original project which was to create a high performance, both musical and electrical, amplifier which was easy to build, relatively cheap and reliable. Possibly 6F6's have become more expensive today than they where by the end of the fifties...
But the major problem is where you will find something close enough to a LC1A though....unless you are very lucky to own a pair.
The Italian CHF replica was very much identical to the original except they had to make the OT's for the occasion purpose. The specified 5W is more a limit for low THD and IMD than the true limit of the amplifier. Clipping starts to occur somewhere well over 7W....
There were two articles: the first one is what you can already find in the originals by Olson and the second is about the replica with pictures, suggestions and relative measurements. There are also shown other replicas, one Japanese with the 42's. The issue number was CHF n. 22.
But the major problem is where you will find something close enough to a LC1A though....unless you are very lucky to own a pair.
The Italian CHF replica was very much identical to the original except they had to make the OT's for the occasion purpose. The specified 5W is more a limit for low THD and IMD than the true limit of the amplifier. Clipping starts to occur somewhere well over 7W....
There were two articles: the first one is what you can already find in the originals by Olson and the second is about the replica with pictures, suggestions and relative measurements. There are also shown other replicas, one Japanese with the 42's. The issue number was CHF n. 22.
6F6Gs are amazing, harmonic content is anyways, old RCAs Bp I have are just otherworldly sounding. push them hard with some voltages then they really just come alive.
have some way later Sylvania BP 6F6GTs those also sound pretty good.
awful low trans/lower power/dissipation and in general they don't sound that Linear to me vs say 6v6/EL84/6BQ5, but harmonics/dynamic content/transparency/resolution is still pretty good and they sound better than many of the run of the mill 6v6/EL84/6BQ5s imo, its kinda like somewhere in between a 6v6 and an EL84/6BQ5 imo, don't come off always sounding really compressed all the time like EL84s/6BQ5s...
have some way later Sylvania BP 6F6GTs those also sound pretty good.
awful low trans/lower power/dissipation and in general they don't sound that Linear to me vs say 6v6/EL84/6BQ5, but harmonics/dynamic content/transparency/resolution is still pretty good and they sound better than many of the run of the mill 6v6/EL84/6BQ5s imo, its kinda like somewhere in between a 6v6 and an EL84/6BQ5 imo, don't come off always sounding really compressed all the time like EL84s/6BQ5s...
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