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Seletronic amps ( Profet being one of iterations , as I remember) predates F5
when Pa published F5 , some members mentioned Frenchy ones as predecessor , so Papa gave them kudos in later F5 related papers
but , as shown in linked patent (few posts above) , concept is known from 1985
and , as usually is , it was certainly known even before patenting
that just shows how's tricky to claim something new in electronics .... so let's enjoy in all of it , as they're damn good jazz standards
some having Devilish twist , some not
Hello Zen Mod. Thank you for your thoughts in the above post.
US 4,031,481 was granted in June 1977 to SONY. The schematic on its frontpage and Abstract suggested using only 4 FETs with triode-like properties to make an amp.
The power amp: Grand Mos by Selectronic appeared in reviews dated Nov. 2000; six years after the expiration of the SONY patent. This power amp was credited to Jean-Marc Plantefeve. The small PCB footprint of this 4 FET amp is neat and compact. No mention of a patent by Selectronic or a flashback to SONY's patent.
The appearance of the second power amp: ProFet by Selectronic was brought to the attention of Mr. Srajan Ebaen of 6 moons during his review of an amp by Mr. Pass.
Mr. Pass rightly acknowledged the contributions of Selectronic/Plantefeve in his articles on F5 [2011], and F7 [2016]; which he said in an earlier post.
It is highly profitable and thus smart to practice expired patents; as an example making generic drugs. Each of Pass, and Plantefeve made generic amps of SONY's patent. Is who dunnit first [Pass or Plantefeve] really important or proves something? No; because the only objective of each was/is to profit at a time of choosing to suit a business plan or a market demand.
US 4,031,481 was granted in June 1977 to SONY. The schematic on its frontpage and Abstract suggested using only 4 FETs with triode-like properties to make an amp.
The power amp: Grand Mos by Selectronic appeared in reviews dated Nov. 2000; six years after the expiration of the SONY patent. This power amp was credited to Jean-Marc Plantefeve. The small PCB footprint of this 4 FET amp is neat and compact. No mention of a patent by Selectronic or a flashback to SONY's patent.
The appearance of the second power amp: ProFet by Selectronic was brought to the attention of Mr. Srajan Ebaen of 6 moons during his review of an amp by Mr. Pass.
Mr. Pass rightly acknowledged the contributions of Selectronic/Plantefeve in his articles on F5 [2011], and F7 [2016]; which he said in an earlier post.
It is highly profitable and thus smart to practice expired patents; as an example making generic drugs. Each of Pass, and Plantefeve made generic amps of SONY's patent. Is who dunnit first [Pass or Plantefeve] really important or proves something? No; because the only objective of each was/is to profit at a time of choosing to suit a business plan or a market demand.
yup
I made typo with 1985 , it was 1975 for US patent , while Japan one is granted year earlier (May 23 1974)
as we all know - Pa made pretty major twist with his feedback scheme , moving it even further in F5 v.2 (name it like that for clarity) with third pot for tweaking of THD spectra
and yet , it goes even further with addition of positive feedback ......
as I said - there are renditions of Jazz standards ........ and there are renditions of Jazz standards
I'm able to make rendition of Pa's gadget and call it Babelfish ........ but it was rarely further simplification and bettering ...... I'm pretty happy to achieve same performance , with handful parts more and - in best case (or in best times) - while having just rough sketch of exact circuit
I made typo with 1985 , it was 1975 for US patent , while Japan one is granted year earlier (May 23 1974)
as we all know - Pa made pretty major twist with his feedback scheme , moving it even further in F5 v.2 (name it like that for clarity) with third pot for tweaking of THD spectra
and yet , it goes even further with addition of positive feedback ......
as I said - there are renditions of Jazz standards ........ and there are renditions of Jazz standards
I'm able to make rendition of Pa's gadget and call it Babelfish ........ but it was rarely further simplification and bettering ...... I'm pretty happy to achieve same performance , with handful parts more and - in best case (or in best times) - while having just rough sketch of exact circuit
Attachments
yup
I made typo with 1985 , it was 1975 for US patent , while Japan one is granted year earlier (May 23 1974)
as we all know - Pa made pretty major twist with his feedback scheme , moving it even further in F5 v.2 (name it like that for clarity) with third pot for tweaking of THD spectra
and yet , it goes even further with addition of positive feedback ......
as I said - there are renditions of Jazz standards ........ and there are renditions of Jazz standards
I'm able to make rendition of Pa's gadget and call it Babelfish ........ but it was rarely further simplification and bettering ...... I'm pretty happy to achieve same performance , with handful parts more and - in best case (or in best times) - while having just rough sketch of exact circuit
Thanks ZM for your thoughts. I fully agree with your analyses. I often do not recognize explicit tweaks and enhancements, which make different schematics read and be valued as the same. A blindspot from inexperience.
Just for the record, I don't post dis-info, I just occasionally refuse to provide
full schematics.
However I have been known to confuse cloners with obscure pc board layout.
Just for the record, I don't post dis-info, I just occasionally refuse to provide
full schematics.
However I have been known to confuse cloners with obscure pc board layout.
I know you don't Papa.
I was referring to one of the early circuits which was created by brother Lynn that got used in the review.
Probably worth reminding people about that so people don't get the wrong idea.
There is enough info here and elsewhere to make your own diy version.
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Thanks eLarson!
labjr: Yeah, it scared me and I've built a 750vdc tube amp! It's not really as bad as it looks. I had never laid out an amp from a schematic, and obviously, I'd never built an enclosure. It actually sounds very impressive, I just don't have an active pre or flea wattamp to drive it right now. It uses Daniels boards, great parts and has a seriously stiff power supply. If I'd purchased an aftermarket enclosure, it would have been a lot easier...Yes, it is a Fugly F4!
Cheers to DIY'ers!
labjr: Yeah, it scared me and I've built a 750vdc tube amp!
It's not really as bad as it looks. I had never laid out an amp from a schematic, and obviously, I'd never built an enclosure. It actually sounds very impressive, I just don't have an active pre or flea wattamp to drive it right now. It uses Daniels boards, great parts and has a seriously stiff power supply. If I'd purchased an aftermarket enclosure, it would have been a lot easier...Yes, it is a Fugly F4! Cheers to DIY'ers!
It can be done but I just built my own version of F7 from scratch.
There are so few parts to it, it makes sense just to build a new amp then you can also do a direct comparison with your F5.
Also remember Lateral mosfets have a pinout of GSD.
The F5 IRF mosfets have a pinout of GDS.
Something to remember when recycling an existing F5 pcb.
Fugly! is underestimation .........
however , what counts is that it sings , and you built it .....
True Dat, Mr Z Mod! You probably don't remember, but back when I built it, I messed up the Peter D's power supply boards, so I just point to point hardwired it. I bought those humongous (no hum!) Superthrough caps from PCx on close out. I wish I had a nice preamp. It really does sound excellent.
Ha!
I didn't take offense, I know it's ugly, but you guys taught me.
Clearly, you've never seen the top plate.
Attachments
Nah, not enough time or resources or desire (lol) to build a new amp. Ive built my F5 (2sk2013 2sj313 version) few years ago, havent even turned it on for a year. Dont have much time for electronics these days, thought to maybe play around with F5 at hand if you could point me in the right direction. Where should the positive feedback be routed, what happens with inherent F5 negative feedback, does it need to change, etc. Either way, someone will get around to it eventualy, there is no rush.