Thank you. That helps. I have a couple of questions.
What are the bias voltages for the standard and pro sockets?
I have never used he wayback machine. Very cool. Is there a way to surf the collection of files that used to be on Kevin's site?
Sorry I really don't know much about the design. It was just the result of googling. What do you mean by Kevin's site?
gilmore.chem.northwestern.edu was/is Kevin Gilmore's site. The http interface seems hung-up.
Kevin Gilmore was a very early website builder, was host for Chu Moy's HeadWize headphone site, and also a developer of electrostatic headphone amplifier, some quite bold. Worked at Northwestern University, Chemistry; but is no longer listed there. Old listing:
Kevin GILMORE | Northwestern University, IL | NU | Department of Chemistry
EDIT: active on another forum:
kevin gilmore - www.Head-Case.org
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To give you the history of this-
Kevin Gilmore along with "Spritzer" ( not real name) -from Iceland used to post on Head-Fi , Spritzer has a business there building electrostatic headphone amplifiers of Kevin,s design which I have to say are high quality --but pricey .
Head-Fi either changed policy or was taken over and all those running or connected to any business were "booted off " the website , this was done as I found out to promote Head-Fi,s own business adventures as I kept getting emails long after I left it to visit Head-Fi promoted exhibitions in London and access to the website was controlled by "third parties" wanting to make $$$$ out of posters info which would mean using a completely open browser not something I will do in this day and age.
Kevin Gilmore along with "Spritzer" ( not real name) -from Iceland used to post on Head-Fi , Spritzer has a business there building electrostatic headphone amplifiers of Kevin,s design which I have to say are high quality --but pricey .
Head-Fi either changed policy or was taken over and all those running or connected to any business were "booted off " the website , this was done as I found out to promote Head-Fi,s own business adventures as I kept getting emails long after I left it to visit Head-Fi promoted exhibitions in London and access to the website was controlled by "third parties" wanting to make $$$$ out of posters info which would mean using a completely open browser not something I will do in this day and age.
Pro bias is around 580 Volts for Stax headphones that use the Pro standard and around 250 Volts for the "Normal " bias.
Thanks Duncan. That helps. I am considering making an SIT balanced amplifier for driving a normal biased set of Stax headphones. I have enough devices to lash one up and give it a go.
Is there any public information on AC current draw of the headphones? I have a pair of Gamma and will have a pair of vintage Lambda.
I have owned Martin Logan CLS and Acoustat 2+2 as well as doing a pair of DIY ESLs many years ago. I like ESL sound.
I know N101N isn't keen on some of the electrostatic energizer circuits but there are plenty of designs on the web including ( if you look for them ) some Kevin Gilmore ones as well.
N101N if it makes you happy I have a Stax box with SB transformers running off the output of a normal amplifier using --yes Stax Lambas --as approved by various UK "golden ears " at the time including the "great " Alvin Gold and yes Hi-Fi choice headphone book has a write up on them.
I too like the "electrostatic sound " --yes I know --not to every-bodies taste I also have the Stax Omega --007 MK 1 which is better than the MK 2 --not so bright a sound so would suite those who like a more smoother but detailed sound probably tube users.
I will get back on your second paragraph Woofertester -never been asked that before.
N101N if it makes you happy I have a Stax box with SB transformers running off the output of a normal amplifier using --yes Stax Lambas --as approved by various UK "golden ears " at the time including the "great " Alvin Gold and yes Hi-Fi choice headphone book has a write up on them.
I too like the "electrostatic sound " --yes I know --not to every-bodies taste I also have the Stax Omega --007 MK 1 which is better than the MK 2 --not so bright a sound so would suite those who like a more smoother but detailed sound probably tube users.
I will get back on your second paragraph Woofertester -never been asked that before.
This will influence bias point for a class A direct drive SIT amplifier. My guess is that 100mA will suffice. At +/- 300V rails, that will be a toasty 120W of idle power.
Yes, that is the only sensible solid state solution. Again, it is sacrilege to use Gilmore`s concoction for Stax headphones.
You do realize that the schematic linked in post 2 is Gilmore's reverse engineering of the srm313, not his own design ? Or do you object to all his amplifiers ?
"Forward engineering " N101N I take it you mean innovative or not resting on traditional design but designs of the "future " ?
If so there are a lot of "Traditionalists " in Audio engineering and those on DIY Audio also but you could say D.Self helped evolve "forward engineering" in Audio and JLH in his day also came out with innovative designs not only in audio but in FM radio .
If so there are a lot of "Traditionalists " in Audio engineering and those on DIY Audio also but you could say D.Self helped evolve "forward engineering" in Audio and JLH in his day also came out with innovative designs not only in audio but in FM radio .