I've been thinking again.
I plan to use a 112A and Hammond 126C interstage to drive the A2 buffer that will drive 833a (GU-48).
Original plan was to use filament bias on the 112A, but I read somewhere (can't find it now ) that cathode bias (and filament bias ?) was not compatible with using an interstage transformer. Any ideas on that ?
When I did a 26 preamp years ago I did grid bias with a 9v battery (-9v) and used a Rod Coleman module for the filament.
Any opinions would be welcome.
112A bias options.
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#1 112A bias options.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#2 Re: 112A bias options.
My opinion is there is a lot of rubbish written on the internet. (he writes on the internet)Any opinions would be welcome.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#3 Re: 112A bias options.
Self referential - I like it - Shall we start a Hofstadter thread on Godel, Escher, Bach: an Eternal Golden Braid?
For external reference, since I suggested it to Philip, have a read of Thomas Mayer on Filament Bias https://vinylsavor.blogspot.com/search?q=filament+bias
For external reference, since I suggested it to Philip, have a read of Thomas Mayer on Filament Bias https://vinylsavor.blogspot.com/search?q=filament+bias
#4 Re: 112A bias options.
As a programmer from the late 70's I prefer recursive solutions where ever possible.JamesD wrote: ↑Fri Jun 12, 2020 1:31 pm Self referential - I like it - Shall we start a Hofstadter thread on Godel, Escher, Bach: an Eternal Golden Braid?
For external reference, since I suggested it to Philip, have a read of Thomas Mayer on Filament Bias https://vinylsavor.blogspot.com/search?q=filament+bias
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#5 Re: 112A bias options.
112a’s very rare in my lab, I’ve killed too many with direct coupling that went wrong. It was a momentous task to balance up a direct coupled capacitorless full amp from a capacitor less power supply.
But the rewards were worth it , just a shame I doubt I have a single working *1a *2a and I think my only pair of 71a.
But when it all worked out in the end it was worth it.
But it’s history, tomorrow is another day.
I know nothing of the things you asked about so I’ll let you google it instead of being you’re google parrot.
But the rewards were worth it , just a shame I doubt I have a single working *1a *2a and I think my only pair of 71a.
But when it all worked out in the end it was worth it.
But it’s history, tomorrow is another day.
I know nothing of the things you asked about so I’ll let you google it instead of being you’re google parrot.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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#6 Re: 112A bias options.
Thanks Paul.Paul Barker wrote: ↑Fri Jun 12, 2020 2:25 pm I know nothing of the things you asked about so I’ll let you google it instead of being you’re google parrot.
Using Google (other search engines are available, or are they ?) is all well and good, but as Nick suggests there is an awful lot of crud to sift through.
I asked the question on here because I respect the opinions of those most likely to respond.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#7 Re: 112A bias options.
I expect it’s all there, but harder to find these days.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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#8 Re: 112A bias options.
I start researching alone then ask other views when I find I’m stuck. Prefer to fix my own lack of knowledge alone!
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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#9 Re: 112A bias options.
Well yes, I was happy to go with filament bias until I read something that put doubt in my mind with regards using it in conjunction with an interstage.Paul Barker wrote: ↑Fri Jun 12, 2020 5:01 pm I start researching alone then ask other views when I find I’m stuck. Prefer to fix my own lack of knowledge alone!
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- Paul Barker
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#10 Re: 112A bias options.
Sounds like an experiment in waiting. Always better to hook it up for yourself and judge for yourself and you’re decisions more informed. If a picture paints a thousand words an ear speaks to you truth, many of the words you’re other point of reference will throw at you are worthless and deceptive.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein