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In Reply to: RE: Cathode Follower Line Stage posted by Triode_Kingdom on May 15, 2017 at 19:10:47
Of course now I scrapped them for a pair of KT77s to drive the 572Bs but I'm not sure how a single triode connected 6W6 is going to have too much gain as a linestage?
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Follow Ups:
'SN7s would allow me to reduce the idle current to 10-15mA, and they won't require as much negative bias. The 6W6 has a much lower Rp, but the 'SN7 will still present an output Z of a few hundred ohms in CF service. That's low enough for anything I'll need to drive.A control amp of this type should exhibit approximately -0.5dB voltage gain. It will provide a large current gain by virtue of the impedance transformation. It should also (hopefully) be entirely transparent.
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Buy Chinese. Bury freedom.
Edits: 05/17/17
Jack
Do you want this for a line stage in a preamp or s gain stage in an amp?
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
I'll probably include switchable tone controls, switched AC outlets, etc.
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Buy Chinese. Bury freedom.
It has everything you are looking for along with tone switching and controlled AC outlets.It is an Anode follower however,it has a phenomenal four tube phono stage and you could convert the output to an cathode follower.
The factory spec alone is incredible and when you upgrade it with Jim's kits,the S/N and bandwidth improves even more.The circuit looks scary at first glance but you later realize it isn't all being used at one time.It is one of the most correct sounding preamps you will ever hear. There is also the Cit 4 which is simpler,but you would have to put in tone switching.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Edits: 05/19/17 05/19/17
Those old beasts are a bit on the rare side. It is also relatively easy to outperform them...even with something simple.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
They need upgrading and some circuit revisions.I have seven on them actually.One is a carcass tho.I said it wasn't an anode follower.It is an anode follower.I can't believe I mistyped that. Anyway,if you are looking for accuracy,these are one of the best tube preamps for that.One would be cool to open up and mod in no holds barred way.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Edits: 05/19/17
~!
The Mind has No Firewall~ U.S. Army War College.
Yes it is.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
One problem with all old preamps of that era is that moving parts like switches and pots are usually heavily worn. My time is better spent designing from scratch (using newer, better parts and technology) than chasing all over the planet looking for replacements. Building new also provides an opportunity to remedy all the issues that engineers of the day either didn't know about or were forced to accept due to the bean counters. I've learned some of the latter the hard way with ham gear. You'd be surprised what was allowed to come out of a transmitter or RF amplifier made in the '50s or '60s, simply because the design was vetted by a factory without access to a spectrum analyzer or 100 MHz scope.
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Buy Chinese. Bury freedom.
Bypass those switches and if you look at the circuit,it isn't all working at once..Now the Citation 4 has tone controls and you can put tone switches in it's place.They do have a bypass switch.If you clean and polish the wafer switches,you are usually good to go.What some people do is put the modern gold contact switches in place of the wafer switches and then use mini toggles in place of the slide switches.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
and they claimed the power transformer was four times the size of the original which is nonsense. For five grand,it got great reviews but they copied the original and put in better switches and a MC step-up trafo.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
nada aqui
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Buy Chinese. Bury freedom.
We need some dynamite.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
nada aqui
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Buy Chinese. Bury freedom.
A 5687 or a 6H6Pi is such an improvement over the 6SN7 for what you have in mind for it.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
As it turns out, none of these tubes will be convenient to use due to biasing requirements. A 6K6 in triode mode will likely require no negative bias supply at the bottom of the choke, and output Z will be only a few hundred ohms. That's the direction I'm headed for the moment. :)
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Buy Chinese. Bury freedom.
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