Zen Mod said:
can you give me few days , to give you exact schematic ?
I'm asking again - which gain and which output impedance you need ?
that's dreky SUSY , with all possible in/out combinations .......... but you already know that
A gain of 10 or 12 would be nice. I'll be using this unit to drive my F4s.
carpenter said:
I should be more specific: I'm using these to drive my F4s that are driving my high-frequency horns!!!I don't require much wattage to do that....
in that case you don't need more than 5x gain .......
for mini F4?
so - if ya agree - that's job for 6DJ8 , on your side of big splash ;
on my side that's job for ECC88 ; decent Ri, decent S , appropriate Mu
sand CCSink in tail, split choke as anode load ......... ups- wrong forum - Sand CCSource(s) on top of each anode .........
with closed FB loop enough decent output imp. - in any case much less than 1K
carpenter said:
well - it is discarded ....... full of unnecessary drek ......
send these worthless OPTs to me - ya know ...... proper disposal etc ......
carpenter said:
Well, it has a relatively high output impeadance. It is ussually easy enough to get down to a few hundred ohms with a tube follower output, without an XFMR. It only uses "RC" loading/coupling, ussually loosing some linearity. A choke loaded
idea might be better. Or maybe an SRPP. I'm planning on pairing an Aikido with an F4 type circuit sans the JFETs 
Oh Yea, it says modified for Hi-Fi use??? Just reminds me of a Guitar input designed to be "overdriven" to Jimi Hendrix land. Or is that this side of a short
flg said:
Well, it has a relatively high output impeadance. It is ussually easy enough to get down to a few hundred ohms with a tube follower output, without an XFMR. It only uses "RC" loading/coupling, ussually loosing some linearity. A choke loaded
Oh Yea, it says modified for Hi-Fi use??? Just reminds me of a Guitar input designed to be "overdriven" to Jimi Hendrix land. Or is that this side of a short
Originally, it was a guitar preamp. I'm sticking with Choky's ideas!
Zen Mod said:
in that case you don't need more than 5x gain .......
for mini F4?
so - if ya agree - that's job for 6DJ8 , on your side of big splash ;
on my side that's job for ECC88 ; decent Ri, decent S , appropriate Mu
sand CCSink in tail, split choke as anode load ......... ups- wrong forum - Sand CCSource(s) on top of each anode .........
with closed FB loop enough decent output imp. - in any case much less than 1K ...
...well - it is discarded ....... full of unnecessary drek ......
send these worthless OPTs to me - ya know ...... proper disposal etc ......
Fisher unit receives much praise on the Internet.... humm, maybe I should rebuild it as originally planned so many, many years ago. Unfortunately, Nelson's designs are so much fun that I never get around to tubes.
And then there's the Pumpkin.......
Perhaps now is the time for a tube pre, yes? I'll go with your ideas, Choky.
Radiotron Designer's Handbook 4th addition: Credit was given to a fellow named Choky for it's attainment. I wondered if this fellow is you...
carpenter said:
Originally, it was a guitar preamp. I'm sticking with Choky's ideas!
ECC83 - anywhere , except in phono stage - is complete wackoo
carpenter said:
..........
Radiotron Designer's Handbook 4th addition: Credit was given to a fellow named Choky for it's attainment. I wondered if this fellow is you...
keep wondering .................
I'll never tell ya entire trip of that rusty pdf ..........
Zen Mod said:
ECC83 - anywhere , except in phono stage - is complete wackoo
keep wondering .................
I'll never tell ya entire trip of that rusty pdf ..........
Ecc83; phono stage; check. The best part, they wanted 7 bucks to read the article. I kept my money in my pocket!
Someday, when we're sharing a glass of wine at the Burning Amp Festival, you can tell all about that manuscript...
Zen Mod said:
can you give me few days , to give you exact schematic ?
I'm asking again - which gain and which output impedance you need ?
that's dreky SUSY , with all possible in/out combinations .......... but you already know that
I would say that I want the tube equivalent of Boz. Around 15 db gain, unbalanced In/out, output impedance max 1 Kohm.
What about an ultra simple tube pre, with one ECC88 for both channels, then Jfet buffered to lower its output impedance...
However,since we are playing with dirty sand here, no tubes. Seems that a mini-ZV8-like Jfet/mosfet preamp is the most probable solution...
Zen Mod said:
Hey Choky, I found this on BRENT JESSEE RECORDING & SUPPLY, INC. website:
Quote:
" 6922:
This is one of two premium versions of the 6DJ8 tube. First of all, it is the same tube as the 6DJ8, and will work wherever a 6DJ8 is needed. It has premium features such as low noise, low microphonics, and usually a longer lifespan. Sylvania made a version that is JAN military spec without gold pins. Amperex made all of theirs with gold plated pins and most have the PQ shield logo, standing for Premium Quality. See note below about Amperex 6922 and Bugle Boy tubes. Some of the later gold pin Amperex have the orange world logo. I have seen both orange and white PQ logos. Some of the early versions also have a number etched into the glass, like the 7308 tubes. These were also made for other manufacturers, and will have that makers name labelled in white, but these are the same gold pin tubes. Amperex opened a factory in New York to make these for the US military (since the government contract specified only USA constructed products) and cranked these and 7308 tubes out. A "made in U.S.A." Amperex tube is not a fake! In fact, these tubes are really excellent. A few were made in Holland for non-military industrial use, but these are rare. Also rare are the "pinched waist" versions of this tube. This is actually a molding flaw which made the glass bottom slightly fatter around the outside than the rest of the tube, and the center of the tube actually dips inward and touches the metal elements inside. Clients report these are incredible sounding tubes, and the upward spiral of prices for the rare pinch waist types seem to bear this out.
RCA 6922 tubes were made by Siemens in Germany, and also have gold pins. These are great tubes, but are not as plentiful. Since the military and some large industries (Tektronix) bought the Amperex made tubes in huge batches, that is what is on the surplus market today."
What do you think? I can get this tube from Parts Express for $10.27 each in lots of 6. This is less than the $15.00 or so for the 6DJ8 from Newark.