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6AU6 replacement

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#21
pancaQe said:
Can anyone suggest a simple, quality 6V6 push pull amp design/schematic. At this point it looks like I'm gonna have to back track anyway. I'm looking at schematics using 6SN7. Any suggestions?
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why not a 6LU8 pp amp instead, at a dollar each, U$4 buys you a quad of output power tube, i made 2 amps based on this and i can definitely say that it is worth it...
 
#22
SY said:
But ultimate origin? Not RCA, I think. The input stage is a poor version of the Williamson (there must be almost 0.3mA going though the cathodyne!), the feedback arrangement is relatively ineffective, and RCA engineers were smart enough to understand feedback from the OPT secondary.

RCA's actual pentode driver amp was quite an excellent and innovative design.
Click to expand...

in later RCA tube databooks, a 50 watter 7027 design using the same topology was presented, almost since the input used a triode pentode type....
 
#28
pancaQe said:
Can anyone suggest a simple, quality 6V6 push pull amp design/schematic. At this point it looks like I'm gonna have to back track anyway. I'm looking at schematics using 6SN7. Any suggestions?
Click to expand...

Here's a schem. I had sitting on my HD. The 6V6's are strapped as triodes, but you could change that.

jeff
 

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#32
A few years ago there was on this forum some criticism on this original RCA circuit with the 6au6 in it. I cannot believe that a leading tube-technology firm of those days would publish crap. This design must have some merits. I will try to build it with a 6sn7 at the front with CCS or VCCS on top of the first tubehalf and a led under it.
Has anyone heard this RCA design with his or her own ears ?

By the way, there are 7-pin sockets that fit in 9-pin holes.
 
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#36
pancaQe said:
Tony, I have a couple GE 6LU8A, I thought they were oscillator amplifier. They're also compactron (tiny)
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it has a 12at7 like triode and a 6v6 like pentode all in one envelope, rated at 14watts plate it is better than 6BQ5 imho...

i also replace 6V6, 6BQ5 with 6GK6, a tv tube and a good performer too...

i tend to favor tv tubes for audio, lots of sleeper tubes that are not hyped and so you can get really cheap....

6LU8 is a compactron, 6LR8 is a novar using the same innards...
 
#38
Jaap said:
A few years ago there was on this forum some criticism on this original RCA circuit with the 6au6 in it. I cannot believe that a leading tube-technology firm of those days would publish crap.
Click to expand...

Understand who the audience was- lowest common denominator mass market manufacturers, especially (for audio) cheap consoles and radios. The main virtues are "cheap" and "reliable." This is why some of us were surprised that an RCA engineer managed to slip the superb 50 watter into the mix.
 
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