John Curl's Blowtorch preamplifier part II

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I'm trying to figure out what causes the signal attenuation.
Gain is set by 1k+180R and 100R (simplified) for one quadrant, and the basic topology of each of the four is like in the picture below, right?
 

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Real schematics are 'messy'. This is because they have to meet so many needs and features.
The PLD2000 was my first effort to make an 'all out' JC-80 based preamp for Parasound. I did only 1/2 the design, and that should be obvious, but I did the 'heart' of the design, the 4 quadrant gain stage.
This preamp never got very popular, although it had lots of features, my name associated with it, and very competitively priced.
The Parasound JC-2 is based on this design and it has been much more successful.
WHY, is what I always hope to convey on this website, but to little avail.
However, one practical suggestion for those interested in a REAL preamp, is to get a PLD2000 used. They should be very cheap on E-bay, and they have 'potential' to be an even 'better' preamp than stock.
Also, even broken, and 'unfixable' getting the chassis for the PARTS alone should be a very worthwhile purchase.
On paper, the differences between the Parasound JC-2 and the PLD2000 are trivial, but there is a world of difference in subjective performance.
 
While the current 'belief' is that differences that are not easily identifiable and measurable, are fictitious, I will not dwell on my personal opinion of the differences between the Para JC-2 and the PLD2000.
I will try to point out some differences, large and small, that made the Para JC-2 a 'winner' and the PLD2000, a 'failure'.
1. Parts quality: The Para JC-2 has better 'quality' caps, but not necessarily of a different material.
2. Parts placement: The Para JC-2 has a 'better' layout.
3. Parts removed: The Para JC-2 has many less PARALLEL caps, that appear to be put in for the 'eye' rather than for the 'ear'.
4. Parts change: Jfets and Mosfets replace any remaining bipolar devices.
5. Better connectors: Nonmagnetic, quality made RCA and XLR connectors replace the cheaper, 'magnetic' ones used in the PLD2000.
6. Better connecting wire where possible.
That is all that I can think of.
The closest comparison that I can make is the difference between a Porsche 924 and a Porsche 944. I've owned and driven both extensively, and I certainly know the difference, but I don't know how to convey it to a general audience.
 
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