Help With Input Stage Comparison?

[The Ballzz]

Twin-5E8-A-Schematic copy.jpg

Well Fine Folks,
These are the two input stages I would like to discuss and learn about.

It appears that in the 5E8-A, when plugged into input #1 of either channel, it drives/feeds both triodes of that channel, in parallel and plugging into #2 drives/feeds only one triode of that channel? The are no grid stoppers, although input #1 appears to see a 500K to ground input/grid leak resistor and input #2 "sees" a 1MEG input/grid leak. I do also note the additional 100K "mixing" at the output of the first triodes on the 5E8-A that do not exist on the 5F8.

With the 5F8, there is only one triode for each channel and input #1 "sees" a 34K grid stop, along with its 1MEG input/grid leak resistor and input #2 "sees" a 68K-ish grid stop and it's kinda voltage divider with the other 68K and 1MEG in series to ground.

Am I reading and deciphering the above correctly, at least loosely?

We are all aware of the mixed results of "jumpering" the 5F8 style input triodes in parallel. My questions and proposed discussion surround the possible benefits and/or pitfalls of combining the two dual parallel triode channels together, in parallel, with their separate volume controls, etc. Now I realize that a simple cable jumper won't work here, but a switch or hardwiring could. Is there any real benefit or am I just piddlin' in the wind?

Thanks In Advance Folks,
Gene

[martin manning]

Got a "Y" cable? That should work fine for experimenting with the 5E8-A.

[The Ballzz]

Got a "Y" cable? That should work fine for experimenting with the 5E8-A.

Well Sir! That would be just dine and fandy! IF I had one. The whole impetus for the questions is whether or not it is worth the extra effort of adding an extra tube to the re-work/rebuild of a 6AQ5 JCM800 that I'm not terribly fond of. I'm already planning on converting the power section to cathode bias 6V6s and a cathodyne PI. Just trying to decide what to do earlier on in the amp! If the whole "four triodes in parallel" is a waste of time/effort/money, I need not bother! On the other hand........?

Thank You, Oh Wise One!
Gene

[martin manning]

I have to believe that arrangement was intended to accommodate multiple instruments.

[Doug R.]

It was a simpler time. You were a big dog back then if you could afford a Fender Twin.